North American Journal of Fisheries Management
ISSN: 0275-5947 (Print) 1548-8675 (Online) Journal homepage: http://www.tandfonline.com/loi/ujfm20
Artificial Reefs under Marina Docks in Southern
Florida
Edwin S. Iversen & Scott P. Bannerot
To cite this article: Edwin S. Iversen & Scott P. Bannerot (1984) Artificial Reefs under Marina
Docks in Southern Florida, North American Journal of Fisheries Management, 4:3, 294-299,
DOI: 10.1577/1548-8659(1984)4<294:ARUMDI>2.0.CO;2
To link to this article: http://dx.doi.org/10.1577/1548-8659(1984)4<294:ARUMDI>2.0.CO;2
Published online: 08 Jan 2011.
Submit your article to this journal
Article views: 13
View related articles
Citing articles: 6 View citing articles
Full Terms & Conditions of access and use can be found at
http://www.tandfonline.com/action/journalInformation?journalCode=ujfm20
Download by: [University of Arizona]
Date: 29 March 2016, At: 09:57
NorthAmericanJournalof FisheriesManagement4:294-299, 1984
¸ Copyrightby the AmericanFisheriesSociety1984
Artificial
Reefs Under Marina
Docks in Southern Florida
EDWIN S. IVERSEN
RosenstielSchoolof Marine and Atmospheric
Science
Divisionof Biologyand LivingResources
4600 RickenbackerCauseway
Miami, Florida 33149
SCOTT P. BANNEROT
National Marine Fisheries Service
Southeast Fisheries Center
Downloaded by [University of Arizona] at 09:57 29 March 2016
75 Virginia Beach Drive
Miami, Florida 33149
ABSTRACT
Placementof large rocks under three recently constructeddocks at a new marina in Biscayne
Bay, Florida providedadditional habitat to a stressedarea. The bottom consistedof an accumulation of black, flocculentmud supportingfew or no fish or macroinvertebrates
prior to placingthe
habitat under the docks.After placement,numerousfish and macroinvertebratesbecameassociated
with the habitat. This techniqne can mitigate some of the ecologicallyadverseeffects of dock
constructionand increasethe standingcropsof fish and macroinvertebrates
beneaththe dock.
A number of marinas have been constructed
ticularly where grassbedsexist. This paper prerecentlyin shallowmarinebay areasin southern sents a simple, economical, and generally
Florida and many more are proposed.Construc- applicablehabitat improvementtechniquethat
tion of marinasmay negativelyimpact the stand- may be usedto counteractsomeof the negative
of marinadevelopmentby increasing
the
ing cropsof fishand macroinvertebrates
in these aspects
areas.Destruction of productive habitat suchas standingcropsof fishand macroinvertebrates
at
turtle grass(Thalassiatestudinum)often occurs the development site.
Our specificobjective was to demonstratethe
during constructionand later by the dredging
effect of turbulence from propellers of vessels effectivenessof this managementtechniqueby
usingthe marina.Eitherindirectdredging
by boat quantitativeobservationsof absoluteabundance
propellersor direct dredgingto accommodate of fish and macroinvertebratestandingcropsbevesselswith deeperdraftsoftencreatesbasinsin fore and after its application.The hypothesiswas
the bottom that soon become anoxic due to acthat habitat improvement would result in large
cumulation of decayingdetritus, discouraging increases in numbers of fish and macroinverteaerobicbiologicalproductivity in the area. The bratesrelativeto standingcropsizebeforeplace-
advent of a marina inevitably causesan influx ment.
Our test of this hypothesiswas qualitative,
of pollution from engine oil and exhaust,oily
madebeforeand afterhabwater pumped into the sea by automatic bilge consistingof censuses
pumps, and various soaps,oils, and detergents itat improvement. A three-dockmarina recently
that enter the environment as boaters clean their
had been constructed in association with the de-
vesselsafter outings.Marina docks may reduce
sunlightreachingthe bottom and hencereduce
productivity of benthic algaeor createan environment unsuitablefor turtle grass.
These negativefactorshave stimulatedenvi-
velopment of a new condominium before the
inceptionof the study.
During three visitsby us to the regionunder
and around the newly built dockson March 15,
March 19, and May 4, 1981, few fish and no
ronmentalagencies(e.g., Florida's Department macroinvertebrates were noted. An earlier visit
of EnvironmentalRegulation)to promulgatereg- on June 19, 1979 by biologistsfrom the Florida
ulations on depth and number of marinas and Department of Environmental Regulation
the number, width, and lengthof docksin ma- showedan area of small (lessthan 2 m in dirinas in order to prevent lossof productionpar- ameter)patchesof very sparseseagrasses.
Tha294
Downloaded by [University of Arizona] at 09:57 29 March 2016
ARTIFICIALREEFS
UNDERMARINADOCKS
,..14.6rn•
Dock
1
•._ 23.8 m
Dock
BISCAYNE
_•
2
295
•_14.6m•
Dock
3
BAY
Figure1. Location
ofthestudy
sitein Biscayne
Bayimmediately
south
ofthedowntown
areaof
Miami,Floridaandthelayoutofmarinadocks.
Largerockswereplaced
fromtheareaofsparse
seagrass
outtotheendsofthedocks.
Thecenter
dockis3.6m wide;theothers
are3.0m wide.
lassia,Halodule,and $yringodiumwerepresent 1981; February8, May 28, August5, and Ocwithin 10 m of shore under Dock 1, 14 m of
tober 23, 1982; and January 9, 1983.
shoreunder Dock 2, and 30 m of shoreunder
Dock 3 (Fig. 1) duringour earlyvisits.
STUDY SITE
This studywas conductedin an area of BiscayneBay, Florida off Miami that was largely
themarinadevelopers
underall threedocksfrom devoidof turtlegrassdueto dredgingmanyyears
onbottom
the offshoreboundaryof grassbedsout to and ago.The newmarinawasconstructed
includingthe dockfacingin waterof about3.3 virtually barrenof any biota due to a layer of
m depth(Fig. 1). This habitatimprovementwas black, flocculentmud more than 29 cm thick.
carriedout duringmid-June1981. Subsequent Mud bottomis a persistentfeatureof the western
observationson the presenceof macroinverte- part of BiscayneBay, from approximatelythe
At the suggestion
of the seniorauthor,rocks
of about 0.6-2.0 m in diameter were placed by
brates and fisheswere made on September 10,
Miami
River
southward to south of Ricken-
296
IVERSENAND BANNEROT
backer Causewaynear Viscaya (about 6.4 km).
This area,whichis about0.8 km wide, normally
doesnot supportseagrasses
or algae,althoughin
someareasvery sparsepatchesof Halodule have
been reported(Roesslerand Beardsley1975).
The docks extend out from shore to a depth
of approximately3.3 m, and rangefrom 39 to
61 m in length (Fig. 1). The rock piles, after
settlement into the mud bottom at the time of
placement, provide between 0.5 and 1.0 m of
relief. The rocksremain submergedat low tide.
Total area coveredby the rock piles is approximately 110 m2.
Downloaded by [University of Arizona] at 09:57 29 March 2016
The marina is located 1 mile south of the mouth
of the Miami River. Sediment load from the river
is negligiblein this part of BiscayneBay. Water
visibility is normally 1.5-3.0 m near shore,increasingto 3.0-4.5 m at the dock facing.
Mœ'rI-IOr•S
Each of the nine censuses(three before placement of the artificial habitat, six after) consisted
of a completeinventory of all fish and macroinvertebratespeciesand individuals presentunder
the threedocksmade by a singlediver. The number of individuals of each specieswas recorded
by slowly swimming the length of each dock,
stoppingfor aslongas necessaryto recordgroups
of individualsand searchcrevicesand openings
in the rock piles and around the pilings. Inaccuracyfrom countingindividualsmore than once
wasminimal. Most fishoccurredeitherin resting
schools(e.g.,lutjanids, haemulids,clupeids,atheriniris)associatedwith localizedregionsof the
artificial habitat or as distinguishableindividuals.
The three censuses before and the first one
pendenceon detailedcensusprotocol);and (3)
difference in abundance of fish and macroinver-
tebratesbeforeand after habitatplacement,from
virtually nothingto relativelylargenumbers,was
easilysufficientto qualitativelyverify the effect
of the technique.
Water visibility tended to be lower (1.5-3.0
m) nearshore,increasing
towardthedockfacings
(3.0-4.5 m). Between-visitvariabilityvariedby
a maximum of 2.0 m but had little effect on
amenability of fish to censusbecausefish and
macroinvertebrates
tendedto remaincloselyassociatedwith the artificial habitat when approachedby the diver.
RESULTS AND DISCUSSION
BiscayneBayhasrelativelyfewareasof rocky
habitat.The additionof artificialhabitat(rocks)
increasedthe number and density of invertebrates and fish. The increase in biota was dra-
matic. Where few macroorganisms
existedbefore, populationsof macroinvertebratesand fishes
became abundant. A list of speciesand total
number observedover the 9 censusdaysbefore
and after placementof the rocksis presentedin
Table
1.
Some increase in number of individuals and
species
wouldbe expecteddueto thehabitatprovided by the dock structurealone. Quantitative
estimates of the influence of dock structure on
standing crops of fish and macroinvertebrates
wouldrequirea controlsitein the samegeneral
area. A qualitativeestimateis possiblefrom our
data, despite the lack of a suitable control site.
The presenceof the rocks appearsto have been
responsiblefor a significantproportion of the
observedincreases.The spiny lobsters(Panuli-
after placement of the rocks were made by a
singlediver (Iversen)free diving with snorkeling
gear. Subsequently,we felt that the use of scuba
gearwould facilitate efficientenumerationof the
largenumbersof fishand macroinvertebrates
that
beganaccumulatingin the vicinity of the rocks.
Thus, the last five censuseswere conductedby a
singlediver (Bannerot)usingscuba.All data were
recorded with pencil on underwater paper. Each
dock required approximately 25 minutes of ef-
the rocks for shelter. The rocks provide additional habitat for daytime restingfor schoolsof
economically valuable haemulid and lutjanid
speciesthat scatterat night to feed.
Gray snappers(Lutjanus griseus)and white
fort. All censuses were made between 1000 and
grunts(HaernulonplurnierObecameparticularly
1600 hours.We believethat any error introduced
by the modification in survey techniqueis relatively small because:(1) depth seldom exceeded
water visibility; (2) the censusconsistedof absolute,rather than relative, counts(reducingde-
abundantin the vicinity of therocks.Both species
are valued by local anglers.Over 100 gray snap-
rusargus),red hind (Epinephelus
guttatus),foureye butterflyfish(Chaetodoncapistratus),green
moray (Gymnothorax funebris), red-banded
coral shrimp(Stenopushispidus),and high-hats
(Equetusacurninatus)dependalmostentirelyon
pers,of which an estimated 30% exceeded20 cm
in total length,wererecordedduringeachcensus
exceptAugust5, 1982. This correspondsto the
ARTIFICIAL REEFSUNDER MARINA DOCKS
Table
1.
List
of fish and macroinvertebrate
Table 1.
Continued.
speciesunder marina docks and total numbers
observed on nine census dates--three
Total
before
and six after placement of large rocks beneath
the docks. Transient schoolingspeciesare denoted by an asterisk.
297
Species
Seabream (Archosargus
rhomboidalis)
Pinfish(Lagodonrhomboides)
bets
37
1
Sciaenidae
Total
Species
Before addition
High-hat (Equetusacuminatus)
bets
Bermudachub(Kyphosus
sectatrix)
1
Chaetodontidae
of rocks
Foureyebutterflyfish(Chaetodoncapistratis)
Invertebrates
1
Pomacanthidae
None
Gray angelfish(Pomacanthusarcuatus)
Frenchangelfish(Pomacanthus
paru)
Fish
6
1
Pomacentridae
Atherinidae
Hardheadsilverside(Atherinomorus
$tipes)*
Downloaded by [University of Arizona] at 09:57 29 March 2016
5
Kyphosidae
After addition
2,350
Invertebrates
Palinuridae
Spinylobster(Panulirusargus)(juveniles)
9
Xanthidae
Stone crab (Menippe mercenaria)
Stenopodidae
Red-bandedcoral shrimp ($tenopushispidus)
2
1
Serranidae
Red hind (Epinephelusguttatus)
Carangidae
Crevallejack (Caranx hippos)
Lutjanidae
Schoolmaster
(Lutjanusapodus)
Gray snapper(Lutjanus griseus)
3
I
4,200
Frenchgrunt (Haemulonfiavolineatum)
Sailor'schoice(Haemulon parrat')
White grunt (Haemulonplumiel')
Bluestripedgrunt (Haemulon sciurus)
Sparidae
Sheepshead
(Archosargus
probatocephalus)
31
Crestedgoby(Lophogobius
Cyprinoides)
3
Bannergoby (Microgobiusmicrolepis)
2
Ostraciidae
5
18
15
spawningperiodfor this specieswhenthe larger
individuals leave inshoreareasand gather on
offshorereefs(Starckand Schroeder1970).Other
recreationally important fish speciesnoted at
1,200 tarpon(Megalops
atlanticus),
greatbarracuda
3,733
(Sphyraenabarracuda),schoolmasters
(LutjarlttSapodus),sheepshead
(Archosargus
probato-
1
cephalus),
crevalle
jacks(Caranxhippos),
and
19
several other haemulids--particularly bluestripedgrunts(Haemulon sciurus).Juvenile spi-
3 ny lobsters
alsobecame
abundant
among
the
685
rocksunderthe dock.
The Shannon-Weaverdiversity function (H')
63
3
wascomputed
forthefishandmacroinvertebrate
90
community
at eachcensus
dateto providea
28
numberfor temporal comparisonover the course
of the studyand to allow researchers
to compare
Haemulidae
Porkfish (Anisotremusvirginicus)
Tomtare (Haemulon aurolineatum)
477
640 various
timesafterthehabitatimprovement
were
Gerreidae
Spotfin mojarra (Eucinostomusargeneteus)
Yellowfin mojarra ( Gerrescinereus)
Mixed spotfinand yellowfin mojarrajuveniles
Stripedmullet(Mugil cephalus)*
Sphyraenidae
Great barracuda(Sphyraenabarracuda)
Bandtailpuffer(Sphoeroides
spenglerO
Checkeredpuffer(Sphoeroides
testudineus)
Atherinidae
Hardheadsilverside(Atherinomorusstipes)*
5
Scrawledcowfish(Lactophrysquadricornis)
Yellow stingray(Urolophusjamaicensis)
Green moray (Gymnothoraxfunebris)
Clupeidae
Falsepilchard(Harengulaclupeola)*
Dwarf herring (Jenkinsialamprotaenia)*
Engraulidae
Dusky anchovy(Anchoalyolepis)*
5
Redtailparrotfish(Sparisomachrysopterum)
Tetraodontidae
Dasyatidae
Southern stingray (Dasyatis americana)
Muraenidae
Rainbow parrotfish(Scarusguacamaia)
Gobiidae
Fish
Myliobatyidae
Spottedeagleray (Aetobatusnarinarl)
Elopidae
Tarport (MegMops atlanticus)
11
Mugilidae
532
Portunidae
Blue crab (Callinectessapidus)
Sergeantmajor (Abudefdufsaxatilus)
Scaridae
of rocks
3
32
5
259
74
8
thesevalueswithotheraquatic
communities.
These values of H' for each censusbefore and
after placementof the artificial habitat under the
docksare shownin Table 2. Schoolsof transient
fishspecies
(clupeids,
engraulids,
atherinids,
and
mugilids),denotedby an asteriskin Table 1, pe-
298
IVERSEN AND BANNEROT
Table 2. Values of Shannon-Weaver diversity
indices (H') before and after placement of artificial
habitat.
Note that H' is zero when one
or no speciesis observed.
no justification in this paper for building additional docks and marinas, particularly in productive seagrassareas. This study was carried
out at a marina newly constructedon an already
barren bottom.
Without
All fish and
macroinvertebrates
Date
March 15, 1981
March 19, 1981
May 4, 1981
Before placement
0
0
0
transient
schooling
fish species
0
0
0
Downloaded by [University of Arizona] at 09:57 29 March 2016
After placement
September 10, 1981
February 8, 1982
May 28, 1982
August 5, 1982
October 23, 1982
January 9, 1983
0.73
0.84
0.72
1.10
1.21
2.00
once-barren
was never used dur-
observed the effect of an active marina
on the
fish and macroinvertebratepopulations.
Basedon this example in BiscayneBay, we
believe that the technique will be effective in
other marinas, docks,and fishingpiers in tropical, subtropical, and temperate marine waters
that have three attributes
0.71
1.11
3.08
1.54
1.51
2.00
riodicallytakeup temporaryresidence
undermost
docksin this areaof BiscayneBay.The H' values
calculated with and without these speciesincludedappearin Table 2. Both valuesare high
relative to the initial
The marina
ing the time of the study; hence, we have not
in common
with this
studysite: (1) water quality sufficientto sustain
substantialfish and macroinvertebratepopulations;(2) a presentlack of habitat suchas rocks
which might attract various fish and macroinvertebratespecies;and (3) a significantnumber
of larvae,juveniles, or adults in the generalvicinity to colonizethe newhabitat.Rocksor other
artificial habitatsshouldbe placedsothey do not
substantiallyreduce water exchangeunder the
dock or pier structuresor interfere with the primary functionsof thedocksor navigationof boats
in marinas.
H' value of zero for the
ACKNOWLEDGMENTS
area.
A substantialbody of literaturedocumentsthe
value of artificial reefscomposedof man-made
or natural objects placed in aquatic environmentsto providebottomhabitatswhichincrease
standingcrops of fish and macroinvertebrates.
Proposedcausalmechanismsincludeconcentration of sparselydistributedindividuals and/or
increasedlocal productivity as a result of the
artificial habitat. Examplesin marine environ-
We thank Ronald Schefer of ABD Manage-
ment Corporation,Miami, Florida, for support
of this project and for his cooperationand assistanceduringthis study.J. A. Bohnsackand E.
D. Prince of the National
Marine
Fisheries Ser-
vice and C. R. Robins and D. de Sylva of the
RosenstielSchool of Marine and Atmospheric
Scienceskindly reviewed the manuscript and
provided useful suggestions.
ments include studies in the Gulf of Mexico
(Wickham et al. 1973; Smith et al. 1979), in the
New York Bight (Zawacki 1969), and in the
coastalwatersof SouthCarolina(Buchanan1973;
Buchananet al. 1974), California (Turner et al.
1969), Washington(Anonymous 1982; Laufle
1982), and Hawaii (Kanayama and Onizuka
1973). Princeand Lambert (1972) reportedon a
communityprojectwhere artificial habitat was
placedundera fishingpierin MontereyBay,Cal-
REFERENCES
ANONYMOUS.
1982.
Artificial
reefs and marine fish-
eriesenhancement.
Marine FisheriesReview44(67): 1-60.
BUCHANAN,
C.C. 1973. Effectsof an artificial habitat
on the marine sport fisheryand economyof Murrells Inlet, South Carolina. Marine Fisheries Re-
view 35(9):15-22.
BUCHANAN,C. C., R. B. STONE,AND R. O. PARKER,
JR. 1974. Effects of artificial reefs on a marine
ifornia. While the use of these artificial habitats
sport fisheryoff South Carolina. Marine Fisheries
Review 36(11):32-38.
wheretheyhavebeenplacedundermarinadocks LAUFLE,J.C. 1982. Biologicaldevelopmentand materialscomparisons
on a PugetSoundartificialreef..
to mitigatesomeof the ecologicallyadverseconTechnical report 72, State of Washington,Deditions causedby the constructionand use of
partmentof Fisheries,Olympia, Washington,USA.
is well recognized,we do not know of any cases
marinas.
It is important to point out that we provide
KANAYAMA,R. K., AND E. W. ONIZUKA. 1973. Artificial reefsin Hawaii. Fish and Game Report 73-
ARTIFICIAL REEFS UNDER MARINA DOCKS
01, Department of Land and Natural Resources,
State of Hawaii, USA.
PRINCE,E. D., ANDT. R. LAMBERT. 1972. Reefs from
tires?Outdoor California 33(3):7-9.
ROESSLER,
M. A., AND G. L. BEARDSLEY.1975. Bis-
cayneBay:Its environmentandproblems.Florida
Scientist37(4):186-204.
299
tigationson the gray snapper,Lutjanus griseus.
Studiesin Tropical OceanographyNumber 10,
Universityof Miami Press,CoralGables,Florida,
USA.
TURNER,C. H., E. E. EBERT,ANDR. R. GIVEN. 1969.
Man-madereef ecology.Fish Bulletin 146, California Departmentof Fish and Game, Sacramen-
SMITH,G. B., D. A. HENSLEY,AND H. H. MATHEWS.
to, California, USA.
1979. Comparativeefficacyof artificial and nat- WICKHAM,D., J. W. WATSON,JR., ANDL. H. OGREN.
ural Gulf of Mexico reefs as fish attractants. Flor-
ida Marine ResourcesPublication35, Florida Department of Natural ResourcesMarine Research
Laboratory,St. Petersburg,Florida,USA.
Downloaded by [University of Arizona] at 09:57 29 March 2016
STARCK,W. A., AND R. E. SCHROEDER.1970. Inves-
1973. The efficacyof midwater artificial structuresfor attractingpelagicsportfish.Transactions
of the American FisheriesSociety102:563-572.
ZAWAC•O,
C. S. 1969. Long Island'sartificial fishing
reefs. New York Conservationist 24:18-21.