REPRODUCTIVE POTENTIAL AND LIFE HISTORY OF SPOTTED GAR
LEPISOSTEUS OCULATUS IN THE UPPER BARATARIA ESTUARY, LOUISIANA
A Thesis
Submitted to the Graduate Faculty
of Nicholls State University
in Partial Fulfillment
of the Requirements for the Degree
Master of Science in Marine and Environmental Biology
By
Olivia Alpha Smith
B. S., Nicholls State University, 2006
Spring 2008
CERTIFICATE
This is to certify that the thesis entitled “Reproductive potential and life history of spotted
gar Lepisosteus oculatus in the upper Barataria Estuary, Louisiana” submitted for the award of
Master of Science to Nicholls State University is a record of authentic, original research
conducted by Miss Olivia Alpha Smith under our supervision and guidance and that no part of
this thesis has been submitted for the award of any other degree, diploma, fellowship, or other
similar titles.
APPROVED:
Allyse Ferrara, Ph.D.
Assistant Professor of
Biological Sciences
Committee Chair
Quenton Fontenot, Ph.D.
Assistant Professor of
Biological Sciences
Committee Member
Gary LaFleur, Jr., Ph.D.
Associate Professor of
Biological Sciences
Committee Member
Enmin Zou, Ph.D.
Associate Professor of
Biological Sciences
Committee Member
SIGNATURE:
DATE:
__________________________
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__________________________
_______________
__________________________
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__________________________
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i
ABSTRACT
The spotted gar Lepisosteus oculatus is a physostomous fish that inhabits bayous, lakes,
and backwater floodplains from the Great Lakes to the Gulf coast and from central Texas to
western Florida. Although this species evolved over 150 million years ago, its reproductive
potential is poorly understood. Gonad histology is useful for the identification and classification
of gonad developmental phases of fish populations. The goal of this study was to characterize
the reproductive potential of a spotted gar population in the upper Barataria Estuary in
southeastern Louisiana using standard histological techniques. This study also focused on age
and size distributions, total fecundity, egg sizes, and gonadosomatic index (GSI). From 5
October 2006 through 26 September 2007, spotted gar were collected weekly to biweekly from
the upper Barataria Estuary, using monofilament gill nets, hook and line, and electrofishing.
Histological samples were used to classify individuals into reproductive phases (immature,
developing, spawning capable/actively spawning, regressing, and regenerating) based on gonad
development. Based on histological analyses, males (N = 94) and most females (N = 123) in this
population may be capable of spawning year round. However, because spawning did not occur
year round, females most likely have a “threshold egg size” that is required for spawning.
Females exhibited determinate fecundity and group-synchronous oocyte development. GSI
peaked in spring and decreased through summer for both males (N = 215) and females (N =
253). Based on histological analyses and GSI values, spawning occurred from March through
May. Mean egg diameter was 2.5 ± 0.3 mm (N = 131) for females collected from 9 February
2007 to 26 September 2007. Mean total fecundity was 6,493 ± 4,225 eggs per fish (N = 192;
mean TL = 579 ± 44 mm). However, based on macroscopic observation of ovaries, the majority
of spawned females did not spawn completely and, instead, retained and reabsorbed a portion of
their eggs (atresia). Therefore, total fecundity estimates are probably overestimates of the
ii
number of eggs annually spawned in the upper Barataria Estuary. Total length and age
distributions were different between males and females. Females were longer than males of the
same age for ages 2 through 5 and were heavier with greater girths than males of the same age
for ages 3 through 5. More females were collected than males in the older age classes (3 to 6
years). The growth rate (k value from von Bertalanffy growth equation) was 0.18. In our
sample, male spotted gar matured by age 1 and 344 mm TL whereas females matured by age 2
and 410 mm TL. The life history strategy of spotted gar is most likely intermediate between
“periodic” and “equilibrium” strategies with closer relation to the “equilibrium” strategy when
compared to existing data from other gar populations. Reproductive characteristics and life
history information from this study will be useful for understanding the reproductive potentials
of gars and for formulating ecosystem-based management plans for the upper Barataria Estuary.
iii
ACKNOWLEDGEMENTS
First and foremost, I would like to thank my advisor, Dr. Allyse Ferrara, for her support
and friendship during my entire educational career at Nicholls State University. She has been an
amazing mentor during these years and has always opened many adventurous doors for me. I
also want to sincerely thank the other members of my committee, Dr. Quenton Fontenot, Dr.
Gary LaFleur, Jr., and Dr. Enmin Zou, for their never-ending assistance and guidance. I
especially want to thank Dr. LaFleur for our many intriguing discussions on oogenesis.
Gratitude is extended to the Department of Biological Sciences and the Bayousphere
Research Laboratory at Nicholls State University for providing vessels, gear, and funding for my
research. This study was also funded by a grant from Coastal Restoration and Enhancement
through Science and Technology (CREST). I want to thank Ms. Dorinda Bearse, Ms. Anke
Tonn, and all of the Nicholls faculty for their unending help and tolerance with me during my
research. Thank you to all of the Nicholls students who assisted in field and lab work, especially
Thomas Widgeon and Tim Clay for reading otoliths. I particularly want to thank Sean Jackson
for his companionship and skills in our adventurous field excursions at night in the upper
Barataria Estuary. Many thanks to Ms. Cheryl Crowder at the LSU School of Veterinary
Medicine for processing my histology slides. Also, Ms. Nancy Brown-Peterson at the Gulf
Coast Research Laboratory was a wealth of knowledge and continuous help with histology.
Lastly, I want to deeply thank my parents, Denise and Dan Smith, for their continual love
and support during my education. They are the reason I made it to where I am today. I also
want to thank my brother, Andre’, for his patience and use of his truck when the department’s
was unavailable and my sister, Madeleine, for her perpetual humor along the way.
iv
TABLE OF CONTENTS
CERTIFICATE ............................................................................................................................i
ABSTRACT ...............................................................................................................................ii
ACKNOWLEDGEMENTS........................................................................................................iv
TABLE OF CONTENTS ............................................................................................................v
LIST OF FIGURES ...................................................................................................................vi
LIST OF TABLES ......................................................................................................................x
INTRODUCTION ......................................................................................................................1
METHODS...............................................................................................................................16
RESULTS.................................................................................................................................26
DISCUSSION...........................................................................................................................57
FUTURE RECOMMENDATIONS ..........................................................................................70
LITERATURE CITED .............................................................................................................71
APPENDIX ..............................................................................................................................79
BIOGRAPHICAL SKETCH.....................................................................................................98
CURRICULUM VITAE ...........................................................................................................99
v
LIST OF FIGURES
Figure 1. Spotted gar collected from the upper Barataria Estuary, Louisiana (photograph by
Sean Jackson) ............................................................................................................4
Figure 2. Location of the Barataria Estuary (dashed line) in southeastern Louisiana. Bar =
103.8 kilometers ........................................................................................................9
Figure 3. Boundaries, major waterways, and some of the major highways (dashed lines) of the
upper Barataria Estuary. Bar = 7.7 kilometers .........................................................10
Figure 4. Oogenesis in fishes (as modified from West 1990; Brown-Peterson 2003). 2N—
diploid; 1N—haploid; GVM—germinal vesicle migration; GVBD—germinal vesicle
break down ..............................................................................................................13
Figure 5. Cystic spermatogenesis in fishes (as modified from Sadleir 1973). SG—
spermatogonium; 2N—diploid; CY—spermatocyst; SC—spermatocytes; 1N—
haploid; ST—spermatids; SZ—spermatozoa............................................................14
Figure 6. Percent of monthly catch of male (N = 215) and female (N = 253) spotted gar
collected from 5 October 2006 to 26 September 2007, in the upper Barataria Estuary.
No fish were collected in January. Numbers above columns indicate the number of
fish collected each month.........................................................................................29
Figure 7. Total length frequency distributions of male (N = 215) and female (N = 253) spotted
gar collected from 5 October 2006 to 26 September 2007, in the upper Barataria
Estuary ....................................................................................................................31
Figure 8. Age frequency distributions of male (N = 207) and female (N = 246) spotted gar
collected from 5 October 2006 to 26 September 2007, in the upper Barataria Estuary
................................................................................................................................32
Figure 9. Relationship between log10 weight and log10 total length for male spotted gar
collected from 5 October 2006 to 26 September 2007, in the upper Barataria Estuary
................................................................................................................................34
Figure 10. Relationship between log10 weight and log10 total length for female spotted gar
collected from 5 October 2006 to 26 September 2007, in the upper Barataria Estuary
................................................................................................................................35
vi
Figure 11. Histological section of a “spawning capable/actively spawning” male spotted gar (TL
= 457 mm) testis with discontinuous/continuous germinal epithelia collected on 26
September 2007, in the upper Barataria Estuary. Bar = 0.1 mm. CY—spermatocyst;
SZ—spermatozoa; GE—germinal epithelium ..........................................................36
Figure 12. Histological section of a “spawning capable/actively spawning” male spotted gar (TL
= 485 mm) testis with discontinuous germinal epithelia collected on 10 March 2007,
in the upper Barataria Estuary. Bar = 0.1 mm. SZ—spermatozoa; GE—germinal
epithelium................................................................................................................37
Figure 13. Seasonal changes in germinal epithelia of male spotted gar (N = 94) collected from 5
October 2006 to 26 September 2007, in the upper Barataria Estuary. No fish were
collected in January. Numbers above columns indicate the number of fish collected
each month. C—continuous germinal epithelia; DC—discontinuous/continuous
germinal epithelia; D—discontinuous germinal epithelia .........................................38
Figure 14. Histological section from the ovary of a “spawning capable/actively spawning”
female spotted gar (TL = 652 mm) collected on 6 December 2006, in the upper
Barataria Estuary. Bar = 1.0 mm. PGO—primary growth oocyte; CAO—cortical
alveolar oocyte; VTGO—vitellogenic oocyte...........................................................39
Figure 15. Monthly reproductive phases for female spotted gar (N = 123) collected from 5
October 2006 to 26 September 2007, in the upper Barataria Estuary. No fish were
collected in January. Numbers above columns indicate the number of fish collected
each month. REGEN—“regenerating” phase; DEV—“developing” phase; SC/AS—
“spawning capable/actively spawning” phase...........................................................40
Figure 16. Histological section from the ovary of a “developing” female spotted gar (TL = 568
mm) collected on 30 June 2007, in the upper Barataria Estuary. Bar = 1.0 mm.
PGO—primary growth oocyte; CAO—cortical alveolar oocyte; VTGO—vitellogenic
oocyte......................................................................................................................41
Figure 17. Histological section from the ovary of a “regenerating” female spotted gar (TL = 530
mm) collected on 23 March 2007, in the upper Barataria Estuary. Bar = 0.5 mm.
PGO—primary growth oocyte; CAO—cortical alveolar oocyte ...............................42
vii
Figure 18. Ovaries from a female spotted gar (TL = 645 mm) collected on 31 May 2007, in the
upper Barataria Estuary: (A) gross appearance of ovaries, (B) histological section of
left portion of left ovary classified as “regressing,” and (C) histological section of
right portion of left ovary classified as “spawning capable/actively spawning.”
Overall, this female was classified as “spawning capable/actively spawning.” Bars =
1.0 mm. PGO—primary growth oocyte; CAO—cortical alveolar oocyte; VTGO—
vitellogenic oocyte; POF—post-ovulatory follicle....................................................44
Figure 19. Histological section from the ovary of a “developing” female and potential virgin
spotted gar (TL = 412 mm) collected on 31 August 2007, in the upper Barataria
Estuary. Bar = 1.0 mm. PGO—primary growth oocyte; CAO—cortical alveolar
oocyte; VTGO—vitellogenic oocyte ........................................................................45
Figure 20. Histological section from the ovary of a “spawning capable/actively spawning”
female spotted gar (TL = 652 mm) collected on 6 December 2006, in the upper
Barataria Estuary. Bar = 0.1 mm. VTGO—vitellogenic oocyte ..............................46
Figure 21. Mean (± SD) gonadosomatic index (GSI) by sample date for male spotted gar (N =
215) collected from 5 October 2006 to 26 September 2007, in the upper Barataria
Estuary. No fish were collected in January ..............................................................47
Figure 22. Mean (± SD) gonadosomatic index (GSI) by sample date for female spotted gar (N =
253) collected from 5 October 2006 to 26 September 2007, in the upper Barataria
Estuary. No fish were collected in January ..............................................................48
Figure 23. Mean monthly egg diameter (± SD) for female spotted gar (N = 131) collected from 9
February 2007 to 26 September 2007, in the upper Barataria Estuary. Means with the
same letter indicate no difference .............................................................................49
Figure 24. Linear relationship between total fecundity and weight of female spotted gar collected
from 5 October 2006 to 26 September 2007, in the upper Barataria Estuary.............50
Figure 25. Linear relationship between total fecundity and total length of female spotted gar
collected from 5 October 2006 to 26 September 2007, in the upper Barataria Estuary
................................................................................................................................51
Figure 26. Linear relationship between estimated count and whole count methods for
determining total fecundity in female spotted gar collected from 5 October 2006 to 26
September 2007, in the upper Barataria Estuary.......................................................54
viii
Figure 27. von Bertalanffy growth curve, maximum theoretical total length (L∞), von Bertalanffy
growth coefficient (k), and time when total length would theoretically equal zero (to)
for spotted gar collected from 5 October 2006 to 26 September 2007, in the upper
Barataria Estuary. L∞ was derived from Suttkus (1963)...........................................55
Figure 28. Catch-curve regression, total annual survival rate (S), total annual mortality rate
(AM), instantaneous rate of total mortality (Z), and theoretical maximum age (Max
age) for spotted gar collected from 5 October 2006 to 26 September 2007, in the
upper Barataria Estuary............................................................................................56
ix
LIST OF TABLES
Table 1.
Processing procedure for histological preparation of spotted gar gonad samples
(Histology Laboratory 2007a). Xylene (Thermo, Pittsburgh, Pennsylvania). P/V—
pressure/vacuum; abs—absolute ..............................................................................19
Table 2.
Staining procedure for histological preparation of spotted gar gonad samples
(Histology Laboratory 2007b). Propar (Anatech, Ltd., Battle Creek, Michigan);
Alcohol, absolute (AAPER Alcohol and Chemical Co., Shelbyville, Kentucky). N—
no; Y—yes; abs—absolute; W—wash .....................................................................20
Table 3.
Reproductive classification system for male and female fishes according to
histological characteristics of gonads (as modified from Brown-Peterson et al. 2007).
Female “regenerating” phase was modified to include cortical alveolar oocytes.
Information on indeterminate fecundity, hydration, and determining
fecundity/spawning frequency was removed (This information either did not pertain
to spotted gar or to this study’s objectives.). PGO—primary growth oocytes; CAO—
cortical alveolar oocytes; VTGO—vitellogenic oocytes; POF—post-ovulatory
follicles; GVM—germinal vesicle migration; GVBD—germinal vesicle break down;
SG—spermatogonia; CY—spermatocysts; SC—spermatocytes; ST—spermatids;
SZ—spermatozoa; GE—germinal epithelia..............................................................21
Table 4.
Description of reproductive classification system for male fishes according to
histological characteristics of gonads (as modified from Brown-Peterson et al. 2007).
SG—spermatogonia; CY—spermatocysts; SC—spermatocytes; ST—spermatids;
SZ—spermatozoa; GE—germinal epithelia..............................................................22
Table 5.
Description of reproductive classification system for female fishes according to
histological characteristics of gonads (as modified from Brown-Peterson et al. 2007).
PGO—primary growth oocytes; CAO—cortical alveolar oocytes; CA—cortical
alveoli; VTGO—vitellogenic oocytes; POF—post-ovulatory follicles......................23
Table 6.
Total number of each fish species collected from 5 October 2006 to 26 September
2007, in the upper Barataria Estuary ........................................................................27
x
Table 7.
Number (N), mean (± SD), and range of total length, pre-pelvic girth, weight, left
gonad weight, right gonad weight, age, and egg diameter for male and female spotted
gar collected from 5 October 2006 to 26 September 2007, in the upper Barataria
Estuary ....................................................................................................................28
Table 8.
Mean (± SD) and range (below mean) for total length (TL; mm), pre-pelvic girth
(mm), and weight (g) of male (N = 207) and female (N = 246) spotted gar for each
age class in which both sexes were collected from 5 October 2006 to 26 September
2007, in the upper Barataria Estuary. Differences between the sexes are marked with
an asterisk ..............................................................................................................30
Table 9.
Number (N), mean (± SD), and range of total fecundity for each age class of female
spotted gar collected from 5 October 2006 to 26 September 2007, in the upper
Barataria Estuary .....................................................................................................53
xi
INTRODUCTION
The ancient garfish family Lepisosteidae consists of two genera (Atractosteus and
Lepisosteus) and sixteen species (Wiley 1976). Only seven gar species are extant (alligator gar
A. spatula, Cuban gar A. tristoechus, tropical gar A. tropicus, spotted gar L. oculatus, longnose
gar L. osseus, shortnose gar L. platostomus, and Florida gar L. platyrhincus) and are confined to
North America (Gilbert and Williams 2002). Lepisosteidae belongs to the Holostean group of
fishes, which first evolved 290 million years ago (mya) during the Permian era and were very
abundant during the Jurassic (206 mya) and Lower Cretaceous periods (146 mya; Rayner 1941).
Extant Holosteans include the gars and bowfin Amia calva (Rayner 1941).
Gars have elongated and cylindrical bodies that contain both bony and cartilaginous
skeletons, posteriorly located dorsal fins, and rounded, abbreviate-heterocercal caudal fins (Eddy
1957; Suttkus 1963; Gilbert and Williams 2002). Members of Lepisosteidae are the exclusive
fish group to possess ganoid scales, which are composed of layers of ganoin and isopedine (Ross
2001). Ganoid scales interlock, providing an armor-like covering that protects gars from
predators (Gilbert and Williams 2002). Gars possess unique gamete transport systems. Unlike
teleosts, male gars excrete urine and sperm through a single duct called the urogenital duct, and
female gars possess a continuous oviduct that extends from the ovary to the vent (Pfieffer 1933;
Sadleir 1973). Additionally, gars are the only freshwater fishes of North America to have toxic
eggs (Brooks 1851; Goodger and Burns 1980).
Gars and bowfin possess physostomous swim bladders, allowing them to respire at the
water’s surface (Potter 1927). When gulping oxygen at the water’s surface, a gar transfers
oxygen to its swim bladder via an open pneumatic duct that connects the dorsal region of the
1
esophagous to the anterior region of the swim bladder (Potter 1925, 1927). In the swim bladder,
atmospheric oxygen is exchanged for carbon dioxide (Potter 1927). The ability to breathe air
allows gars and bowfin to withstand hypoxic conditions (dissolved oxygen; DO < 2 mg/L),
which are exacerbated at high temperatures, unlike many teleosts (Potter 1927; Eddy 1957;
McCormack 1967; Renfro and Hill 1970; Hill et al. 1972; De Roth 1973). De Roth (1973)
reported that the frequency of aerial respiration of spotted gar increases with increased
temperature and is more common at night. The capacity to breathe air may help to explain why
gars have somewhat reduced gill surface areas as compared to many teleosts (Landolt and Holt
1975). Smatresk (1986) demonstrated that aerial respiration in the longnose gar is controlled by
external chemoreceptors in or near the gills and that gill respiration is controlled by internal
chemoreceptors in or near the branchial circulation.
The range of spotted gar includes the southern Great Lakes to the Gulf of Mexico and
central Texas to western Florida (Douglas 1974). Spotted gar are commonly found in bayous,
lakes, and backwater floodplains (Goodyear 1966; Douglas 1974; Snedden et al. 1999; Fontenot
et al. 2001; Bonvillain 2006; Davis 2006). According to Goodyear (1966), spotted gar from the
Mississippi Gulf coast are often found in shallow waters and prefer areas of thick vegetation or
cover, such as fallen trees. In the Atchafalaya River Basin, Louisiana, Snedden et al. (1999)
described the movement of spotted gar onto inundated floodplains during periods of high water
in spring months and their association with shorelines during periods of low water in fall and
winter months. Spotted gar prefer salinities ranging from 0 to 10 ppt although they have been
observed in salinities of 18 ppt in Mississippi (Goodyear 1966). Spotted gar and Florida gar
appear to be the least salt tolerant of the gar species (Suttkus 1963). In many areas, spotted gar
2
are top predators that control the abundance of lower trophic level species (Scarnecchia 1992;
Ostrand et al. 2004).
Adult spotted gar are brown to olive on their dorsal and upper lateral regions with lighter
shades on their lower lateral and ventral regions (Figure 1; Ross 2001; Gilbert and Williams
2002). This species is often darker in color than the other gar species (Hoese and Moore 1998).
The dorsal, anal, and pelvic fins possess brown bars, and all fins are spotted (Ross 2001). The
signature brown and black spots on the mid-dorsal region appear when the fish is 100 to 150 mm
total length (TL; Suttkus 1963). Spotted gar are distinct from other gar species by the presence
of large spots on their heads (Ross 2001). Spotted gar living in darker colored and turbid waters
are often darker in color than are those in clearer waters (Suttkus 1963).
Spotted gar are sexually dimorphic in that females are typically longer and heavier than
same age males (Tyler and Granger 1984; Ferrara 2001; Love 2002). Love (2002) reported that
females collected in the Lake Pontchartrain Estuary, Louisiana, live longer than males.
Additionally, females possess longer snouts than males; however, the ratio of snout length to
head length changes with fish size and is, therefore, not an accurate identifier of sex (Suttkus
1963). Love (2002) reported that females in the Lake Pontchartrain Estuary have longer snouts
than males when mass, snout width, body depth, and age are considered. Little information
exists, however, on the snout morphology of different populations.
Prey species of spotted gar include a variety of arthropods and smaller fish species.
Goodyear (1967) documented blue crabs Callinectes sapidus and fiddler crabs Uca spp. as
common prey items of spotted gar from the Mississippi Gulf coast. Smaller fish species that
have been reported by stomach analyses include bluegill Lepomis macrochirus (Tyler and
3
Figure 1. Spotted gar collected from the upper Barataria Estuary, Louisiana (photograph by
Sean Jackson).
4
Granger 1984), mosquitofish Gambusia affinis, pirate perch Aphredoderus sayanus, pygmy
sunfish Elassoma zonatum (Dugas et al. 1976), and gizzard shad Dorosoma cepedianum
(Bonham 1941). Dugas et al. (1976) also described spotted gar feeding on crayfish Procambarus
spp. in the Atchafalaya River Basin.
Spotted gar feed primarily at night (Snedden et al. 1999) or during incoming or high tides
in coastal areas (Goodyear 1967). Spotted gar are “lie-in-wait” predators that remain motionless
or swim very slowly when stalking prey before quickly snapping at their targets (Ostrand et al.
2004). According to Echelle and Riggs (1972), spotted gar are more abundant in shallow waters
at night in Lake Texoma, Texas and Oklahoma, than during the day, and this abundance could
indicate aggregations of feeding spotted gar. Spotted gar have few predators, but Valentine et al.
(1972) reported that Lepisosteus spp. comprised 8 % of the diets of the American alligator
Alligator mississippiensis in 1961 in southwestern Louisiana. Other predators of spotted gar
include river otters Lontra canadensis and recreational fishermen (A. Ferrara and Q. Fontenot,
Nicholls State University, personal communication).
In the past, gars were often considered nuisance predators of game and commercial fishes
(Gowanloch 1939, 1940; Suttkus 1963). Accordingly, some management programs for gar
species emphasized eradication techniques (Sutton 1998), including electricity (Burr 1931) and
traps (Gowanloch 1940). In more recent years, however, gars are enjoyed as game and food fish
in the southeastern United States (Sutton 1998). In 2003, the value of Louisiana commercial
fisheries landings for gars (alligator gar, longnose gar, shortnose gar, and spotted gar combined)
was greater than $515,000 (LDWF 2003). Recently, research has been conducted on gar ecology
(Snedden et al. 1999; Ferrara 2001; García de Leόn et al. 2001; Love 2004), and management
5
and conservation plans have been developed for some gar populations in the United States
(Scarnecchia 1992; Todd 2005).
Gars are not threats to game fish populations and sometimes act as scavengers (Eddy
1957; Suttkus 1963; García de Leόn et al. 2001). Spotted gar usually choose their prey by
vulnerability and availability (Scott 1968) and more often feed on non-game fishes, such as
gizzard shad, instead of game fishes, such as smallmouth bass Micropterus dolomieu and spotted
bass Micropterus punctulatus (Bonham 1941). According to Echelle and Riggs (1972), the most
abundant species in young gar (alligator gar, longnose gar, shortnose gar, and spotted gar)
stomachs from Lake Texoma in 1965 was the Mississippi silverside Menidia audens, probably
because this species has also been documented as the most abundant species in shallow waters of
the lake. Dugas et al. (1976) also reported that although crayfish were a component (13 %) of
spotted gar diets in the Atchafalaya River Basin in 1974 and 1975, spotted gar predation was not
harmful to the crayfish harvest.
Length and timing of spawning periods for spotted gar vary across the species’ range.
Tyler and Granger (1984) reported that the earliest spotted gar spawning event in Lake
Lawtonka, Oklahoma, was 22 April 1981, and the latest was 10 June 1982. Peak spawning time
for this population was mid-May (Tyler and Granger 1984). Echelle and Riggs (1972) reported
that spotted gar spawned in dead vegetation in calm waters in Lake Texoma and that spawning
occurred between mid-April through May (temperature range: 20 - 30 °C). Spotted gar
collected in Lake Seminole, Georgia, spawned from late spring to early summer (Ferrara 2001).
The spawning period of a spotted gar population in the Lake Pontchartrain Estuary was February
to June in 1999 (Love 2004). A population of Florida gar, a species of similar size to spotted
6
gar, from north central Florida was reported to spawn from February to March of 1998 (Orlando
et al. 2003, 2007).
Fertilization in spotted gar is external (Suttkus 1963). When spawning, a single female is
followed by three to five males in shallow, vegetated water (Tyler and Granger 1984). Love
(2004) described a spotted gar spawning event in April 1997, where six to eight fish were sighted
near vegetation in water that was approximately 1.5 m in depth. Two of the fish were larger than
the others and were assumed to be females (Love 2004). After spawning, gars typically leave the
spawning site (Suttkus 1963). Tyler and Granger (1984) reported that a spawning event in Lake
Lawtonka was interrupted by the onset of cooler temperatures and turbidity as a result of
precipitation.
In 2005, during induced spawning of spotted gar in the Bayousphere Research
Laboratory at Nicholls State University, Louisiana, spawned eggs adhered to the sides and
bottom of the spawning tank and to artificial vegetation (mean water temperature = 20.6 °C;
Boudreaux 2005). Fish were injected with Ovaprim© on 23 April, spawning began on 25 April,
and hatching was first observed on 30 April (Boudreaux 2005). After hatching, larvae attached
to the walls of the holding tank and artificial vegetation via their anterior suctoral discs and
began swimming 5 days later (Boudreaux 2005). Echelle and Riggs (1972) also noted that larval
gars will attach to a film on the water’s surface in aquaria. Spotted gar adults do not exhibit
parental care after spawning (Suttkus 1963). According to studies in Lake Texoma, spotted gar
are approximately 8 mm TL at hatching (Echelle and Riggs 1972).
Yolk sac larval gars aggregate near their spawning sites, usually attached to vegetation or
debris (Simon and Wallus 1989). If larvae become unattached from their substrates, they will
7
sink (Echelle and Riggs 1972) or will swim to re-attach to available substrates (A. Ferrara,
Nicholls State University, personal communication). Simon and Wallus (1989) reported that the
majority of larval gar (longnose gar and spotted gar) were collected from the top meter of the
water column in the Ohio and Tennessee River Basins and were collected during the day. Larval
spotted gar can grow at a rate of 1.7 mm per day (range: 1.3 - 2.3 mm per day; Simon and
Wallus 1989). The suctoral disc in spotted gar disappears at approximately 17.6 mm TL, and the
yolk sac is completely absorbed at greater lengths (Simon and Wallus 1989). After absorption of
the yolk sac, gars disperse and begin aerial respiration and feeding (Echelle and Riggs 1972). In
spotted gar, flexion commences at 21.9 mm TL, and all of the fin rays have begun development
by 35.9 mm TL (Simon and Wallus 1989).
This study was conducted in the upper reaches of the Barataria Estuary, Louisiana. The
Barataria Estuary is bordered by the Mississippi River to the east and Bayou Lafourche to the
west (Figure 2) and contains cypress swamps, freshwater marsh, intermediate marsh, brackish
marsh, and saltwater marsh. The upper Barataria Estuary is a cypress-tupelo swamp that
includes the following major waterways: Grand Bayou, Bayou Citamon, Bayou Chevreuil, the
St. James Canal, and Lac Des Allemands, which drain in an east-southeast direction (Figure 3).
Overall, 41.5 % of the upper Barataria Estuary is forested wetlands (Braud et al. 2006).
Agricultural lands comprise 38.0 % of land use in the upper Barataria Estuary (Braud et al.
2006), and many of these lands drain into the St. James Canal. The upper Barataria Estuary once
received an annual floodpulse from the Mississippi River. However, due to levee construction,
the upper Barataria Estuary is no longer annually inundated by a predictable floodpulse.
Presently, inundation of the upper Barataria Estuary floodplain results from heavy, local
precipitation (Sklar and Conner 1979).
8
N
Figure 2. Location of the Barataria Estuary (dashed line) in southeastern Louisiana. Bar =
103.8 kilometers.
9
N
Mississippi
River
Highway
70
Bayou
Citamon
St. James
Canal
Bayou
Chevreuil
Bayou
Lafourche
Highway
20
Lac
Des
Allemands
Highway
3127
Grand Bayou
Lake
Beouf
Highway
90
Figure 3. Boundaries, major waterways, and some of the major highways (dashed lines) of the
upper Barataria Estuary. Bar = 7.7 kilometers.
10
The timing and duration of a river-driven floodpulse correspond with the spawning
periods of many fish species in large-river floodplains (Junk et al. 1989). During periods of high
water, many species of fish (e.g., spotted gar and bowfin) move onto inundated floodplains to
feed and spawn in the shallow, vegetated waters (Snedden et al. 1999; Bonvillain 2006; Davis
2006). Therefore, the lack of an annual, river-driven, predictable floodpulse may have negative
impacts on the reproductive success of floodplain-dependent fish species. When floodplaindependent species are denied access to suitable spawning habitat, the reproductive output of the
populations may decline. Additionally, when the floodpulse is absent, primary and secondary
production decrease in floodplain systems, reducing food availability for fish species that forage
on the inundated floodplain (Bayley 1995).
In 2006, macroscopic examination of bowfin ovaries from the upper Barataria Estuary
revealed egg atresia (retention and reabsorption of eggs) in 96 % of females sampled from
February to May (N = 136; Davis 2006). Apparently, in 2006, the majority of bowfin did not
spawn in this system. Bowfin typically move onto inundated floodplains during periods of high
water to spawn and forage (Davis 2006). Water levels in the upper Barataria Estuary were below
that needed for inundation of the adjacent floodplain during the bowfin’s spawning season
(February through March) in 2006 (Davis 2006; Estay 2007). However, based on
gonadosomatic indices (GSI), the gizzard shad population in the upper Barataria Estuary
spawned from late March through May 2006 (Fontenot 2006). Additionally, GSI, age
distributions, and size distributions have been determined for bowfin (Davis 2006) and gizzard
shad (Fontenot 2006) populations in the upper Barataria Estuary. Unlike the bowfin and gizzard
shad populations, there is little information on the life history and reproduction of spotted gar in
the upper Barataria Estuary. Before the current thesis, only GSI, gross examination of gonads,
11
and egg counts have been used to describe the reproduction of spotted gar (Tyler and Granger
1984; Ferrara 2001; Love 2004). Therefore, a detailed analysis is needed to better understand
the reproductive cycle of spotted gar in this system.
Gonad histology is the most accurate method for assessing gonad development (West
1990) and involves microscopically examining a portion of gonads to classify individuals into
reproductive phases. As male and female fishes progress through their reproductive cycles, they
undergo phases that are identifiable with the use of gonad histological techniques. Individuals
can be identified as immature (not capable of spawning), developing (active gametogenesis and
not capable of spawning), mature (capable of or actively spawning), regressing (retention and
reabsorption of gametes), and regenerating (preparation of new generation of gametes; BrownPeterson et al. 2007). By quantifying and categorizing individual males and females into
reproductive phases, a population’s reproductive cycle can be better analyzed.
Gonad histological techniques are typically used on fish species of high economic value
and have been successfully applied to a variety of species, including common snook
Centropomus undecimalis (Lowerre-Barbieri et al. 2003), spotted seatrout Cynoscion nebulosus
(Brown-Peterson et al. 1988), cobia Rachycentron canadum (Brown-Peterson et al. 2002), and
northern anchovy Engraulis mordax (Hunter and Macewicz 1984). However, gonad histology
has been used to describe the reproductive cycle of only two gar species, Florida gar (Orlando et
al. 2003, 2007) and tropical gar (A. Hernández-Franyutti, Universidad Juárez Autόnoma de
Tabasco, personal communication). By accurately defining different stages of oogenesis (Figure
4) and spermatogenesis (Figure 5), individual spotted gar can be classified into reproductive
phases based on gonad development. Histological techniques can be used to more specifically
describe the reproductive biology of the spotted gar population in the upper Barataria Estuary.
12
Primary Growth Oocytes
Perinucleolar Oocyte (2N)
Chromatin Nucleolar Oocyte (2N)
Oogonium (2N)
Germinal
Vesicle
Nucleolus/
Nucleoli
Vitellogenic Oocyte (2N)
CA Oocyte (2N)
Vitelline Envelope
Follicle
Cell
Yolk Vesicle
Thecal
Cell
Cortical
Alveoli
Final Oocyte Maturation (species-specific):
Lipid Coalescence, GVM, GVBD, Yolk
Coalescence, Hydration, Meiosis I (release
of first polar body), Ovulation
Ripe Oocyte (2N)
Ova (1N)
Figure 4. Oogenesis in fishes (as modified from West 1990;
Brown-Peterson 2003). 2N—diploid; 1N—haploid; GVM—
germinal vesicle migration; GVBD—germinal vesicle break down.
13
Spawning and Meiosis II
(release of second polar body)
Remain as Primary SG
or “Stem” Cells
CY with
Primary SC
(2N)
Mitosis
CY with
Secondary SC
(1N)
Mitosis
Primary SG
(2N)
Secondary SG
(2N)
Meiosis I
CY with SZ
(1N)
CY with ST
(1N)
Meiosis II
Spermiogenesis
Spermiation (released into lumens of lobules)
SZ Travel to Sperm Ducts
Spawning
Figure 5. Cystic spermatogenesis in fishes (as modified from Sadleir 1973). SG—
spermatogonium; 2N—diploid; CY—spermatocyst; SC—spermatocytes; 1N—haploid; ST—
spermatids; SZ—spermatozoa.
14
Additionally, gonad histology can verify macroscopic observations of spawning and egg atresia
in spotted gar. When combined with GSI, fecundity, and age and size distribution data,
histological analyses of gonads can produce a detailed reproductive characterization of this
spotted gar population.
There is a lack of life history information on spotted gar populations due to the notion
that spotted gar are a limitless, non-game species. Population models designed for the
population in the upper Barataria Estuary could be developed and modified for spotted gar
populations elsewhere. Specifically, information from this study will be useful for regions, such
as the northern United States and southern Canada, that are interested in spotted gar management
and conservation.
The goal of this study was to describe reproductive phases and to determine the life
history of spotted gar in the upper Barataria Estuary. This study included histological analyses
of gonad development and assessment of life history characteristics. The specific objectives of
this project included the following:
1.) Document and quantify reproductive phases of male and female spotted gar in the upper
Barataria Estuary for a year using standard histological techniques,
2.) Determine sex-specific age and size distributions of spotted gar in the upper Barataria
Estuary,
3.) Quantify sex-specific, seasonal changes in GSI of spotted gar in the upper Barataria
Estuary,
4.) Quantify age-specific fecundity of female spotted gar in the upper Barataria Estuary, and
5.) Quantify seasonal changes in egg size of female spotted gar in the upper Barataria
Estuary.
15
METHODS
Field Sampling
Spotted gar were collected weekly to biweekly from 5 October 2006 to 26 September
2007 (except for January 2007) in the upper Barataria Estuary, using monofilament gill nets,
hook and line, and electrofishing. Monofilament gill nets were either 28 or 50 m long and 1.8 m
deep and contained one of three different bar mesh combinations (38 mm, 95 mm, or 25.4
mm/38 mm experimental bar mesh). Gill nets were placed parallel to the bank, either near small
channels with floodplain access or large beds of floating (e.g., water hyacinth Eichhornia spp.)
and/or submerged (e.g., coontail Ceratophyllum demersum) aquatic vegetation. Electrofishing
was conducted with a 5.0kW Smith-Root (Generator Powered Pulsator) Electrofisher System.
Spotted gar were stored in an ice chest until being processed in the Bayousphere Research
Laboratory at Nicholls State University. All fish were processed within 17 hours of collection.
At each sample location, dissolved oxygen (mg/L), temperature (ºC), specific
conductance (µS), and salinity (ppt) were measured with a handheld YSI 85 meter (Yellow
Springs Instruments, Yellow Springs, Ohio). If sampling occurred between 1000 and 1600 hours
central standard time (CST) and when cloud cover was minimal, Secchi disk depth (cm) was
measured to determine water clarity. At the intersection of Bayou Citamon, Bayou Chevreuil,
and the man-made canal that connects to Grand Bayou, a Louisiana Department of Natural
Resources’ (LDNR) staff gauge was used to measure relative water level (cm).
Laboratory Processing
In the Bayousphere Research Laboratory, each individual was assigned a unique
identification number. Total length (mm), pre-pelvic girth (mm), and body weight (g) were
16
measured for each spotted gar. To retrieve the gonads, spotted gar were cut from the vent to the
head using tin snips. Sex determination was based on the gross examination of gonads and
gamete release pathways (Ferrara and Irwin 2001). Photographs were taken of whole ovaries for
macroscopic examination. Left and right gonad weights (g) were measured. GSI was calculated
according to the equation derived by Snyder (1983):
GSI = (gonad weight) / (total body weight) x 100.
Each month (except for January 2007), up to fifteen male and fifteen female spotted gar
were used for gonad histology. Using a scalpel, a small portion (approximately 1 g) of one
gonad from each individual was removed and preserved in a labeled vial containing 10 % neutral
buffered formalin (NBF; Fisher Scientific, Kalamazoo, Michigan). Ten fresh eggs, prior to
preservation, were randomly selected from the ovaries of each female spotted gar, and egg
diameters (mm) were measured using digital calipers (Davis 2006). Egg diameters were only
measured for large, visible eggs sampled from 9 February 2007 to 26 September 2007. The
remaining portions of whole gonads were preserved in labeled jars containing 10 % non-buffered
formalin (Fisher Scientific, Fair Lawn, New Jersey). For each spotted gar, sagittal otoliths were
removed, washed, dried, and placed in labeled, plastic vials for age determination (Ferrara 2001).
Gonad Histology, Fecundity, and Age Determination
Gonad histology samples were cut (approximately 5 mm thick), placed in labeled tissue
cassettes, and preserved in 75% ethyl alcohol (StatLab, Lewisville, Texas) for 1 to 6 days before
being sent to Louisiana State University (LSU). Samples were processed onto microscope slides
by the Histology Laboratory in the Department of Pathobiological Sciences at the LSU School of
Veterinary Medicine. Samples were subjected to a dehydration series and embedded in paraffin
17
(McCormick Scientific, St. Louis, Missouri; Table 1). Samples were then sliced at
approximately 5 µm and subjected to staining with hematoxylin and eosin (Anatech, Ltd., Battle
Creek, Michigan; Table 2). Slides were viewed using compound and/or dissecting microscopes,
and digital photographs were taken of each slide. Male and female samples were classified into
corresponding reproductive phases based on a modification of the system developed by BrownPeterson et al. (2007; Table 3). Descriptions of the modified reproductive classification system
were established for males (Table 4) and females (Table 5) to provide physical/visual
descriptions of spotted gar gonad histology. For histological analyses of both sexes, the
“spawning capable” and “actively spawning” phases were combined. In males, the
distinguishing factor for these two phases is the gross observation of free flowing milt, which
was not observed in this study. The distinguishing factor for females is the ability to age postovulatory follicles, which has not yet been determined.
Total fecundity, the number of advanced vitellogenic eggs in an ovary at a particular time
(Hunter et al. 1992), was determined by counting all visible eggs in a 10 % (by weight)
subsample of each ovary (Ladonski 1998). Total number of eggs in each ovary was extrapolated
by multiplying the number of eggs in the 10 % subsample by 10 (estimated count). Total
fecundity estimates did not include females that showed macroscopic evidence of recent
spawning (N = 61). Each month, whole counts of both ovaries were determined for two
randomly selected female spotted gar (whole count).
Multiple readers (N = 3) determined ages of individual spotted gar by examining annuli
on whole sagittal otoliths submerged in water using a dissecting microscope (Ferrara 2001).
18
Table 1. Processing procedure for histological preparation of spotted gar gonad samples
(Histology Laboratory 2007a). Xylene (Thermo, Pittsburgh, Pennsylvania). P/V—
pressure/vacuum; abs—absolute.
Reagent
Laboratory
Station
Alcohol, 70 %
1
Until start
Alcohol, 80 %
2
Alcohol, 95 %
Time (minutes) Temperature (°C)
P/V
Stir
Ambient
No
On
30
Ambient
No
On
3
30
Ambient
No
On
Alcohol, abs
4
30
Ambient
No
On
Alcohol, abs
5
30
Ambient
No
On
Xylene
6
30
Ambient
No
On
Xylene
7
40
Ambient
No
On
Xylene
8
50
Ambient
No
On
Paraffin
Left
30
60
Yes
On
Paraffin
Middle
40
60
Yes
On
Paraffin
Right
50
60
Yes
On
19
Table 2. Staining procedure for histological preparation of spotted gar gonad samples
(Histology Laboratory 2007b). Propar (Anatech, Ltd., Battle Creek, Michigan); Alcohol,
absolute (AAPER Alcohol and Chemical Co., Shelbyville, Kentucky). N—no; Y—yes; abs—
absolute; W—wash.
Event
Laboratory Station
Reagent
Time (minutes)
Exact
1
Oven
Oven 65 °C
8:00
N
2
1
Propar
2:00
N
3
2
Propar
2:00
N
4
3
Propar
1:00
N
5
4
Alcohol, abs
0:30
N
6
5
Alcohol, 90 %
0:30
N
7
6
Alcohol, 80 %
0:30
N
8
W5
Wash
0:30
N
9
9
Hematoxylin
2:30
Y
10
W4
Wash
1:00
N
11
10
Acid Alcohol
0:05
Y
12
W3
Wash
0:30
N
13
11
Ammonia Water
1:00
Y
14
W2
Wash
0:30
N
15
12
Alcohol, 95 %
1:00
N
16
13
Eosin
1:00
Y
17
14
Alcohol, 95 %
0:30
N
18
15
Alcohol, abs
0:30
N
19
16
Alcohol, abs
0:30
N
20
17
Alcohol, abs
0:30
N
21
18
Xylene
1:00
N
22
Exit
Xylene
0:30 - 15:00
N
20
Male
Small testes, only primary SG, no lumens in lobules.
Initiation of spermatogenesis and formation of CY. Secondary
SG, primary SC, secondary SC, ST, and SZ can be present in CY.
No SZ in lumens of lobules or sperm ducts. GE continuous.
SZ in lumens of loblues and/or sperm ducts. All stages of
spermatogenesis (SG, SC, and ST) can be present. CY
throughout testis. GE continuous or discontinuous.
Histologically undistinguishable from “actively pawning” phase.
SZ in lumens of lobules and/or sperm ducts. All stages of
spermatogenesis (SG, SC, and ST) can be present. CY
throughout testis. GE continuous or discontinuous.
Histologically undistinguishable from “spawning capable” phase.
Residual SZ in lumens of lobules and sperm ducts. Widely
scattered CY near periphery containing ST. SG proliferation and
GE regeneration common in periphery of testis.
No CY. Lumens of lobules small or nonexistent. Proliferation of
primary, occasionally secondary, SG throughout testis. Residual
SZ may be present in lumens of lobules and sperm ducts.
Phase
Immature
Developing
Spawning
capable
Actively
spawning
Regressing
Regenerating
Only oogonia, PGO, and CAO present. Muscle
bundles, enlarged blood vessels, thick ovarian wall
and/or late atresia may be present.
Atresia present (any stage). Majority of VTGO
undergoing early atresia. Less-developed oocytes
often present. POF may be present.
Ovulating (spawning) or approximately 12 hours
prior to or after spawning as indicated by either
GVM, GVBD/hydrated oocytes, or POF <~12 hours
old. Atresia of late VTGO may be present.
VTGO predominant. Some atresia and old POF
may be present. Less-developed oocytes often
present.
PGO, CAO, early VTGO, and mid VTGO may be
present. No POF. Some atresia can be present.
Only oogonia and PGO present. Usually no atresia.
Female
Table 3. Reproductive classification system for male and female fishes according to histological characteristics of gonads (as
modified from Brown-Peterson et al. 2007). Female “regenerating” phase was modified to include cortical alveolar oocytes.
Information on indeterminate fecundity, hydration, and determining fecundity/spawning frequency was removed (This information
either did not pertain to spotted gar or to this study’s objectives.). PGO—primary growth oocytes; CAO—cortical alveolar oocytes;
VTGO—vitellogenic oocytes; POF—post-ovulatory follicles; GVM—germinal vesicle migration; GVBD—germinal vesicle break
down; SG—spermatogonia; CY—spermatocysts; SC—spermatocytes; ST—spermatids; SZ—spermatozoa; GE—germinal epithelia.
Table 4. Description of reproductive classification system for male fishes according to
histological characteristics of gonads (as modified from Brown-Peterson et al. 2007). SG—
spermatogonia; CY—spermatocysts; SC—spermatocytes; ST—spermatids; SZ—spermatozoa;
GE—germinal epithelia.
Phase
Description
Immature
Only primary SG present along edges of lobules. Primary SG are large
and stained light purple. Lobules present with no lumens inside (Each
lobule is an individual circle with its own germ cells.).
Developing
Secondary SG (smaller and darker than primary SG) give rise to CY that
form along edges of lobules. CY are clusters of cells in the same stage of
spermatogenesis. Secondary SG, primary SC, secondary SC, ST, and SZ
may be present in CY. As spermatogenesis proceeds from SG to SZ,
cells become smaller, are more abundant, and are more darkly stained.
ST and SZ are similar in appearance except that SZ possess bright pink
tails. No SZ are present in lumens of lobules. Throughout testis, GE is
continuous, indicating that lobules are completely lined with CY.
Spawning capable
SZ have been released into lumens (empty space in middle of lobules)
and sperm ducts. Sperm ducts are stained bright pink and are a series of
“tubes” that eventually lead to the vas efferentia of the testis. SZ are
scattered in lumens and not in tight clusters as in CY. SG, SC, and ST
may also be present in CY. GE can be continuous or discontinuous
(lobules are not completely lined by CY) throughout testis.
Histologically undistinguishable from “actively spawning” phase.
Actively spawning
SZ released into lumens of lobules and sperm ducts. SG, SC, and ST
may also be present in CY. GE may be continuous or discontinuous
throughout testis. Histologically undistinguishable from “spawning
capable” phase except for macroscopic examination of free flowing milt
(with gentle pressure) from fish’s vent.
Regressing
Majority of lumens are empty except for a few with residual SZ. Some
residual SZ in sperm ducts. Scattered CY containing ST near edge of
testis. Formation of primary SG and regeneration of GE near edge of
testis.
Regenerating
No CY present. Lumens are small and difficult to see. Formation of
primary and secondary SG throughout entire testis. Sometimes, residual
SZ in lumens and sperm ducts.
22
Table 5. Description of reproductive classification system for female fishes according to
histological characteristics of gonads (as modified from Brown-Peterson et al. 2007). PGO—
primary growth oocytes; CAO—cortical alveolar oocytes; CA—cortical alveoli; VTGO—
vitellogenic oocytes; POF—post-ovulatory follicles.
Phase
Description
Immature
Oogonia typically not visible. PGO are small and stained dark
purple. PGO nuclei are large and stained light pink. Tissue and
cells are “tightly” associated and not scattered.
Developing
PGO present. CAO are slightly larger and stained light purple. CA
are small, light purple spheres that form a circle inside CAO. Early
VTGO are similar to CAO (in size) but possess small, bright pink
yolk vesicles that form a circle inside VTGO. Mid VTGO have
substantially more yolk vesicles and are larger in size. Mid VTGO
possess a thin, pink, striated vitelline envelope. PGO, CAO, early
VTGO, and mid VTGO possess follicle and thecal cells (thin
purple layers surrounding oocyte) that may be difficult to
distinguish. Atresia includes degraded structures. Early atresia of
late VTGO are “degraded” VTGO with loss of yolk vesicles. Late
atresia are light purple structures with several “empty holes,”
indicating previous location of fatty tissue. Atresia may also occur
on CAO, early VTGO, mid VTGO, and late VTGO.
Spawning capable
Late VTGO are prominent and are more than twice the size of mid
VTGO. Late VTGO possess a wide, pink vitelline envelope and a
thin outer layer of purple follicle and thecal cells. PGO and CAO
also present. Old POF are thick, convoluted strands of light purple
follicle cells. Early and late atresia may be present.
Actively spawning
Few late VTGO present. PGO and CAO also present. New POF
are prominent and are thin, dark purple convoluted strands. Some
early atresia of late VTGO may be present.
Regressing
Early and late atresia present. Majority of cells are “degraded.”
PGO, CAO, and sometimes old POF present. Many scattered cells
from old POF and atretic cells are present.
Regenerating
Only PGO and CAO present. Muscle bundles are scattered and
thick. Blood vessels often enlarged. Is similar to “immature” in
appearance but oocytes are more scattered and tissues are loose or
“used” in appearance. Late atresia may be present.
23
Statistical Analyses
A chi-square test was used to compare sex-specific differences in catch throughout the
sampling year (SAS 2003). Two-sample student’s t-tests (assuming equal variance) were used to
determine if males and females differed in TL, girth, and weight for each age class (in which
both sexes were collected) and to determine whether left and right gonad weights were different
for each sex. Kolmogorov-Smirnov two-sample tests were used to compare the distributions of
TL and age between the sexes. Total length and weight were log10-transformed, and linear
regressions were used to quantify the relationships between the two measurements for each sex
(SAS 2003). Seasonality of reproductive phases was plotted separately for male and female
spotted gar to identify the spawning season. Mean GSI was plotted separately for males and
females for each sample date and was used with histological analyses to identify the spawning
season. Linear regressions were used to quantify the relationships between total fecundity and
weight and between total fecundity and TL for female spotted gar (SAS 2003). Mean fecundity
was calculated for each age class. A linear regression was used to quantify the relationship
between the estimated count and the whole count methods for estimating total fecundity (SAS
2003). Mean egg diameter was plotted by month. Mean egg diameter was log10-transformed
and subjected to a two-way analysis of variance (ANOVA) followed by Tukey’s post hoc
comparison to determine monthly differences (SAS 2003). Mean TLs at age were calculated for
each sex. Even though TL of females differed from males in the same age classes, a single von
Bertalanffy growth curve was developed for both sexes (FAST Version 3.0; Slipke and Maceina
2001) due to the absence of individuals in some age classes (e.g., age 1 females). The L∞ was
forced to 819 mm, the maximum TL reported by Suttkus (1963). Maximum theoretical TL (L∞),
von Bertalanffy growth coefficient (k), and time when TL would theoretically equal zero (to)
were determined (Slipke and Maceina 2001). A catch-curve regression was used to determine
24
instantaneous rate of total mortality (Z), total annual mortality rate (AM), total annual survival
rate (S), and theoretical maximum age of spotted gar (Slipke and Maceina 2001). All tests were
based on α = 0.05.
25
RESULTS
Field Data
A total of 615 spotted gar were collected from 5 October 2006 to 26 September 2007, in
the upper Barataria Estuary. Four-hundred and sixty-eight of these individuals were used for this
study, and the remainder were released. Eighteen additional fish species were collected during
this study (Table 6). Overall, more female spotted gar (N = 253) were collected than males (N =
215; Table 7). The sex ratio of females to males was 1.2 : 1. Females dominated the catch
throughout the sampling period except in February, March, and April (Figure 6). In July, the
number of females collected equaled number of males collected (Figure 6). In February, more
males were collected than females (chi-square, P < 0.0001). In October, more females were
collected than males (chi-square, P < 0.0001). Dissolved oxygen ranged from 0.13 to 14.82
mg/L with an average of 2.33 ± 2.09 mg/L (± standard deviation; SD). Temperature ranged from
8.4 to 32.6 °C with an average of 20.9 ± 7.5 °C. Specific conductance ranged from 99.0 to
1,136.0 µS with an average of 225.4 ± 170.6 µS. Secchi disk depth ranged from 0 to 100 cm
with an average of 35 ± 18 cm. Salinity ranged from 0.0 to 0.6 ppt with an average of 0.1 ± 0.1
ppt. Water level ranged from 33.53 to 91.44 cm with an average of 66.25 ± 17.37 cm.
Laboratory Data
Females were longer than males for all age classes in which both sexes were collected
(Table 8). Females were heavier and had greater girths than males in age classes 3, 4, and 5 but
not age class 2 (Table 8). Left ovaries were heavier than right ovaries (P < 0.0001), but no
difference was observed between left and right testes weights (P = 0.2325; Table 7). Total length
(Figure 7) and age (Figure 8) frequency distributions were different for males and females.
26
Table 6. Total number of each fish species collected from 5 October 2006 to 26 September
2007, in the upper Barataria Estuary.
Species
Common Name
Lepisosteus oculatus
Spotted gar
615
Dorosoma cepedianum
Gizzard shad
226
Ictalurus furcatus
Blue catfish
39
Pomoxis nigromaculatus
Black crappie
35
Amia calva
Bowfin
34
Ictalurus punctatus
Channel catfish
27
Mugil cephalus
Striped mullet
10
Ictiobus bubalus
Smallmouth buffalo
8
Lepomis macrochirus
Bluegill
6
Micropterus salmoides
Largemouth bass
5
Morone mississippiensis
Yellow bass
5
Dorosoma petenense
Threadfin shad
4
Lepomis microlophus
Redear sunfish
4
Aplodinotus grunniens
Freshwater drum
3
Chaenobryttus gulosus
Warmouth
3
Ameiurus spp.
Bullhead
2
Micropogonias undulatus
Atlantic croaker
2
Atractosteus spatula
Alligator gar
1
Cyprinus carpio
Common carp
1
Total
Number
1,030
27
Table 7. Number (N), mean (± SD), and range of total length, pre-pelvic girth, weight, left
gonad weight, right gonad weight, age, and egg diameter for male and female spotted gar
collected from 5 October 2006 to 26 September 2007, in the upper Barataria Estuary.
Variable
N
Mean ± SD
Range
Total length (mm)
215
520 ± 36
344 - 585
Girth (mm)
215
166 ± 14
103 - 206
Weight (g)
215
589.0 ± 124.8
148.5 - 1,050.0
Left gonad weight (g)
215
4.91 ± 2.83
0.27 - 13.26
Right gonad weight (g)
215
4.59 ± 2.85
0.00 - 15.79
Age (years)
207
3.0 ± 0.8
1-5
Total length (mm)
253
578 ± 49
410 - 729
Girth (mm)
253
184 ± 19
115 - 249
Weight (g)
253
802.9 ± 244.4
212.5 - 1,710.0
Left gonad weight (g)
253
40.40 ± 30.72
1.08 - 166.30
Right gonad weight (g)
253
27.41 ± 21.19
0.35 - 113.93
Age (years)
246
3.4 ± 0.8
2-6
Egg diameter (mm)
131
2.5 ± 0.3
1.1 - 3.6
Males
Females
28
89
23
10
48 136
56
39
13
14
20
20
Figure 6. Percent of monthly catch of male (N = 215) and female (N = 253) spotted gar
collected from 5 October 2006 to 26 September 2007, in the upper Barataria Estuary. No fish
were collected in January. Numbers above columns indicate the number of fish collected each
month.
29
Table 8. Mean (± SD) and range (below mean) for total length (TL; mm), pre-pelvic girth (mm),
and weight (g) of male (N = 207) and female (N = 246) spotted gar for each age class in which
both sexes were collected from 5 October 2006 to 26 September 2007, in the upper Barataria
Estuary. Differences between the sexes are marked with an asterisk.
Age (years)
Measurement
Male Mean ± SD
(Range)
Female Mean ± SD
(Range)
2
TL*
504 ± 29
(425 - 560)
532 ± 47
(410 - 610)
3
TL*
524 ± 25
(465 - 585)
571 ± 43
(483 - 724)
4
TL*
540 ± 24
(500 - 585)
590 ± 46
(495 - 715)
5
TL*
543 ± 26
(492 - 580)
628 ± 46
(573 - 729)
2
Girth
162 ± 13
(128 - 185)
167 ± 20
(115 - 202)
3
Girth*
167 ± 11
(145 - 193)
181 ± 16
(150 - 249)
4
Girth*
172 ± 11
(151 - 206)
189 ± 18
(157 - 234)
5
Girth*
175 ± 11
(158 - 191)
205 ± 19
(173 - 233)
2
Weight
536.5 ± 116.4
(249.5 - 810.5)
600.2 ± 169.6
(212.5 - 910.0)
3
Weight*
594.9 ± 96.5
(382.5 - 863.0)
764.0 ± 210.4
(419.0 - 1,710.0)
4
Weight*
657.4 ± 117.7
(442.5 - 1,050.0)
857.8 ± 227.8
(488.5 - 1,500.0)
5
Weight*
672.0 ± 118.6
(475.0 - 838.5)
1,074.6 ± 292.9
(653.0 - 1,610.0)
30
Figure 7. Total length frequency distributions of male (N = 215) and female (N = 253) spotted
gar collected from 5 October 2006 to 26 September 2007, in the upper Barataria Estuary.
31
Figure 8. Age frequency distributions of male (N = 207) and female (N = 246) spotted gar
collected from 5 October 2006 to 26 September 2007, in the upper Barataria Estuary.
32
Weight increased with increased total length for males (Figure 9) and females (Figure 10).
All male spotted gar used for histological analyses (N = 94) were placed in the “spawning
capable/actively spawning” phase. Therefore, males in the “spawning capable/actively
spawning” phase were separated into groups based on the presence of purely continuous
germinal epithelia, discontinuous/continuous germinal epithelia (Figure 11), or purely
discontinuous germinal epithelia (Figure 12). Active spermatogenesis is indicated by numerous
spermatocysts and continuous germinal epithelia (Brown-Peterson et al. 2002), which appear
after the spawning season when males are preparing for the next spawning season. Less active
spermatogenesis can be indicated by few spermatocysts and discontinuous germinal epithelia
(Brown-Peterson et al. 2002). Testes undergoing little spermatogenesis that possess large
amounts of spermatozoa in the lumens of the lobules are primarily used for sperm storage instead
of sperm production (Grier et al. 1987). Discontinuous germinal epithelia were prominent from
October through April and also in June and August, and discontinuous/continuous germinal
epithelia became prominent in March and remained present through September (Figure 13). The
only occurrence of purely continuous germinal epithelia was in September (Figure 13).
Of all females used for histological analyses (N = 123), the majority were placed in the
“spawning capable/actively spawning” phase (N = 107; Figure 14). During each month of the
sampling period, females classified as “spawning capable/actively spawning” were more
prevalent than females of any other phases (Figure 15). Females classified as “developing”
(Figure 16) were collected during October, November, March, May, June, and August (Figure
15), and females classified as “regenerating” (Figure 17) were collected during February, March,
and May (Figure 15). On 31 May 2007, a female spotted gar was collected in which half of her
ovaries was classified as “spawning capable/actively spawning” while the other half was
33
Figure 9. Relationship between log10 weight and log10 total length for male spotted gar collected
from 5 October 2006 to 26 September 2007, in the upper Barataria Estuary.
34
Figure 10. Relationship between log10 weight and log10 total length for female spotted gar
collected from 5 October 2006 to 26 September 2007, in the upper Barataria Estuary.
35
Lobule
with a
continuous
GE
SZ in
lumen
CY
Figure 11. Histological section of a “spawning capable/actively spawning” male spotted gar
(TL = 457 mm) testis with discontinuous/continuous germinal epithelia collected on 26
September 2007, in the upper Barataria Estuary. Bar = 0.1 mm. CY—spermatocyst; SZ—
spermatozoa; GE—germinal epithelium.
36
SZ in lumen
Lobule with
a discontinuous GE
Figure 12. Histological section of a “spawning capable/actively spawning” male spotted gar
(TL = 485 mm) testis with discontinuous germinal epithelia collected on 10 March 2007, in the
upper Barataria Estuary. Bar = 0.1 mm. SZ—spermatozoa; GE—germinal epithelium.
37
15
7
3
15
14
9
10
3
4
6
8
Figure 13. Seasonal changes in germinal epithelia of male spotted gar (N = 94) collected from 5
October 2006 to 26 September 2007, in the upper Barataria Estuary. No fish were collected in
January. Numbers above columns indicate the number of fish collected each month. C—
continuous germinal epithelia; DC—discontinuous/continuous germinal epithelia; D—
discontinuous germinal epithelia.
38
PGO
Late VTGO
Atretic egg
CAO
Figure 14. Histological section from the ovary of a “spawning capable/actively spawning”
female spotted gar (TL = 652 mm) collected on 6 December 2006, in the upper Barataria
Estuary. Bar = 1.0 mm. PGO—primary growth oocyte; CAO—cortical alveolar oocyte;
VTGO—vitellogenic oocyte.
39
14
15
7
10
15
8
15
10
4
14
11
Figure 15. Monthly reproductive phases for female spotted gar (N = 123) collected from 5
October 2006 to 26 September 2007, in the upper Barataria Estuary. No fish were collected in
January. Numbers above columns indicate the number of fish collected each month. REGEN—
“regenerating” phase; DEV—“developing” phase; SC/AS—“spawning capable/actively
spawning” phase.
40
CAO
PGO
Early VTGO
Figure 16. Histological section from the ovary of a “developing” female spotted gar (TL = 568
mm) collected on 30 June 2007, in the upper Barataria Estuary. Bar = 1.0 mm. PGO—primary
growth oocyte; CAO—cortical alveolar oocyte; VTGO—vitellogenic oocyte.
41
CAO
PGO
Figure 17. Histological section from the ovary of a “regenerating” female spotted gar (TL = 530
mm) collected on 23 March 2007, in the upper Barataria Estuary. Bar = 0.5 mm. PGO—
primary growth oocyte; CAO—cortical alveolar oocyte.
42
“regressing” (Figure 18). Therefore, the overall phase selected for this female was “spawning
capable/actively spawning.” No “immature” females were collected during this study; however,
two females classified as “developing” possessed closely associated primary growth oocytes and
cortical alveolar oocytes, which is a characteristic of fish that have never spawned (N. BrownPeterson, University of Southern Mississippi, personal communication; Figure 19). Both of
these females were collected on 31 August 2007.
Atretic eggs were observed throughout the year in the alpha and beta stages (early atresia)
and in the gamma and delta stages (late atresia; Figure 20). These stages were defined by Hunter
and Macewicz (1984) and were based on work by Bretschneider and Duyvene de Wit (1947) and
Lambert (1970). Additionally, post-ovulatory follicles (Figure 18B) were observed every month
throughout the year except for January (no fish collected during this month), October, and June.
Post-ovulatory follicles were typically observed individually and not in clusters.
Mean GSI by sample date increased in spring and decreased through late summer for
males (Figure 21) and females (Figure 22). Based on mean GSI values and histological analyses,
spawning occurred from March through May. Mean egg diameter ranged from 1.5 mm in
August to 2.9 mm in March and averaged 2.5 ± 0.3 mm (N = 131; Figure 23).
Total fecundity ranged from 1,200 to 21,350 eggs per fish with an average of 6,493 ±
4,225 eggs per fish (mean TL = 579 ± 44 mm). Mean number of eggs per gram of ovary-free
body weight was 9 ± 5 eggs/g of ovary-free body weight. Only females collected during and just
prior to the spawning season (February through May) were used to determine the mean number
of eggs per gram of ovary-free body weight (N = 89). Total fecundity was more closely related
to weight (Figure 24) than total length (Figure 25). On average, mean total fecundity
43
“Spawning capable/
actively spawning”
“Regressing”
A
PGO
CAO
POF
Atretic
egg
B
Late
VTGO
PGO
Atretic
egg
CAO
C
Figure 18. Ovaries from a female spotted gar (TL = 645 mm) collected on 31 May 2007, in the
upper Barataria Estuary: (A) gross appearance of ovaries, (B) histological section of left portion
of left ovary classified as “regressing,” and (C) histological section of right portion of left ovary
classified as “spawning capable/actively spawning.” Overall, this female was classified as
“spawning capable/actively spawning.” Bars = 1.0 mm. PGO—primary growth oocyte; CAO—
cortical alveolar oocyte; VTGO—vitellogenic oocyte; POF—post-ovulatory follicle.
44
Mid
VTGO
PGO
Early
VTGO
CAO
Figure 19. Histological section from the ovary of a “developing” female and potential virgin
spotted gar (TL = 412 mm) collected on 31 August 2007, in the upper Barataria Estuary. Bar =
1.0 mm. PGO—primary growth oocyte; CAO—cortical alveolar oocyte; VTGO—vitellogenic
oocyte.
45
Early
atretic
egg
Late
atretic
egg
Late
VTGO
Figure 20. Histological section from the ovary of a “spawning capable/actively spawning”
female spotted gar (TL = 652 mm) collected on 6 December 2006, in the upper Barataria
Estuary. Bar = 0.1 mm. VTGO—vitellogenic oocyte.
46
Figure 21. Mean (± SD) gonadosomatic index (GSI) by sample date for male spotted gar (N =
215) collected from 5 October 2006 to 26 September 2007, in the upper Barataria Estuary. No
fish were collected in January.
47
Figure 22. Mean (± SD) gonadosomatic index (GSI) by sample date for female spotted gar (N =
253) collected from 5 October 2006 to 26 September 2007, in the upper Barataria Estuary. No
fish were collected in January.
48
A
A
A
A
A
B
C
BC
Figure 23. Mean monthly egg diameter (± SD) for female spotted gar (N = 131) collected from
9 February 2007 to 26 September 2007, in the upper Barataria Estuary. Means with the same
letter indicate no difference.
49
R2 = 0.43
P < 0.0001
N = 192
Total fecundity = 11.87(Weight) - 3,096.00
0
Figure 24. Linear relationship between total fecundity and weight of female spotted gar
collected from 5 October 2006 to 26 September 2007, in the upper Barataria Estuary.
50
0
Figure 25. Linear relationship between total fecundity and total length of female spotted gar
collected from 5 October 2006 to 26 September 2007, in the upper Barataria Estuary.
51
increased with age (Table 9). The estimated count and whole count methods for determining
total fecundity were similar (R2 = 0.98; P < 0.0001; Figure 26).
According to macroscopic observation of ovaries, more than 15 % of spotted gar females
spawned from February through June. However, approximately 61 % of spawned females did
not spawn completely and retained and reabsorbed some amount of eggs. Spawning was also
confirmed by the collection of juvenile spotted gar in April (S. Jackson, Nicholls State
University, unpublished data).
Spotted gar exhibited values of 0.18 and -2.777 for k and to, respectively (Figure 27).
Catch-curve analysis revealed values of 16.8 %, 83.2 %, -1.78, and 6.4 years for S, AM, Z, and
theoretical maximum age, respectively, for spotted gar (Figure 28).
52
Table 9. Number (N), mean (± SD), and range of total fecundity for each age class of female
spotted gar collected from 5 October 2006 to 26 September 2007, in the upper Barataria Estuary.
Age (years)
N
Mean ± SD
Range
2
17
5,158 ± 4,273
1,360 - 16,350
3
97
6,130 ± 3,552
1,200 - 20,110
4
63
6,910 ± 4,687
1,920 - 21,350
5
11
9,238 ± 5,440
2,595 - 18,500
6
1
15,760
-
53
Figure 26. Linear relationship between estimated count and whole count methods for
determining total fecundity in female spotted gar collected from 5 October 2006 to 26 September
2007, in the upper Barataria Estuary.
54
R2 = 0.88
P = 0.0052
N = 453
Lt = 819(1-e-0.18(t + 0.2777))
where:
L∞ = 819 mm
k = 0.18
to = -2.777
Figure 27. von Bertalanffy growth curve, maximum theoretical total length (L∞), von
Bertalanffy growth coefficient (k), and time when total length would theoretically equal zero (to)
for spotted gar collected from 5 October 2006 to 26 September 2007, in the upper Barataria
Estuary. L∞ was derived from Suttkus (1963).
55
R2 = 0.90
P = 0.0530
N= 386
S = 16.8 %
AM = 83.2 %
Z = -1.78
Max age = 6.4 years
Ln (number) = -1.78(Age) + 11.42
Figure 28. Catch-curve regression, total annual survival rate (S), total annual mortality rate
(AM), instantaneous rate of total mortality (Z), and theoretical maximum age (Max age) for
spotted gar collected from 5 October 2006 to 26 September 2007, in the upper Barataria Estuary.
56
DISCUSSION
Field Data
More spotted gar were collected than any other species during this study. Previous
studies in the upper Barataria Estuary that targeted different fish species also collected high
percentages of spotted gar in relation to other fish species (38%, Davis 2006; 11%, Fontenot
2006). In February, the number of males collected was significantly higher than the number of
females. Prior to spawning seasons, male and female gars typically exhibit increases in sex
steroid hormones, indicating active gametogenesis (Orlando et al. 2003, 2007). Females utilize
these hormones for oogenesis while males probably do not utilize hormones nearly as much for
spermatogenesis, which does not require as much energy as does oogenesis. The increase in
hormones most likely causes males to become more active (Martin 1976). Because spotted gar
in the upper Barataria Estuary spawned in March, males probably possessed high hormone levels
in February, resulting in greater activity. Therefore, the male-dominated catch in February may
be attributed to greater susceptibility to gear, resulting from greater activity.
Gonad Histology—Males
Based on histological analyses, spermiated spermatozoa were present in all males, thus
indicating that male spotted gar may be capable of spawning year round. Orlando et al. (2003)
used a classification scheme derived from Grier (1981), in which reproductive phase was
identified by the mean percentage of each stage of spermatogenesis (spermatogonia,
spermatocytes, spermatids, and spermatozoa) present for each month. Orlando et al. (2003)
found that male Florida gar also possess spermatozoa year round; however, the mean monthly
percentage of spermatozoa was always less than 50 %. Gonad histological techniques have
57
typically been applied to females more than males (Hunter and Goldberg 1980; Hunter and
Macewicz 1984; Treasurer and Holliday 1981; Hunter et al. 1986). Histological studies of male
gonad development have typically focused on species with high economic value, such as spotted
seatrout (Brown-Peterson et al. 1988) and cobia (Brown-Peterson et al. 2002). However, the
males of these species typically undergo phases similar to the “regressing” and “regenerating”
phases used in this study and are not capable of spawning throughout the year.
Although male spotted gar may be capable of spawning year round, the germinal
epithelia changed during the year as spermatogenesis activity increased and decreased. The
onset of discontinuous/continuous germinal epithelia in the spring most likely reflects males that
spawned and were beginning spermatogenesis again. These data, in combination with GSI
values, indicate a spawning season from March to May. Because spermatogenesis should cease
after spawning while males are in the “regressing” and “regenerating” phases, germinal epithelia
should be discontinuous during these phases (Brown-Peterson et al. 2007). Spermatocysts do not
typically appear until a male reaches the “developing” and “spawning capable” phases (BrownPeterson et al. 2007), which can be weeks or months after the spawning season (Brown-Peterson
et al. 2002). Due to the presence of discontinuous/continuous germinal epithelia during and
directly after the spawning season and the absence of males in the “regressing” and
“regenerating” phases, males in this population may undergo these phases quickly. Additionally,
because males with discontinuous/continuous germinal epithelia were collected every month
except during the colder months (November, December, and February), male spotted gar may be
capable of performing spermatogenesis throughout the year except during colder months when
metabolic rates are low.
58
Gonad Histology—Females
The majority of females fell into the “spawning capable/actively spawning” phase.
Primary growth oocytes, cortical alveolar oocytes, and late vitellogenic oocytes were observed
each month, similar to the findings of Orlando et al. (2007) in Florida gar. Orlando et al. (2007)
used a classification scheme derived from Wallace and Selman (1981), in which reproductive
phase was identified by the mean percentage of four stages of oogenesis (oogonia, primary
growth oocytes, previtellogenic oocytes, and vitellogenic oocytes) present for each month. The
mean monthly percentage of vitellogenic oocytes in Florida gar was less than 50 % during every
month (Orlando et al. 2007). Females of several other fish species do not often possess
vitellogenic oocytes outside of the spawning season and are, thus, not capable of spawning year
round. For instance, the spotted seatrout, a batch spawner, only possessed late vitellogenic
oocytes from March through October and December in south Texas from 1982 to 1985 (BrownPeterson et al. 1988).
Beginning in March, the occurrence of females in the “regenerating” and “developing”
phases increased. The absence of females in these two phases in April was most likely due to
small sample size (N = 8). The onset of the “regenerating” and “developing” phases most likely
represents females that spawned and were preparing for the next spawning season. In
combination with GSI values, this information agrees with histology of males that spawning
occurred from March to May. After spawning, females typically undergo active atresia to
reabsorb remaining eggs (“regressing” phase) and assemble primary growth oocytes and cortical
alveolar oocytes for the next spawning season (“regenerating” phase; Brown-Peterson et al.
2007). These two phases can require weeks or months for completion (Brown-Peterson et al.
1988). Due to the collection of “regenerating” and “developing” females during and directly
59
after the spawning season and the lack of “regressing” females, females in this population may
undergo the “regressing” phase quickly.
Gonad histology also verified atresia of eggs in female spotted gar. Atretic eggs were
observed throughout the sampling period and included the alpha, beta, gamma, and delta stages
(Hunter and Macewicz 1984). Additionally, post-ovulatory follicles were observed during
almost every month in which female spotted gar were collected. Post-ovulatory follicles
degenerate into an unidentifiable structure within 48 hours in many species, such as northern
anchovy (Hunter and Goldberg 1980) and skipjack tuna Katsuwonus pelamis (Hunter et al.
1986). However, because spotted gar have larger eggs (mean egg diameter = 2.5 ± 0.3 mm) than
many other fish species (Treasurer and Holliday 1981; Brown-Peterson et al. 1988; Abdoli et al.
2005), spotted gar probably have larger post-ovulatory follicles that may require longer periods
to degenerate to an unidentifiable state. Post-ovulatory follicles were typically observed
individually and not in clusters, giving no indication of additional spawning seasons.
Furthermore, analyses of GSI values and egg diameters also do not support the presence of
additional spawning seasons in this population.
“Spawning capable/actively spawning” females were collected every month throughout
the sampling period although spawning occurred from March to May. An undeveloped spotted
gar oocyte is of similar size or larger than a mature oocyte of many other species, such as the
spotted seatrout (mean yolk globular oocyte diameter = 0.200 - 0.375 mm; Brown-Peterson et al.
1988). Large egg size increases the chance for offspring survival. Consequently, female spotted
gar probably have a “threshold egg size,” above which an egg is suitable for spawning.
Therefore, even though “spawning capable/actively spawning” females were collected every
60
month, female spotted gar were probably not capable of spawning during every month of this
study. Sufficient egg sizes and external stimuli are most likely required for spawning to occur.
GSI
Environmental factors, such as temperature and photoperiod, strongly influence timing
and duration of spawning seasons (de Vlaming 1972). Lower latitudes have warmer
temperatures and longer growing seasons than do higher latitudes. Therefore, populations at
lower latitudes typically exhibit early and/or extended spawning seasons, which have been
documented in gizzard shad (Fontenot 2006) and cyprinids (Alburnops spp., Cyprinella spp.,
Hybopsis spp., and Notropis voluceltus; Gotelli and Pyron 1991). Environmental cues trigger the
hypothalamus to release gonadotropin hormone-releasing hormones that activate the anterior
pituitary to secrete gonadotropin hormones (Jameson 1988). Common gonadotropins in fish
include GtH I and GtH II, which are produced in both sexes (Lin et al. 2004). Gonadotropins
travel to the gonads and activate follicle and thecal cells that surround oocytes or Leydig and
Sertoli cells that surround spermatocysts to produce sex steroid hormones (e.g., testosterone and
estrogen), which are used for gametogenesis (Jameson 1988).
The spotted gar population in the upper Barataria Estuary is located near the southern
edge of the species’ range and is the most southern population in which reproductive data have
been recorded (Echelle and Riggs 1972; Tyler and Granger 1984; Ferrara 2001; Love 2004).
Based on histological analyses and GSI values for both sexes, this population spawned from
March through May. This population (N29°54’25.90’’, W90°47’43.18’’) has an earlier and
longer spawning season than spotted gar populations in more northern regions, such as Lake
Lawtonka (N34°45’24.88’’, W98°30’50.04’’; Tyler and Granger 1984), Lake Texoma
61
(N33°53’06.97’’, W96°36’22.42’’; Echelle and Riggs 1972), and Lake Seminole
(N30°46’34.76’’, W84°47’55.24’’; Ferrara 2001). The spotted gar population from the Lake
Pontchartrain Estuary (N30°07’52.59’’, W90°08’00.38’’) is located at similar latitudes to the
upper Barataria Estuary and has a slightly earlier and longer spawning season from February
through June (Love 2004). Mean monthly GSI from the Lake Pontchartrain Estuary population
peaked at similar values and times as did the upper Barataria Estuary population, with the
exception that male GSI from the Lake Pontchartrain Estuary peaked in October (Love 2004).
Egg Diameters
Egg diameter measurements decreased from June through July and remained low through
September. Because only visible eggs were measured, measurements taken during the spawning
season most likely included eggs that would have eventually been reabsorbed instead of
spawned. Because all egg diameter measurements were much lower after June and included
eggs that would probably be matured and spawned for the spawning season of the next year, the
majority of spawning and atresia were most likely completed before July. Additionally, new
eggs that will mature for the next spawning season were large enough to be measured with
digital calipers by July. Love (2004) documented a decrease in spotted gar egg diameters in the
Lake Pontchartrain Estuary during the same months. Results were similar in Florida gar with a
decrease in egg diameter from July through September (Orlando et al. 2007). Additionally,
mean egg diameters from this study were similar to egg diameters of Florida gar (Orlando et al.
2007) but were smaller than egg diameters of spotted gar from the Lake Pontchartrain Estuary
(Love 2004). During the spawning season, mean egg diameter from the Lake Pontchartrain
Estuary spotted gar was 3.02 ± 0.02 mm (Love 2004), which is larger than mean egg diameters
from any month of this study.
62
Fecundity
Mean total fecundity for spotted gar was 6,493 ± 4,225 eggs per fish from females that
had not recently spawned. This mean is greater than the maximum fecundity that Ferrara (2001)
found for the spotted gar population in Lake Seminole. Love (2004) separated female spotted
gar from the Lake Pontchartrain Estuary into pre-spawn (September through January) and postspawn (July to August) periods and found mean fecundities of 9,500 eggs per fish and 4,500
eggs per fish, respectively. The average of these two values is similar to the mean total fecundity
of the current population. Additionally, total fecundity increased with increased total length and
increased weight, and Love (2004) found similar trends in spotted gar from the Lake
Pontchartrain Estuary.
According to Hunter et al. (1992), female spotted gar exhibit determinate fecundity. In
fishes with determinate fecundity, total fecundity before the spawning season is equal to
potential annual fecundity, the total number of vitellogenic oocytes that a female matures in a
year (not including atresia; Hunter et al. 1992). Determinate fecundity is represented by a clear
distinction between late vitellogenic oocytes and primary growth/cortical alveolar oocytes, a
characteristic of fish with group-synchronous oocyte development (Wallace and Selman 1981;
Hunter et al. 1992). Other indicators of determinate fecundity include a decrease in the number
of late vitellogenic oocytes as the spawning season progresses and the random occurrence of
atresia throughout the spawning season (Hunter et al. 1992). In contrast, in fishes with
indeterminate fecundity, potential annual fecundity is not set before spawning and primary
growth/cortical alveolar oocytes are matured and spawned throughout the spawning season
(Hunter et al. 1992).
63
Incomplete Spawning
Estimating the percentage of females that spawned using macroscopic observation of
ovaries does not easily account for partial or incomplete spawning. According to macroscopic
observation of spotted gar ovaries collected from February through June, the majority of females
in the upper Barataria Estuary did not spawn in 2007 (85 %), and of the females that did spawn
(15 %), most did not spawn all of their eggs and underwent atresia (61% of spawned females).
The percentage of spawned females could be an underestimate because each female may have
partially spawned and may not have macroscopically exhibited characteristics that would have
identified the fish as having spawned. However, macroscopic observation verified that very few
female spotted gar spawned all of their eggs (6 %). Because the majority of female spotted gar
did not spawn completely, total fecundity estimates may be overestimates of the number of eggs
annually spawned in the upper Barataria Estuary.
Pesticides and other environmental contaminants may have adverse effects on the
reproduction of a variety of animals through disruption of the endocrine system (Guillette et al.
2000; Oehlmann et al. 2000; Orlando et al. 2004). The upper Barataria Estuary is surrounded by
agricultural lands, in which sugarcane is the dominant crop (Braud et al. 2006). Atrazine, a
widely used herbicide, is often applied to sugarcane in south Louisiana (Demcheck and
Swarzenski 2003) and has been identified as one of the possible causes of the recent decline in
global amphibian populations (Hayes et al. 2002). Atrazine and other contaminants have been
found in waterways where fish populations exhibited reproductive anomalities, including
intersex (L. Iwanowicz, USGS, personal communication). Atrazine exposure has also been
documented to alter steroid levels and cause testicular structural disruption and increased levels
of ovarian atresia in fish (Spanò et al. 2003). Demcheck and Swarzenski (2003) found atrazine
64
(mean concentration = 0.38 mg/L) at a site in Bayou Chevreuil in March, May, June, and August
of 1999. Because the upper Barataria Estuary no longer receives freshwater input from the
Mississippi River, the detected atrazine probably originated from local input, most likely from
agricultural lands that surround the estuary. Additionally, spotted gar was listed as one of nine
fish species of concern in the lower Mississippi River for high rates of bioaccumulation of
environmental contaminants (Watanabe et al. 2003), and gonadal cysts have been documented in
spotted gar in petroleum-contaminated water bodies in Louisiana (Thiyagarajah et al. 2000).
Hence, atrazine and other environmental contaminants may have adversely impacted the
reproductive health of the spotted gar population in the upper Barataria Estuary, possibly
resulting in decreased reproductive potential.
Spawning Strategies
Incomplete spawning of female spotted gar may reflect spawning behavior in which
small batches of eggs are released throughout the entire spawning season. This strategy is
representative of batch spawners, such as the spotted seatrout in south Texas (Brown-Peterson
and Thomas 1988; Brown-Peterson et al. 1988), which spawn several times over a period of
several months (Murua and Saborido-Rey 2003). Batch spawners spawn a group of eggs and
then recruit and spawn new batches of eggs from their vitellogenic oocyte reserve during the
same spawning season (Murua and Saborido-Rey 2003). Therefore, batch spawners usually
exhibit asynchronous oocyte development, in which all stages of oogenesis are present in the
ovary simultaneously (Wallace and Selman 1981). Because female spotted gar in the “spawning
capable/actively spawning” phase typically contained only two generations of oocytes (late
vitellogenic oocytes and primary growth/cortical alveolar oocytes), female spotted gar exhibit
group-synchronous oocyte development and are most likely not batch spawners (Wallace and
65
Selman 1981). Orlando et al. (2007) also documented female Florida gar as having groupsynchronous oocyte development.
Johnson and Noltie (1997) and Orlando et al. (2003) reported that longnose gar and
Florida gar, respectively, are total spawners, which spawn all of their eggs in a very short time
period (Murua and Saborido-Rey 2003). Due to a spawning season of intermediate length, a lack
of completely spent ovaries, and group-synchronous oocyte development, spotted gar probably
fall between the batch and total spawning patterns, spawning a few times throughout the
spawning season. To increase offspring survival, spawning may occur more than once during
the spawning season. As a result, temporary, unfavorable conditions may lead to mortality of a
portion of and not all offspring produced for that spawning season.
Maturity and Growth
No immature males were collected in this study. However, three age 1 males were
collected, which were the smallest males collected. Histological samples taken from two of the
three age 1 males were classified as “spawning capable/actively spawning.” Therefore, male
spotted gar probably mature (defined as 100 % of each sex does not fall into “immature” phase
as indicated by Brown-Peterson et al. 2007) by age 1 and 344 mm TL. Love (2004) documented
similar findings for male spotted gar in the Lake Pontchartrain Estuary. He reported that males
matured before age 2, and the smallest mature male was 285 mm standard length (SL; Love
2004).
No immature or age 1 females were collected during this study. However, age 2 females
were collected (N = 23), and several (N = 9) were classified as “spawning capable/actively
spawning.” Additionally, two age 2 females were classified as “developing” and potential
66
virgins and were the smallest females collected. Therefore, females in this population probably
mature by age 2 and 410 mm TL. According to Love (2004), female spotted gar in the Lake
Pontchartrain Estuary matured before age 2, and the smallest mature female was 395 mm SL.
Female spotted gar reach greater total lengths than males. In fish populations, females
typically grow to greater maximum lengths than do males (Parker 1992). As was observed in
this study, older and larger females produce more eggs, potentially leading to production of more
offspring (Jalabert 2005). Young males (ages 1 and 2) were classified as “spawning
capable/actively spawning,” and can, therefore, produce enough sperm for spawning.
Consequently, large males and, thus, large testes are probably not essential for increasing the
number of offspring.
Spotted gar from this study (k = 0.18) grow faster than bowfin (k = 0.08; Davis 2006) in
the upper Barataria Estuary and alligator gar (k = 0.03) and longnose gar (k = 0.17) across the
southeastern United States (Ferrara 2001). However, spotted gar from Lake Seminole exhibit a
higher growth rate (k = 0.30; Ferrara 2001) than spotted gar in the upper Barataria Estuary.
Populations in more northern regions may exhibit faster growth rates because of shorter growing
seasons (Conover 1990). Because no age 1 females were collected, the von Bertalanffy growth
coefficient (k) may not reflect the actual growth rate of spotted gar. Love (2004) documented
that male and female spotted gar in the Lake Pontchartrain Estuary were of similar lengths
during the first year and that males grew faster than the females during the first four years.
Afterward, both sexes had slower growth rates with females growing faster than males (Love
2004).
67
The Kolmogorov-Smirnov two-sample test revealed that age distributions were different
for males and females. More females were collected than males in the older age classes (ages 3
through 6) while more males were collected in the younger age classes (ages 1 and 2).
According to catch-curve analysis, the theoretical maximum age of this population was 6.4 years.
Ferrara (2001) and Love (2004) both found age 10 spotted gar in Lake Seminole and the Lake
Pontchartrain Estuary, respectively; therefore, spotted gar in the upper Barataria Estuary might
exhibit higher mortality rates. Catch-curve analysis from this study produced a high AM (83.2
%), which may explain the lack of fish older than 6 years.
Life History Classification
Understanding life history strategies can lead to better management of fisheries and
ecosystems (King and McFarlane 2003). Winemiller and Rose (1992) created a system for
classifying many North American fishes into three life history categories based on age at
maturation, length at maturation, maximum length, longevity, maximum clutch size, mean clutch
size, egg size, range of egg sizes, duration of spawning season, number of spawning bouts per
year, parental care, time to hatch, larval growth rate, young of the year (YOY) growth rate, adult
growth rate, and fractional adult growth. The “periodic” strategists are long-lived fish that
typically mature late, grow to large sizes, and produce many offspring (Winemiller and Rose
1992). The “equilibrium” strategists are usually K-selected strategists of intermediate sizes that
produce large eggs and small clutches and exhibit parental care (Winemiller and Rose 1992).
The “opportunistic” strategists are usually small, somewhat r-selected fish that mature early,
grow quickly, and produce small clutches frequently over a long time period (Winemiller and
Rose 1992). Additionally, many species often exhibit intermediate strategies among the three
strategies described above.
68
Winemiller and Rose (1992) reported other large ancient fish (e.g., lake sturgeon
Acipenser fulvescens and paddlefish Polyodon spathula) as “periodic” strategists. Ferrara (2001)
described the life history strategies of three species of gar (alligator gar, longnose gar, and
spotted gar) in the southern United States and found that spotted gar were the least “periodic,”
and alligator gar were the most “periodic.” The spotted gar from the upper Barataria Estuary
mature early, grow quickly, reach large sizes, exhibit high parental investment (vitellogenesis),
and produce many, large eggs. Therefore, spotted gar in the upper Barataria Estuary are most
likely intermediates between “periodic” and “equilibrium” strategies. However, spotted gar are
most likely closer to the “equilibrium” strategy because of their faster growth, younger
maturation, smaller size, and lower fecundity as compared to other gar species (Ferrara 2001).
Davis (2006) also reported bowfin in the upper Barataria Estuary as being intermediates between
“periodic” and “equilibrium” strategies. The bowfin spawn seasonally, produce large clutches of
eggs, and exhibit parental care (nest building and guarding of offspring; Scott and Crossman
1973); therefore, the bowfin are also closer to the “equilibrium” strategy (Davis 2006).
In conclusion, male spotted gar in the upper Barataria Estuary may be capable of
spawning year round. Most females appear to be capable of spawning year round; however,
spawning only occurred from March through May. Spawning most likely occurred when a
“threshold egg size” was reached and when external stimuli (e.g., temperature and photoperiod)
triggered the fish to begin spawning. Additionally, because the majority of spawned females did
not spawn completely, total fecundity estimates are most likely overestimates of the number of
eggs annually spawned in the upper Barataria Estuary.
69
FUTURE RECOMMENDATIONS
In order to more accurately determine spawning times of spotted gar, the degeneration
rates of post-ovulatory follicles should be studied in a laboratory setting. By sacrificing females
at specific intervals after spawning, gonad histology can be used to “age” post-ovulatory follicles
and provide a timeline of the degeneration of a spotted gar post-ovulatory follicle (Hunter et al.
1986). This information can then be applied to wild spotted gar to better understand spawning
times by observing the appearances of post-ovulatory follicles (Hunter et al. 1986).
Additionally, if possible, multiple sections should be taken from ovaries and testes of laboratoryspawned and wild spotted gar for histological analyses to observe any differences in gonad
development along latitudinal and longitudinal gradients in the gonads.
Future histological analyses of spotted gar gonads from the upper Barataria Estuary
would assist in understanding the dynamics of this population’s reproductive cycle over a longer
time period. A comparison of this population to one in a floodplain that receives freshwater
input, such as the Atchafalaya River Basin, would provide a detailed analysis of how the annual
river-driven floodpulse potentially affects the reproductive potential of spotted gar. Finally,
other aging structures should be explored in spotted gar, such as cross-sections of scales, which
have been applied to alligator gar in Oklahoma (E. Brinkman, Oklahoma State University,
personal communication).
70
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20061005
20061005
20061005
20061005
20061005
20061005
20061005
20061005
20061011
20061011
20061011
20061011
20061011
20061011
20061021
20061021
20061021
ID #
1824
1823
1732
1822
1745
1742
1741
1746
1744
1743
1820
1813
1815
1814
1811
1810
1575
1843
1840
TL
555
570
550
567
534
665
587
593
582
636
581
628
560
519
583
546
535
556
591
Girth
178
176
171
183
169
200
175
177
167
190
183
201
173
158
171
173
176
176
176
Weight
683.0
673.0
653.0
761.0
580.0
1,040.0
751.0
774.0
674.5
896.0
795.0
1,600.0
688.5
553.0
716.5
646.0
571.5
684.0
781.5
Sex
F
F
F
F
F
F
F
F
F
F
M
F
F
F
F
F
M
F
F
LGWt RGWt
27.13
25.07
21.76
11.17
45.96
23.72
52.26
34.08
19.39
14.50
37.76
27.45
37.25
28.45
33.19
18.52
15.44
10.48
18.35
8.06
6.01
9.93
75.68
51.04
33.61
21.37
24.00
14.40
29.82
15.91
29.64
14.39
3.89
3.65
31.78
13.31
24.65
17.80
GSI
7.6
4.9
10.7
11.3
5.8
6.3
8.7
6.7
3.8
2.9
2.0
7.9
8.0
6.9
6.4
6.8
1.3
6.6
5.4
Mean
egg
diameter
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Histological Phase
SC/AS
SC/AS
.
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
.
SC/AS
.
.
Male
GE
.
.
.
.
.
.
.
.
.
.
DC
.
.
.
.
.
D
.
.
Age
4
3
3
3
3
4
3
.
4
4
3
6
3
3
4
4
5
3
3
Fec
4,560
4,180
8,160
9,500
3,820
7,550
7,190
.
3,060
2,830
.
15,760
4,960
5,250
3,930
4,340
.
4,810
3,890
Appendix I. Collection date (year month day), identification number (ID #), total length (TL; mm), pre-pelvic girth (mm), weight (g),
sex, left gonad weight (LGWt; g), right gonad weight (RGWt; g), gonadsomatic index (GSI), mean egg diameter (mm), histological
phase, state of male germinal epithelia (Male GE), age (years), and total fecundity (Fec; eggs per fish) of spotted gar collected from 5
October 2006 to 26 September 2007, in the upper Barataria Estuary. M—male; F—female; SC/AS—“spawning capable/actively
spawning” phase; REGEN—“regenerating” phase; DEV—“developing” phase; D—discontinuous germinal epithelia; DC—
discontinuous/continuous germinal epithelia; C—continuous germinal epithelia.
Collection
Date
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
ID #
8888
1573
1838
6666
5555
1570
1569
1568
4444
3333
2222
1564
1844
1563
1826
1561
1111
1560
1836
1559
1558
1557
1841
1850
1849
1556
Total
Length
615
546
591
589
603
651
534
536
564
674
564
624
683
534
549
535
729
514
595
638
579
523
503
501
531
546
Girth
192
165
193
174
187
179
163
173
173
207
173
200
196
159
174
168
232
160
194
204
183
168
158
163
163
170
Weight
929.0
601.5
880.0
741.0
815.5
867.5
553.5
628.5
671.5
1,150.0
661.0
1,070.0
1,030.0
517.0
673.0
567.0
1,610.0
521.0
892.5
1,050.0
752.5
577.5
533.5
543.5
548.0
630.5
Sex
F
M
F
F
F
F
F
M
F
F
F
F
F
M
F
F
F
F
F
F
F
M
M
F
M
F
LGWt RGWt
47.31
25.51
2.42
2.79
42.75
30.55
14.25
9.27
32.54
24.37
15.53
11.31
16.82
12.69
1.61
1.99
15.13
8.85
64.55
38.54
17.32
11.95
74.37
48.55
5.35
3.37
3.58
5.50
23.58
17.87
41.75
21.65
71.44
37.88
27.72
19.26
52.63
33.97
33.04
24.85
22.79
14.46
4.84
8.25
4.70
2.62
28.19
11.58
3.54
3.76
36.65
22.29
GSI
7.8
0.9
8.3
3.2
7.0
3.1
5.3
0.6
3.6
9.0
4.4
11.5
0.8
1.8
6.2
11.2
6.8
9.0
9.7
5.5
5.0
2.3
1.4
7.3
1.3
9.3
Mean
egg
diameter
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Histology
Phase
.
SC/AS
.
.
.
.
.
SC/AS
.
.
.
.
DEV
SC/AS
.
.
.
.
.
.
.
SC/AS
SC/AS
.
SC/AS
.
Male
GE
.
D
.
.
.
.
.
D
.
.
.
.
.
DC
.
.
.
.
.
.
.
D
D
.
D
.
Age
3
3
4
4
4
4
3
.
2
4
3
3
3
3
3
4
5
4
3
3
5
.
3
3
3
3
Fec
6,020
.
7,170
2,490
4,750
2,900
3,030
.
2,750
12,080
2,330
13,470
.
.
4,520
6,700
11,400
4,980
8,131
5,180
3,040
.
.
3,470
.
6,810
Collection
Date
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061021
20061026
20061026
ID #
1847
1842
1834
1831
1832
1803
1555
1848
1833
1829
1802
1808
1845
1837
1804
1846
1801
1827
1807
1828
1805
1809
1806
1839
1430
1435
Total
Length
556
553
585
546
540
656
724
581
560
547
587
586
515
567
360
553
527
585
566
588
551
570
586
543
578
643
Girth
178
170
166
163
167
215
249
180
180
177
173
184
182
186
105
175
178
188
171
195
172
165
191
187
176
202
Weight
694.5
659.0
672.5
569.5
589.5
1,210.0
1,710.0
786.0
717.5
683.0
740.0
826.0
696.0
820.0
181.0
710.5
646.0
790.0
608.0
867.0
662.0
633.0
849.0
855.0
731.0
1,050.0
Sex
F
M
F
F
F
F
F
F
F
F
F
F
M
F
M
F
F
F
F
F
F
F
F
F
F
F
LGWt RGWt
34.15
14.53
1.92
1.42
10.39
9.02
25.04
23.42
28.65
18.94
106.63 66.52
96.46
91.11
45.15
32.44
39.27
26.41
34.92
21.92
37.40
25.34
40.86
33.81
7.24
7.16
36.22
39.43
1.44
0.99
57.82
21.59
41.42
23.19
37.72
38.65
3.87
2.91
51.87
32.33
30.55
19.50
16.05
8.56
61.13
31.38
15.86
8.89
38.71
25.41
37.52
26.14
GSI
7.0
0.5
2.9
8.5
8.1
14.3
11.0
9.9
9.2
8.3
8.5
9.0
2.1
9.2
1.3
11.2
10.0
9.7
1.1
9.7
7.6
3.9
10.9
2.9
8.8
6.1
Mean
egg
diameter
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Histology
Phase
.
SC/AS
.
.
.
.
.
.
.
.
.
.
SC/AS
.
SC/AS
.
.
.
.
.
.
.
.
.
.
.
Male
GE
.
DC
.
.
.
.
.
.
.
.
.
.
D
.
D
.
.
.
.
.
.
.
.
.
.
.
Age
3
3
4
3
3
5
3
3
4
3
.
3
3
4
.
3
4
5
4
3
3
3
3
4
4
3
Fec
5,240
.
2,310
4,590
5,100
17,660
16,500
8,990
4,940
5,232
5,610
6,370
.
6,760
.
8,340
5,960
6,440
.
7,490
4,550
2,130
9,470
2,190
5,240
5,740
Collection
Date
20061026
20061026
20061026
20061026
20061026
20061026
20061026
20061026
20061026
20061026
20061026
20061026
20061026
20061026
20061026
20061026
20061026
20061026
20061102
20061102
20061102
20061102
20061102
20061102
20061102
20061102
ID #
1440
1432
1431
1437
1449
1439
1445
1442
1436
1448
1434
1447
1444
1438
1433
1443
1441
1446
1598
1597
1428
1596
1600
1595
1429
1427
Total
Length
525
535
544
523
526
555
625
686
627
693
581
553
585
600
655
574
693
493
504
573
540
536
557
582
628
566
Girth
159
164
166
165
166
165
196
224
188
214
176
176
184
176
209
185
220
146
158
173
162
170
168
181
191
171
Weight
555.0
593.0
638.0
602.5
611.0
648.5
946.5
1,400.0
850.0
1,295.0
736.5
699.5
818.5
747.0
1,205.0
800.0
1,425.0
439.0
509.5
653.0
599.0
616.5
615.0
754.0
917.5
683.0
Sex
M
F
F
M
M
F
F
F
F
F
F
F
F
F
F
F
F
M
M
F
M
F
F
F
F
F
LGWt RGWt
2.89
2.25
25.21
12.08
21.21
13.66
5.68
3.67
3.38
2.88
12.45
6.50
51.13
26.48
46.44
21.97
19.14
11.44
44.27
28.35
14.65
5.93
42.22
21.05
44.46
23.53
22.40
20.32
72.98
28.44
37.95
23.97
57.59
36.45
2.52
1.45
7.03
4.58
29.82
30.80
3.68
3.29
29.14
22.27
3.37
1.82
26.62
16.50
32.57
19.37
29.22
22.76
GSI
0.9
6.3
5.5
1.6
1.0
2.9
8.2
4.9
3.6
5.6
2.8
9.0
8.3
5.7
8.4
7.7
6.6
0.9
2.3
9.3
1.2
8.3
0.8
5.7
5.7
7.6
Mean
egg
diameter
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Histology
Phase
SC/AS
.
.
SC/AS
SC/AS
.
.
.
.
.
.
.
.
.
.
.
.
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
DEV
SC/AS
SC/AS
SC/AS
Male
GE
DC
.
.
D
D
.
.
.
.
.
.
.
.
.
.
.
.
D
D
.
D
.
.
.
.
.
Age
3
3
3
3
2
3
3
5
3
4
3
3
3
3
3
3
3
.
2
5
4
2
.
.
3
4
Fec
.
3,170
3,470
.
.
1,530
6,970
5,350
2,970
6,590
2,180
6,860
5,670
3,430
9,210
5,630
7,890
.
.
5,680
.
4,240
.
3,760
4,080
4,350
Collection
Date
20061102
20061110
20061110
20061116
20061116
20061116
20061116
20061116
20061116
20061116
20061116
20061121
20061121
20061121
20061121
20061206
20061206
20061206
20061206
20061227
20061227
20061227
20061227
20061229
20061229
20070209
ID #
1599
1402
1403
1577
1578
1580
1581
1584
1585
1593
1594
1574
7777
1572
1571
1565
1562
1567
1566
1404
1405
1406
1407
1409
1408
1414
Total
Length
571
598
647
562
585
547
567
617
535
562
515
557
550
590
555
500
652
545
541
550
495
540
505
552
533
515
Girth
186
201
208
176
186
182
170
177
165
167
157
167
183
192
156
162
217
174
182
194
162
173
163
174
166
161
Weight
768.0
961.0
1,100.0
679.0
785.5
739.0
635.5
752.0
572.5
654.0
488.5
626.5
683.5
825.0
527.5
537.5
1,200.0
636.5
649.5
732.5
475.5
614.0
530.5
591.5
545.5
551.5
Sex
F
F
F
M
F
M
F
F
M
M
F
F
F
F
M
M
F
F
F
F
M
F
M
F
F
M
LGWt RGWt
42.10
28.42
84.06
37.46
60.50
43.20
4.63
5.28
50.33
45.98
12.26
8.16
39.43
25.24
13.97
6.23
6.01
5.04
5.52
7.62
18.82
15.17
16.05
8.76
41.47
23.56
23.06
10.66
1.41
1.89
3.38
2.64
60.36
45.64
36.24
27.77
39.57
25.57
41.78
21.31
2.93
2.42
36.38
37.36
6.03
2.75
30.17
10.90
14.28
24.39
3.02
5.73
GSI
9.2
12.6
9.4
1.5
12.3
2.8
10.2
2.7
1.9
2.0
7.0
4.0
9.5
4.1
0.6
1.1
8.8
10.1
10.0
8.6
1.1
12.0
1.7
6.9
7.1
1.6
Mean
egg
diameter
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Histology
Phase
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
.
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
Male
GE
.
.
.
D
.
D
.
.
D
D
.
.
.
.
D
D
.
.
.
.
D
.
D
.
.
D
Age
3
3
5
3
4
4
3
5
4
3
4
3
3
5
3
3
4
3
3
3
3
2
.
3
3
3
Fec
5,880
11,270
9,260
.
7,810
.
4,620
.
.
.
2,010
2,558
5,710
2,595
.
.
8,800
5,320
6,298
3,990
.
6,040
.
3,530
2,689
.
Collection
Date
20070209
20070209
20070209
20070209
20070209
20070209
20070209
20070209
20070209
20070209
20070209
20070209
20070209
20070209
20070209
20070209
20070209
20070209
20070209
20070209
20070209
20070209
20070209
20070209
20070209
20070219
ID #
1416
1415
1413
1412
1411
1410
1417
1418
1419
1420
1421
1422
1423
1424
1425
1100
1099
1098
1097
1096
1095
1094
1093
1092
1091
1146
Total
Length
545
510
510
475
585
480
545
535
535
480
550
515
545
670
595
570
525
495
535
515
550
485
585
555
520
503
Girth
184
157
161
162
206
159
175
190
178
157
169
184
171
222
185
174
167
161
190
171
175
168
173
175
165
145
Weight
744.5
463.5
476.5
435.0
1,050.0
486.0
712.0
777.5
525.5
433.0
607.0
690.0
600.0
1,300.0
792.5
710.5
521.5
488.5
698.0
576.5
639.0
528.0
742.0
684.5
526.0
446.5
Sex
M
M
M
M
M
M
M
M
M
M
M
M
M
F
F
M
M
M
M
M
M
M
M
M
M
M
LGWt RGWt
2.72
6.23
3.56
3.30
3.76
4.38
2.45
2.04
13.26
10.21
4.00
4.59
8.99
9.61
6.94
7.40
2.69
2.38
3.55
2.60
3.63
3.05
11.71
13.28
5.63
4.12
66.00
50.04
65.45
39.76
6.28
3.42
3.90
5.36
4.70
5.33
11.94
8.22
6.58
5.15
5.85
4.59
5.76
6.43
5.88
4.83
4.91
3.94
7.34
6.55
1.50
1.62
GSI
1.2
1.5
1.7
1.0
2.2
1.8
2.6
1.8
1.0
1.4
1.1
3.6
1.6
8.9
13.3
1.4
1.8
2.1
2.9
2.0
1.6
2.3
1.4
1.3
2.6
0.7
Mean
egg
diameter
.
.
.
.
.
.
.
.
.
.
.
.
.
2.7
2.7
.
.
.
.
.
.
.
.
.
.
.
Histology
Phase
SC/AS
.
.
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
.
.
.
SC/AS
.
SC/AS
SC/AS
.
.
.
.
.
.
.
.
.
.
SC/AS
Male
GE
D
.
.
D
D
D
D
D
.
.
.
D
.
.
.
.
.
.
.
.
.
.
.
.
.
D
Age
4
2
3
2
4
3
3
3
3
2
3
3
3
5
3
3
3
2
3
3
3
2
4
3
2
3
Fec
.
.
.
.
.
.
.
.
.
.
.
.
.
8,480
8,090
.
.
.
.
.
.
.
.
.
.
.
Collection
Date
20070219
20070219
20070219
20070219
20070219
20070219
20070219
20070219
20070219
20070219
20070219
20070219
20070219
20070219
20070219
20070219
20070219
20070219
20070219
20070219
20070219
20070303
20070303
20070303
20070303
20070303
ID #
1140
1604
1614
1613
1143
1612
1605
1144
1610
1609
1606
1141
1603
1608
1145
1611
1602
1148
1607
1147
1142
1770
1968
1961
1951
1953
Total
Length
506
529
539
559
546
510
560
545
565
513
604
525
539
610
483
501
515
554
344
490
475
583
542
571
500
534
Girth
162
168
169
174
168
159
179
180
192
174
205
173
175
215
150
179
167
192
103
158
148
178
169
184
158
162
Weight
557.0
634.0
597.0
682.0
589.5
534.0
728.0
773.0
837.0
634.0
997.5
669.0
706.0
1,150.0
419.0
663.0
567.0
851.0
148.5
526.0
412.0
707.0
649.0
755.5
506.5
589.0
Sex
M
M
F
F
F
M
M
M
F
M
F
M
M
F
F
M
F
M
M
M
M
F
M
F
M
M
LGWt RGWt
4.03
4.55
6.66
6.14
2.17
1.22
22.25
16.53
15.59
12.02
3.33
2.83
9.11
7.72
11.73
11.90
56.76
44.81
5.21
8.80
76.42
41.52
7.87
5.65
12.88
9.47
136.90 79.93
4.94
4.62
7.78
7.72
14.09
12.84
8.84
10.90
0.77
0.66
5.58
4.25
2.31
2.45
34.06
11.91
7.95
5.36
44.26
34.51
5.01
5.30
8.25
4.83
GSI
1.5
2.0
0.6
5.7
4.7
1.2
2.3
3.1
12.1
2.2
11.8
2.0
3.2
18.9
2.3
2.3
4.7
2.3
1.0
1.9
1.2
6.5
2.1
10.4
2.0
2.2
Mean
egg
diameter
.
.
.
2.4
2.6
.
.
.
2.4
.
2.8
.
.
2.6
2.4
.
2.6
.
.
.
.
.
.
2.0
.
.
Histology
Phase
SC/AS
.
REGEN
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
.
.
SC/AS
SC/AS
.
SC/AS
.
SC/AS
.
.
SC/AS
SC/AS
.
SC/AS
.
Male
GE
D
.
.
.
.
D
D
D
.
D
.
.
.
.
.
.
.
.
D
.
.
.
D
.
D
.
Age
3
3
4
4
4
5
2
3
3
2
3
3
3
4
3
3
3
3
1
3
3
3
3
4
3
3
Fec
.
.
.
2,333
2,360
.
.
.
8,760
.
9,672
.
.
15,080
.
.
1,980
.
.
.
.
3,020
.
11,130
.
.
Collection
Date
20070303
20070303
20070303
20070303
20070303
20070303
20070303
20070303
20070303
20070303
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070310
ID #
1959
1796
1799
1956
1962
1958
1793
1798
1795
1794
1242
1207
1784
1221
1203
1215
1210
1217
1777
1224
1778
1222
1201
1783
1214
1213
Total
Length
559
551
560
545
605
551
633
656
575
559
535
485
525
510
540
525
580
580
530
580
515
535
505
520
550
515
Girth
167
178
185
171
200
179
200
209
201
176
175
160
185
157
166
158
186
175
165
191
173
169
167
169
175
163
Weight
687.0
731.5
810.5
717.0
982.0
717.0
930.0
1,100.0
963.0
707.0
630.5
503.0
729.5
534.5
638.5
533.5
761.5
679.0
604.5
791.5
642.5
585.0
546.0
584.5
662.5
562.5
Sex
M
M
M
M
F
M
F
F
F
F
F
M
M
M
M
M
F
F
M
M
M
F
M
M
F
M
LGWt RGWt
3.00
1.67
8.10
6.82
6.51
13.32
9.93
9.07
106.05 63.91
7.21
9.15
45.31
33.92
45.32
32.36
99.94
79.03
9.27
7.09
32.95
45.21
4.96
5.84
7.41
10.36
3.71
5.55
3.96
3.72
1.81
2.04
28.06
24.19
25.48
28.10
3.46
2.60
8.03
11.48
12.51
8.94
10.00
7.51
5.26
4.34
5.38
5.16
23.80
10.65
5.07
4.82
GSI
0.7
2.0
2.4
2.6
17.3
2.3
8.5
7.1
18.6
2.3
12.4
2.1
2.4
1.7
1.2
0.7
6.9
7.9
1.0
2.5
3.3
3.0
1.8
1.8
5.2
1.8
Mean
egg
diameter
.
.
.
.
2.6
.
2.6
2.7
2.9
.
2.6
.
.
.
.
.
2.8
2.5
.
.
.
2.5
.
.
2.5
.
Histology
Phase
SC/AS
.
SC/AS
.
.
.
.
SC/AS
SC/AS
DEV
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
.
SC/AS
SC/AS
.
.
.
SC/AS
.
.
.
.
Male
GE
D
.
D
.
.
.
.
.
.
.
.
D
D
D
D
.
.
.
.
.
.
.
.
.
.
.
Age
3
3
2
2
3
3
4
3
5
.
3
.
3
2
5
3
4
4
4
5
2
3
3
3
4
3
Fec
.
.
.
.
16,190
.
5,910
4,010
13,220
.
5,340
.
.
.
.
.
3,137
3,870
.
.
.
1,200
.
.
2,710
.
Collection
Date
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070310
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
ID #
1248
1789
1202
1204
1209
1206
1249
1781
1779
1788
1780
1782
1220
1218
1208
1776
1205
1790
1235
1226
1229
1488
1477
1481
1476
1326
Total
Length
485
505
535
515
550
520
540
500
531
500
539
523
541
515
513
517
550
570
580
550
515
515
525
565
570
533
Girth
165
157
182
160
182
180
180
164
161
155
176
175
173
177
167
175
190
191
183
172
165
167
163
175
180
160
Weight
516.0
534.5
650.0
573.5
721.0
647.0
613.5
578.5
548.5
502.5
647.0
603.5
639.0
576.0
565.5
591.5
784.0
838.5
769.0
707.5
602.5
619.5
573.0
659.0
829.0
559.5
Sex
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
F
F
M
M
F
F
M
F
LGWt RGWt
5.32
4.55
3.28
2.52
2.02
5.62
4.88
3.77
3.15
5.98
8.00
8.88
2.48
1.94
6.53
6.26
7.54
2.86
4.33
3.50
7.31
5.09
5.04
3.64
2.84
2.65
6.54
4.95
6.05
12.92
6.67
5.56
8.83
7.88
10.83
0.34
25.97
23.67
32.22
23.74
6.97
7.28
4.41
5.11
22.60
14.20
21.55
14.03
4.45
6.51
16.04
5.50
GSI
1.9
1.1
1.2
1.5
1.3
2.6
0.7
2.2
1.9
1.6
1.9
1.4
0.9
2.0
3.4
2.1
2.1
1.3
6.5
7.9
2.4
1.5
6.4
5.4
1.3
3.8
Mean
egg
diameter
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
2.7
2.7
.
.
2.5
2.6
.
2.7
Histology
Phase
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Male
GE
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Age
2
2
3
3
4
2
3
3
3
4
3
3
5
4
2
2
3
5
3
3
4
.
4
4
5
2
Fec
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
2,970
3,960
.
.
3,100
2,430
.
1,360
Collection
Date
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
ID #
1350
1348
1479
1496
1498
1347
1491
9999
1494
1495
1227
1236
1345
1232
1480
1478
1234
1487
1493
1492
1483
1237
1233
1497
1344
1482
Total
Length
530
510
575
570
560
550
505
575
552
567
530
550
510
522
525
540
560
497
600
595
520
530
535
615
575
610
Girth
184
165
198
180
178
170
158
191
172
165
175
165
170
173
172
180
179
175
204
194
172
160
169
206
188
191
Weight
735.0
602.0
850.0
767.0
662.5
637.0
490.5
895.0
618.0
633.0
645.5
651.0
569.5
620.0
624.0
768.0
690.5
663.0
995.0
884.5
612.5
573.5
623.5
1,000.0
792.0
916.0
Sex
M
M
F
M
M
F
F
F
M
F
M
M
M
M
M
M
F
M
F
F
M
F
M
F
F
F
LGWt RGWt
10.16
9.02
3.84
4.07
80.47
42.00
6.59
9.32
7.00
6.78
39.22
0.35
17.51
13.68
12.19
8.72
3.82
6.13
47.16
58.33
12.47
15.79
4.42
3.43
7.31
6.16
2.42
3.18
4.24
2.68
3.59
4.55
15.13
12.22
8.94
6.59
105.76 68.13
42.23
6.03
2.62
5.31
3.01
1.88
6.22
5.30
13.49
10.11
46.32
43.91
55.76
44.43
GSI
2.6
1.3
14.4
2.1
2.1
6.2
6.4
2.3
1.6
16.7
4.4
1.2
2.4
0.9
1.1
1.1
4.0
2.3
17.5
5.5
1.3
0.9
1.8
2.4
11.4
10.9
Mean
egg
diameter
.
.
2.8
.
.
2.7
2.5
.
.
2.6
.
.
.
.
.
.
2.7
.
2.5
2.6
.
.
.
2.7
2.7
2.5
Histology
Phase
.
SC/AS
SC/AS
.
SC/AS
SC/AS
SC/AS
.
SC/AS
.
.
.
.
.
.
.
.
.
.
.
.
REGEN
.
.
.
.
Male
GE
.
D
.
.
D
.
.
.
D
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Age
3
3
3
3
3
2
.
.
3
3
4
3
4
5
2
4
4
3
4
4
2
3
5
4
4
4
Fec
.
.
9,870
.
.
2,220
2,300
.
.
9,480
.
.
.
.
.
.
1,920
.
13,160
3,340
.
.
.
.
.
.
Collection
Date
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070323
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
ID #
1489
1240
1343
1485
1342
1484
1228
1490
1231
1238
1486
1239
1336
1329
1325
1470
1473
1474
1313
1308
1323
1309
1314
1303
1317
1319
Total
Length
530
527
510
497
635
515
520
572
557
515
517
535
510
485
495
577
575
577
620
530
530
565
545
665
530
595
Girth
182
178
160
175
202
171
164
197
182
172
171
150
164
159
170
180
175
178
194
170
175
182
179
233
169
186
Weight
717.5
685.5
544.0
606.5
1,500.0
603.5
607.0
874.0
744.5
618.0
626.0
590.0
569.5
451.0
581.5
760.5
660.0
729.5
927.0
609.0
667.0
729.5
699.5
1,525.0
589.5
833.5
Sex
M
M
M
M
F
M
M
F
F
M
M
M
M
F
M
F
M
F
F
M
M
F
M
F
F
F
LGWt RGWt
8.92
6.56
6.93
6.85
7.12
5.62
5.27
4.88
37.54
20.25
6.58
6.01
2.46
3.39
55.20
46.17
8.55
5.11
4.05
4.63
5.48
5.38
4.76
4.88
3.55
5.38
15.58
6.86
7.21
5.79
12.47
11.12
6.38
5.99
30.66
19.54
27.38
25.99
3.14
2.04
5.23
5.48
33.89
20.94
7.52
8.92
166.30 98.78
26.37
26.03
45.77
29.54
GSI
2.2
2.0
2.3
1.7
3.9
2.1
1.0
11.6
1.8
1.4
1.7
1.6
1.6
5.0
2.2
3.1
1.9
6.9
5.8
0.9
1.6
7.5
2.4
17.4
8.9
9.0
Mean
egg
diameter
.
.
.
.
2.8
.
.
2.9
2.5
.
.
.
.
2.5
.
2.5
.
2.6
2.7
.
.
2.5
.
2.8
2.6
2.6
Histology
Phase
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Male
GE
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Age
4
2
4
3
3
3
3
3
4
3
4
3
3
2
2
4
3
4
3
3
3
3
2
5
2
3
Fec
.
.
.
.
.
.
.
.
.
.
.
.
.
1,840
.
.
.
4,150
3,530
.
.
5,080
.
18,500
3,870
6,080
Collection
Date
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
20070329
ID #
1
1475
1310
1322
1307
1320
1312
1318
1315
1311
1316
1321
1304
1468
1301
1306
1305
1469
1302
1472
1471
1328
1330
1335
1334
1333
Total
Length
560
565
525
583
530
545
570
577
650
527
570
615
555
560
467
485
603
530
475
515
495
385
505
555
620
610
Girth
202
200
170
184
176
168
194
199
208
177
183
195
175
190
146
157
196
169
144
181
168
112
190
191
212
190
Weight
910.0
836.5
564.0
752.0
648.0
608.0
798.0
834.0
1,075.0
652.5
800.5
881.0
702.0
755.0
382.5
465.0
968.0
611.0
388.5
677.0
570.0
200.5
672.5
707.0
1,025.0
834.0
Sex
F
F
F
F
M
F
F
F
F
M
F
F
F
F
M
M
F
M
M
M
F
M
M
F
F
F
LGWt RGWt
134.91 88.21
82.43
66.04
16.25
11.50
42.71
25.53
8.77
10.52
23.63
17.12
50.51
37.84
48.62
32.29
8.98
7.47
6.58
7.69
20.85
17.98
33.49
25.88
35.29
32.28
66.36
36.90
1.67
1.54
4.30
1.21
58.21
46.75
3.38
2.00
3.07
2.44
10.14
6.96
38.56
35.40
0.74
0.78
9.27
10.01
35.63
22.65
148.41 107.15
24.42
35.00
GSI
24.5
17.7
4.9
9.1
3.0
6.7
11.1
9.7
1.5
2.2
4.9
6.7
9.6
13.7
0.8
1.2
10.8
0.9
1.4
2.5
13.0
0.8
2.9
8.2
24.9
7.1
Mean
egg
diameter
2.7
2.4
2.3
2.8
.
2.7
2.7
2.9
.
.
2.7
2.9
2.9
2.9
.
.
2.8
.
.
.
2.8
.
.
2.9
2.6
2.8
Histology
Phase
.
SC/AS
SC/AS
SC/AS
SC/AS
.
.
.
.
SC/AS
.
.
.
.
SC/AS
.
.
.
.
.
.
.
.
.
.
.
Male
GE
.
.
.
.
D
.
.
.
.
D
.
.
.
.
DC
.
.
.
.
.
.
.
.
.
.
.
Age
2
2
4
2
3
3
4
4
4
3
3
4
3
2
3
3
3
3
2
3
4
1
3
3
3
2
Fec
16,350
14,510
3,410
4,220
.
2,790
6,110
5,840
.
.
2,250
3,540
5,070
7,940
.
.
8,050
.
.
.
5,630
.
.
3,641
20,110
3,730
Collection
Date
20070329
20070412
20070412
20070412
20070412
20070412
20070412
20070412
20070412
20070412
20070412
20070412
20070412
20070412
20070412
20070412
20070412
20070412
20070412
20070412
20070412
20070412
20070412
20070412
20070412
20070418
ID #
1331
1459
1393
1458
1397
1454
1396
1460
1392
1385
1455
1398
1400
1462
1387
1399
1457
1394
1389
1390
1395
1388
1461
1456
1386
1980
Total
Length
585
615
557
570
555
542
492
680
715
550
585
583
570
425
615
592
520
555
615
540
535
630
430
598
595
555
Girth
194
223
182
223
184
166
164
234
217
174
193
180
184
128
211
195
172
175
200
169
165
222
129
222
202
167
Weight
877.0
1,300.0
711.5
1,175.0
752.5
592.5
560.0
1,500.0
1,375.0
642.5
863.0
726.0
781.5
249.5
1,125.0
867.5
642.5
657.5
976.0
581.5
589.0
1,300.0
298.5
1,175.0
933.0
607.5
Sex
F
F
M
F
M
F
M
F
F
M
M
F
M
M
F
F
M
F
F
F
M
F
M
F
F
M
LGWt RGWt
50.38
31.30
128.46 79.68
6.14
6.59
139.63 88.66
6.64
4.05
20.30
8.61
4.55
4.07
156.34 107.81
18.91
8.36
5.18
5.82
4.26
7.05
58.21
44.97
8.17
5.78
3.44
3.52
118.17 94.29
48.54
34.65
11.53
6.45
48.38
35.17
48.57
34.92
34.88
30.47
5.23
3.26
124.26 94.64
3.51
1.80
154.58 113.93
122.45 64.19
5.63
3.55
GSI
9.3
16.0
1.8
19.4
1.4
4.9
1.5
17.6
2.0
1.7
1.3
14.2
1.8
2.8
18.9
9.6
2.8
12.7
8.6
11.2
1.4
16.8
1.8
22.9
20.0
1.5
Mean
egg
diameter
2.9
2.8
.
2.9
.
2.9
.
2.6
2.7
.
.
2.6
.
.
2.5
2.9
.
.
2.6
2.8
.
2.6
.
2.6
2.5
.
Histology
Phase
.
.
.
.
.
.
.
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
.
.
.
.
.
.
.
.
.
.
.
.
SC/AS
Male
GE
.
.
.
.
.
.
.
.
.
D
DC
.
D
.
.
.
.
.
.
.
.
.
.
.
.
D
Age
4
4
3
4
5
2
3
4
4
4
3
4
4
2
4
4
3
4
4
3
2
4
2
4
3
4
Fec
6,060
13,680
.
15,220
.
1,740
.
21,350
.
.
.
8,360
.
.
17,060
5,750
.
.
5,930
4,090
.
15,440
.
20,430
17,070
.
Collection
Date
20070418
20070418
20070418
20070418
20070418
20070418
20070418
20070418
20070418
20070418
20070418
20070425
20070425
20070425
20070425
20070425
20070425
20070425
20070425
20070425
20070425
20070425
20070425
20070425
20070425
20070425
ID #
1981
1353
1355
1977
1354
1978
1979
1356
1976
1983
1982
1124
1050
1037
1043
1049
1123
1045
1047
1001
1042
1044
1122
1048
1002
1038
Total
Length
500
515
522
542
500
475
485
505
547
530
465
560
555
550
515
595
635
615
493
510
492
550
565
507
550
550
Girth
151
157
162
162
154
153
148
156
182
162
148
177
164
172
164
181
214
195
159
159
148
163
181
166
178
188
Weight
442.5
528.0
551.0
559.0
480.0
407.5
447.5
494.0
690.0
535.0
405.0
701.0
642.0
678.5
546.5
739.0
1,175.0
1,000.0
491.5
506.0
426.0
574.0
765.5
554.0
721.5
752.5
Sex
M
M
M
M
M
M
M
F
F
M
M
F
F
M
F
F
F
F
M
M
M
M
M
M
M
F
LGWt RGWt
3.78
4.13
3.57
4.01
3.03
3.16
3.51
3.26
4.11
4.17
2.89
2.66
4.01
3.19
25.60
14.27
86.41
53.15
4.88
5.01
4.74
3.41
22.26
17.36
30.93
23.64
5.97
4.87
18.50
16.30
40.34
27.93
60.94
33.70
47.90
35.51
8.42
1.47
3.96
3.44
4.45
3.39
4.22
3.55
5.86
6.88
3.45
3.36
5.36
4.88
99.94
58.15
GSI
1.8
1.4
1.1
1.2
1.7
1.4
1.6
8.1
20.2
1.8
2.0
5.7
8.5
1.6
6.4
9.2
8.1
8.3
2.0
1.5
1.8
1.4
1.7
1.2
1.4
21.0
Mean
egg
diameter
.
.
.
.
.
.
.
2.7
2.6
.
.
.
2.4
.
2.6
2.7
2.6
2.4
.
.
.
.
.
.
.
2.5
Histology
Phase
SC/AS
SC/AS
.
.
.
.
.
SC/AS
SC/AS
.
.
.
.
.
SC/AS
SC/AS
SC/AS
.
SC/AS
SC/AS
SC/AS
.
.
.
.
.
Male
GE
D
DC
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
D
D
D
.
.
.
.
.
Age
4
3
3
3
3
3
3
3
3
3
3
3
2
4
2
3
3
4
3
4
2
4
4
2
3
4
Fec
.
.
.
.
.
.
.
2,753
12,070
.
.
.
.
.
2,370
4,630
6,270
4,064
.
.
.
.
.
.
.
14,020
Collection
Date
20070425
20070425
20070425
20070425
20070425
20070502
20070502
20070502
20070502
20070502
20070502
20070502
20070502
20070502
20070502
20070502
20070519
20070519
20070519
20070519
20070519
20070519
20070519
20070519
20070519
20070519
ID #
1003
1004
1005
1040
1006
1020
1075
1072
1022
1071
1069
1074
1070
1073
1023
1021
1058
1057
1053
1056
2000
1060
1054
1051
1052
1055
Total
Length
580
520
570
500
520
497
602
590
585
527
605
590
515
606
507
540
465
540
540
525
535
515
540
605
660
585
Girth
176
165
176
162
153
148
179
198
186
162
194
189
161
202
153
154
144
171
178
172
157
158
162
190
206
180
Weight
762.0
565.5
719.5
512.5
523.0
458.5
766.0
915.5
825.5
538.0
919.0
827.0
536.0
982.5
496.0
525.5
395.5
613.5
672.0
590.5
521.5
493.5
574.5
864.5
1,075.0
765.5
Sex
M
M
M
M
M
M
F
F
F
F
F
F
F
F
M
M
M
F
F
F
F
M
M
F
F
F
LGWt RGWt
12.74
7.81
5.50
6.47
4.51
5.50
4.51
3.34
3.64
3.01
3.92
3.84
11.58
7.99
35.63
21.63
38.71
30.43
4.79
3.08
34.50
24.32
51.58
35.15
40.86
29.83
113.49 72.38
2.45
3.16
2.35
2.96
1.26
0.94
32.04
15.98
43.96
34.79
22.20
14.82
3.72
2.52
2.39
2.70
1.76
4.57
41.29
35.11
14.08
8.52
52.30
38.65
GSI
2.7
2.1
1.4
1.5
1.3
1.7
2.6
6.3
8.4
1.5
6.4
10.5
13.2
18.9
1.1
1.0
0.6
7.8
11.7
6.3
1.2
1.0
1.1
8.8
2.1
11.9
Mean
egg
diameter
.
.
.
.
.
.
.
2.6
2.6
.
2.5
2.5
2.5
2.6
.
.
.
2.6
2.5
2.5
.
.
.
2.6
.
2.6
Histology
Phase
.
.
.
.
.
.
REGEN
SC/AS
SC/AS
DEV
.
.
.
.
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
REGEN
SC/AS
SC/AS
SC/AS
REGEN
SC/AS
Male
GE
.
.
.
.
.
.
.
.
.
.
.
.
.
.
DC
D
DC
.
.
.
.
D
D
.
.
.
Age
4
3
3
2
3
2
3
3
3
3
3
3
4
3
3
3
2
3
3
3
3
3
3
3
4
4
Fec
.
.
.
.
.
.
.
4,250
4,680
.
6,830
5,509
5,570
13,140
.
.
.
3,610
5,840
2,380
.
.
.
5,160
.
.
Collection
Date
20070519
20070531
20070531
20070531
20070531
20070531
20070531
20070531
20070531
20070531
20070531
20070531
20070531
20070531
20070531
20070531
20070531
20070531
20070615
20070615
20070615
20070615
20070615
20070620
20070620
20070620
ID #
1999
1900
1699
1889
1698
1693
1899
1695
1894
1897
1890
1891
1892
1893
1697
1692
1696
1898
1688
1687
1686
1685
1684
1682
1680
1681
Total
Length
522
530
562
690
530
625
608
535
513
645
522
517
630
520
503
508
550
503
475
633
575
578
503
352
473
598
Girth
164
153
177
225
163
190
201
178
158
191
157
164
200
155
158
150
166
160
145
207
188
200
153
107
147
206
Weight
539.0
514.0
751.5
1,425.0
642.0
895.5
984.0
676.5
501.0
965.0
517.5
544.5
985.0
484.5
524.5
450.0
605.0
496.5
405.0
1,075.0
817.0
893.5
470.0
165.0
435.0
995.0
Sex
M
M
M
F
M
F
F
M
M
F
F
M
F
M
M
M
F
M
M
F
F
F
F
M
M
F
LGWt RGWt
1.94
0.86
2.56
1.54
2.58
2.83
58.58
71.90
1.73
3.05
41.31
32.36
71.81
52.48
2.27
2.24
1.62
2.15
50.79
33.68
29.36
23.02
1.77
2.27
65.86
41.21
1.99
1.69
2.00
2.35
3.07
1.20
4.09
3.23
3.03
1.77
0.83
0.82
116.15 80.39
10.05
5.41
59.10
30.58
13.94
14.27
0.27
0.23
1.68
1.58
98.83
70.81
GSI
0.5
0.8
0.7
9.2
0.7
8.2
12.6
0.7
0.8
8.8
10.1
0.7
10.9
0.8
0.8
0.9
1.2
1.0
0.4
18.3
1.9
10.0
6.0
0.3
0.7
17.0
Mean
egg
diameter
.
.
.
.
.
2.6
2.7
.
.
2.5
2.4
.
2.5
.
.
.
.
.
.
2.6
.
2.8
2.7
.
.
2.7
Histology
Phase
SC/AS
.
.
.
.
SC/AS
.
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
.
SC/AS
.
.
REGEN
.
SC/AS
SC/AS
DEV
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
Male
GE
DC
.
.
.
.
.
.
D
D
.
.
DC
.
DC
.
.
.
.
DC
.
.
.
.
D
D
.
Age
2
4
5
4
4
3
5
4
2
4
2
3
3
3
3
2
2
3
3
4
3
4
3
1
3
3
Fec
.
.
.
.
.
3,970
.
.
.
.
3,640
.
7,096
.
.
.
.
.
.
14,180
.
5,340
.
.
.
.
Collection
Date
20070620
20070630
20070630
20070630
20070630
20070712
20070712
20070712
20070712
20070712
20070712
20070712
20070712
20070712
20070712
20070725
20070725
20070725
20070725
20070809
20070809
20070809
20070809
20070809
20070809
20070809
ID #
1683
1679
1678
1677
1676
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1264
1262
1263
1261
1271
1268
1269
1272
1270
1274
1273
Total
Length
660
562
585
597
568
490
496
502
535
630
510
507
550
607
520
531
545
484
508
570
492
500
500
517
680
558
Girth
208
186
188
190
174
156
163
162
164
210
161
163
173
208
177
160
170
157
154
186
158
158
167
158
229
182
Weight
1,120.0
791.0
911.5
861.0
693.0
495.0
549.5
522.0
602.5
1,125.0
532.0
575.5
683.0
1,001.0
638.0
577.5
620.0
444.5
484.0
752.5
475.0
524.0
542.5
526.0
1,425.0
757.0
Sex
F
F
F
F
F
F
M
M
M
F
M
M
F
F
F
M
F
F
M
F
M
M
M
F
F
M
LGWt RGWt
26.57
23.27
10.43
14.86
7.51
8.26
25.56
22.54
4.11
2.97
5.65
4.01
1.80
1.37
0.90
0.51
0.88
0.71
15.32
9.42
0.53
0.55
0.73
0.86
10.46
6.58
54.32
36.40
25.94
27.28
1.22
1.14
18.59
14.43
11.73
7.32
0.78
0.55
13.89
8.43
0.88
0.50
1.27
0.92
1.31
0.85
6.70
5.01
24.97
14.98
1.73
0.78
GSI
4.5
3.2
1.7
5.6
1.0
2.0
0.6
0.3
0.3
2.2
0.2
0.3
2.5
9.1
8.3
0.4
5.3
4.3
0.3
3.0
0.3
0.4
0.4
2.2
2.8
0.3
Mean
egg
diameter
2.8
.
.
2.4
.
.
.
.
.
.
.
.
.
2.5
2.5
.
1.9
1.9
.
1.9
.
.
.
.
1.9
.
Histology
Phase
SC/AS
SC/AS
SC/AS
SC/AS
DEV
.
.
.
.
.
SC/AS
SC/AS
.
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
DEV
SC/AS
SC/AS
Male
GE
.
.
.
.
.
.
.
.
.
.
DC
DC
.
.
.
D
.
.
DC
.
DC
D
D
.
.
DC
Age
3
3
4
3
2
3
3
3
4
4
3
3
3
5
4
3
4
3
2
4
5
3
3
2
5
.
Fec
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Collection
Date
20070809
20070816
20070816
20070816
20070831
20070831
20070831
20070831
20070831
20070831
20070831
20070831
20070831
20070916
20070916
20070916
20070916
20070916
20070916
20070926
20070926
20070926
20070926
20070926
20070926
20070926
ID #
1275
1653
1651
1652
2875
2874
2873
2950
2949
2948
2947
2946
2945
2787
2782
2783
2786
2784
2785
2797
2846
2841
2800
2842
2799
2848
Total
Length
543
607
606
498
410
412
522
505
660
635
522
530
615
630
550
507
545
528
511
472
606
575
501
541
497
530
Girth
179
194
209
158
120
115
172
150
215
185
163
181
204
197
171
157
180
177
162
157
198
188
161
169
154
165
Weight
719.5
903.0
1,075.0
497.0
217.5
212.5
596.5
454.5
1,175.0
842.0
495.5
640.5
990.0
1,050.0
635.5
509.5
673.0
623.0
530.5
458.0
943.0
828.5
493.5
582.5
441.0
583.5
Sex
M
F
F
F
F
F
M
F
F
F
F
F
F
F
M
M
F
F
F
M
F
F
M
F
F
F
LGWt RGWt
2.31
1.86
36.82
28.66
27.85
16.43
7.71
3.82
1.09
0.81
1.08
0.81
0.79
0.85
15.83
14.67
57.98
33.65
21.63
18.05
18.62
12.88
35.69
24.39
33.69
17.42
36.90
25.88
5.26
7.19
2.73
2.15
27.88
19.10
35.86
22.38
27.42
15.27
4.40
3.56
66.95
31.46
51.29
37.68
3.73
3.86
23.58
12.23
17.64
14.73
30.67
21.95
GSI
0.6
7.3
4.1
2.3
0.9
0.9
0.3
6.7
7.8
4.7
6.4
9.4
5.2
6.0
2.0
1.0
7.0
9.3
8.0
1.7
10.4
10.7
1.5
6.1
7.3
9.0
Mean
egg
diameter
.
2.5
2.6
.
.
.
.
1.7
1.6
1.5
2.2
1.9
1.5
2.1
.
.
2.1
2.0
1.8
.
2.5
2.1
.
1.9
1.9
2.2
Histology
Phase
SC/AS
SC/AS
SC/AS
DEV
DEV
DEV
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
.
SC/AS
SC/AS
SC/AS
SC/AS
Male
GE
D
.
.
.
.
.
D
.
.
.
.
.
.
.
DC
DC
.
.
.
DC
.
.
C
.
.
.
Age
4
5
5
3
2
2
3
3
4
4
3
3
4
4
3
3
4
3
3
2
4
3
3
3
2
2
Fec
.
.
.
.
.
.
.
5,600
.
5,290
.
.
.
8,050
.
.
5,030
7,190
.
.
11,407
12,860
.
.
4,070
6,829
Collection
Date
20070926
20070926
20070926
20070926
20070926
20070926
20070926
ID #
2847
2843
2850
2844
2845
2798
2849
Total
Length
555
527
591
488
578
553
457
Girth
183
180
190
158
184
174
145
Weight
722.0
678.0
824.0
497.0
799.0
691.0
400.0
Sex
F
M
F
M
M
F
M
LGWt RGWt
35.35
35.51
6.88
5.16
65.53
25.99
2.89
2.48
12.30
0.00
46.04
28.02
4.09
3.92
GSI
9.8
1.8
11.1
1.1
1.5
10.7
2.0
Mean
egg
diameter
2.2
.
2.3
.
.
2.0
.
Histology
Phase
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
SC/AS
Male
GE
.
DC
.
DC
DC
.
DC
Age
3
2
4
2
4
3
2
Fec
9,120
.
9,640
.
.
.
.
BIOGRAPHICAL SKETCH
Olivia Alpha Smith was born on 15 August 1984, in Morgan City, Louisiana. After
graduating as one of the valedictorians from Berwick High School in Berwick, Louisiana, in
2002, Olivia attended Nicholls State University. During her undergraduate studies, Olivia
worked with induced spawning and laboratory care of spotted gar and bowfin in the Bayousphere
Research Laboratory. Olivia graduated magna cum laude and with honors from Nicholls State
University in May of 2006 with a B. S. in Biology with a concentration in Marine Biology and a
minor in Chemistry. In June of 2006, Olivia enrolled in the graduate program in Marine and
Environmental Biology at Nicholls State University. Olivia conducted research on gonad
histology and life history of spotted gar Lepisosteus oculatus in the upper Barataria Estuary,
Louisiana. Olivia assisted with research on zebra mussels Dreissena polymorpha in Bayou
Lafourche, Louisiana, and gonad histology of alligator gar Atractosteus spatula from the lower
Terrebonne Estuary, Louisiana. While at Nicholls State University, Olivia was a teaching
assistant for two freshmen biology laboratories and was President of Biology Society, a student
organization. During her undergraduate and graduate degrees at Nicholls State University,
Olivia participated in study abroad programs in the Solomon Islands, England, and Costa Rica.
After graduation in the Spring of 2008, Olivia will either continue her education in a doctorate
program or seek employment as a biologist.
98
CURRICULUM VITAE
Olivia Alpha Smith
Graduate Student
Nicholls State University
1833 HWY 182 E.
Morgan City, LA 70380
(985) 518-4318
SmitO905@its.nicholls.edu
EDUCATION
M. S. Marine and Environmental Biology. May 2008. Nicholls State University, Thibodaux,
Louisiana, 70310. Thesis title: Reproductive potential and life history of spotted gar
Lepisosteus oculatus in the upper Barataria Estuary, Louisiana. GPA: 4.000. Hours
earned: 38.00.
B. S. Biology with a concentration in Marine Biology and a minor in Chemistry. May 2006.
Graduated magna cum laude and with Honors. Nicholls State University, Thibodaux,
Louisiana, 70310. GPA: 3.804. Hours earned: 157.00.
TEACHING EXPERIENCE
August 2006 - May 2008: Taught introductory freshmen biology laboratories at Nicholls State
University that surveyed basic biological processes and the plant and animal kingdoms.
December 2006: Teaching assistant to Dr. Allyse Ferrara for Nicholls State University Honors
Biology course in Costa Rica.
August 2005 - May 2006: Assisted with introductory freshmen biology laboratory at Nicholls
State University that surveyed the plant and animal kingdoms.
RESEARCH EXPERIENCE
August 2006 - May 2008: Reproductive potential and life history of spotted gar Lepisosteus
oculatus in the upper Barataria Estuary, Louisiana.
99
June 2007 - May 2008: Zebra mussel Dreissena polymorpha survey of Bayou Lafourche,
Louisiana.
April 2007 - February 2008: Histological examination of alligator gar Atractosteus spatula
gonads from the lower Terrebonne Estuary, Louisiana.
January 2006 - May 2006: An exploratory study on the impacts of three prominent
contaminants on crustaceans in South Louisiana.
May 2005 - March 2006: Nitrite and ammonia LC50’s for small juvenile spotted gar
Lepisosteus oculatus.
June 2004 - August 2004: The effects of increased nutrient supply on phytoplankton in the
Barataria Estuary, Louisiana.
EMPLOYMENT
June 2007 - May 2008: Graduate Research Assistant, Nicholls State University, Department of
Biological Sciences. Assisted in a zebra mussel survey of Bayou Lafourche and in a study on the
spawning and life history of alligator gar.
August 2005 - May 2008: Graduate Teaching Assistant, Nicholls State University, Department
of Biological Sciences. Taught introductory freshmen biology laboratories that surveyed the
plant and animal kingdoms.
January 2005 - May 2006: Undergraduate Laboratory Assistant, Nicholls State University,
Department of Biological Sciences. Assisted in the care and maintenance of spotted gar,
alligator gar, bowfin, and paddlefish and water quality monitoring and maintenance.
SCIENTIFIC PRESENTATIONS
2008 Smith, O. A., A. M. Ferrara, Q. C. Fontenot, and G. J. LaFleur, Jr. Reproductive potential
of spotted gar Lepisosteus oculatus in the upper Barataria Estuary, Louisiana. 17 April
2008. Research Week Poster Competition, Nicholls State University, Thibodaux,
Louisiana (poster presentation).
2008 Smith, O. A., A. M. Ferrara, Q. C. Fontenot, and G. J. LaFleur, Jr. Preliminary
assessment of reproductive potential of spotted gar Lepisosteus oculatus in the upper
Barataria Estuary, Louisiana. 14 March 2008. 82nd Annual Meeting of the Louisiana
Academy of Sciences, Natchitoches, Louisiana.
100
2008 Smith, O. A., A. M. Ferrara, Q. C. Fontenot, and G. J. LaFleur, Jr. Preliminary
assessment of reproductive potential of spotted gar Lepisosteus oculatus in the upper
Barataria Estuary, Louisiana. 7 March 2008. Meeting of the Coastal Restoration and
Enhancement through Science and Technology (CREST), New Orleans, Louisiana.
2008 Smith, O. A., A. M. Ferrara, Q. C. Fontenot, and G. J. LaFleur, Jr. Preliminary
assessment of reproductive potential of spotted gar Lepisosteus oculatus in the upper
Barataria Estuary, Louisiana. 1 March 2008. 16th Annual Meeting of the Southern
Division of the American Fisheries Society, Wheeling, West Virginia.
2008 Fontenot, Q. C., A. M. Ferrara, J. G. Davis, M. D. Dantin, J. F. Fontenot, S. M. Jackson,
M. S. Estay, and O. A. Smith. Initial fisheries investigations of a hydrologically altered
large river floodplain. 1 March 2008. 16th Annual Meeting of the Southern Division of
the American Fisheries Society, Wheeling, West Virginia.
2008 Smith, O. A., A. M. Ferrara, Q. C. Fontenot, and G. J. LaFleur, Jr. Histological
examination of alligator gar Atractosteus spatula gonads from the lower Terrebonne
Estuary, Louisiana. 22 February 2008. 3rd Annual Meeting of the Alligator Gar Working
Group, Thibodaux, Louisiana (invited presentation).
2008 Smith, O. A., A. M. Ferrara, Q. C. Fontenot, and G. J. LaFleur, Jr. Preliminary
assessment of reproductive potential of spotted gar Lepisosteus oculatus in the upper
Barataria Estuary, Louisiana. 31 January 2008. 29th Annual Meeting of the Louisiana
Chapter of the American Fisheries Society, Baton Rouge, Louisiana.
2007 Smith, O. A., A. M. Ferrara, Q. C. Fontenot, and G. J. LaFleur, Jr. Assessment of life
history characteristics of spotted gar Lepisosteus oculatus in the upper Barataria Estuary,
Louisiana. 22 September 2007. Annual Calypseaux Expedition of the Department of
Biological Sciences of Nicholls State University, Louisiana Universities Marine
Consortium (LUMCON), Cocodrie, Louisiana.
2007 Fontenot, Q. C., A. M. Ferrara, M. D. Dantin, J. F. Fontenot, O. A. Smith, S. M. Jackson,
and J. G. Davis. Hypoxia in the swamp. Grand Isle Dead Zone Conference, Grand Isle,
Louisiana (invited presentation).
2007 Dantin, M. D., O. A. Smith, A. M. Ferrara, and G. J. LaFleur, Jr. Nicholls State
University Biology Society integrates students into real biology. 1 February 2007. 28th
Annual Meeting of the Louisiana Chapter of the American Fisheries Society, Thibodaux,
Louisiana (poster presentation).
2006 Smith, O. A., and E. Zou. An exploratory study on the impacts of three prominent
contaminants on crustaceans in south Louisiana. 11 April 2006. Annual Honors
Program Research Symposium, Nicholls State University, Thibodaux, Louisiana.
101
INTERNSHIPS
April 2007 - November 2007: Commercial Alligator Gar Fishery in Terrebonne Parish,
Louisiana. Supervisor: Mr. Rickey Verrett, Commerial Alligator Gar Fisherman. Duties: set
and retrieved jug lines, cleaned fish, and recorded total length, girth, weight, age, and
reproductive data on collected fish.
September 2006 - November 2006: Bayou Lafourche Fresh Water District, Thibodaux,
Louisiana. Supervisor: Mr. Archie P. Chaisson, Jr., Director. Duties: removed aquatic invasive
plant species from Bayou Lafourche and assisted with maintenance of salt water control
structure.
June 2004 - August 2004: Louisiana Universities Marine Consortium (LUMCON), Cocodrie,
Louisiana. Supervisor: Dr. Nancy N. Rabalais, Executive Director. Duties: conducted research
on the effects of increased nutrient supply on phytoplankton in the Barataria Basin, Louisiana.
July 2003 - August 2003: USGS National Wetlands Research Center, Lafayette, Louisiana.
Supervisor: Dr. Thomas C. Michot, Research Biologist.
SKILLS
Boat and trailer operation, pirogue operation, gill net sampling, seine sampling, water quality
monitoring (pH, dissolved oxygen, temperature, specific conductance, salinity, Secchi disk
depth, ammonia, and nitrite), larval fish traps, fish identification, fish otolith removal, and fish
otolith aging. Software skills: Microsoft Word, Microsoft Excel, Microsoft Power Point, FAST,
SAS, and some experience with ArcGIS.
LABORATORY EXPERIENCE
Care and maintenance of live fish, induced spawning of spotted gar, larvae rearing, water quality
monitoring and maintenance, and spectrophotometry.
HONORS AND AWARDS
2008 The Catina Brandt Outstanding Graduate Student in Marine and Environmental Biology.
Department of Biological Sciences, Nicholls State University.
2008 1st Place Graduate Student Research Poster Competition, Nicholls State University.
2008 Overall Graduate Student Award, Research Week Committee, Nicholls State University.
102
2008 2nd Place Student Presentation. 29th Annual Meeting of the Louisiana Chapter of the
American Fisheries Society.
2007 R. H. “Dickie” and Charlene Barker Excellence in Marine and Environmental Biology
Endowed Scholarship.
2006 Coastal Restoration and Enhancement through Science and Technology (CREST) Grant.
2006 Dr. Burt Wilson Biology Honors Award. Department of Biological Sciences. Nicholls
State University.
2006 Senior Achievement Award. Department of Biological Sciences. Nicholls State
University.
2006 Motivatit Outstanding Marine Biology Major Award. Department of Biological Sciences.
Nicholls State University.
2006 Dr. Richard Morvant, Sr., Outstanding Biology Major Award. Department of Biological
Sciences. Nicholls State University.
2006 Completion of the Honors Program at Nicholls State University.
2006 Phi Kappa Phi Honor Society Inductee. Nicholls State University Chapter.
2006 National Marine Fisheries Service and Virginia Tech’s Marine Resources Population
Dynamics Workshop.
2005 Dr. James G. Ragan Marine Biology Service Award. Department of Biological Sciences.
Nicholls State University.
2005 University of California at Santa Barbara Pacific Islands Field Training Program in
Solomon Islands (funded by National Science Foundation).
2004 Nicholls State University’s Honors Study Abroad Program in Plymouth, England.
2002 Alpha Lambda Delta Freshman Honor Society Inductee. Nicholls State University
Chapter.
2002 Academic Excellence Scholarship. Nicholls State University.
2002 Valedictorian Scholarship. Nicholls State University.
103
MEMBERSHIP AND SERVICES
Louisiana Chapter of the American Fisheries Society (EXCOM Committee Member)
Parent Society of the American Fisheries Society
International Network for Lepisosteid Fish Research and Management
Lepisosteid Research and Management Committee
World Aquaculture Society
Phi Kappa Phi
Nicholls State University Biology Society—President (January 2007-December 2007)
104