SEASONAL FISH ASSEMBLAGES OF BAYOU LAFOURCHE
UPSTREAM AND DOWNSTREAM OF THE
THIBODAUX WEIR
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
Heather Pace Dyer
Bachelor of Science, University of Louisiana at Lafayette, 2005
Fall 2007
CERTIFICATE
This is to certify that the thesis entitled “Seasonal Fish Assemblages of Bayou
Lafourche Upstream and Downstream of the Thibodaux Weir” submitted for the award of
Master of Science to the Nicholls State University is a record of authentic, original
research conducted by Ms. Heather Pace Dyer 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
David Schultz, Ph.D.
Associate Professor of
Biological Sciences
Committee Member
SIGNATURE:
DATE:
________________________
_________________
________________________
_________________
_______________________
_________________
i
ABSTRACT
Bayou Lafourche in southeastern Louisiana flows 172.2 km through the heart of
the Barataria-Terrebonne National Estuary System (BTES) from the Mississippi River to
the Gulf of Mexico. In 1904, Bayou Lafourche was disconnected from the Mississippi
River by the construction of a permanent levee in Donaldsonville. The hydrology of
Bayou Lafourche was permanently altered by this event and became principally driven by
local precipitation. In 1955, the Walter Lemann Pump Station was installed in
Donaldsonville to alleviate water quality problems in Bayou Lafourche such as
stagnation and saltwater intrusion. In 1969, a weir was installed in Thibodaux to help
regulate upstream water levels and to ensure an adequate drinking water supply for the
surrounding parishes.
Bayou Lafourche historically served as a conveyance system for freshwater and
nutrients from the Mississippi River to the marshes of lower Lafourche and Terrebonne
Parishes. Due to hydrologic modification, Bayou Lafourche no longer serves in this
capacity. In 1996, the Mississippi River Reintroduction into Bayou Lafourche project
was proposed, which suggested that Bayou Lafourche could effectively transport
freshwater, sediments and nutrients to approximately 489 km2 of fresh marsh, brackish
marsh, and salt marsh located in lower Barataria and Terrebonne Parishes. The major
components of this project included dredging Bayou Lafourche from Donaldsonville to
Thibodaux, increasing flow from 5.6 m3s-1 to 28.3 m3s-1, and removal of the Thibodaux
weir.
The effects of the proposed hydrologic changes to Bayou Lafourche are unclear
and few published studies examined the fish fauna of Bayou Lafourche. Specific
ii
objectives of this study were to estimate seasonal abundance, diversity, and distribution
of the adult fish assemblages of Bayou Lafourche and to predict possible effects that
removal of the weir may have on the fish community of Bayou Lafourche.
We collected fishes from fifteen sites located upstream and downstream of the
Thibodaux weir from 09 February 2006 to 05 October 2007, using monofilament gill nets
and electrofishing. A total of 5,503 fishes representing 50 species from 16 families were
collected. There were no seasonal differences in overall fish abundance or diversity
between upstream and downstream sites. There were differences in species composition
in samples collected upstream and downstream of the weir. We collected four species
downstream of the weir, including estuarine species, that were not collected upstream of
the weir. We collected eight species upstream of the weir that were not collected
downstream of the weir. Centrarchidae comprised over 70% of the electrofishing
samples. Hierarchical clustering analysis of electrofishing data separated upstream and
downstream communities for all seasons.
The data gathered in this study should be useful in the assessment of the Bayou
Lafourche fish community following the proposed removal of the Thibodaux weir.
Currently, the weir does not appear to affect the diversity or abundance of fishes
inhabiting the surrounding areas. However, the weir does serve as a physical barrier to
the upstream and downstream movement of fishes. If the weir is removed the fish
community will benefit from increased habitat and resource availability.
iii
ACKNOWLEDGEMENTS
I would like to thank my committee members Dr. Allyse Ferrara, Dr. Quenton
Fontenot, and Dr. David Schultz for giving their time to help with my research and for
reviewing my thesis. I would like to thank the many graduate students who helped in the
field and laboratory throughout this study. I especially thank Olivia Smith, Clint Troxler,
and Sean Jackson who helped in the field countless times and devoted many hours in the
laboratory cutting up fish and taking data. I would like to thank Dr. Earl Melancon for
his continuous encouragement and support during my time here in graduate school. I
would like to thank Mr. Archie Chaisson of the Bayou Lafourche Fresh Water District
who patiently answered all my questions regarding Bayou Lafourche.
I would like to thank my husband, Steve Dyer, who has supported me in all my
endeavors and believed in my abilities without fail for many years. I would like to thank
my family, Ron and Valerie Pace, Shannon Wojciechowski, and Kelley Pace for their
encouragement throughout all my adventures.
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……………………………………………………………………………...12
RESULTS…………………………………………………………………………….....22
DISCUSSION…………………………………………………………………………...56
LITERATURE CITED……………………………………………………………….....73
APPENDIX I…………………………………………………………………………….81
APPENDIX II…………………………………………………………………………...82
APPENDIX III…………………………………………………………………………..98
BIOGRAPHICAL SKETCH…………………………………………………………...100
CURRICULUM VITAE………………………………………………………………..101
v
LIST OF FIGURES
Figure 1.
Bayou Lafourche extends 172.2 km from the Mississippi River to the
Gulf of Mexico creating the border between the Barataria Estuary
and the Terrebonne Estuary……………………………….................2
Figure 2.
Map of the study area located between Donaldsonville, LA and
Raceland, LA. Donaldsonville sites were located at approximately
river km one. All other sampling sites were located between north
Thibodaux (river km 40.6, US-6 site) and Raceland (river km 76,
DS-4 site)..………………………………………………………….9
Figure 3.
The weir located in Thibodaux, LA at river km 55 (29°47'55.42"N,
90°49'12.92"W). Photo was taken on 04 October 2007, from the
southeast bank of Bayou Lafourche………………………………..11
Figure 4.
Map of sampling sites located between Donaldsonville, LA, and
Raceland, LA. GPS coordinates, river kilometers and sampling dates
are listed for each site in Table 1. Individual site codes are defined in
Appendix II. ……………………………………………………….13
Figure 5.
Mean (±SD) seasonal monofilament gill net CPUE at JLC for all
seasons sampled from 09 February 2006 to 30 July 2007. Means with
the same letter indicate no difference. No fish were collected
WIN07……………………………...…...….……………………....29
Figure 6.
Mean (+SD) seasonal monofilament gill net CPUE at the primary
downstream site NSU for all seasons sampled from 09 February 2006
to 30 July 2007. There were no differences among seasons at the
NSU site……….….………………………………………………...30
Figure 7.
Summer 2006 monofilament gill net CPUE for sites JLC, NSU, and
DON. The CPUE at the DON site was higher than the JLC and NSU
sites (ANOVA, overall p = 0.0006). Means with the same letter
indicate no difference.……….……………………………………..31
Figure 8.
Margalef’s index of species richness (d) per season for samples
collected from primary sites JLC and NSU from 09 February 2006 to
30 July 2007, using monofilament gill nets…..….…………………34
Figure 9.
Pielou’s Evenness Index (J’) for samples collected from sites JLC
and NSU from 09 February 2006 to 30 July 2007, using
monofilament gill nets...…………………………....……………....35
vi
Figure 10.
Simpson’s index of diversity for samples collected at the JLC and
NSU sites from 09 February 2006 to 30 July 2007, using
monofilament gill nets……………………………………………...36
Figure 11.
Dendrogram for hierarchical clustering (group average linking) using
the Bray-Curtis similarity matrix (y-axis) for samples collected using
monofilament gill nets from 09 February 2006 to 30 July 2007. Xaxis abbreviations are as follows: WIN06US = winter 2006 upstream,
SUM07US = summer 2007 upstream, WIN07US = winter 2007
upstream, WIN07DS = winter 2007 downstream, WIN06DS = winter
2006 downstream, FAL06US = fall 2006 upstream, SPR07US =
spring 2007 upstream, SPR07DS = spring 2007 downstream,
SPR06DS = spring 2006 downstream, SUM06DS = summer 2006
downstream, FAL06DS = fall 2006 downstream, SUM07DS =
summer 2007 downstream, SPR06US = spring 2006 upstream,
SUM06US = summer 2006
upstream…………………………………………………………….37
Figure 12.
Centrarchids collected using electrofishing at the Donaldsonville,
upstream, and downstream sites. The family comprised more than
70% of the total abundance at each site…..………………………..40
Figure 13.
Seasonal diversity (Simpson’s index of diversity) and CPUE for
samples collected at the Donaldsonville site using electrofishing on
09 May 2007, 30 August 2007, and 05 October 2007. Number of
fishes collected in each sample is indicated by N…….……………42
Figure 14.
Mean (±SD) CPUE (number fishes per minute of electrofishing) per
season for samples collected using electrofishing at the upstream and
downstream sites from 22 March 2007 to 04 October 2007. There
was no difference in CPUE at upstream or downstream sites during
the three seasons sampled.………………………………………….43
Figure 15.
Dendrogram for hierarchical clustering (group average linking) using
the Bray-Curtis similarity matrix (y-axis) for samples collected from
upstream and downstream sites using electrofishing from 22 March
2007 to 04 October 2007. ……………………...………………….47
Figure 16.
Dendrogram for hierarchical clustering (group average linking) using
the Bray-Curtis similarity matrix (y-axis) for samples collected from
the Donaldsonville site using electrofishing on 09 May 2007, 30
August 2007, and 05 October 2007………………………………...48
vii
Figure 17.
Water temperature (°C) seasonal mean (±SD) for the JLC and NSU
sites from 09 February 2006 to 04 October 2007…………………..49
Figure 18.
Mean seasonal (±SD) dissolved oxygen (mg/L) for the JLC and NSU
sites from 09 February 2006 to 04 October 2007. The dissolved
oxygen at the NSU site was higher than the JLC site during the fall
2007 (t-test, p = 0.0009). The dashed line indicates hypoxic level of
2.0 mg/L. Asterisk indicates significance….………………………50
Figure 19.
Dissolved oxygen (mg/L) at the primary sites, JLC and NSU, from
09 February 2006 to 04 October 2007. Dissolved oxygen levels fell
below the hypoxic level of 2.0 mg/L (dashed line) on four dates at
the JLC site and one date at the NSU site. There were no differences
between JLC and NSU sites.…………………….………………....52
Figure 20.
Seasonal mean (±SD) Secchi disc depth for the JLC and NSU sites
from 09 February 2006 to 04 October 2007. The JLC site had higher
secchi depth than NSU during fall 2006 (p = 0.001)……………….53
Figure 21.
The aquatic macrophyte hydrilla Hydrilla verticillata was abundant
during the summer and fall of 2006. The water at the site was clear
with visibility reaching > 200 cm, which is the bottom of Bayou
Lafourche………………………………..………………………….54
Figure 22.
Specific conductance (µS cm-1) at the JLC and NSU sites from 09
February 2006 to 04 October 2007……………………….………...55
Figure 23.
Alabama shad Alosa alabamae (TL = 428 mm, weight = 795 g)
collected using a 25 m long x 1.8 m deep monofilament gill net with
25.4 mm and 38 mm experimental bar mesh. The fish was collected
on 17 March 2006, at the NSU site located downstream of the
Thibodaux weir. The fish had severe lacerations suggesting that it
passed through the Donaldsonville pump station turbine and over the
Thibodaux weir. Positive identification of the fish was made by
counting the gill rakers (photo insert), measuring body depth and by
the presence of a small notch at the tip
of the upper jaw (Ross 2002)……………………………………….58
Figure 24.
Eight species were collected upstream but not downstream of the
weir (top). Four species were collected downstream but not upstream
of the weir (bottom). Fishes were collected between 09 February
2006 and 05 October 2007 using monofilament gill nets and
electrofishing……………………………………………………….60
viii
Figure 25.
Approximately 15 cm of rainfall caused the overtopping of the
Thibodaux weir on 22 October 2007. This type of high water event
occurs approximately twice per year (A. Chaisson, BLFWD personal
communication)……………………………………………………71
ix
LIST OF TABLES
Table 1.
Study site location and number of samples collected from 09 February
2006 to 05 October 2007, using monofilament gill nets and/or two pass
boat electrofishing. JLC and NSU sites were the primary Thibodaux,
LA, sites and were sampled approximately twice monthly from 09
February 2006 to 30 July 2007, using monofilament gill nets. Sites US1 through US-7 and DS-1 through DS-6 were representative upstream
and downstream sites and were sampled once each using monofilament
gill nets and/or electrofishing. Site code abbreviations are defined in
Appendix I……………………………………………………………14
Table 2.
Scientific name, common name, and number captured for 688 fishes
collected from Bayou Lafourche from 09 February 2006 to 30 July
2007, using monofilament gill nets. Upstream site includes fishes
collected at the Donaldsonville site (N = 26). Species are arranged by
number collected at the upstream
sites………………………….………………………………………..23
Table 3.
Scientific name, common name and abundance of 4,815 fishes
collected from Bayou Lafourche from 22 March 2007 to 05 October
2007, using electrofishing. Species are arranged in order of
abundance collected at upstream
sites……………………………………………………………………24
Table 4.
Ten species that were not reported in previous Bayou Lafourche fish
fauna study (Shultz 1996). The fish were collected from Bayou
Lafourche using monofilament gill nets and electrofishing between 09
February 2006 and 05 October 2007. Also listed are family, scientific
name, common name, site from which fish were collected, and total
number of individuals collected during this study. DON =
Donaldsonville (upstream of weir), DS-1 and DS-3 = randomly
selected downstream sites, JLC = Jean Lafitte Center (upstream of
weir), NSU = Nicholls State University (downstream of weir). Families
are listed in phylogenetic order, oldest families first…..……………..26
x
Table 5.
Percentage of catch for eleven families collected in three
Donaldsonville samples, 27 upstream samples, and 27 downstream
samples from 09 February 2006 to 30 July 2007, using monofilament
gill nets. Upstream percentage includes fishes collected at the JLC
primary site and randomly selected sites US-1 and US-2. Downstream
totals include fishes collected at the NSU primary site and randomly
selected DS-1 and DS-2 combined. Families are arranged in order of
percentage of caught at the upstream sites. Site code definitions are
listed in Appendix I………………………………………….……….27
Table 6.
Monofilament gill net CPUE by species for fishes collected at the
upstream sites (JLC, US -1, and US-2) and downstream sites (NSU,
DS-1, DS-2) from 09 February 2006 to 30 July 2007. Information listed
include scientific name, mean CPUE ± SD by site, and ANOVA pvalue (α = 0.05)………………………………………………………32
Table 7.
Percentage of total catch for each family collected at upstream,
downstream, and Donaldsonville sites from 22 March 2007 to 05
October 2007, using electrofishing. Upstream totals include the JLC
primary site and randomly selected sites US-1, US-2, and US-4 through
US-7. Downstream totals include the NSU primary site and randomly
selected DS-1 and DS-6. Families are arranged in order of abundance
caught at the upstream sites. Site code definitions are listed in
Appendix I.……………………………………………………………39
Table 8.
Five species had higher electrofishing CPUE at the Donaldsonville site
than the combined upstream sites and combined downstream sites from
22 March 2007 to 05 October 2007. Information included in listing is
scientific name, mean CPUE ± SD and Tukey group………………...44
Table 9.
.
Simpson’s index of diversity, Margalef’s index of richness, Pielou’s
evenness index, and abundance (total number fishes collected) values
for samples collected from JLC and NSU sites using electrofishing
from 22 March 2007 to 04 October 2007. …..……………………….45
xi
INTRODUCTION
Bayou Lafourche and the Barataria-Terrebonne National Estuary System
Bayou Lafourche in southeastern Louisiana runs through the heart of the
Barataria-Terrebonne National Estuary System (BTES). Bayou Lafourche is the border
between the Barataria and Terrebonne Estuaries (Figure 1) flowing 172.2 km from the
Mississippi River to the Gulf of Mexico (McKensie et al. 1995; Emmer et al. 2003). The
BTES was defined and protected by the Barataria–Terrebonne National Estuary Program
(BTNEP) and the Environmental Protection Agency (EPA) in September 1990, and
encompasses approximately 16,835 km2 (McKensie et al. 1995). The inclusion of the
BTES in the National Estuary Program helps to prevent activities from occurring within
the complex that threaten the system’s water supply, harm fish, shellfish, or wildlife
populations within the estuarine complex or negatively impact recreational opportunities
for the residents of the estuary (BTNEP 1995).
Approximately 2,000 years ago Bayou Lafourche was the main distributary of the
Mississippi River. Approximately 800-1,000 years ago the River changed its primary
course to the current path near New Orleans (Cadmus Group 2003). The natural levees
of Bayou Lafourche were built during the active years as the River’s main distributary
(Cadmus Group 2003). Once the Mississippi River changed course, flow of the Bayou
Lafourche distributary lessened and channel width decreased (Cadmus Group 2003).
Bayou Lafourche was historically used for fishing, recreation and travel by local
residents. Steamboats and other vessels carried passengers and commerce the length of
the bayou between Donaldsonville and the Gulf of Mexico (Brasseaux and Fontenot
2004; Emmer et al. 2003). In approximately 1830, a canal was built by the
1
Baton Rouge, LA
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Donaldsonville, LA
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Saint Charles, LA
Ba
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Terrebonne
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Barataria
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50 kilometers
GULF OF MEXICO
Figure 1. Bayou Lafourche extends 172.2 km from the Mississippi River to the Gulf
of Mexico creating the border between the Barataria Estuary and the Terrebonne
Estuary.
2
Lafourche and Terrebonne Navigation Company, connecting Bayou Lafourche to Bayou
Terrebonne in Thibodaux. The company built the canal to facilitate passage of sugarcane
freight between Terrebonne Parish and New Orleans markets via Donaldsonville (Emmer
et al. 2003). The city of Thibodaux became a busy trade and transportation hub for
agricultural commerce within the region (Lafourche Heritage Society 1988). Due to the
profitable agricultural output of the area, community leaders recognized the need to
protect bayou-side communities from seasonal flooding. Although natural levees were
already formed adjacent to Bayou Lafourche, discussion of damming the head of the
bayou at the Mississippi River began in the 1840s (Emmer et al. 2003). In 1904, Bayou
Lafourche was disconnected from the Mississippi River when local residents built a dam
that was later replaced by the Mississippi River flood control levee (CH2M HILL 2005).
The flood control levee is a barrier to the flow of Mississippi River water into Bayou
Lafourche (Jaymac Consultants 2006).
During planning and building of the Bayou Lafourche dam, and subsequent levee
at the Mississippi River junction, the potential consequences of removing Mississippi
River water and sediments from the system were unknown. Community leaders were
seeking a solution for the problematic spring floods that often destroyed homes and
businesses (Emmer et al. 2003). When Bayou Lafourche was disconnected from the
Mississippi River in 1904, and the hydrology of Bayou Lafourche and the surrounding
wetlands was permanently altered. The Mississippi River levee in Donaldsonville made
Bayou Lafourche into a long, slender reservoir (CH2M HILL 2005). The hydrology of
Bayou Lafourche became driven by local precipitation. Several consequences of reduced
flow became clear in the following decades. In the late 1930s and early 1940s Bayou
3
Lafourche was described as stagnant and suffering from persistent aquatic vegetation
such as water hyacinths, Eichhornia crassipes (Emmer et al. 2003; Jaymac Consultants
2006). The loss of freshwater flow down Bayou Lafourche allowed periodic saltwater
intrusion as far as the central reaches of Bayou Lafourche in St. Charles, LA (river km
64.5). In 1930, a 27 km pipeline was built to bring water from the Mississippi River to
Thibodaux for drinking water supply (Emmer et al. 2003). Throughout the 1930s and
1940s the availability of drinking water for Lafourche Parish from Bayou Lafourche
became problematic (A. Chaisson, Bayou Lafourche Fresh Water District, personal
communication). The Bayou Lafourche Fresh Water District (BLFWD) addressed the
potable water supply problem with plans to build a pump and siphon station at the
historic junction of the Mississippi River and Bayou Lafourche. In 1955, the Walter
Lemann Pump Station was installed in Donaldsonville and is still in service today. The
pump station operates by siphoning water from the Mississippi River when the river stage
is greater than 4.8 meters and pumps water from the River at other times (Jaymac
Consultants 2006). The pump station has a siphoning capacity of 11.3 m3s-1 and a
pumping capacity of 9.6 m3s-1. The actual mean flow in Donaldsonville is approximately
7.0 m3s-1, which is the equivalent of 600 million liters per day (CH2M HILL 2005).
In 1969, a weir was installed in Thibodaux to help regulate upstream water levels
by retaining water, creating a reservoir of freshwater in Bayou Lafourche above the weir.
The Thibodaux weir acts as a water retention system and ensures an adequate drinking
water supply for Lafourche Parish (CH2M HILL 2005).
Historically, the Mississippi River served to counteract regional subsidence by
transporting freshwater, sediments, and nutrients via its distributaries such as Bayou
4
Lafourche (CH2M HILL 2005) throughout the BTES. However, due in part to major
hydrologic modification (Louisiana Department of Natural Resources 1998) of the area,
Louisiana coastal wetlands are being lost at an approximate rate of 65 to 91 km2 yr-1
(Raynie and Beasley 2000). In the decades after disconnecting Bayou Lafourche and
other similar distributaries from the Mississippi River southeast Louisiana marshes have
had major land loss due to subsidence and conversion of land to open water (Reed et al.
2003). Several freshwater diversion projects have been proposed and some have been
implemented in southeast Louisiana in an effort to combat coastal erosion (Louisiana
Department of Natural Resources 1998). Discharge of Bayou Lafourche is diminished
due to slow movement of water and sediments, diminished channel capacity, choking
aquatic vegetation, and occasional saltwater intrusion (A. Chaisson, BLFWD, personal
communication).
Mississippi River Water Reintroduction into Bayou Lafourche
Bayou Lafourche no longer transports historic amounts of Mississippi River
water, sediments, or nutrients to the surrounding wetlands. Most of the sediment that is
carried through the pump station at Donaldsonville, drops out of suspension due to low
flow velocity, and accumulates in the channel of Bayou Lafourche (CH2M HILL 2005).
In 1993, the Louisiana Coastal Wetlands Restoration Plan proposed the use of Bayou
Lafourche as a freshwater and sediment conveyance system (CH2M HILL 2005). In
1995, the Mississippi River Water Reintroduction into Bayou Lafourche (MRRBL)
proposal was developed by the Environmental Protection Agency (EPA) and the
BLFWD. The proposal suggested that Bayou Lafourche could effectively transport
freshwater, sediments, and nutrients to approximately 489 km2 of wetlands including,
5
fresh marsh, brackish marsh, and salt marsh located in the lower Barataria and
Terrebonne estuaries. The MRRBL project was selected for inclusion on the Coastal
Wetlands Planning, Protection and Restoration Act (CWPPRA) Fifth Priority List in
1996. The inclusion of the MRRBL project on the annual CWPPRA priority list of
projects provided funding for the initial planning phase of the project. The MRRBL
project was approved for further development under the CWPPRA in 2001 (CH2M HILL
2005).
The original MRRBL proposal suggested diverting 57 m3s-1 of Mississippi River
water into Bayou Lafourche at Donaldsonville to carry freshwater, sediments, and
nutrients to surrounding wetlands while meeting the demands of downstream water
system withdrawals (CH2M HILL 2005). After extensive evaluation of the hydraulic
capacity of Bayou Lafourche it was determined that an appropriate level of water
discharge for this project would be approximately 28.3 m3s-1. This flow regime takes into
account bayou-side property development, bank stability, and project cost effectiveness
(CH2M HILL 2005). The major components of the project, as it is currently proposed,
include the construction of a new pump station in Donaldsonville to increase discharge
capacity from ~5.6 m3s-1 to ~11.3 m3s-1. Dredging upstream portions (Donaldsonville to
Thibodaux) of Bayou Lafourche would be required to ensure increased flow will not raise
surface levels and impinge on private property rights. The final component of the project
is the removal of the Thibodaux weir and replacement with inflatable weirs or other water
control system to ensure an adequate drinking water supply.
6
Hydrologic Modification and the Fish Community
The effects of proposed hydrologic changes to Bayou Lafourche on the
ichthyofauna are unknown. It is probable that the hydrologic modifications to Bayou
Lafourche during the early to mid-twentieth century had significant effects on the aquatic
community. Patterns of diversity and aquatic community structure are related to
streamflow patterns (Poff and Ward 1989). Strong associations between functional and
taxonomic composition of fish assemblages and hydrological regimes have been found
on a regional scale (Poff and Allan 1995). Construction of water retention structures may
alter habitat, and thus negatively impact fish populations and aquatic communities
(Schlosser and Ebel 1989; Jurajda 1995). The fragmentation of Bayou Lafourche by
structures such as the levee in Donaldsonville, the Thibodaux weir, and the Gulf
Intracoastal Waterway created an altered aquatic community. This disjointedness may
affect the fish community of Bayou Lafourche because many fishes move substantial
distances within waterways for reproductive and foraging purposes (McKeown 1984;
Northcote 1984; Harris and Mallen-Cooper 1994). Other studies have found that
structures such as weirs and dams create obstacles to fish movement and can affect
population structure (Harris and Mallen-Cooper 1994; Lucas and Frear 1997).
Fish behavior is strongly influenced by abiotic hydrological factors such as water
volume, current velocity, and water temperature (Grossman et al. 1998; Schlosser 1985).
Temporal variability in fish assemblages tends to be high in warm water,
anthropogenically altered streams (Schlosser 1982). A frequent problem with analyzing
effects of human modifications of river systems is the absence of baseline data prior to
the alteration (Bain et al. 2000). Ideally, a comparison could be made between abiotic
7
conditions and the biotic community before and after a modification using premodification and post-modification data. Unfortunately, Bayou Lafourche has been the
focus of few published ecological studies (Schultz 1996; Rodrigue 2005). One
ichthyofauna study using seines at 90 stations between Donaldsonville and Port Fourchon
(Schultz 1996) collected over 25,000 fish representing 40 families and 110 species.
Because there is no pre-modification data to make a comparison, this study serves
as a baseline assessment of the current Bayou Lafourche fish community. The goal of
this study was to provide quantitative data on the seasonal abundance, diversity, and
distribution of adult fishes inhabiting Bayou Lafourche upstream and downstream of the
Thibodaux weir. This research may provide data useful in determining the effect that
removal of the Thibodaux weir may have on the fish community of Bayou Lafourche.
Specific objectives of this study were to estimate seasonal abundance and diversity of
adult fishes inhabiting Bayou Lafourche upstream and downstream of the Thibodaux
weir. We propose the possible impact that removal of the Thibodaux weir may have on
fish distribution and migratory behavior of potamodromous and anadromous fishes that
inhabit Bayou Lafourche. Finally, this study will serve as a baseline assessment of the
current fish community for use in predicting impacts of future hydrologic modifications.
Description of Study Area
The study area was located between the headwaters of Bayou Lafourche, near the
Donaldsonville railroad bridge (river km 1.2; 30° 5'49.27"N 90°59'47.99"W) and the
Theriot canal boat launch near Raceland, LA (river km 76; 29°44'16.51"N,
90°38'49.44"W; Figure 2). The study site located furthest upstream on Bayou Lafourche
in Donaldsonville was located 1.2 river km from the junction of Bayou Lafourche and the
8
N
Donaldsonville, LA (Origin of Bayou Lafourche)
x, LA
odau
b
i
h
T
Raceland, LA
Ba
yo
u
La
f
ou
rc
h
M
iss
iss
ip p
iR
ive
r
e
50 kilometers
GULF OF MEXICO
Figure 2. Map of the study area located between Donaldsonville and Raceland, LA.
Donaldsonville sites were located at approximately river km one. All other sampling sites
were located between north Thibodaux (river km 40.6, US-6 site) and Raceland (river km
76, DS-4 site).
9
Mississippi River (river km 0). Channel width of Bayou Lafourche ranges from
20 to 40 m over the first 50 km between Donaldsonville and Thibodaux (Schultz 1996).
However, several reaches of upper Bayou Lafourche are narrower than 20 m during the
growing season due to aquatic macrophyte and algae growth (Jaymac Consultants 2006).
In some years the channel of Bayou Lafourche near Donaldsonville narrows to a few
meters of passable waterway between vegetated banks (A. Chaisson, BLFWD, personal
communication). The banks near the Donaldsonville site have heavy vegetation
consisting of non-native taro plant Taro spp., woody shrubs, and trees. Donaldsonville
also has a narrower channel and two pools (~ 3 m deep) at the location of the pump
station discharge pipes. Hydrilla H. verticillata grows in thick mats from Labadieville to
Raceland. In 1996, the BLFWD began using U.S. Army Corps of Engineers cutting
machines, which mow the hydrilla and other submerged macrophytes (Jaymac
Consultants 2006). Within the study area Bayou Lafourche is approximately 1.5 to 2.0 m
deep (Schultz 1996). The substratum is primarily mud with occasional patches of sand
(CH2M HILL 2005). The riparian zone of Bayou Lafourche consists of intermixed bankside commercial and residential development and mixed vegetation (CH2M HILL 2005).
The weir is located at river km 55 in Thibodaux, LA (Figure 3).
10
Figure 3. Weir located in Thibodaux, LA, at river km 55 (29°47'55.42"N,
90°49'12.92"W). Photo was taken on 04 October 2007, from the western bank of
Bayou Lafourche.
11
METHODS
Collection Sites
Fish were collected from 15 sites from 09 February 2006 to 05 October 2007.
Two primary sites, one upstream of the weir and one downstream of the weir were
sampled approximately one to three times per month throughout this study (Figure 4).
The primary site upstream of the weir was located at the Jean Lafitte Acadian Cultural
Center (JLC), 314 St. Mary Street, Thibodaux, LA, approximately 0.5 km upstream of
the Thibodaux weir. The primary site downstream of the weir was located at the Nicholls
State University (NSU) dock, approximately 2.0 km downstream of the Thibodaux weir.
Additionally, six randomly selected sites (US-1, US-2, US-4, US-5, US-6, and US-7)
upstream of the weir and six randomly selected sites (DS-1, DS-2, DS-3, DS-4, and DS5) downstream of the weir were sampled once. The Donaldsonville, LA, site was located
at the headwaters of Bayou Lafourche approximately 1.6 km from the Mississippi River.
The Donaldsonville (DON) site was sampled five times (06 July 2006, 26 September
2006, 09 May 2007, 30 August 2007, and 05 October 2007) during the twenty month
study to collect fishes that may have passed through the pump station into Bayou
Lafourche from the Mississippi River and to determine which species may inhabit a
habitat with slightly higher flow.
Collection Methods
Samples were collected using monofilament gill nets or two-pass boat
electrofishing to reduce gear selectivity for fish size and swimming behavior.
Monofilament gill nets were chosen as the primary gear for this study because this
12
DON
Mississippi River
N
Bayou Lafourche
US-6
US-5
US-4
US-7
Thibodaux Weir
Primary Sites
NSU
US-1
US-2 JLC
DS-6
DS-3
Random Sites
DS-2
DS-4
DS-1
DS-5
Donaldsonville
1 river km
Figure 4. Map of sampling sites located between Donaldsonville, LA, and Raceland, LA.
GPS coordinates, river kilometers and sampling dates are listed for each site in Table 1.
Individual site codes are defined in Appendix I.
13
14
passive gear is easy to deploy, is effective in shallow water habitats, and does not require
a motor boat to deploy (Hubert 1996). We also used boat-mounted two pass
electrofishing to collect samples during the second year of this study. Electrofishing is an
efficient method for assessing the biota of non-wadeable waters. Several benefits of this
technique include the ability to catch many fish over a large range of sizes and species.
The method also allows for sampling in habitat that is not suitable for net deployment
such as in and near vegetation and in areas with woody debris (Meador 2005).
Monofilament gill nets
Fish Collection
Monofilament gill nets were used to capture fish from 09 February 2006 to 31
July 2007, at the two primary Thibodaux sites, JLC and NSU. Gill nets were set using
small flat-bottomed boats, the R/V Amphiüma and the R/V Tou Lou Lou. Gill nets were
set one to three times per month at the primary sites with most months having two sample
dates. Monofilament gill nets were used at the Donaldsonville site on 06 July 2006, 26
September 2006, and 09 May 2007. Gill nets were also deployed on 22 May 2007 and 23
May 2007, at two randomly selected sites upstream (US-1 and US-2) and two randomly
selected sites downstream (DS-1 and DS-2) of the Thibodaux weir.
At each site, five 23 m long x 1.8 m deep monofilament gill nets of various bar
mesh sizes (two 38 mm bar mesh, two 25.4 mm and 38 mm experimental bar mesh, and
one 95 mm bar mesh) were set randomly along the shoreline. Nets were deployed
approximately one meter from the bank and stretched towards the middle of the bayou at
approximately a 45° angle. Nets were deployed and left to soak for approximately 3-4
15
hours. Fish were removed from each net, separated by site and net, and taken back to the
laboratory for processing.
Two pass boat electrofishing
Fish collection
During the 2007 field season, fish were collected in early spring (March), late
spring (May), late summer (August), and early fall (September) using a boat mounted 5.0
kW Smith-Root Model GPP (Generator Powered Pulsator) Electrofisher System. Pulsed
DC, 60 pulses/second, was used at various percents of maximum range to maintain
approximately 5 amperes of current. A 30 cm diameter ring-shaped anode and 10 mm
mesh dip net were used to collect stunned fishes. Two passes along opposing shorelines
were made while current was applied in approximately five second intervals for a total of
500 seconds. Applied current time was measured in seconds and was recorded on the
GPP system counter. All electrofishing was conducted during daylight.
Electrofishing was conducted during the spring 2007, summer 2007, and fall
2007, seasons at the two primary Thibodaux sites and the Donaldsonville site. Six
randomly selected sites located above the weir and five randomly selected sites located
below the weir were each sampled once using electrofishing. After collection, all fish
were transported on ice to the laboratory for processing.
Sample Processing
Fish were visually identified to the species level. If a species was unknown or
ambiguous a taxonomic key was used for positive identification (Ross 2002).
16
Water Quality
Dissolved oxygen (DO; mg/L), water temperature (°C), and specific conductance
(µS/cm) were measured during each sampling trip using a handheld dissolved oxygentemperature-specific conductance meter (YSI Model 85™; Yellow Springs Instruments,
Yellow Springs, Ohio). Secchi disc depth (cm) was also measured. Water quality was
measured at both Thibodaux sites (JLC and NSU) during all collection trips after 17 July
2006. Prior to this date, water quality was measured only at the JLC site. Water quality
was not measured at the DS-2 site on 23 May 2007, due to inclement weather.
Statistical Analysis
Seasons were designated as winter (December – February), spring (March –
May), summer (June – August), and fall (September – November). Winter 2006 only
included February 2006, the month the study began. Winter 2007 included December
2006 and February 2007. No sampling occurred during January 2007. Total abundance
for each species and family was calculated by site and season. All data were analyzed by
gear type.
Monofilament gill nets
Percent Abundance by Family
Percent abundance for each family was determined for seven sites located
upstream and downstream of the weir for all seasons combined. Upstream percent
abundance was calculated by dividing the total number of fishes collected from a family
by the total number of fishes collected at all upstream sites. Downstream percent
17
abundance was calculated by dividing the total number of fishes collected from a family
by the total number of fishes collected all downstream sites. Donaldsonville percent
abundance was calculated by dividing the total number of fishes collected from a family
by the total number of fishes collected at the DON site.
Catch per Unit Effort (CPUE)
Gill net catch per unit effort (CPUE) was determined for each site by dividing the
number of fish captured by each net divided by the total number of minutes each net was
deployed. The mean CPUE of all nets per site and sample date was calculated. Nonnormal CPUE data were transformed [ln(x+1)] and a one-way analysis of variance
(ANOVA) and Tukey’s post hoc comparison was used to determine seasonal differences
in CPUE (number fishes per net hour) within sites and between sites for the seven
seasons sampled. Total CPUE for species was compared for differences between
upstream and downstream combined sites using one-way ANOVA and Tukey’s post hoc
comparison.
Community Diversity
Species richness was determined using Margalef’s index, which is a measure of
the species present for the given number of individuals present and estimated species
richness independent of sample size (Clarke and Gorley 2006):
d = (S-1) / log N
Where;
N = the total number of individuals
S = the total number of species.
18
Equitability was calculated using Pielou’s evenness index:
J’ = H’/H’ max = H’/ log S
Where;
H’ = the maximum possible Shannon-Weiner diversity
index value if all species were equally abundant
H’ max = log S
S = the total number of species.
Species diversity was calculated using Simpson’s index of diversity:
1-λ
Where;
λ = ∑ ni(ni -1) / N(N-1)
λ is the probability that any two randomly chosen
individuals from the sample are the same species
Simpson’s index takes into account the number of species, the total number of individuals
and the proportion of the total that occurs for each species (Brower et al. 1998; Clarke
and Gorley 2006). Simpson’s index is an expression of the probability of interspecific
encounter (Hurlburt 1971) with values ranging from zero to one where a higher value
reflects higher diversity. Individual sample values for Margalef’s index of species
richness, Pielou’s evenness index and Simpson’s index of diversity were calculated using
PRIMER v.6 multivariate ecological research statistics software.
19
Community Similarity
A zero-adjusted Bray-Curtis similarity coefficient matrix was constructed using
square root transformed abundance data for each site and season to decrease the statistical
effect of the most abundant species and allow influence of intermediate species (Clarke
and Gorley 2006). A dendrogram of hierarchical clustering (group-average linking) was
produced using the Bray-Curtis similarities matrix results for site and season. The BrayCurtis similarity coefficient matrix and hierarchical clustering analysis and were
produced using PRIMER v.6
Two pass boat electrofishing
Percent Abundance by Family
Percent abundance for each family was determined for seven sites located
upstream and downstream of the weir for all seasons combined. Upstream percent
abundance was calculated by dividing the total number of fishes collected from a family
by the total number of fishes collected at JLC and two randomly selected upstream sites.
Downstream percent abundance was calculated by dividing the total number of fishes
collected from a family by the total number of fishes collected at NSU and two randomly
selected downstream sites. Donaldsonville percent abundance was calculated by dividing
the total number of fishes collected from a family by the total number of fishes collected
at the DON site.
Catch per Unit Effort (CPUE)
Electrofishing CPUE (number fish per minute) was determined by dividing the
total number of fish captured per sample by the number of seconds electrofished. The
20
[ln(x+1)] transformation of CPUE data followed by a one-way analysis of variance
(ANOVA) and Tukey’s post hoc comparison was used to determine seasonal differences
in seasonal CPUE within sites and among sites for the three seasons sampled (SAS
2006). Total CPUE for species was compared for differences among sites using one-way
ANOVA and Tukey’s post hoc comparison.
Community Diversity
Species richness (Margalef’s index), equitability (Pielou’s evenness index), and
diversity (Simpson’s index of diversity) were calculated for each site and season using
PRIMER v.6.
Community Similarity
A zero-adjusted Bray-Curtis similarity coefficient matrix was constructed using
square root transformed abundance data for each site and season to decrease the statistical
effect of the most abundant species and allow influence of intermediate species (Clarke
and Gorley 2006). A dendrogram of hierarchical clustering (group-average linking) was
produced using the Bray-Curtis similarities matrix results for site and season. The BrayCurtis similarity coefficient matrix and hierarchical clustering analysis were produced
using PRIMER v.6.
Water quality
Mean temperature, dissolved oxygen, and Secchi disc depth were compared
between the JLC and NSU sites by season using Student’s t-test (α = 0.05). Water
quality data was analyzed using SigmaStat 3.5 statistical analysis software.
21
RESULTS
A total of 5,503 fishes representing 50 species in 16 families were collected from
15 sites on Bayou Lafourche using monofilament gill nets and two-pass boat
electrofishing. Six hundred eighty-eight fishes representing 28 species from 17 genera
and 11 families were collected from seven sites using monofilament gill nets (Table 2).
A total of 4,815 fishes representing 47 species from 33 general and 16 families were
collected using electrofishing (Table 3).
Ten species not previously documented in Bayou Lafourche (Schultz 1996) were
collected during this study (Table 4). One Alabama shad Alosa alabamae was collected
at the NSU site downstream of the Thibodaux weir.
Monofilament gill nets
Percent Abundance by Family
Fishes from eight families were captured at JLC. Centrarchids were most
abundant at JLC comprising 62% of the JLC catch (Table 5). Fishes from five families
comprised 96% of the total catch at this location. Eleven families were collected using
monofilament gill nets at NSU. Clupeids were most abundant at the NSU site equaling
30% of the catch (Table 5). The five most abundant families caught at the NSU site
totaled 94% of the catch. Twenty six fishes from six families were collected from DON
with the most abundant family being Ictaluridae, comprising 30% of the DON catch
(Table 5).
22
Table 2. Scientific name, common name, and number captured for 688 fishes collected
from Bayou Lafourche from 09 February 2006 to 30 July 2007, using monofilament gill
nets. Upstream site includes fishes collected at the Donaldsonville site (N = 26). Species
are arranged by number collected at the upstream sites.
SCIENTIFIC NAME
COMMON NAME
Micropterus salmoides
Mugil cephalus
Lepisosteus oculatus
Ictalurus punctatus
Lepomis microlophus
Chaenobryttos gulosus
Lepomis macrochirus
Dorosoma cepedianum
Lepomis megalotis
Lepomis miniatus
Ictiobus bubalus
Pomoxis nigromaculatus
Aplodinotus grunniens
Lepisosteus osseus
Ameiurus natalis
Morone mississippiensis
Erimyzon oblongus
Morone chrysops
Micropterus punctulatus
Alosa alabamae
Alosa chrysochloris
Amia calva
Carpiodes carpio
Cyprinus carpio
Dorosoma petenense
Elops saurus
Ictalurus furcatus
Lepomis cyanellus
Largemouth bass
Striped mullet
Spotted gar
Channel catfish
Redear sunfish
Warmouth
Bluegill
Gizzard shad
Longear sunfish
Redspotted sunfish
Smallmouth buffalo
Black crappie
Freshwater drum
Longnose gar
Yellow bullhead catfish
Yellow bass
Creek chubsucker
White bass
Spotted bass
Alabama shad
Skipjack herring
Bowfin
River carpsucker
Common carp
Threadfin shad
Ladyfish
Blue catfish
Green sunfish
TOTAL
23
NUMBER CAPTURED
Upstream
101
52
39
27
24
23
16
12
9
7
5
5
4
4
2
2
1
1
1
0
0
0
0
0
0
0
0
0
Downstream
27
105
36
36
8
8
3
84
3
1
4
0
1
11
0
3
0
0
0
1
9
2
1
3
2
3
1
1
335
353
Table 3. Scientific name, common name and total number captured of 4,815 fishes collected
from Bayou Lafourche from 22 March 2007 to 05 October 2007, using electrofishing.
Species are arranged in order of abundance collected at upstream sites. Upstream totals
combine JLC and randomly selected sites located upstream of the weir. Downstream totals
combine NSU and randomly selected sites located downstream of the weir.
SCIENTIFIC NAME
Lepomis miniatus
Lepomis megalotis
Micropterus salmoides
Lepomis macrochirus
Mugil cephalus
Gambusia affinis
Menidia beryllina
Lepomis microlophus
Poecilia latipinna
Notemigonus crysoleucas
Lepisosteus oculatus
Chaenobryttus gulosus
Anguilla rostrata
Lucania parva
Dorosoma cepedianum
Aphredoderus sayanus
Heterandria formosa
Ameiurus natalis
Ictiobus bubalus
Labidesthes sicculus
Pimephales vigilax
Cyprinella lutrensis
Ictalurus punctatus
Cyprinus carpio
Lythrurus fumeus
Aplodinotus grunniens
Amia calva
Cyprinella venusta
Micropterus punctulatus
Pimiphales notatus
Anchoa mitchilli
COMMON NAME
Red spotted sunfish
Longear sunfish
Largemouth bass
Bluegill
Striped mullet
Mosquitofish
Inland silverside
Redear sunfish
Sailfin molly
Golden shiner
Spotted gar
Warmouth
American eel
Rainwater killifish
Gizzard shad
Pirate perch
Least killifish
Yellow bullhead catfish
Smallmouth buffalo
Brook silverside
Bullhead minnow
Red shiner
Channel catfish
Common carp
Ribbon shiner
Freshwater drum
Bowfin
Blacktail shiner
Spotted bass
Fathead minnow
Bay anchovy
24
NUMBER CAPTURED
Donaldsonville
Upstream
Downstream
633
357
21
93
80
32
13
1
4
0
18
42
10
34
16
0
0
0
19
3
20
135
6
8
0
4
0
22
14
4
0
607
302
190
164
104
94
84
62
53
46
37
25
21
17
9
6
6
5
4
4
4
3
3
2
2
1
1
1
1
1
0
166
43
268
337
190
8
18
82
4
15
21
27
1
1
6
0
0
1
7
5
0
14
10
14
0
1
0
0
0
0
34
Table 3. (con’t)
SCIENTIFIC NAME
Pomoxis nigromaculatus
Fundulus chrysotus
Brevoortia patronus
Alosa chrysochloris
Lepomis symmetricus
Carpiodes carpio
Elops saurus
Ictalurus furcatus
Ictiobus cyprinellus
Dorosoma petenense
Lepisosteus osseus
Lepomis cyanellus
Morone saxatilis
Opsopoeodus emiliae
Ctenopharygodon idella
COMMON NAME
Black crappie
Golden topminnow
Menhaden
Skipjack herring
Bantam sunfish
River carpsucker
Ladyfish
Blue catfish
Bigmouth buffalo
Threadfin shad
Longnose gar
Green sunfish
Striped bass
Pugnose minnow
Grass carp
TOTAL
25
NUMBER CAPTURED
Donaldsonville
Upstream
Downstream
2
0
0
0
0
3
0
0
0
4
9
6
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
19
14
13
9
5
1
1
1
1
0
0
0
0
0
0
1619
1859
1337
Table 4. Ten species that were not reported in previous Bayou Lafourche fish fauna
study (Shultz 1996). The fish were collected from Bayou Lafourche using monofilament
gill nets and electrofishing between 09 February 2006 and 05 October 2007. Also listed
are family, scientific name, common name, site from which fish were collected, and total
number of individuals collected during this study. DON = Donaldsonville (upstream of
weir), DS-1 and DS-3 = randomly selected downstream sites, JLC = Jean Lafitte Center
(upstream of weir), NSU = Nicholls State University (downstream of weir). Families are
listed in phylogenetic order, oldest families first.
Family
Scientific Name
Common Name
Lepisosteidae
Lepisosteius osseus
Longnose gar
JLC, NSU,
DON
14
Amiidae
Amia calva
Bowfin
JLC, NSU
3
Clupeidae
Alosa alabamae
Alabama shad
NSU
1
Cyprinidae
Ctenopharyngodon
idella
Grass carp
DON
1
Cyprinidae
Pimephales notatus
Bluntnose minnow DON
4
Catostomidae
Carpiodes carpio
River carpsucker
DON, DS-1
4
Catostomidae
Erimyzon oblongus
Creek chubsucker
JLC
1
Catostomidae
Ictiobus bubalus
Smallmouth
buffalo
JLC, DON,
NSU, DS-3
30
Catostomidae
Ictiobus cyprinellus
Bigmouth buffalo
NSU
1
Moronidae
Morone
mississippiensis
Yellow bass
DON, JLC,
NSU, DS-1
14
26
Site(s)
Captured
Number
Captured
Table 5. Percentage of catch for eleven families collected in three Donaldsonville
samples, 27 upstream samples, and 27 downstream samples from 09 February 2006
to 30 July 2007, using monofilament gill nets. Upstream percentage includes fishes
collected at the JLC primary site and randomly selected sites US-1 and US-2.
Downstream totals include fishes collected at the NSU primary site and randomly
selected DS-1 and DS-2 combined. Families are arranged in order of percentage of
caught at the upstream sites. Site code definitions are listed in Appendix I.
% of Catch
Family Name
Donaldsonville
Centrarchidae
Mugilidae
Lepisosteidae
Ictaluridae
Clupeidae
Catostomidae
Moronidae
Sciaenidae
Elopidae
Amiidae
Cyprinidae
Upstream
57.9
15.5
12.6
6.5
3.6
1.9
1.0
1.0
0.0
0.0
0.0
26.9
15.4
15.4
34.6
3.8
0.0
3.8
0.0
0.0
0.0
0
27
Downstream
14.4
29.7
10.5
10.5
26.9
1.4
3.1
0.9
0.6
1.1
0.9
Catch per Unit Effort (CPUE)
There were no differences among mean seasonal CPUE within the JLC (Figure
5), or NSU (Figure 6). Seasonal CPUE was compared between the primary Thibodaux
sites, JLC and NSU. The DON site was also included in the comparisons for the three
seasons that it was sampled. DON (0.650 ± 0.42) CPUE was higher than JLC CPUE
(0.207 ± 0.30) and NSU (0.310 ± 0.32) during summer 2006 (p = 0.0006, Figure 7).
There were no other differences in mean seasonal CPUE among the JLC, NSU and DON
sites.
Seasonal CPUE was compared among the randomly selected sites above or below
the weir and the corresponding primary site sample. CPUE for samples collected on 22
May 2007, from sites US-1 and US-2 were compared to the CPUE for the 21 May 2007,
JLC sample. The US-1 (2.22 ± 0.1.17) site had higher CPUE than the US-2 (0.480 ±
0.46) site and JLC (0.472 ± 0.56, p = 0.0131). There was no difference in CPUE for the
downstream primary site, NSU, and the randomly selected downstream sites, DS-1 and
DS-2.
Total gill net CPUE was higher for combined downstream sites (NSU, DS-1, DS2) of the weir compared to combined upstream (JLC, US-1, US-2) sites for gizzard shad,
channel catfish, and yellow bass (Table 6). Largemouth bass CPUE was higher for the
combined upstream sites than the combined downstream sites (Table 6).
28
Mean (±SD) CPUE (number fishes per net hour)
3.25
3.00
2.75
2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0.00
A
A
A
WIN06
A
A
A
SPR06 SUM06 FAL06 WIN07
SPR07 SUM07
Season
Figure 5. Mean (±SD) seasonal monofilament gill net CPUE at JLC for all
seasons sampled from 09 February 2006 to 30 July 2007. Means with the
same letter indicate no difference. No fish were collected WIN07.
29
Mean (±SD) CPUE (# fishes per net hour) .
3.25
3.00
2.75
2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0.00
A
A
A
A
A
A
WIN06
A
SPR06 SUM06 FAL06 WIN07 SPR07 SUM07
Season
Figure 6. Mean (+SD) seasonal monofilament gill net CPUE at the
primary downstream site NSU for all seasons sampled from 09 February
2006 to 30 July 2007. There were no differences among seasons at the
NSU site.
30
Mean (±SD) Seasonal CPUE (# fishes per net hour) .
1.25
A
1.00
0.75
B
B
0.50
0.25
0.00
JLC
NSU
DON
Figure 7. Summer 2006 monofilament gill net CPUE for sites JLC, NSU, and
DON. The CPUE at the DON site was higher than the JLC and NSU sites
(ANOVA, overall p = 0.0006). Means with the same letter indicate no
difference.
31
Table 6. Monofilament gill net CPUE by species for fishes collected at the upstream sites
(JLC, US -1, and US-2) and downstream sites (NSU, DS-1, DS-2) from 09 February 2006
to 30 July 2007. Information listed include scientific name, mean CPUE ± SD by site, and
ANOVA p-value (α = 0.05).
Species
US Mean ± SD
DS Mean ± SD
p – value
Dorosoma cepedianum
0.145 ± 0.10
0.193 ± 0.05
0.0003
Ictalurus punctatus
0.041 ± 0.12
0.081 ± 0.18
0.0326
Micropterus salmoides
0.213 ± 0.81
0.062 ± 0.17
0.0342
Morone mississippiensis
0.004 ± 0.05
0.027 ± 0.01
0.0238
32
Community Diversity
Downstream and upstream primary sites had the highest species richness during
spring 2007. JLC species richness ranged from 0.63 on 11 September 2006, to 2.89 on
01 May 2007 (Figure 8). The NSU species richness ranged from 0 on 05 December 2006
(1 species), to 2.72 on 31 October 2006 (8 species).
Equitability or evenness was highest at JLC, with a Pielou’s evenness index value
of 1 on 20 February 2007 (2 species), 06 June 2007 (4 species), and 30 July 2007 (3
species; Figure 9). Evenness at NSU was lowest, with an evenness index value of 0.52,
on 09 February 2006 (5 species), and highest with an evenness index value of 1 on 15
June 2006 (2 species) and 31 August 2006 (2 fishes).
Diversity at JLC was highest on 09 February 2006, 30 March 2007, and 01 May
2007 (0.81; Figure 10), and was lowest on 20 February 2007 (0; Figure 10). Diversity at
NSU was highest on 31 October 2006 (0.84; Figure 10) and lowest on 05 December 2006
and 06 March 2007 (0; Figure 10).
Community Similarity
Six pairings were found to be greater than 50% similar based on the Bray-Curtis
similarity coefficient and hierarchical cluster analysis. Four of the six groupings were
paired by site and two were paired by season (Figure 11). The samples within these two
groups were 48% similar to their own group and 37% similar to the other group. Smaller
groupings were isolated within one of the 40% groups but there was no pattern of
similarity based on season or site.
33
NSU
2.7
2.4
2.1
1.8
1.5
1.2
0.9
0.6
0.3
8/9/2007
6/9/2007
4/9/2007
2/9/2007
12/9/2006
10/9/2006
8/9/2006
6/9/2006
4/9/2006
0
2/9/2006
Margalaf's Index of Species Richness (d) .
JLC
3
Date
Figure 8. Margalef’s index of species richness (d) per season for samples
collected from primary sites JLC and NSU from 09 February 2006 to 30 July
2007, using monofilament gill nets.
34
JLC
NSU
0.8
0.6
0.4
0.2
6/9/07
4/9/07
2/9/07
12/9/06
10/9/06
8/9/06
6/9/06
4/9/06
0
2/9/06
Peilou's Evenness Index ( J' ) .
1
Date
Figure 9. Pielou’s Evenness Index (J’) for samples collected from sites JLC
and NSU from 09 February 2006 to 30 July 2007, using monofilament gill
nets.
35
NSU
6/9/2007
4/9/2007
2/9/2007
12/9/2006
10/9/2006
8/9/2006
6/9/2006
4/9/2006
2/9/2006
.
Simpson's Diversity Index (1- λ)
JLC
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Date
Figure 10. Simpson’s index of diversity for samples collected at the JLC and
NSU sites from 09 February 2006 to 30 July 2007, using monofilament gill nets.
36
Transform: Square root
Resemblance: S17 Bray Curtis similarity (+d)
40
60
SUM06US
SPR06US
SUM07DS
FAL06DS
SUM06DS
SPR06DS
SPR07DS
SPR07US
FAL06US
WIN06DS
WIN07DS
WIN07US
100
SUM07US
80
WIN06US
Bray-Curtis Similarity (%)
20
Season
Figure 11. Dendrogram for hierarchical clustering (group average linking) using the
Bray-Curtis similarity matrix (y-axis) for samples collected using monofilament gill
nets from 09 February 2006 to 30 July 2007. X-axis abbreviations are as follows:
WIN06US = winter 2006 upstream, SUM07US = summer 2007 upstream,
WIN07US = winter 2007 upstream, WIN07DS = winter 2007 downstream,
WIN06DS = winter 2006 downstream, FAL06US = fall 2006 upstream, SPR07US
= spring 2007 upstream, SPR07DS = spring 2007 downstream, SPR06DS = spring
2006 downstream, SUM06DS = summer 2006 downstream, FAL06DS = fall 2006
downstream, SUM07DS = summer 2007 downstream, SPR06US = spring 2006
upstream, SUM06US = summer 2006 upstream.
37
Electrofishing
Percent Abundance by Family
Fishes from 17 families were collected using electrofishing from 14 sites
upstream and downstream of the weir. Centrarchidae was the most abundant family
collected, comprising more than 70% of the total catch for the Donaldsonville, upstream,
and downstream sites (Table 7). Fishes in thirteen families were collected from the
Donaldsonville site. The sample consisted of 72.2% Centrarchid and 11.9% Cyprinid.
Eleven other families collected at Donaldsonville each constituted less than five percent
each of the total sample (Table 7). Eleven species from Centrarchidae were collected
using electrofishing. Five species from the genus Lepomis and largemouth bass
Micropterus salmoides were the most abundant (Figure 12). Fishes from 14 families
were captured at upstream sites. The upstream sample consisted of 72.7% Centrarchid
and less than 6% each of 13 other families (Table 7). Fourteen families were collected at
the downstream sites. Centrarchids were the most abundant family with 71.4%, followed
by Mugilids with 14.3% of the total downstream catch (Table 7). Twelve other families
collected from downstream sites, each constituted less than 3% of the catch (Table 7).
38
Table 7. Percentage of total catch for each family collected at upstream,
downstream, and Donaldsonville sites from 22 March 2007 to 05 October 2007,
using electrofishing. Upstream totals include the JLC primary site and randomly
selected sites US-1, US-2, and US-4 through US-7. Downstream totals include the
NSU primary site and randomly selected DS-1 and DS-6. Families are arranged in
order of abundance caught at the upstream sites. Site code definitions are listed in
Appendix I.
% of Catch
Family Name
Centrarchidae
Fundulidae
Mugilidae
Atherinidae
Cyprinidae
Poecilidae
Lepisosteidae
Anguillidae
Clupeidae
Ictaluridae
Aphredoderidae
Catostomidae
Amiidae
Sciaenidae
Elopidae
Engraulidae
Moronidae
DONALDSONVILLE
72.2
4.1
4.9
1.0
11.9
0.2
1.7
0.6
1.4
0.4
0.0
1.2
0.0
0.2
0.0
0.0
0.2
UPSTREAM
72.7
6.0
5.6
4.7
3.2
3.2
2.0
1.1
0.5
0.4
0.3
0.2
0.1
0.1
0.0
0.0
0.0
39
DOWNSTREAM
71.4
1.7
14.3
1.7
3.2
0.3
1.6
0.1
0.5
0.9
0.0
0.6
0.0
0.1
0.1
2.6
0.0
Donaldsonville
Upstream
Downstream
700
500
400
300
200
100
P.
nigromaculatus
L.symmetricus
L. cyanellus
M. punctulatus
Chaenobryttus
gulosus
L. microlophus
L. macrochirus
M. salmoides
L. megalotis
0
L. miniatus
Total Abundance
600
Figure 12. Centrarchids collected using electrofishing at the Donaldsonville,
upstream, and downstream sites. The family comprised more than 70% of the
total abundance at each site.
40
Catch per Unit Effort (CPUE)
The 2007 mean seasonal electrofishing CPUE at the Donaldsonville (Figure 13)
and upstream (Figure 14) sites and was high in spring and declined in the summer and
fall although no differences were found among seasons. Redspotted sunfish made up 56%
of the spring 2007 DON sample. The redspotted sunfish combined with longear sunfish
equaled 70% of the total spring catch at Donaldsonville. Seasonal mean CPUE for the
downstream sites was similar for all seasons (Figure 14). There was no difference in
CPUE among the Donaldsonville, upstream, and downstream electrofishing samples
during spring 2007.
Electrofishing CPUE by species was higher in Donaldsonville than the upstream
and downstream sites for five species: red shiner, blacktail shiner, smallmouth buffalo,
spotted bass, and bullhead minnow (Table 8). Bluegill CPUE was higher (overall p =
0.0016) downstream (2.30 ± 0.84) than both upstream (0.984 ± 0.60) and Donaldsonville
(0.930 ± 0.67). Largemouth bass CPUE was higher (overall p = 0.0078) downstream
(1.83 ± 0.98) than Donaldsonville (0.21 ± 0.05) but not higher than upstream sites in
Thibodaux (1.14 ± 0.418).
Community Diversity
The upstream and downstream samples were similar in species richness, evenness and
diversity in spring 2007, summer 2007 and fall 2007 (Table 9). JLC diversity ranged
from 0.73 in late spring 2007 to 0.86 in summer 2007. The NSU diversity ranged from
0.58 in late spring to 0.81 in early spring summer and fall 2007. Diversity and
abundance were inversely related for Donaldsonville (Figure 13).
41
3.5
N = 1098
0.9
0.8
3
0.7
2.5
0.6
2
0.5
1.5
0.4
0.3
N = 334
1
N = 187
0.5
0.2
0.1
0
0
SPR07
SUM07
FAL07
Season
Figure 13. Seasonal diversity (Simpson’s index of diversity) and CPUE
for samples collected at the Donaldsonville site using electrofishing on
09 May 2007, 30 August 2007, and 05 October 2007. Number of fishes
collected in each sample is indicated by N.
42
Simpson's index of diversity (1 - λ).
Mean (± SD) CPUE (# fishes per minute) .
1
4
Mean (±SD ) CPUE (# fishes per minute) .
Upstream
1.6
Downstream
1.4
1.2
1
0.8
0.6
0.4
0.2
0
SPR07
SUM07
FAL07
Season
Figure 14. Mean (±SD) CPUE (number fishes per minute of
electrofishing) per season for samples collected using electrofishing at
the upstream and downstream sites from 22 March 2007 to 04 October
2007. There was no difference in CPUE at upstream or downstream
sites during the three seasons sampled.
43
Table 8. Five species had higher electrofishing CPUE at the Donaldsonville site
than the combined upstream sites and combined downstream sites from 22 March
2007 to 05 October 2007. Information included in listing is scientific name, mean
CPUE ± SD and Tukey group.
Species
DON Mean
CPUE ± SD
US Mean
CPUE ± SD
DS Mean
CPUE ± SD
Cyprinella lutrensis
1.35 ± 1.23 A
0.018 ± 0.029 B
0.093 ± 0.028 B
Cyprinella venusta
0.220 ± 0.18 A
0
0.006 ± 0.02 B
Ictiobus bubalus
0.190 ± 0.15 A
0.024 ± 0.04 B
Micropterus punctulatus
0.140 ± 0.05 A
0.006 ± 0.02 B
0
Pimephales vigilax
0.200 ± 0.25 A
0.024 ± 0.01 B
0
44
0.047 ± 0.07 B
45
Community Similarity
The downstream samples were approximately 72% similar to each other and the
upstream sites were approximately 68% similar to each other (Figure 15). Within the
upstream and downstream groups the summer and fall samples in both groups were
separated into secondary pairs that were more than 80% similar (Figure 15). Hierarchical
cluster analysis for the Donaldsonville samples grouped the summer and fall together at
approximately 70% similar to each other and approximately 55% similar to the spring
sample (Figure 16).
Water Quality
Mean seasonal water temperature for the JLC site ranged from 10.9°C in winter
2007 to 29.1°C in summer 2007 (Figure 17). The NSU mean seasonal temperature
ranged from 11.2°C in winter 2007 to 29.2°C in summer 2006 (Figure 17). There were
no differences in mean water temperatures between the JLC and NSU sites for any
season.
Mean seasonal dissolved oxygen levels for the JLC site ranged from 2.2 mg/L in
fall 2006 to 7.4 mg/L in winter 2007 (Figure 18). The NSU site had the lowest mean
dissolved oxygen levels in summer 2006 at 2.8 mg/L and the highest levels in winter
2007 at 8.1 mg/L (Figure 18). There was a difference in the mean seasonal dissolved
oxygen at the JLC site and NSU site during fall 2007 (p = 0.0009). Although the
seasonal mean levels of dissolved oxygen never reached hypoxic levels (2.0 mg/L) at
either primary site, individual samples at the JLC site reached hypoxic levels on four
46
Transform: Square root
Resemblance: S17 Bray Curtis similarity (+d)
70
80
FAL07US
SUM07US
SPR07US
FAL07DS
100
SUM07DS
90
SPR07DS
Bray-Curtis Similarity (%)
60
Figure 15. Dendrogram for hierarchical clustering (group average linking) using
the Bray-Curtis similarity matrix (y-axis) for samples collected from upstream and
downstream sites using electrofishing from 22 March 2007 to 04 October 2007.
47
Transform: Square root
Resemblance: S17 Bray Curtis similarity (+d)
50
70
80
SUM07DON
100
FAL07DON
90
SPR07DON
Bray-Curtis Similarity (%)
60
Figure 16. Dendrogram for hierarchical clustering (group average linking) using the
Bray-Curtis similarity matrix (y-axis) for samples collected from the Donaldsonville
site using electrofishing on 09 May 2007, 30 August 2007, and 05 October 2007.
48
35
JLC
NSU
Temperature ( °C)
.
30
25
20
15
10
5
0
WIN06 SPR06 SUM06 FAL 06 WIN07 SPR07 SUM07 FAL07
Season
Figure 17. Water temperature (°C) seasonal mean (±SD) for the JLC and
NSU sites from 09 February 2006 to 04 October 2007.
49
12
JLC
NSU
11
Dissolved oxygen (mg/L) .
10
9
8
7
6
*
5
4
3
2
1
0
WIN06 SPR06 SUM06 FAL 06 WIN07 SPR07 SUM07 FAL07
Season
Figure 18. Mean seasonal (±SD) dissolved oxygen (mg/L) for the JLC and NSU
sites from 09 February 2006 to 04 October 2007. The dissolved oxygen at the
NSU site was higher than the JLC site during the fall 2007 (t-test, p = 0.0009).
The dashed line indicates hypoxic level of 2.0 mg/L. Asterisk indicates
significance.
50
dates from July 2006 to October 2006 (Figure 19). Dissolved oxygen levels at the NSU
site dipped below 2.0 mg/L on one occasion, August 2006 (Figure 19).
There was a wide range in Secchi disc depth measurements throughout the study.
At the JLC site, mean secchi disc depth ranged from 31 ± 15.6 cm in summer 2007 to 169
± 27.0 cm in fall 2006 (Figure 20). There was abundant aquatic vegetation at the JLC
site throughout the summer and fall of 2006, which probably removed sediment from the
water column (Figure 21). On 11 September 2006, Secchi disc depth measured > 203
cm, which was the bottom of Bayou Lafourche at this site. Mean Secchi disc depth at the
NSU site ranged from 42.8 ± 20.3 cm in summer 2007 to 113.2 ± 24.9 cm in fall 2006.
Fall 2006 Secchi disc depth was higher at the JLC site than the NSU site (p = 0.001).
Specific conductance at the JLC site ranged from 200.4 µS cm-1 on 06 June 2007,
to 521 µS cm-1 on 11 September 2006. The specific conductance at the NSU site ranged
from 229.5 µS cm-1 on 05 December 2006 to 511 µS cm-1 on 11 September 2006 (Figure
22).
51
JLC
NSU
10
8
6
4
2
10/9/2007
8/9/2007
6/9/2007
4/9/2007
2/9/2007
12/9/2006
10/9/2006
8/9/2006
6/9/2006
4/9/2006
0
2/9/2006
Dissolved oxygen (mg/L)
.
12
Date
Figure 19. Dissolved oxygen (mg/L) at the primary sites, JLC and NSU, from
09 February 2006 to 04 October 2007. Dissolved oxygen levels fell below the
hypoxic level of 2.0 mg/L (dashed line) on four dates at the JLC site and one
date at the NSU site. There were no differences between JLC and NSU sites.
52
220
200
JLC
NSU
*
Secchi disc depth (cm)
.
180
160
140
120
100
80
60
40
20
0
WIN06 SPR06 SUM06 FAL 06 WIN07 SPR07 SUM07 FAL07
Season
Figure 20. Seasonal mean (±SD) Secchi disc depth for the JLC and NSU
sites from 09 February 2006 to 04 October 2007. The JLC site had higher
secchi depth than NSU during fall 2006 (p = 0.001).
53
Figure 21. The aquatic macrophyte hydrilla Hydrilla verticillata was abundant during
the summer and fall of 2006. The water at the site was clear with visibility reaching >
200 cm, which is the bottom of Bayou Lafourche.
54
JLC
NSU
500
400
300
200
100
10/9/07
8/9/07
6/9/07
4/9/07
2/9/07
12/9/06
10/9/06
8/9/06
6/9/06
4/9/06
0
2/9/06
Specific conductance (µS cm-1)
.
600
Date
Figure 22. Specific conductance (µS cm-1) at the JLC and NSU sites from
09 February 2006 to 04 October 2007.
55
DISCUSSION
Dams and weirs are common human alterations to North American waterways
(Poff and Hart 2002; McLaughlin et al. 2006; Harford and McLaughlin 2007) and
although dams and weirs provide many benefits to human society, these obstructions
cause changes to the lotic environment upstream and downstream of the structure
(Kanehl et al. 1997). Dams are a major factor contributing to the extirpation of obligate
riverine species such as many cyprinids (Linfield 1985; Winston et al. 1991; Lucas and
Batley 1996; Lucas and Frear 1997) and declining fisheries for anadromous species such
as Pacific salmon (Nehlsen et al. 1991) American shad Alosa sapidissima, blueback
herring A. aestivalis (Moyle and Leidy 1992; Lenhart 2003) and American eel Anguilla
rostrata (McCleave 2001; Lenhart 2003). Today there is growing awareness of the
problems created by dams and weirs and some are being removed, although there are few
studies documenting the recovery of a system following removal of a dam or weir
(Schuman 1995).
Little research has been conducted on the ichthyofauna of Bayou
Lafourche(Schultz 1996). One objective of this study was to document the species that
inhabit Bayou Lafourche upstream and downstream of the Thibodaux weir. During this
study we collected ten species that were not documented in the Schultz (1996) study of
the fish fauna of Bayou Lafourche (Table 4). I collected one new cyprinid species, the
bluntnose minnow and one Moronid, yellow bass. One Alabama shad was collected
downstream of the weir on 17 March 2006. Alabama shad is an anadromous Clupeid that
inhabits large rivers that drain into the Gulf of Mexico (Ross 2002). Although Alabama
shad was formerly found in the Mississippi River as far north as Illinois it is now
56
primarily found between the Suwanee River (GA and FL) in the east and the Mississippi
River (Ross 2002). Alabama shad makes winter and early spring spawning migrations
when water temperature is approximately 17°C (Ross 2002). Populations of American
shad have declined due to the construction of locks on rivers and intolerance to increased
siltation (Ross 2002). Alabama shad is currently listed as a species of special concern by
the United States Fish and Wildlife Service due to recent population declines (Ross
2002). The Alabama shad we collected had large lacerations on its side suggesting it
traveled through the Donaldsonville pump station turbines and passed over the
Thibodaux weir, possibly during a spawning migration up the Mississippi River (Figure
23).
Schultz (1996) did not collect any Catostomids. I collected four species from the
family, including the river carpsucker, creek chubsucker, smallmouth buffalo, and
bigmouth buffalo. Creek chubsucker undergoes a spring spawning migration, moving
upstream and into smaller tributaries (Curry and Spacie 1984). I collected one creek
chubsucker from the JLC site on 09 February 2006. This fish occurs throughout the
Mississippi River Basin in highly vegetated streams or ditches (Wagner and Cooper
1963). Creek chubsucker migrates upstream before spawning in late April or early May
and prefers to spawn in small creeks or tributaries that have swift flow over sand or
gravel beds (Wagner and Cooper 1963). There are no small tributaries upstream of the
weir in Bayou Lafourche and very little sand or gravel substrate is present, which may
explain the collection of only one individual.
57
Figure 23. Alabama shad Alosa alabamae (TL = 428 mm, weight = 795 g) collected
using a 25 m long x 1.8 m deep monofilament gill net with 25.4 mm and 38 mm
experimental bar mesh. The fish was collected on 17 March 2006, at the NSU site
located downstream of the Thibodaux weir. The fish had severe lacerations suggesting
that it passed through the Donaldsonville pump station turbine and over the Thibodaux
weir. Positive identification of the fish was made by counting the gill rakers (photo
insert), measuring body depth and by the presence of a small notch at the tip of the upper
jaw (Ross 2002).
58
I collected 30 smallmouth buffalo, a large sucker species that is native to the
Mississippi River Basin from Canada to Louisiana (Ross 2002). Smallmouth buffalo
prefer sluggish backwater habitats as opposed to main channels (Baker et al. 1991). One
bigmouth buffalo, was collected downstream of the weir. Like the smallmouth buffalo,
bigmouth buffalo prefer sluggish water as opposed to main channel habitats and is found
throughout the Mississippi River Basin (Baker et al. 1991). We collected a variety of
catostomid species during this study. The larger species such as smallmouth buffalo and
bigmouth buffalo usually inhabit low flow habitats while the smaller species such as the
river carpsucker, quillback and creek chubsucker occupy areas with faster flow (Fuiman
1985; Smith 1992).
Fish communities located upstream and downstream of the Thibodaux weir were
similar in abundance and diversity, which may be surprising because Bayou Lafourche
has been hydrologically modified. Upstream and downstream communities were similar
in overall fish abundance, species richness, evenness, and seasonal diversity. There were
many common species between the two sites; however, there were species collected
downstream of the weir that were not collected upstream of the weir and species were
collected upstream of the weir that were not collected downstream of the weir (Figure
24).
Skipjack herring, ladyfish, bay anchovy, and gulf menhaden were collected
downstream of the weir but were not collected upstream of the weir. Gulf menhaden, an
estuarine species, was collected in the spring electrofishing sample at the downstream
sites. No menhaden were collected upstream of the weir suggesting that upstream
movement in Bayou Lafourche
59
Mississippi River
Morone saxatilis Striped bass (N=3)
N
Opsopoeodus emilae Bluntnose minnow (N=4)
Pimephales vigilax Bullhead minnow (N=20)
Micropterus punctulatus Spotted bass (N=14)
Lythrurus fumeus Ribbon shiner (N=2)
Cyprinella venusta Blacktail shiner (N=2)
Aphredoderus sayanus Pirate perch (N=6)
Primary Sites
Heterandria formosa Least killifish (N=6)
Donaldsonville
Bayou Lafourche
Thibodaux Weir
Anchoa mitchilli Bay anchovy (N=34)
Brevoortia patronus Gulf menhaden (N=13)
Alosa chrysochloris Skipjack herring (N=9)
Elops saurus Ladyfish (N=4)
1 river km
Figure 24. Eight species were collected upstream but not downstream of the weir
(top). Four species were collected downstream but not upstream of the weir (bottom).
Fishes were collected between 09 February 2006 and 05 October 2007 using
monofilament gill nets and electrofishing.
60
was blocked by the weir. Gulf menhaden spawn offshore from October to April and the
young of the year move into estuaries or fresh water systems in late winter and early
spring (Turner et al. 1969). Turner et al. (1969) collected young menhaden in salinities
less than 0.5 ppt. In Bayou Lafourche we collected 13 gulf menhaden on 22 March 2007,
in salinities of 0.2 ppt. There were no water quality differences between the JLC and
NSU sites in spring 2007 when the bay anchovy and gulf menhaden were collected
downstream of the weir (Figures 18, 19 and 21). There does not appear to be a
temperature or salinity gradient that would prevent the movement of these fishes further
upstream. I concluded that the weir serves as a physical barrier to the upstream
movement of the euryhaline fishes we collected.
Eight species were collected upstream of the weir that were not downstream of
the weir. Spotted bass were collected in Donaldsonville and at a randomly selected
upstream site (US-1). Schultz (1996) collected 13 spotted bass from six sites in the upper
portions of Bayou Lafourche. Spotted bass generally inhabit areas with greater flow than
do largemouth bass (Ross 2002). We collected 14 spotted bass at the DON site where the
water exits the pump station at an average discharge (7.0 m3s-1) slightly higher than the
discharge in Thibodaux (5.6 m3s-1). Spotted bass may prefer the higher flow rate at the
Donaldsonville site and the upper bayou than the lower flow rate at the Thibodaux sites.
Three striped bass were collected from the Donaldsonville site in the summer 2007
electrofishing sample. Striped bass were not collected from any other site in this study;
however, Schultz (1996) collected striped bass from sites upstream and downstream of
the weir.
61
I collected two cyprinid species upstream of the weir that were not collected
downstream of the weir. Ribbon shiners inhabit clear to occasionally turbid waters in
moderate size streams or rivers and are often found in pools and backwaters (Felley and
Hill 1983). Blacktail shiners usually inhabit areas with moderate to swift current (Baker
and Ross, 1981; Baker et al. 1991) although some reservoir dwelling populations inhabit
lower velocity waters (Baker et al. 1991).
I collected pirate perch and least killifish upstream of the weir. Both of these
species prefer quiet areas with heavy vegetative cover (Ross et al. 1987; Ross 2002),
which is very abundant in the upstream portions of Bayou Lafourche.
I collected bullhead minnows, bluntnose minnows, and pugnose minnows from
the Donaldsonville site. The bullhead minnow prefers backwater areas with slow moving
water and mud or silt substrata (Rutledge and Beitinger 1989). The bullhead minnow is
tolerant of high temperatures and turbidity and low dissolved oxygen levels (Rutledge
and Beitinger 1989). The bluntnose minnow prefers habitats with sandy substrata and
tolerates moderately high temperatures (Kowalski et al. 1978). The pugnose minnow is
usually found in clear water (Trautman 1981). All three species consume detritus and
insect larvae from plant surfaces and are strongly associated with weedy areas with
emergent and submerged aquatic vegetation (Ross 2002). Upstream portions of Bayou
Lafourche have abundant vegetative cover and higher water clarity than do downstream
portions, which are preferable to these minnow species.
Centrarchids were consistently collected from Bayou Lafourche throughout this
study and comprised over 70% of the electrofishing catch at the upstream, downstream
and Donaldsonville sites and nearly 60% of the gill net catch upstream of the weir. One
62
reason for the high percent of centrarchids in the upstream catch is a sampling anomaly
that occurred on 31 October 2006, when we collected 85 centrarchids using gill nets. On
this date we collected 45 largemouth bass and only four non-centrarchid fishes. Many
centrarchid species use aquatic vegetation as habitat and on 30 October 2006 and 31
October 2006, the BLFWD used large cutting machines to mow aquatic vegetation
upstream of the JLC site. I hypothesized that the centrarchids were pushed out of the
mowed area by the cutters and became concentrated at the JLC site between the mowing
activity and the Thibodaux weir.
Gizzard shad catch per unit effort was higher at downstream sites than upstream
sites using monofilament gill nets. I believe the gizzard shad swim upstream during the
spring spawning season are blocked from further migration by the Thibodaux weir. I
collected 94 gizzard shad downstream of the weir and 11 upstream of the weir using gill
nets. Over 50% of the downstream gizzard shad were collected between 09 February
2006 and 10 May 2006. During the 2005 spring spawning season, gizzard shad were
documented moving into and out of Bayou Chevreuil, a nearby unimpounded system and
potential spawning habitat (Fontenot 2006). Shad may seasonally migrate into and out of
Bayou Chevreuil to spawn. This movement is blocked in Bayou Lafourche by the
Thibodaux weir at river km 55, which may be the upstream limit for downstream
populations of gizzard shad migrating up Bayou Lafourche. However, downstream
populations of gizzard shad may move into Lake Beouf or other connected areas of the
BTES via small channels and canals. Upstream populations of gizzard shad probably
move upstream as far as Donaldsonville and but are prevented from moving into the
Mississippi River by the pump station.
63
The differences in seasonal abundances or gillnet CPUE may be influenced by the
capture of individual species in high quantities during a few sample dates or due to gear
effectiveness in different conditions. There was abundant aquatic vegetation at both
primary sites that sometimes made gill net deployment difficult (Figure 22). This was
particularly problematic at the JLC site when the BLFWD mowed aquatic vegetation
upstream of our nets. As the nets soaked and collected floating vegetation the nets may
became less effective at catching fish and CPUE may have been skewed. Water clarity at
the upstream site during summer and fall 2006 may have decreased gillnet effectiveness
by allowing fish to see the net. In contrast, the electrofishing CPUE was similar among
sites and seasons. Electrofishing effort and methods were consistent throughout the three
seasons and at the fourteen sites and therefore I feel confident that these samples provide
an accurate assessment of the fish populations upstream and downstream of the weir.
Water quality and fish community analyses indicate Bayou Lafourche is currently
a stable system. Fluctuations in water quality parameters such as temperature and
dissolved oxygen responded equally to local seasonal patterns, as there were no
differences between the two primary sites. Additionally, there were no differences
between upstream and downstream fish abundance and community diversity. However,
Bayou Lafourche has experienced human modifications that have shaped the current fish
community. The Bayou Lafourche fish community responded as the aquatic environment
changed following three major hydrologic modifications: the initial damming of the
headwaters in 1903, the installation of the pump station in 1955, and the installation of
the Thibodaux weir in 1969. Each of these events altered the hydrology of Bayou
Lafourche, which may have altered the fish community.
64
Hydrologic variability of a river controls its physical, chemical and biological
character (Yeager 1993). In most cases, alteration of hydrology by impounding rivers
decreases flow variability and results in a change in the faunal composition, biomass, and
diversity (Fitz 1968; Edwards 1978). A river ecosystem may be considered stable if it
has reduced fluctuations in energy flows and is able to maintain the community structure
and functionality despite environmental variations (Vannote et al. 1980). Hydrologically
variable systems will contain more habitat generalists and tolerant species than will stable
systems (Poff and Ward 1989). Environments with hydrologic variability usually select
for species that have generalized feeding strategies are associated with silt and mud
substrata, have wide geographic ranges, and are characterized by preference for low
water velocity (Poff and Allan 1995). Aquatic systems with little hydrologic variability
are considered stable and tend to have fishes that are silt-intolerant, trophic specialists
and are associated with fast or moderately flowing water (Poff and Allan 1995).
Historically, protection of a riverine water body focused on the minimum flow
necessary rather than the regime of flow characteristics needed for a healthy system (Poff
et al. 1997). Natural flow regime can change over hours, days, seasons, years and longer.
Volume and timing of streamflow is crucial to the ecological integrity of the system (Poff
et al. 1997) and is often considered the limiting factor in distribution and abundance of
riverine species (Power et al. 1995; Resh et al. 1998). Determination of a water body’s
natural flow regime is made after years of observing the fluctuations in quantity, timing
and variability of the flow. Five components of changing hydrologic conditions are
considered necessary to maintain the ecological integrity of a riverine system: frequency,
magnitude, duration, timing and rate (Poff and Ward 1989). Bayou Lafourche
65
experiences very little hydrologic change as it has been artificially controlled for over
100 years. Discharge has been maintained at ~5.6 m3s-1 by the BLFWD since installation
of the pump station in 1959. Bayou Lafourche is an artificially stable system that
experiences very little seasonal hydrologic variability. Flood-type events are dependent
upon localized rain events rather than seasonal flood pulse and are thus infrequent, of
short duration, and the timing and predictability does not necessarily correspond to
biological needs of the fish community.
Anthropogenic hydrologic alteration disrupts the equilibrium of water and
sediment movement and alters the “steady state” that is based on consistent patterns and
adjustments in the relationship between stream width, depth, velocity and sediment load
(Vannote 1980). Habitat is largely defined by the physical processes of the system,
especially movement of water and sediment between the channel and floodplain (Poff et
al. 1997). Over long periods of time in a natural system, some river systems can offer
free-flowing, floodplain, and low-water habitat depending upon the flow regime during
that time period (Poff et al. 1997). Upstream portions of Bayou Lafourche between
Donaldsonville and Thibodaux have few opportunities for fish to reach backwater habitat,
even during infrequent times of high water.
Community structure is dynamic and adjusts to changes in abiotic and biotic
variables and barrier such as a weir may affect the transport of nutrients and organic
matter, thus affecting the relationships between autotrophs and heterotrophs within the
system (Vannote et al. 1980). However, small barriers are less likely to change the
abiotic variables of the waterbody (Poff et al. 1997). The Thibodaux weir may be small
enough that it does not influence the surrounding area to a large degree. Furthermore,
66
disturbance or alteration does not always decrease diversity. Theories on the influence of
disturbance in an aquatic environment suggest that where alteration is minimal species
diversity is reduced because of competitive exclusion among species. If the level of
disturbance increases in intensity or frequency it eliminates some species and diversity
will decrease, thus diversity may be the highest when disturbance is at an intermediate
level (Connell 1978; Huston 1979).
Connectivity may also be a factor in community dynamics of Bayou Lafourche.
Upstream reaches of Bayou Lafourche have a one-way connection to the Mississippi
River. Fishes can enter Bayou Lafourche through the pump station in Donaldsonville but
cannot easily travel back through to the River. It is possible that the number and
diversity of fishes entering Bayou Lafourche from the Mississippi River system is
increasing diversity upstream of the weir. Downstream of the weir, habitat availability
increases as Bayou Lafourche continues south through the Barataria and Terrebonne
Estuaries. Bayou Lafourche is connected to Lake Boeuf via the Theriot Canal, the
Intracoastal Waterway, and the Gulf of Mexico, which all present opportunities for fish
movement and subsequent increased diversity.
I believe that connectivity of Bayou Lafourche to two diverse ecosystems, the
Mississippi River and the Gulf of Mexico, allows this artificially controlled system to
maintain diverse fish assemblages both upstream and downstream of the Thibodaux weir.
However, I also believe that it is important to the health of the larger surrounding
ecosystem, the BTES, that an approximation of normal flow regime is restored to Bayou
Lafourche. There are several possible benefits of a natural flow regime in Bayou
Lafourche. Increased water and nutrients being conveyed down Bayou Lafourche and
67
deposited in surrounding wetlands will help increase productivity and health of those
wetlands, which in turn supports fish populations (Louisiana Department of Natural
Resourches 1998). Flow variation mimicking natural flow regimes would support those
fishes dependent upon high or low water periods for portions of their life cycle or an
environmental cue (Poff et al. 1997).
The exact response of the Bayou Lafourche fish community to the weir removal
and increased flow is difficult to predict. Increased abundances of darters, catostomids
and cyprinids occurred after the removal of a dam in Wisconsin, which were probably
due to the fishes’ ability to move freely within a larger geographic range following
removal of the structure (Kanehl et al. 1997). Increased flow should positively affect
species in Bayou Lafourche that prefer higher flow velocities such as cyprinids, blue
catfish, spotted bass and small suckers. Introduction of more water into Bayou Lafourche
may have a negative impact on the larger species of catostomids such as the smallmouth
and bigmouth buffalo. Under high flow these two species seek out floodplains or small
tributaries rather than remaining in the main channel (Baker et al. 1991; Ross 2002).
Greater flow conditions may cause a shift catostomid species in Bayou Lafourche from
large species to small species such as the creek chubsucker and quillback (Fuiman 1985;
Smith 1992).
Removal of the Thibodaux weir will allow fishes to more easily move up and
down Bayou Lafourche. Currently, there is probably little exchange between the
upstream and downstream populations of fishes due to obstructed movement by the weir.
Occasional heavy rain events make it possible for fish to swim upstream over the weir.
Overtopping of the weir occurs if 15 cm or more rain falls in less than 24 hours. In 2001,
68
the water level of Bayou Lafourche rose from an average of 1.2 m to 3.4 m due to
Tropical Storm Allison, which brought 76 cm of rainfall within 2-3 days (A. Chaisson,
BLFWD, personal communication). Most recently overtopping occurred on 22 October
2007, when approximately 15 cm of rain fell within 24 hours (Figure 25). Overtopping
of the weir allows the fish to move upstream and downstream of the weir freely without
obstruction.
Under normal conditions most fishes can pass over the weir in a downstream
direction but cannot move back upstream over the structure. Most studies focus on
obstruction of upstream migratory fish movement but few focuses on the inability of fish
to move downstream due to impoundment. Radio-tagging studies in Australia have
documented two perch species, golden perch Macquaria ambigua and Murray cod
Maccullochella peelii peelii, that are sometimes reluctant to move downstream either
over or through regulating structures and will often exhibit a circling pattern near the
structure (O’Connor et al. 2006) before heading back upstream (Jepsen et al. 1998; Haro
et al. 1998). Consequences to biological processes of fishes such as feeding and
spawning caused by obstructed downstream movement are less well understood than are
the consequences of impeded upstream movement (O’Connor et al. 2006). However,
downstream movement is probably equally important as upstream movement to the life
histories of fishes that utilize large stretches of a river system for spawning or feeding
(O’Connor et al. 2006). Cyprinid and catostomid fishes exhibit upstream migratory
behavior as well as movement in response to water current (Schwalme et al. 1985; Monk
et al. 1989; Rodriguez-Ruiz and Gradado-Lorencio 1992; Bunt 2001). Seasonal
69
migratory behavior by fish like cyprinids is triggered by river flow and temperature
fluctuations (Linfield 1985).
70
Figure 25. Approximately 15 cm of rainfall caused the overtopping of the Thibodaux
weir on 22 October 2007. This type of high water event occurs approximately twice
per year (A. Chaisson, BLFWD personal communication).
71
In an unobstructed river system, the movement patterns of cyprinids are a combination of
active movements, both upstream and downstream, interspersed with periods of passive
downstream displacement and seasonal aggregation during winter (Linfield 1985).
Large, mature cyprinids exhibit a tendency for upstream movement and will aggregate in
headwaters (Linfield 1985), which I saw with catches of large cyprinids in
Donaldsonville. If the weir is removed the cyprinid and catostomid fishes should be free
to move upstream and downstream in Bayou Lafourche on a seasonal basis.
Dams and other barriers to movement may prevent movement of fishes causing
decreases in migration, gene flow and colonization (Warren and Pardew 1998; Pringle et
al. 2000). Although this study did not find differences in fish communities upstream and
downstream of the weir the removal of the weir should have positive effects on fishes
that seasonally migrate either within the freshwater system from the lower estuary.
Currently the upstream and downstream assemblages have few opportunities for mixing.
Small scale fish movement allows an individual to occupy the most beneficial habitat to
support survival and growth (Gowan and Fausch 2002). Large scale movement is usually
part of life history behavior such as spawning migrations, in response to large
disturbances, or to colonize vacant habitats (Brown and Kodric-Brown 1977; Peterson
and Bayley 1993; Northcote 1984). Movement is a critical process that allows fishes to
meet their resource needs in spatially and temporally variable stream environments
(Schlosser and Angermeier 1995). The elimination of the weir as a barrier will allow the
fishes in Bayou Lafourche a natural range of movement within the system, which should
benefit the fish population by providing increased habitat and resource availability.
72
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Vannote, R.L., G.W. Minshall, K.W. Cummins, J.R. Sedell, and C.E. Cushing. 1980. The
river continuum concept. Canadial Journal of Fisheries and Aquatic Sciences 37:130137.
Wagner, B.A., E.L. Cooper. 1963. Population density, growth, and fecundity of the creek
chubsucker, Erimyzon oblongus. Copeia 1963(2):350-357.
79
Warren, M.L., Jr., and Pardew, M.G. 1998. Road crossings as barriers to small-stream fish
movement. Transactions of the American Fisheries Society 127:637-644.
Winston, M.R., C.M. Taylor, and J. Pigg. 1991. Upstream extirpation of four minnow
species due to damming of a prairie stream. Transactions of the American Fisheries
Society 120:98-105
Yeager, B.L. 1993. Dams. Pages 57 - 114 in Impacts on warmwater streams: Guidelines for
Evaluation. C.F. Bryan and D.A. Rutherford editors. American Fisheries Society,
Bethesda, Maryland.
80
81
Appendix II. Listing of all fish collected from 09 February 2006 to 05 October 2007 using
monofilament gill nets and electrofishing. Information listed includes date,
site, species code, gear type used (Net = gill net, Shock = electrofishing), number collected,
mean total length (mm), mean weight (g). Site abbreviations and information are listed in
Appendix I. Information is listed in chronological order. Species code information is listed
in Appendix III.
Date
Site
Species
Gear
Number
Length
Weight
20060209
20060209
20060209
20060209
20060209
20060209
20060209
20060209
20060209
20060209
20060209
20060220
20060220
20060220
20060220
20060220
20060220
20060317
20060317
20060317
20060317
20060317
20060317
20060317
20060317
20060317
20060406
20060406
20060406
20060406
JLC
JLC
JLC
JLC
JLC
JLC
NSU
NSU
NSU
NSU
NSU
JLC
NSU
NSU
NSU
NSU
NSU
JLC
JLC
JLC
JLC
NSU
NSU
NSU
NSU
NSU
JLC
JLC
JLC
JLC
Do_cep
Er_obl
Ic_pun
Le_oss
Mo_chr
Mu_cep
Ap_gru
Do_cep
Ic_pun
Lep_cya
Mu_cep
Mi_sal
Am_cal
Ap_gru
Do_cep
Le_ocu
Mu_cep
Do_cep
Ic_pun
Le_ocu
Mi_sal
Al_ala
Do_cep
Mi_sal
Mo_mis
Mu_cep
Do_cep
Ic_pun
Mi_sal
Mu_cep
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
2
1
1
1
1
2
1
26
3
1
3
1
1
1
7
1
2
1
2
1
2
1
1
2
2
4
3
1
4
3
354
236
220
640
239
343
254
301
284
135
287
390
519
175
195
548
330
332
324
557
275
428
315
273
232
290
366
396
263
345
575
139
74
501
184
382
154
321
279
37
275
911
1,210
46
63
578
357
458
331
662
310
795
345
291
225
290
600
660
214
426
82
20060406
20060406
20060406
20060406
20060406
20060406
20060406
20060406
20060427
20060427
20060427
20060427
20060427
20060427
20060427
20060427
20060427
20060427
20060427
20060427
20060510
20060510
20060510
20060510
20060510
20060510
20060510
20060602
20060602
20060602
20060602
20060602
20060602
20060602
20060602
20060615
20060615
20060615
20060615
20060615
20060615
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
JLC
JLC
JLC
JLC
JLC
JLC
NSU
NSU
NSU
NSU
NSU
NSU
JLC
JLC
JLC
JLC
JLC
NSU
NSU
JLC
JLC
NSU
NSU
NSU
NSU
NSU
NSU
JLC
JLC
JLC
JLC
JLC
NSU
Do_cep
Do_pet
Ic_pun
Le_ocu
Lep_gul
Mi_sal
Mo_mis
Mu_cep
Le_ocu
Le_oss
Lep_mic
Mi_sal
Mu_cep
Po_nig
Do_cep
Ic_pun
Le_ocu
Lep_gul
Mi_sal
Mu_cep
Ap_gru
Ic_pun
Le_ocu
Mi_sal
Mu_cep
Do_cep
Mu_cep
Ic_pun
Mu_cep
Do_cep
Ic_pun
Le_ocu
Mi_sal
Mo_mis
Mu_cep
Do_cep
Ic_pun
Lep_meg
Lep_mic
Mu_cep
Cyp_car
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
83
9
2
1
1
1
1
2
5
6
1
1
2
3
1
8
1
4
1
1
1
1
2
2
3
4
2
3
1
2
4
1
3
2
1
6
2
1
1
1
2
1
274
185
306
650
178
250
260
239
425
1,000
.
203
220
145
277
428
459
153
189
342
374
213
496
289
318
259
318
379
352
185
305
403
178
75
265
302
242
104
146
313
480
291
68
291
1,080
155
238
293
138
253
3,490
.
105
120
42
267
877
383
102
112
385
703
87
452
349
366
149
346
653
470
194
155
523
185
77
303
237
121
28
660
339
1,550
20060615
20060628
20060628
20060628
20060628
20060628
20060628
20060706
20060706
20060706
20060706
20060706
20060706
20060717
20060717
20060717
20060717
20060717
20060717
20060717
20060717
20060801
20060801
20060801
20060801
20060801
20060801
20060801
20060831
20060831
20060831
20060831
20060831
20060831
20060831
20060831
20060911
20060911
20060911
20060911
20060911
NSU
NSU
NSU
NSU
NSU
NSU
NSU
DON
DON
DON
DON
DON
DON
JLC
JLC
JLC
NSU
NSU
NSU
NSU
NSU
JLC
JLC
JLC
JLC
NSU
NSU
NSU
JLC
JLC
JLC
JLC
JLC
JLC
NSU
NSU
JLC
JLC
JLC
NSU
NSU
Ic_pun
Cyp_car
Do_cep
Ic_pun
Le_ocu
Mi_sal
Mu_cep
Do_cep
Ic_pun
Le_ocu
Mi_sal
Mo_mis
Mu_cep
Ic_bub
Le_ocu
Mi_sal
Do_cep
El_sau
Ic_pun
Le_ocu
Mu_cep
Le_ocu
Lep_mac
Lep_meg
Mi_sal
Do_cep
El_sau
Mu_cep
Ic_pun
Le_ocu
Lep_mac
Mi_sal
Mu_cep
Po_nig
Le_ocu
Mi_sal
Ic_bub
Lep_mic
Mi_sal
Al_chr
Do_cep
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
84
1
1
4
2
1
1
2
1
5
2
2
1
2
1
1
3
2
1
1
2
1
1
2
3
1
5
1
1
1
1
2
4
1
2
1
1
1
4
18
3
3
323
230
283
425
495
224
250
290
422
468
350
243
269
442
546
288
323
170
.
503
317
502
119
116
332
330
217
336
425
484
134
298
242
190
392
230
640
197
285
255
271
474
217
299
760
465
.
185
215
1,064
340
640
204
347
600
580
363
400
24
.
493
400
509
39
36
578
357
43
363
862
461
50
378
153
133
200
162
3,650
155
298
133
340
20060911
20060911
20060911
20060911
20060927
20060927
20060927
20060927
20060927
20060927
20060927
20060927
20060927
20061024
20061024
20061024
20061024
20061031
20061031
20061031
20061031
20061031
20061031
20061031
20061031
20061031
20061031
20061031
20061031
20061031
20061031
20061031
20061031
20061031
20061031
20061031
20061109
20061109
20061109
20061109
20061109
NSU
NSU
NSU
NSU
DON
DON
JLC
JLC
JLC
JLC
JLC
NSU
NSU
NSU
NSU
NSU
NSU
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
JLC
JLC
NSU
NSU
NSU
El_sau
Lep_gul
Mi_sal
Mu_cep
Mi_sal
Mu_cep
Ic_bub
Ic_pun
Lep_gul
Mi_sal
Mu_cep
Do_cep
Mi_sal
Do_cep
Le_ocu
Mi_sal
Mu_cep
Do_cep
Ic_bub
Ic_pun
Lep_gul
Lep_mac
Lep_meg
Lep_mic
Lep_min
Mi_sal
Mo_mis
Po_nig
Al_chr
Do_cep
Ic_pun
Lep_gul
Lep_mic
Mi_sal
Mo_mis
Mu_cep
Ic_pun
Mu_cep
Ic_bub
Ic_pun
Mi_sal
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
85
1
2
1
1
1
1
2
1
1
1
2
3
1
2
1
2
2
1
1
2
13
10
2
9
4
44
2
2
1
3
3
1
1
1
1
2
1
2
2
1
1
290
142
352
213
276
232
463
515
154
185
349
345
.
280
640
285
330
387
640
383
174
126
135
200
122
260
240
214
245
366
310
162
139
302
207
408
670
340
519
555
205
158
77
727
102
239
135
1,750
1,500
60
83
521
459
.
264
1,225
348
401
561
3,650
529
118
39
41
153
45
261
218
146
108
622
261
76
47
389
1,235
815
2,750
415
2,250
1,825
103
20061109
20061205
20070220
20070220
20070220
20070220
20070220
20070306
20070306
20070306
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
20070322
NSU
NSU
JLC
JLC
NSU
NSU
NSU
JLC
JLC
NSU
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
Mu_cep
Mu_cep
Ic_pun
Mi_sal
Ic_pun
Mi_sal
Mu_cep
Mi_sal
Mu_cep
Mu_cep
An_ros
Cy_car
Cy_lut
Ga_aff
La_sic
Le_ocu
Lep_gul
Lep_mac
Lep_meg
Lep_mic
Lep_min
Lu_par
Me_ber
Mi_sal
Mu_cep
No_cry
An_mit
Br_pat
Cy_car
Ga_aff
La_sic
Le_ocu
Lep_gul
Lep_mac
Lep_meg
Lep_mic
Lep_min
Me_ber
Mi_sal
Mu_cep
No_cry
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
86
2
4
1
1
1
2
3
1
2
6
3
1
1
22
2
3
3
26
26
21
84
7
5
14
2
1
6
13
1
2
4
4
2
54
4
6
44
11
5
13
1
378
336
.
325
535
328
325
403
346
283
307
790
.
.
.
425
161
83
92
114
74
.
.
236
304
180
.
.
536
.
.
488
101
94
102
151
73
.
253
341
.
583
370
.
638
1,675
655
370
1,250
419
231
61
7,100
.
.
.
180
82
19
22
44
12
.
.
230
285
70
.
.
2,260
.
.
528
45
23
22
69
13
.
243
413
.
20070330
20070330
20070330
20070330
20070330
20070330
20070330
20070330
20070330
20070330
20070330
20070330
20070417
20070417
20070417
20070417
20070417
20070417
20070501
20070501
20070501
20070501
20070501
20070501
20070501
20070501
20070501
20070501
20070501
20070501
20070501
20070501
20070501
20070501
20070501
20070509
20070509
20070509
20070509
20070509
20070509
JLC
JLC
JLC
JLC
JLC
JLC
NSU
NSU
NSU
NSU
NSU
NSU
JLC
NSU
NSU
NSU
NSU
NSU
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
DON
DON
DON
DON
DON
DON
Ic_pun
Le_ocu
Lep_meg
Lep_mic
Lep_min
Mi_sal
Al_chr
Am_cal
Ic_pun
Le_ocu
Lep_mic
Mo_mis
Lep_mic
Do_cep
Lep_gul
Lep_mic
Mi_sal
Mu_cep
Do_cep
Ic_pun
Le_ocu
Le_oss
Lep_mac
Lep_meg
Lep_min
Mi_sal
Mu_cep
Do_cep
Ic_pun
Le_ocu
Lep_gul
Lep_meg
Lep_mic
Mi_sal
Mu_cep
Ic_bub
An_ros
Cy_car
Cy_lut
Cy_ven
Do_pet
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Shock
Shock
Shock
Shock
Shock
Shock
87
2
2
1
1
1
2
2
1
1
8
1
1
2
2
1
2
1
4
1
1
5
1
1
1
1
1
4
1
7
6
2
2
3
1
18
4
1
1
91
14
2
319
496
122
142
112
305
233
540
400
535
186
205
127
300
166
125
386
295
425
380
488
1,085
120
110
108
178
310
360
311
482
194
122
138
320
267
584
342
1,062
54
61
158
344
552
34
58
35
447
91
1,700
675
627
133
153
42
189
106
38
867
284
1,050
751
496
3,900
33
35
30
79
357
460
467
467
143
37
46
534
222
3,036
73
16,100
2
2
39
20070509
20070509
20070509
20070509
20070509
20070509
20070509
20070509
20070509
20070509
20070509
20070509
20070509
20070509
20070509
20070509
20070509
20070509
20070509
20070509
20070509
20070509
20070509
20070509
20070509
20070521
20070521
20070521
20070521
20070521
20070521
20070521
20070521
20070521
20070521
20070521
20070522
20070522
20070522
20070522
20070522
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
JLC
JLC
JLC
JLC
JLC
NSU
NSU
NSU
NSU
NSU
NSU
US-1
US-1
US-1
US-1
US-1
Ga_aff
Ic_pun
Ic_pun
La_sic
Le_ocu
Le_ocu
Le_oss
Le_oss
Lep_cya
Lep_gul
Lep_mac
Lep_mac
Lep_meg
Lep_min
Lu_par
Me_ber
Mi_pun
Mi_pun
Mi_sal
Mi_sal
Mu_cep
Mu_cep
Pi_vig
Po_lat
Po_nig
Le_ocu
Lep_gul
Lep_mic
Mi_sal
Mu_cep
Al_chr
Ic_fur
Ic_pun
Le_ocu
Mi_sal
Mu_cep
Am_cal
Am_nat
An_ros
Ap_gru
Ap_say
Shock
Net
Shock
Shock
Net
Shock
Net
Shock
Shock
Shock
Net
Shock
Shock
Shock
Shock
Shock
Net
Shock
Net
Shock
Net
Shock
Shock
Shock
Shock
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Shock
Net
Shock
Net
Shock
88
4
4
5
3
1
3
1
3
4
33
1
55
150
616
34
4
1
6
2
5
1
41
16
2
1
2
1
1
1
3
1
1
3
1
1
4
1
1
3
1
4
37
475
476
72
552
509
790
977
88
79
120
55
63
58
38
78
315
222
243
223
275
223
55
44
139
510
120
179
219
354
225
435
275
540
320
286
670
159
363
401
51
<1
1,392
1,416
<1
672
534
1,060
3,733
24
23
37
4
6
4
<1
3
461
213
222
172
239
138
2
<1
38
567
44
115
148
497
97
903
241
581
537
262
3,350
25
182
869
3
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
US-1
US-1
US-1
US-1
US-1
US-1
US-1
US-1
US-1
US-1
US-1
US-1
US-1
US-1
US-1
US-1
US-1
US-1
US-2
US-2
US-2
US-2
US-2
US-2
US-2
US-2
US-2
US-2
US-2
US-2
US-2
US-2
US-2
US-2
US-2
US-2
US-2
US-2
JLC
JLC
JLC
Cy_lut
Do_cep
Le_ocu
Le_ocu
Lep_gul
Lep_gul
Lep_mac
Lep_meg
Lep_meg
Lep_mi
Lep_mic
Lep_min
Lep_min
Lu_par
Mi_sal
Mi_sal
Mu_cep
Mu_cep
Am_nat
Apl_gr
Cy_lut
Do_cep
Ga_aff
He_for
Ic_pun
La_sic
Le_ocu
Le_ocu
Lep_gul
Lep_gul
Lep_mac
Lep_meg
Lep_mic
Lep_mic
Lep_min
Mi_sal
Mu_cep
Po_lat
An_ros
Ap_say
Ga_aff
Shock
Shock
Net
Shock
Net
Shock
Shock
Net
Shock
Shock
Net
Net
Shock
Shock
Net
Shock
Net
Shock
Shock
Net
Shock
Shock
Shock
Shock
Shock
Shock
Net
Shock
Net
Shock
Shock
Shock
Net
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
89
1
3
8
3
2
4
31
1
48
4
1
1
134
2
6
13
17
21
2
1
1
1
8
3
1
1
3
9
1
2
5
85
4
3
126
13
8
2
1
1
8
80
282
485
369
165
162
93
123
79
118
132
110
76
40
277
206
272
262
240
391
93
147
36
27
504
82
543
576
130
163
93
76
241
228
82
118
317
39
272
41
31
5
233
482
151
122
98
22
48
11
36
46
33
10
1
382
213
243
211
324
895
9
33
1
<1
1,806
3
356
888
53
106
19
12
225
248
14
102
389
1
39
1
<1
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070522
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
DS-1
DS-1
DS-1
DS-1
DS-1
DS-1
DS-1
DS-1
DS-1
DS-1
DS-1
DS-1
DS-1
DS-1
DS-1
DS-1
DS-1
DS-1
DS-1
DS-1
DS-1
DS-2
DS-2
DS-2
DS-2
DS-2
DS-2
He_for
Ic_bub
Le_ocu
Lep_gul
Lep_mac
Lep_meg
Lep_mic
Lep_min
Lu_par
Ly_fum
Me_ber
Mi_sal
Mu_cep
No_fum
An_mit
Ca_car
Cy_car
Cy_car
Ic_pun
Ic_pun
Le_ocu
Le_ocu
Lep_gul
Lep_mac
Lep_mac
Lep_meg
Lep_meg
Lep_mic
Lep_min
Lep_min
Mi_sal
Mi_sal
Mo_mis
Mu_cep
Mu_cep
Al_chr
Ap_gru
Do_cep
Ic_pun
Le_ocu
Mi_sal
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Net
Net
Shock
Net
Shock
Net
Shock
Shock
Net
Shock
Net
Shock
Shock
Net
Shock
Net
Shock
Net
Net
Shock
Net
Net
Net
Net
Net
Net
90
2
2
6
3
31
48
12
123
2
1
1
14
11
1
27
1
1
2
2
1
1
3
4
1
25
1
20
5
1
18
1
20
3
4
3
1
1
1
1
3
5
25
560
590
168
95
70
149
70
35
33
30
131
313
29
45
349
666
291
195
435
421
511
125
124
101
107
91
114
120
71
225
120
236
319
316
271
.
276
277
546
265
<1
3,350
844
116
24
7
102
8
<1
<1
<1
87
369
<1
.
539
3,298
2,795
129
1,195
243
460
51
35
28
31
17
30
37
10
126
74
140
340
373
166
.
195
191
607
332
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070523
20070606
20070606
20070606
20070606
20070606
20070606
20070606
20070606
20070630
20070630
20070630
20070630
20070630
20070630
20070630
20070630
20070630
20070630
20070630
20070630
20070730
20070730
20070730
DS-2
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
JLC
JLC
JLC
JLC
NSU
NSU
NSU
NSU
JLC
JLC
JLC
JLC
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
JLC
JLC
JLC
Mu_cep
An_ros
Cy_car
Ga_aff
Ic_bub
Ic_cyp
Ic_pun
La_sic
Le_ocu
Lep_gul
Lep_mac
Lep_meg
Lep_mic
Lep_min
Mi_sal
Mu_cep
Po_lat
Po_nig
Ic_pun
Le_ocu
Lep_gul
Mi_sal
Le_ocu
Le_oss
Lep_mac
Mu_cep
Do_cep
Le_gul
Le_ocu
Lep_gul
Ic_bub
Ic_pun
Le_mac
Le_ocu
Lep_mic
Mi_sal
Mo_mis
Mu_cep
Am_nat
Lep_gul
Mu_cep
Net
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
Net
91
17
1
2
2
1
1
1
1
4
8
17
5
10
16
16
30
1
1
1
1
1
1
2
1
1
1
1
1
3
2
1
3
1
1
1
1
1
8
1
1
1
266
281
616
35
422
412
426
82
419
148
119
92
148
84
149
298
39
265
451
570
.
203
502
894
117
302
375
170
606
181
457
402
121
521
160
222
188
304
215
160
323
213
49
3,225
1
1,200
1,900
929
2
278
91
37
27
62
19
92
317
1
296
1,200
638
.
1,350
460
2,050
38
284
604
100
901
133
1,525
824
38
475
84
142
111
305
142
120
382
20070730
20070730
20070730
20070730
20070730
20070730
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
20070816
NSU
NSU
NSU
NSU
NSU
NSU
US-4
US-4
US-4
US-4
US-4
US-4
US-4
US-4
US-4
US-4
US-5
US-5
US-5
US-5
US-5
US-5
US-5
US-5
US-5
US-5
US-5
US-5
US-5
US-5
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
Al_chr
Do_cep
Ic_bub
Ic_pun
Mi_sal
Mu_cep
An_ros
Ap_say
Le_ocu
Lep_mac
Lep_meg
Lep_mic
Lep_min
Mi_sal
Mu_cep
Po_lat
Am_nat
Cy_ven
Do_cep
Ga_aff
Lep_mac
Lep_meg
Lep_mic
Lep_min
Lu_par
Me_ber
Mi_sal
Mu_cep
No_cry
Po_lat
Am_nat
An_ros
Ga_aff
La_sic
Le_ocu
Lep_gul
Lep_mac
Lep_meg
Lep_mic
Lep_min
Lu_par
Net
Net
Net
Net
Net
Net
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
92
1
1
1
4
1
1
1
1
1
15
10
3
15
14
31
2
1
1
3
19
14
1
1
17
1
28
26
8
5
24
2
11
1
1
7
7
18
8
2
32
2
257
330
445
341
210
322
337
55
385
112
83
169
87
191
325
.
279
.
351
.
84
82
154
75
.
.
130
341
.
.
227
331
.
.
484
163
120
84
143
89
.
135
411
1,300
534
135
383
55
2
179
32
14
94
15
180
609
.
373
.
438
.
11
11
75
10
.
.
66
491
.
.
167
86
.
.
566
113
37
15
65
19
.
20070816
20070816
20070816
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
20070817
JLC
JLC
JLC
DS-3
DS-3
DS-3
DS-3
DS-3
DS-3
DS-3
DS-3
DS-3
DS-3
DS-3
DS-3
DS-3
DS-3
DS-4
DS-4
DS-4
DS-4
DS-4
DS-4
DS-4
DS-4
DS-4
DS-4
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
Mi_sal
Mu_cep
No_cry
Ap_gru
Do_cep
Fu_chr
Ic_bub
Le_ocu
Lep_gul
Lep_mac
Lep_meg
Lep_mic
Lep_sym
Mi_sal
Mu_cep
No_cry
Po_nig
Cy_car
Fu_chr
Ic_pun
Le_ocu
Lep_mac
Lep_mic
Lep_min
Mi_sal
Mu_cep
Po_nig
An_mit
Cy_car
Do_cep
Ga_aff
Ic_pun
Le_ocu
Lep_gul
Lep_mac
Lep_meg
Lep_mic
Lep_min
Me_ber
Mi_sal
Mu_cep
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
93
25
5
32
1
1
5
2
2
1
34
1
1
1
51
30
3
1
3
2
2
9
51
11
30
51
18
10
1
1
1
2
2
3
2
37
1
2
23
4
37
11
150
383
.
426
325
.
301
364
68
95
117
154
.
115
284
.
236
582
42
349
520
112
128
70
129
241
225
48
695
287
.
403
485
175
104
104
168
81
.
117
273
98
656
.
1,100
341
.
278
267
7
21
34
67
.
68
278
.
213
267
1
408
687
32
44
10
64
178
149
1
6,425
218
.
801
463
129
30
22
90
15
.
70
249
20070817
20070817
20070817
20070830
20070830
20070830
20070830
20070830
20070830
20070830
20070830
20070830
20070830
20070830
20070830
20070830
20070830
20070830
20070830
20070830
20070830
20070830
20070830
20070830
20070830
20070830
20070830
20070830
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
NSU
NSU
NSU
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
US-6
US-6
US-6
US-6
US-6
US-6
US-6
US-6
US-6
US-6
US-6
US-6
US-6
No_cry
Po_lat
Po_nig
An_ros
Ap_gru
Ca_car
Cy_car
Cy_lut
Cy_ven
Do_cep
Do_pet
Ga_aff
Ic_bub
Le_ocu
Le_oss
Lep_cya
Lep_gul
Lep_mac
Lep_meg
Lep_mic
Lep_min
Me_ber
Mi_pun
Mi_sal
Mo_sax
Mu_cep
Pi_not
Po_nig
An_ros
Ap_gru
Ap_say
Do_cep
Ga_aff
He_for
Ic_bub
Le_ocu
Lep_gul
Lep_mac
Lep_meg
Lep_mic
Lep_min
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
94
11
1
1
4
4
3
3
32
5
5
2
24
12
6
2
2
3
11
155
1
11
3
3
8
3
27
4
1
1
1
1
1
36
1
1
3
6
10
40
5
14
.
.
205
245
582
406
812
.
.
250
.
.
540
496
345
79
106
72
101
63
74
.
265
235
76
319
.
182
331
395
85
393
.
.
745
492
72
117
70
113
82
.
.
145
28
3,663
2,155
8,660
.
.
262
.
.
2,933
474
66
8
28
7
25
5
12
.
258
209
5
388
.
107
54
1,100
8
634
.
.
7,600
539
8
35
8
27
16
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071003
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
US-6
US-6
US-6
US-6
US-6
US-6
US-7
US-7
US-7
US-7
US-7
US-7
US-7
US-7
US-7
US-7
US-7
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
JLC
DS-5
DS-5
DS-5
DS-5
DS-5
DS-5
DS-5
DS-5
DS-5
DS-5
Lu_par
Me_ber
Mi_sal
Mu_cep
No_chr
Po_lat
An_ros
Ic_pun
Le_ocu
Lep_mac
Lep_meg
Lep_mic
Lep_min
Mi_sal
Mu_cep
No_chr
Pi_not
Cy_car
Do_cep
Ic_bub
Le_ocu
Lep_mac
Lep_meg
Lep_mic
Lep_min
Me_ber
Mi_pun
Mi_sal
Mu_cep
No_chr
Pi_vig
Am_nat
Cy_car
Cy_lut
Do_cep
El_sau
Ic_pun
Le_ocu
Lep_gul
Lep_mac
Lep_meg
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
95
3
47
21
9
2
25
1
2
2
11
11
6
33
17
3
4
1
1
1
1
3
3
25
5
29
3
1
33
6
2
4
1
3
14
2
1
1
4
10
44
2
.
.
191
354
87
.
403
411
603
99
63
180
75
138
409
103
2
690
349
585
452
113
69
173
64
67
218
190
400
104
50
365
597
175
333
257
397
435
145
96
104
.
.
187
537
6
.
289
952
932
22
6
118
10
66
557
8
.
5,450
486
3,550
374
27
8
98
6
2
124
158
585
10
1
260
3,967
50
311
77
520
418
76
25
23
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071004
20071005
20071005
20071005
20071005
20071005
20071005
20071005
20071005
DS-5
DS-5
DS-5
DS-5
DS-5
DS-5
DS-5
DS-6
DS-6
DS-6
DS-6
DS-6
DS-6
DS-6
DS-6
DS-6
DS-6
DS-6
DS-6
DS-6
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
NSU
DON
DON
DON
DON
DON
DON
DON
DON
Lep_mic
Lep_min
Lu_par
Me_ber
Mi_sal
Mu_cep
Po_nig
Cy_car
Fu_chr
Ga_aff
Ic_bub
Ic_pun
Lep_mac
Lep_meg
Lep_mic
Lep_min
Lep_sym
Mi_sal
Mu_cep
Po_lat
Cy_car
Ga_aff
Ic_bub
Ic_fur
Ic_pun
Le_ocu
Lep_mac
Lep_meg
Lep_mic
Me_ber
Mi_sal
Mu_cep
Po_lat
An_ros
Cy_car
Cy_lut
Cy_ven
Do_cep
Ga_aff
Ic_bub
Ic_pun
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
96
25
20
1
2
45
48
6
1
7
1
3
1
55
4
5
15
4
15
15
1
1
1
1
1
2
1
20
6
17
1
28
24
1
5
5
12
3
11
4
3
1
103
74
.
.
177
274
242
543
.
.
584
340
117
113
100
61
34
251
269
.
635
.
610
771
338
212
111
55
69
.
124
304
.
322
678
.
.
326
.
512
355
30
11
.
.
120
213
209
2,150
.
.
3,867
351
34
28
33
5
1
229
216
.
3,650
.
4,225
6,610
337
25
26
4
13
.
55
283
.
.
4,420
.
.
458
.
2,183
463
20071005
20071005
20071005
20071005
20071005
20071005
20071005
20071005
20071005
20071005
20071005
20071005
20071005
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
DON
Le_ocu
Le_oss
Lep_gul
Lep_mac
Lep_meg
Lep_min
Me_ber
Mi_pun
Mi_sal
Mu_cep
Op_emi
Pi_vig
Po_lat
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
Shock
97
9
4
6
27
52
6
6
5
8
12
2
4
2
507
333
140
95
83
82
.
288
265
325
.
.
.
592
127
68
21
15
14
.
339
301
348
.
.
.
APPENDIX III. Species codes, scientific name and common name of
fishes collected from 09 February 2006 to 05 October 2007. Information is
listed in alphabetical order.
Species Code
Scientific Name
Common Name
Al_ala
Al_chr
Am_nat
Am_cal
An_mit
An_ros
Ap_say
Ap_gru
Br_pat
Ca_car
Ch_gul
Ct_ide
Cy_lut
Cy_ven
Cy_car
Do_cep
Do_pet
El_sau
Er_obl
Fu_chr
Ga_aff
He_for
Ic_fur
Ic_pun
Ic_bub
Ic_cyp
La_sic
Le_ocu
Le_oss
Lep_cya
Lep_mac
Lep_meg
Lep_mic
Alosa alabamae
Alosa chrysochloris
Ameiurus natalis
Amia calva
Anchoa mitchilli
Anguilla rostrata
Aphredoderus sayanus
Aplodinotus grunniens
Brevoortia patronus
Carpiodes carpio
Chaenobryttus gulosus
Ctenopharygodon idella
Cyprinella lutrensis
Cyprinella venusta
Cyprinus carpio
Dorosoma cepedianum
Dorosoma petenense
Elops saurus
Erimyzon oblongus
Fundulus chrysotus
Gambusia affinis
Heterandria formosa
Ictalurus furcatus
Ictalurus punctatus
Ictiobus bubalus
Ictiobus cyprinellus
Labidesthes sicculus
Lepisosteus oculatus
Lepisosteus osseus
Lepomis cyanellus
Lepomis macrochirus
Lepomis megalotis
Lepomis microlophus
Alabama shad
Skipjack herring
Yellow bullhead catfish
Bowfin
Bay anchovy
American eel
Pirate perch
Freshwater drum
Gulf menhaden
River carpsucker
Warmouth
Grass carp
Red shiner
Blacktail shiner
Common carp
Gizzard shad
Threadfin shad
Ladyfish
Creek chubsucker
Golden topminnow
Mosquitofish
Least killifish
Blue catfish
Channel catfish
Smallmouth buffalo
Bigmouth buffalo
Brook silverside
Spotted gar
Longnose gar
Green sunfish
Bluegill
Longear sunfish
Redear sunfish
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Lep_min
Lep_syn
Lu_par
Ly_fum
Me_ber
Mi_pun
Mi_sal
Mo_chr
Mo_mis
Mo_sax
Mu_cep
No_cry
Op_emi
Pi_vig
Pi_not
Po_lat
Po_nig
Lepomis miniatus
Lepomis symmetricus
Lucania parva
Lythrurus fumeus
Menidia beryllina
Micropterus punctulatus
Micropterus salmoides
Morone chrysops
Morone mississippiensis
Morone saxatilis
Mugil cephalus
Notemigonus crysoleucas
Opsopoeodus emiliae
Pimephales vigilax
Pimiphales notatus
Poecilia latipinna
Pomoxis nigromaculatus
Red spotted sunfish
Bantam sunfish
Rainwater killifish
Ribbon shiner
Inland silverside
Spotted bass
Largemouth bass
White bass
Yellow bass
Striped bass
Striped mullet
Golden shiner
Pugnose minnow
Bullhead minnow
Fathead minnow
Sailfin molly
Black crappie
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BIOGRAPHICAL SKETCH
Heather Pace Dyer was born on August 7, 1974, on Loring Air Force Base in
Limestone, Maine to James and Valerie Pace. Heather graduated from Auburn High
School in Auburn, WA in 1992. Heather first became interested in Fisheries Biology
after working in a salmon cannery near Bristol Bay, Alaska in 1997 and 1999. Heather
and her husband Steve moved to Louisiana in 2000 to pursue Steve’s commercial diving
career. Heather and earned her B.S. in Resource Biology and Biodiversity from
University of Louisiana at Lafayette in 2005. Heather worked for 18 months as an
undergraduate intern at the National Wetlands Research Center in Lafayette, Louisiana in
the laboratory of Dr. Karen McKee studying the effects of elevated CO2 levels on salt
marsh plant communities. Heather interned for Dr. Edward Chesney at Louisiana
Universities Marine Consortium during the summer of 2005 study responses of first
feeding larval fishes to an engineered macroparticulate diet. Heather enrolled in the
Marine and Environmental Biology graduate program and Nicholls State University in
January 2006. Heather will begin employment as a General Biologist at the National
Wetlands Research Center in December 2007. Heather plans to pursue a Ph.D. in
Fisheries Biology in the future.
100
CURRICULUM VITAE
HEATHER PACE DYER
Department of Biological Sciences
Bayousphere Research Lab
hpdyer@cox.net
Nicholls State University
Thibodaux, LA 70310
121 Kirkwood Lane
Youngsville, LA 70592
CURRENT RESEARCH
Seasonal fish assemblages of Bayou Lafourche upstream and downstream of the Thibodaux weir.
EDUCATION
Master of Science, Marine & Environmental Biology: Nicholls State University, December 2007
Bachelor of Science, Resource Biology & Biodiversity: University of Louisiana at Lafayette, December 2005
RESEARCH EXPERIENCE
Teaching Assistant – Nicholls State University
Department of Biological Sciences
Supervisor: Quenton Fontenot, Ph.D., Asst. Professor (985) 449-7062 quenton.fontenot@nicholls.edu
Present
Instruct introductory laboratory course focusing on basic principles of the scientific method and
biological techniques.
Intern – Estuarine Habitats & Coastal Fisheries
National Oceanic and Atmospheric
Administration, NMFS
Supervisor: Lawrence P. Rozas, Ph.D., Fisheries Biologist (337) 291-2118 lawrence.rozas@noaa.gov
9/2006 – 10/2006
Assisted in the field work of the NOAA/EPA teams studying the species diversity and abundance of
marsh, marsh edge, and submerged aquatic vegetation. Techniques included drop sampling and growth
chamber experiments in three habitat types along the Louisiana and Florida coasts.
Individual Investigator – Human Subject Mercury Content Study
Harvard School of Public Health
Supervisor: David B. Senn, Ph.D., Primary Investigator dsenn@hsph.harvard.edu
7/2006 – 8/2006
Interviewed subjects regarding fish consumption. Obtained data such as amount, type, frequency and
geographical source of fish consumed. Obtained hair sample used for mercury analysis from subject.
101
Intern – Wetlands Ecology and Global Climate Change National Wetlands Research Center
Supervisor: Karen McKee, Ph.D., Wetland Ecologist kmckee@usgs.gov
2/2004 – 12/2005
Wetland vegetation response to global climate change. Assisted with greenhouse studies, lab and field work.
Intern – Fisheries Biology & Larval Culture Louisiana Universities Marine Consortium
Supervisor: Edward J. Chesney, Ph.D., Fisheries Biologist (985) 851-2800 echesney@lumcon.edu
Summer 2005
Internship focused on early life history of estuarine fishes. Duties included egg capture, hatching, larval rearing,
and plankton production. Personal research studied behavior of first-feeding larvae in the presence of a
microparticulate diet.
Intern – Wetland Community Ecology University of Louisiana, Lafayette – Department of Biology
Supervisor: Susan Mopper, Ph.D., Ecologist (337) 482-6277 mop@louisiana.edu
3/2003 – 10/2003
Physiological response of Iris hexagona (Louisiana wild iris) to environmental stressors such as increased
salinity, flooding and predatory herbivory.
COURSEWORK & STATISTICS
Relevant Courses Completed:
Biostatistics, Fisheries Management, Marine & Environmental Biology, Ichthyology, Marine Field Ecology,
Marine Vertebrate Zoology, Biostatistics, Applied Ecology, Ecological Restoration
Statistics & Computer Skills:
MS Office, SAS, SigmaStat, SigmaPlot, JMP, FAST
Field & Laboratory Skills:
Operation of small boats and trailers, gill nets, seines, boat mounted electrofishing, larval fish traps, fish
identification, external tagging, VIE (visible implant elastomer) tagging, otolith removal, water quality
monitoring, tank maintenance and data management, above and below ground biomass sample processing, marsh
vegetation field work.
MEMBERSHIPS & AWARDS
•
•
•
•
•
•
•
•
•
2007 1st Place Poster Presentation, Nicholls State University Research Week
2007 2nd Place Poster Presentation, American Fisheries Society Louisiana Chapter Annual Meeting
2006 Coastal Restoration and Enhancement through Science & Technology (CREST) Research Grant
2006 Rockefeller State Wildlife Scholarship
2004 LUMCON Summer Scholarship
2004 Robert Theall Resource Biology Scholarship, University of Louisiana at Lafayette
American Fisheries Society, National and Louisiana Chapter
Native Fish Conservancy
Nicholls State University Biology Society
102
SCIENTIFIC PRESENTATIONS
2007
Dyer, H.P., A.M. Ferrara and Q.C. Fontenot. Adult fish distribution in Bayou Lafourche above and
below the Thibodaux weir. Annual Meeting of Louisiana Chapter of the American Fisheries Society,
Thibodaux, Louisiana (poster presentation).
2006
Dyer, H.P. Fish assemblages of Bayou Lafourche above and below the Thibodaux weir. 16 Sept 2006.
Calypseaux Graduate Student Symposium, Cocodrie, Louisiana.
103