BULLETIN OF MARINE SCIENCE 37(1) 3-10 1985

USE OF MAN-MADE REEFS TO CONCENTRATESNAPPER (LUTJANIDAE) AND GRUNTS (HAEMULIDAE)

IN BAHAMIAN WATERS

William S Alevizon Jonathan C GorhamRebecca Richardson and Sheryl A McCarthy

ABSTRACT

The feasibility of using man-made reefs to concentrate populations offood fishes (Lutjan-idae and Haemulidae) was investigated in Bahamian waters Fourteen reef units constructedof PVC pipe and concrete blocks were installed in seagrass beds and sand bottom habitatsat depths of 4-5 m in July of 1982 The units were highly successful in attracting the targetspecies and appear to offer a promising method of substantially increasing the readily avail-able protein supply for islanders throughout the Caribbean at a relatively low cost Com-parisons of the fish communities associated with natural patch reefs and man-made reefs inboth habitats suggest that reef structure is subordinate to source of recruitment as a deter-minant of reef fish community structure

Islanders throughout the world traditionally depend heavily on their fisheryresources for protein Although Caribbean reef systems are typically populatedby hundreds offish species relatively few of these fishes are of sufficient size foodquality and catchability to be profitably harvested for food Thus the problemof providing adequate protein for the increasing human populations of Caribbeanislands has become of considerable concern

Two groups of fishes which appear to offer the promise of representing anincreased contribution to the protein needs of Caribbean islanders are certaingrunts of the genus Haemulon and snappers of the genus Lutjanus These fishesare common in inshore lagoonal waters of the Caribbean wherever small coralheads rock outcroppings or man-made objects (eg old automobiles etc) pro-vide structural complexity to the substrate Such features are utilized as shelterareas during the day when fish congregate in large numbers At night grunts andsnappers leave their daytime shelter to feed on a wide variety of small invertebratesfound in the sand and seagrasses which surround the occasional reefs The move-ment patterns and foraging behavior of some of these grunts have been welldocumented (McFarland et al 1979) and the habits of certain of the snappersappear to be highly similar Because the home reef is used only as a shelter siteduring times of inactivity its composition and structure can vary widely and stillbe acceptable to these fishes This makes the use of artificial reefs in the maricultureof these fishes a highly promising endeavor since suitable shelter is apparentlythe major limiting resource

The main objective of this research was to investigate the possibility that smallman-made reefs might represent an efficient and economical means of providingharvestable quantities of high quality food fishes (snappers and grunts) in a varietyof inshore habitats in the Bahamas Man-made reefs of varying composition andstructure have been placed in marine habitats throughout the world during thelast 20 years and have generally proven effective at concentrating fishes Howeverthe types and numbers of fishes attracted have varied widely In almost everysuch venture the primary object has been simply to provide fish habitat the reefswere not targeted for particular species through siting andor design Thus ourapproach differs from most previous efforts in one major aspect our intent was

3

By

4 BULLETIN OF MARINE SCIENCE VOL 37 NO I 1985

X artificial reefs~~ grass bedscor a Ire e f s

N

i-

i

NORTH WEST

PROVIDENCE CHANNEL

LITTLE BAHAMA BANK

xX

X

Figure I The research area located at the eastern end of Grand Bahama Island (26deg3SN 77degS0W)

to develop reefs designed and located so as to attract and support maximumpopulations of a few selected species We investigated the effects of reef size andsiting on fish population growth and eventual community structure attainedAdditionally we compared community structure of fishes inhabiting small naturalreefs with that attained on man-made units sited in the same areas

METHODS

All field work was conducted in waters near Deep Water Cay located at the eastern end of GrandBahama Island (Fig I) The area is relatively isolated with minimal human activity and the full rangeof Caribbean island inshore habitat-types is readily accessible including extensive coral reef systemsmangroves seagrass beds and sand flats

Field testing of man-made reefs began in early July 1982 Individual reef units were constructed of12 standard concrete building blocks and PVC pipe (Fig 2a) and could be installed in combinationto provide a variety of reef sizes and configurations PVC subsections were assembled onshore andfinal reef assembly was accomplished on site by a team ofthree workers Reefs were built and installedat a rate of about one reef unit per day Scuba was helpful for reef installation but not necessary

By the end of July 14 reef units were deployed These were arranged in configurations of one twoand four units per reef A set of all three configurations was installed in lagoonal seagrass beds about2 km seaward and west of Mcleans Town Grand Bahama and another set installed on a mainlysandy substrate about 4-6 km offshore ofSweetings Cay on the Little Bahama Bank (Fig I) The twositing areas differed in several major respects In addition to the difference in the nature ofthe substrate(sand versus seagrass) the reefs sited off Mcleans Town were within 100 m of the inshore marginof an extensive natural fringing reef system In contrast the units sited on the Little Bahama Bankwere about 8-10 km from the nearest extensive natural reef The two areas communicate by meansof shallow tidal creeks which run through extensive mangrove areas (Fig I) This arrangement allowedfor the assessment of the effects of differing reef size and siting on the recruitment of fishes

Recruitment was documented by visual censusing of the reefs beginning shortly after their instal-

ALEVIZON ET AL MAN-MADE REEFS IN BAHAMAS 5

210 LAGOONAL GRASSBEOS

00

27

03

70

00

TIMElOAY91

LITTLE BAHAMA BANK

00 00

Figure 2 Population growth of fishes on man-made reefs sited in two habitats near Deep Water CayBahamas

lation The small size and shallow depth of the reefs allowed a snorkeler to accurately census all butthe very small or cryptic fishes Censuses were repeated periodically for approximately I year afterinstallation when fish populations had presumably approached equilibrium densities and communitystructures (Nolan 1975 Stone et aI 1979 Bohnsack and Talbot 1980)

The fish communities observed on the man-made reefs about 1 year after installation were compandwith those inhabiting comparably sized and sited natural patch reefs A total of 42 small patch reefsranging in size from approximately 065 to 135 m2 in area were investigated Twenty-eight ofthese occurred on the Little Bahama Bank about 1-3 km offshore Fourteen occurred in the lagoonalseagrass habitat adjacent to a fringing reef Thus the natural reefs investigated were located in areascomparable (in terms of habitat-type and distance from the main reef system) to those in which man-made units had been installed

Figure 3 (A) Installed two-unit reef Little Bahama Bank (July 1983) (B) Standing stock of fish atman-made reef sited in lagoonal seagrass beds (December 198245 months after installation) Standingstock of fish at man-made reef Little Bahama Bank (March 1983 about 9 months after installation)_

6 BULLETIN OF MARINE SCIENCE VOL 37 NO I 1985

2 UNIT

bullbull1 UNIT

40 eo 120 100 200 20 280 320 380

LITTLE BAHAMA BANK

bullbull UNIT

20

40 eo 120 180 200 2-40 280 320 300

LAGOONAL OAASSBEOS~w 120

~m 100~Wo 80

T1MEIOAYS)

Figure 4 Population growth of target fishes (snappers and grunts) on man-made reefs sited in twohabitats near Deep Water Cay Bahamas

Field investigation of the natural patch reefs involved two distinct aspects censusing of residentfish communities and measuring of reef size and structure Fish censusing was accomplished by asnorkeler who took a single visual count of all fishes found in the immediate vicinity of the reef Fourmeasures of reef size and structure were taken on each reef censused An estimate of surface area wasgenerated by converting a measurement of maximum circumference into the surface area of a hemi-sphere To define vertical development an index was calculated by dividing the maximum height(vertical distance from the substrate to the highest point on the reef) by the total surface area (estimatedas described above) This index reflects differences in reef shape since reefs of the same height butdifferent diameters would generate correspondingly different values A rugosity index indicating thedegree of surface texture was generated after the method of Luckhurst and Luckhurst (1978) Thedegree of undercut reflects the presence of caves and ledges near the base of the reef necessarymicrohabitats for some species It was expressed as the ratio of the circumference at the level of thesubstrate to the maximum circumference The obtained values of each of these measuresindices werefound to approximate a normal distribution within each habitat Thus reefs from the two habitatswere tested for significant differences in these characteristics by Students (-test

RESULTS

Recruitment of marine organisms on the man-made reefs was rapid The firstarrivals (fish and sea urchins) were observed within 48 h of reef installation Majordifferences in the pattern of fish recruitment were apparent between units placedin the two habitats (Fig 3) Whereas fish populations reached maximal levels in50-60 days on the lagoonal grassbed reefs two of the three reefs sited on theLittle Bahama Bank continued to display marked increases in resident fish pop-ulations throughout the 12-month study period The recruitment of sessile plantsand animals as well as mobile invertebrates (eg gastropods sea urchins crabsand spiny lobster) also generally occurred very rapidly throughout the summerand early fall with a decreased rate evident during the late fall and winter Thegrowth of fish populations and epibiota on the structures was photographicallydocumented in Figure 2 Although the prototype reef was not designed with specialprovisions for attracting spiny lobster (Panulurus spp) these were observed oc-casionally on the reefs throughout the study They appeared to take up residencefor a short while and then move on The maximum number observed in a singlecensus was 24 (four-unit reef Little Bahama Bank)

The reefs were highly successful and efficient in attracting the target species(Fig 4) Regardless of location or configuration of the reefs snappers and gruntsformed the overwhelmingly dominant component of the fish fauna observedthroughout the monitoring period Target fishes comprised over 90 of all fishesinhabiting the man-made reefs sited on the Little Bahama Bank at years end andfrom about 45 to 75 on reefs sited in the lagoonal seagrass habitat Bothjuveniles and adults appeared early and were evident throughout

ALEVIZON ET AL MAN-MADE REEFS IN BAHAMAS 7

Table 1 Diversity of fishes observed on natural and man-made reefs near Deep Water Cay Bahamas(data from man-made reefs represents the results of censusing resident fish populations 12 monthsafter installation)

Number species observed

Seaward grass beds Little Bahama Bank

Family

AcanthuridaeApogonidaeBalistidaeCarangidaeChaetodontidaeDiodontidaeHolocentridaeLabridaeLutjanidaeMullidaeMuraenidaeOrectolobidaePomacentridaeHaemulidaeScaridaeScianidaeSerranidaeSparidaeSynodontidaeSphyranidaeTetradontidae

Community parametersSpecies diversity (H)Species richness (S)Species evenness (J)

Natural(N = 28)

2II36II

22I

4I

24528074

Manmiddotmade(N = 3)

I2I

II3I

25I

2

21622070

Natural(N= 14)

I23

I252

16625051

Man-made(N = 3)

2

I2II

1078051

The efficiency of the units in attracting grunt and snapper appeared to be un-related to overall reef size (ie arrangement into one-unit two-unit or four-unitreefs) Grunts recruited were mainly the white grunt Haemulon plumieri and thebluestriped grunt Haemulon sciurus The majority of snapper recruited were thegrey snapper Lutjanus griseus and the lane snapper Lutjanus synagris After Iyear of recruitment the density of target fishes ranged from 40 to 62 per reef unitwith an estimated average weight of 05 to 07 kg per fish The single exceptionto this trend occurred on the one unit reef sited in the lagoonal grassbeds onwhich 113 target fishes were counted in the final census However the discrepancywas due entirely to a school of 51 small (lt 100 mm standard length) lane snapperwhich had taken up residence since the prior (March 1983) census

The location of the reefs resulted in three notable differences in terms of re-cruitment of fishes First the initial recruitment rate was much higher on thelagoonal grassbed reefs although after about 8 months the target fish populationsizes on a per reef-unit basis were equitable on all reefs (Fig 4) Secondly thenumber of species observed on the lagoonal grassbed reefs was considerably higher(Table I) Finally the target species composition differed somewhat with locationwith snappers generally representing a larger proportion of adult target fishes onthe Little Bahama Bank reefs The first two effects of location (more rapid re-cruitment and higher diversity of lagoonal grassbed units) are most likely attrib-utable to the relative proximity of the lagoonal grassbed units to extensive natural

8 BULLETIN OF MARINE SCIENCE VOL 37 NO I 1985

Table 2 Comparison of four structural characteristics of patch reefs in two different habitats nearDeep Water Cay Bahamas (the means of each measure were compared by Students t-test)

Measured values

Structural characteristic

Area (m2)

Surface rugosity indexVertical development indexDegree of undercut index

Lagoonal grassbeds(N = 14)x (plusmnSE)

284 (plusmn0859)128 (plusmn0038)626 (plusmn20l8)085 (plusmn0022)

Lillie Bahama Bank(N = 28)x (plusmnSE)

209 (plusmn0205)126 (plusmn0035)436 (plusmn571)090 (plusmn003I)

109035113106

p

gt010gt010gt010gt010

reef areas which serve as the main source of recruitment The final difference(proportion of snappers) may be due to differences in the behavior andor eco-logical requirements ofthe two families of target species This same general resultwas also evident on the natural reefs (Table I)

The size and structure of the natural patch reefs investigated in both habitatswere found to be highly similar Significant between-habitat differences could notbe detected in any of the four measures utilized for these comparisons (Table 2)The composition and diversity characteristics of the fish communities recruitedto the man-made reefs and those found on the natural patch reefs are comparedin Table 1 In general the community structure and diversity of fishes inhabitingman-made and natural reefs sited in the same habitat appear more similar thando those characteristics of the fish communities associated with either type (man-made or natural) compared among habitats The overall fish diversity (H) andspecies richness (S) appeared considerably higher on the natural (as comparedwith man-made) patch reefs on the Little Bahama Bank However it must bekept in mind that these diversity characteristics were calculated on very differentsample sizes (number of reefs censused) Increased sample size would be expectedto primarily affect the species richness component of diversity which is wherethe major discrepancies occurred The evenness component (1) is identical forboth types of reefs from the Bank habitat and nearly identical for both typesfrom the seagrass habitat despite the differences in sample sizes Similarity in thestructures of the fish communities inhabiting the man-made and natural reefs wasquantified by the Bray-Curtis similarity index (Clifford and Stephenson 1975)which is relatively insensitive to differences in sample size These results (Table3) support the conclusion that the fish communities of man-made and naturalreefs sited in the same habitat were more similar than those of either type com-pared among habitats

DISCUSSION

Man-made reefs suitably sited appear to offer a promising means of substan-tially increasing the availability of high quality protein for islanders throughoutthe western Atlantic region The present investigation was concluded before thesustainable yield of the units could be empirically determined Nonetheless thestanding stock and recruitment data obtained indicate that units sited reasonablyclose to extensive natural recruitment sources (eg fringing reefs) might be ex-pected to sustain harvests of 20 or more adult target fishmonth with an averageweight of 05-07 kgfish The initial cost of raw materials needed to build ourreef units was about $70unit If the cost of whole fresh fish is taken to be $2lb

ALEYIZON ET AL MAN-MADE REEFS IN BAHAMAS 9

Table 3 Similarity of community structures of reef fishes residing on man-made and natural patchreefs near Deep Water Cay Bahamas [similarity compared by habitat and reef type is quantified bythe Bray-Curtis index of similarity (IS)]

Comparison

By habitat (Little Bahama Bank ys grassbed)Natural patch reefsMan-made reef units

By reef type (natural vs man-made)

Lagoonal grassbedsLittle Bahama Bank

IS

055062

065075

(retail) a harvest of 20 Ibmonth would represent a continuing return valued atabout $40month The occasional harvesting of spiny lobster would represent anadditional return

Further research will be required to establish the long term effectiveness of suchman-made reefs deployed in large numbers The dynamic interactions betweennatural and man-made reefs are poorly understood and conflicting informationis present in the current literature For example Stone et a1 (1979) built a 500-tire reef close to a comparably sized natural reef off south Florida and concluded(p 11) that the artificial reef did not diminish the resident population ofthe natural reefby attracting them to the new habitat Most ofthe resident species were recruited to the artificial reef as juveniles In contrast we found thatthe majority of recruits to our man-made units were adults presumably recruited(in the lagoonal grassbed habitat) from the nearby fringing reef andor mangroveareas

It must be kept in mind that the long term productivity of man-made reefs inthe context investigated here is predicted on the unverified assumption that asfishes are recruited the recruitment source is capable of replacing its losses at acomparable rate Large recruitment pools (from areas such as extensive fringingreefs) may be able to sustain high recruitment rates to many man-made unitswhereas more restricted recruitment pools (such as those associated with isolatedpatch reefs) would be expected to sustain correspondingly lower rates of recruit-ment In this context it is worth noting that McFarland (1983) documented thesemi-lunar influx of post-larval grunts (Haemulon flavolineatum) on patch reefsoff St Croix US Virgin Islands If the regular loss of adults from such areascorrespondingly increases the survival and possibly growth rates of this regularsupply of young it seems plausible that for some fishes sizable losses from anatural recruitment source might be quickly replaced in tropical reef situationsClearly this is an area where further research is badly needed

The role of reef structure as a determinant of community structure of residentreef fishes has been emphasized by some authors (Risk 1972 Gladfelter andGladfelter 1978 Gladfelter et a1 1980) Others have tended to view reef structureas playing a relatively minor role in comparison to the process of recruitment(Russell et a1 1974 Sale and Dybdahl 1975 Sale 1978 1979 1980) Our resultsstrongly support the latter view The vast differences in structure between thenatural and man-made units appeared clearly subordinate to siting (ie natureand distance of the major recruitment source) in determining reef fish communitystructure This point is emphasized as it is of major interest to the rapidly in-creasing use of man-made reefs as fish attractants

10 BULLETINOFMARINESCIENCEVOL37 NO I 1985

ACKNOWLEDGMENTS

The authors wish to thank Mr and Mrs Perkins Sams whose generosity made this work possibleWe also thank the Bahamian government for permission to conduct this research

LITERATURE CITED

Bohnsack J A and F H Talbot 1980 Species-packing by reef fishes on Australian and Caribbeanreefs an experimental approach Bull Mar Sci 30 710-723

Clifford H T and W Stephenson 1975 An introduction to numerical classification AcademicPress New York 299 pp

Gladfelter W B and E H Gladfelter 1978 Fish community structure as a function of habitatstructure on West Indian patch reefs Revista de Biologica Tropical 26 65-84

--- J Ogden and E H Gladfelter 1980 Similarity and diversity among patch reef fish com-munities a comparison between tropical western Atlantic (Virgin Island) and tropical centralPacific (Marshall Islands) reefs Ecology 61 1156-1168

Luckhurst B E and K Luckhurst 1978 Diurnal space utilization in coral reef fish communitiesMar BioI 49 325-332

McFarland W N 1983 Periodic recruitment of French grunts HaemulonjIavolineatum from theoffshore plankton Abstract Vol 63rd Annual Meeting Amer Soc Ich and Herp TallahasseeHorida P 22

-- J C Ogden and J N Lythgoe 1979 The influence of light on the twilight migrations ofgrunts Env Bio Fishes 4 9-22

Nolan R S 1975 The ecology of patch reef fishes PhD Thesis Univ of California 230 ppRisk M J 1972 Fish diversity on a coral reef in the Virgin Islands Atoll Research Bull 153 1-

6Russell B c F H Talbot and S Domm 1974 Patterns of colonization of artificial reefs by coral

reef fishes Pages 217-225 in Proceedings of the 2nd International Symposium on Coral ReefsVol I Great Barrier Reef Committee Brisbane Australia

Sale P F 1978 Coexistence of coral reef fishes a lottery for living space Envir BioI Fishes 3 85-102

--- 1979 Recruitment loss and coexistence in a guild of territorial coral reef fishes Oecologia42 159-178

--- 1980 Assemblages of fish on patch reefs-predictable or unpredictable Env BioI Fishes5 243-249

--- and R Dybdahl 1975 Determinants of community structure for coral reef fishes in anexperimental habitat Ecology 56 1343-1355

Stone R B H L Pratt R O Parker Jr and G E Davis 1979 A comparison offish populationon an artificial and natural reef in the Florida Keys Mar Fish Rev 41(9) I-II

DATEACCEPTED August 6 1984

ADDRESS Department of Biological Sciences Florida Institute of Technology Melbourne Florida32901

ALEVIZON ET AL MAN-MADE REEFS IN BAHAMAS 5

210 LAGOONAL GRASSBEOS

00

27

03

70

00

TIMElOAY91

LITTLE BAHAMA BANK

00 00

Figure 2 Population growth of fishes on man-made reefs sited in two habitats near Deep Water CayBahamas

lation The small size and shallow depth of the reefs allowed a snorkeler to accurately census all butthe very small or cryptic fishes Censuses were repeated periodically for approximately I year afterinstallation when fish populations had presumably approached equilibrium densities and communitystructures (Nolan 1975 Stone et aI 1979 Bohnsack and Talbot 1980)

The fish communities observed on the man-made reefs about 1 year after installation were compandwith those inhabiting comparably sized and sited natural patch reefs A total of 42 small patch reefsranging in size from approximately 065 to 135 m2 in area were investigated Twenty-eight ofthese occurred on the Little Bahama Bank about 1-3 km offshore Fourteen occurred in the lagoonalseagrass habitat adjacent to a fringing reef Thus the natural reefs investigated were located in areascomparable (in terms of habitat-type and distance from the main reef system) to those in which man-made units had been installed

Figure 3 (A) Installed two-unit reef Little Bahama Bank (July 1983) (B) Standing stock of fish atman-made reef sited in lagoonal seagrass beds (December 198245 months after installation) Standingstock of fish at man-made reef Little Bahama Bank (March 1983 about 9 months after installation)_

6 BULLETIN OF MARINE SCIENCE VOL 37 NO I 1985

2 UNIT

bullbull1 UNIT

40 eo 120 100 200 20 280 320 380

LITTLE BAHAMA BANK

bullbull UNIT

20

40 eo 120 180 200 2-40 280 320 300

LAGOONAL OAASSBEOS~w 120

~m 100~Wo 80

T1MEIOAYS)

Figure 4 Population growth of target fishes (snappers and grunts) on man-made reefs sited in twohabitats near Deep Water Cay Bahamas

Field investigation of the natural patch reefs involved two distinct aspects censusing of residentfish communities and measuring of reef size and structure Fish censusing was accomplished by asnorkeler who took a single visual count of all fishes found in the immediate vicinity of the reef Fourmeasures of reef size and structure were taken on each reef censused An estimate of surface area wasgenerated by converting a measurement of maximum circumference into the surface area of a hemi-sphere To define vertical development an index was calculated by dividing the maximum height(vertical distance from the substrate to the highest point on the reef) by the total surface area (estimatedas described above) This index reflects differences in reef shape since reefs of the same height butdifferent diameters would generate correspondingly different values A rugosity index indicating thedegree of surface texture was generated after the method of Luckhurst and Luckhurst (1978) Thedegree of undercut reflects the presence of caves and ledges near the base of the reef necessarymicrohabitats for some species It was expressed as the ratio of the circumference at the level of thesubstrate to the maximum circumference The obtained values of each of these measuresindices werefound to approximate a normal distribution within each habitat Thus reefs from the two habitatswere tested for significant differences in these characteristics by Students (-test

RESULTS

Recruitment of marine organisms on the man-made reefs was rapid The firstarrivals (fish and sea urchins) were observed within 48 h of reef installation Majordifferences in the pattern of fish recruitment were apparent between units placedin the two habitats (Fig 3) Whereas fish populations reached maximal levels in50-60 days on the lagoonal grassbed reefs two of the three reefs sited on theLittle Bahama Bank continued to display marked increases in resident fish pop-ulations throughout the 12-month study period The recruitment of sessile plantsand animals as well as mobile invertebrates (eg gastropods sea urchins crabsand spiny lobster) also generally occurred very rapidly throughout the summerand early fall with a decreased rate evident during the late fall and winter Thegrowth of fish populations and epibiota on the structures was photographicallydocumented in Figure 2 Although the prototype reef was not designed with specialprovisions for attracting spiny lobster (Panulurus spp) these were observed oc-casionally on the reefs throughout the study They appeared to take up residencefor a short while and then move on The maximum number observed in a singlecensus was 24 (four-unit reef Little Bahama Bank)

The reefs were highly successful and efficient in attracting the target species(Fig 4) Regardless of location or configuration of the reefs snappers and gruntsformed the overwhelmingly dominant component of the fish fauna observedthroughout the monitoring period Target fishes comprised over 90 of all fishesinhabiting the man-made reefs sited on the Little Bahama Bank at years end andfrom about 45 to 75 on reefs sited in the lagoonal seagrass habitat Bothjuveniles and adults appeared early and were evident throughout

ALEVIZON ET AL MAN-MADE REEFS IN BAHAMAS 7

Table 1 Diversity of fishes observed on natural and man-made reefs near Deep Water Cay Bahamas(data from man-made reefs represents the results of censusing resident fish populations 12 monthsafter installation)

Number species observed

Seaward grass beds Little Bahama Bank

Family

AcanthuridaeApogonidaeBalistidaeCarangidaeChaetodontidaeDiodontidaeHolocentridaeLabridaeLutjanidaeMullidaeMuraenidaeOrectolobidaePomacentridaeHaemulidaeScaridaeScianidaeSerranidaeSparidaeSynodontidaeSphyranidaeTetradontidae

Community parametersSpecies diversity (H)Species richness (S)Species evenness (J)

Natural(N = 28)

2II36II

22I

4I

24528074

Manmiddotmade(N = 3)

I2I

II3I

25I

2

21622070

Natural(N= 14)

I23

I252

16625051

Man-made(N = 3)

2

I2II

1078051

The efficiency of the units in attracting grunt and snapper appeared to be un-related to overall reef size (ie arrangement into one-unit two-unit or four-unitreefs) Grunts recruited were mainly the white grunt Haemulon plumieri and thebluestriped grunt Haemulon sciurus The majority of snapper recruited were thegrey snapper Lutjanus griseus and the lane snapper Lutjanus synagris After Iyear of recruitment the density of target fishes ranged from 40 to 62 per reef unitwith an estimated average weight of 05 to 07 kg per fish The single exceptionto this trend occurred on the one unit reef sited in the lagoonal grassbeds onwhich 113 target fishes were counted in the final census However the discrepancywas due entirely to a school of 51 small (lt 100 mm standard length) lane snapperwhich had taken up residence since the prior (March 1983) census

The location of the reefs resulted in three notable differences in terms of re-cruitment of fishes First the initial recruitment rate was much higher on thelagoonal grassbed reefs although after about 8 months the target fish populationsizes on a per reef-unit basis were equitable on all reefs (Fig 4) Secondly thenumber of species observed on the lagoonal grassbed reefs was considerably higher(Table I) Finally the target species composition differed somewhat with locationwith snappers generally representing a larger proportion of adult target fishes onthe Little Bahama Bank reefs The first two effects of location (more rapid re-cruitment and higher diversity of lagoonal grassbed units) are most likely attrib-utable to the relative proximity of the lagoonal grassbed units to extensive natural

8 BULLETIN OF MARINE SCIENCE VOL 37 NO I 1985

Table 2 Comparison of four structural characteristics of patch reefs in two different habitats nearDeep Water Cay Bahamas (the means of each measure were compared by Students t-test)

Measured values

Structural characteristic

Area (m2)

Surface rugosity indexVertical development indexDegree of undercut index

Lagoonal grassbeds(N = 14)x (plusmnSE)

284 (plusmn0859)128 (plusmn0038)626 (plusmn20l8)085 (plusmn0022)

Lillie Bahama Bank(N = 28)x (plusmnSE)

209 (plusmn0205)126 (plusmn0035)436 (plusmn571)090 (plusmn003I)

109035113106

p

gt010gt010gt010gt010

reef areas which serve as the main source of recruitment The final difference(proportion of snappers) may be due to differences in the behavior andor eco-logical requirements ofthe two families of target species This same general resultwas also evident on the natural reefs (Table I)

The size and structure of the natural patch reefs investigated in both habitatswere found to be highly similar Significant between-habitat differences could notbe detected in any of the four measures utilized for these comparisons (Table 2)The composition and diversity characteristics of the fish communities recruitedto the man-made reefs and those found on the natural patch reefs are comparedin Table 1 In general the community structure and diversity of fishes inhabitingman-made and natural reefs sited in the same habitat appear more similar thando those characteristics of the fish communities associated with either type (man-made or natural) compared among habitats The overall fish diversity (H) andspecies richness (S) appeared considerably higher on the natural (as comparedwith man-made) patch reefs on the Little Bahama Bank However it must bekept in mind that these diversity characteristics were calculated on very differentsample sizes (number of reefs censused) Increased sample size would be expectedto primarily affect the species richness component of diversity which is wherethe major discrepancies occurred The evenness component (1) is identical forboth types of reefs from the Bank habitat and nearly identical for both typesfrom the seagrass habitat despite the differences in sample sizes Similarity in thestructures of the fish communities inhabiting the man-made and natural reefs wasquantified by the Bray-Curtis similarity index (Clifford and Stephenson 1975)which is relatively insensitive to differences in sample size These results (Table3) support the conclusion that the fish communities of man-made and naturalreefs sited in the same habitat were more similar than those of either type com-pared among habitats

DISCUSSION

Man-made reefs suitably sited appear to offer a promising means of substan-tially increasing the availability of high quality protein for islanders throughoutthe western Atlantic region The present investigation was concluded before thesustainable yield of the units could be empirically determined Nonetheless thestanding stock and recruitment data obtained indicate that units sited reasonablyclose to extensive natural recruitment sources (eg fringing reefs) might be ex-pected to sustain harvests of 20 or more adult target fishmonth with an averageweight of 05-07 kgfish The initial cost of raw materials needed to build ourreef units was about $70unit If the cost of whole fresh fish is taken to be $2lb

ALEYIZON ET AL MAN-MADE REEFS IN BAHAMAS 9

Table 3 Similarity of community structures of reef fishes residing on man-made and natural patchreefs near Deep Water Cay Bahamas [similarity compared by habitat and reef type is quantified bythe Bray-Curtis index of similarity (IS)]

Comparison

By habitat (Little Bahama Bank ys grassbed)Natural patch reefsMan-made reef units

By reef type (natural vs man-made)

Lagoonal grassbedsLittle Bahama Bank

IS

055062

065075

(retail) a harvest of 20 Ibmonth would represent a continuing return valued atabout $40month The occasional harvesting of spiny lobster would represent anadditional return

Further research will be required to establish the long term effectiveness of suchman-made reefs deployed in large numbers The dynamic interactions betweennatural and man-made reefs are poorly understood and conflicting informationis present in the current literature For example Stone et a1 (1979) built a 500-tire reef close to a comparably sized natural reef off south Florida and concluded(p 11) that the artificial reef did not diminish the resident population ofthe natural reefby attracting them to the new habitat Most ofthe resident species were recruited to the artificial reef as juveniles In contrast we found thatthe majority of recruits to our man-made units were adults presumably recruited(in the lagoonal grassbed habitat) from the nearby fringing reef andor mangroveareas

It must be kept in mind that the long term productivity of man-made reefs inthe context investigated here is predicted on the unverified assumption that asfishes are recruited the recruitment source is capable of replacing its losses at acomparable rate Large recruitment pools (from areas such as extensive fringingreefs) may be able to sustain high recruitment rates to many man-made unitswhereas more restricted recruitment pools (such as those associated with isolatedpatch reefs) would be expected to sustain correspondingly lower rates of recruit-ment In this context it is worth noting that McFarland (1983) documented thesemi-lunar influx of post-larval grunts (Haemulon flavolineatum) on patch reefsoff St Croix US Virgin Islands If the regular loss of adults from such areascorrespondingly increases the survival and possibly growth rates of this regularsupply of young it seems plausible that for some fishes sizable losses from anatural recruitment source might be quickly replaced in tropical reef situationsClearly this is an area where further research is badly needed

The role of reef structure as a determinant of community structure of residentreef fishes has been emphasized by some authors (Risk 1972 Gladfelter andGladfelter 1978 Gladfelter et a1 1980) Others have tended to view reef structureas playing a relatively minor role in comparison to the process of recruitment(Russell et a1 1974 Sale and Dybdahl 1975 Sale 1978 1979 1980) Our resultsstrongly support the latter view The vast differences in structure between thenatural and man-made units appeared clearly subordinate to siting (ie natureand distance of the major recruitment source) in determining reef fish communitystructure This point is emphasized as it is of major interest to the rapidly in-creasing use of man-made reefs as fish attractants

10 BULLETINOFMARINESCIENCEVOL37 NO I 1985

ACKNOWLEDGMENTS

The authors wish to thank Mr and Mrs Perkins Sams whose generosity made this work possibleWe also thank the Bahamian government for permission to conduct this research

LITERATURE CITED

Bohnsack J A and F H Talbot 1980 Species-packing by reef fishes on Australian and Caribbeanreefs an experimental approach Bull Mar Sci 30 710-723

Clifford H T and W Stephenson 1975 An introduction to numerical classification AcademicPress New York 299 pp

Gladfelter W B and E H Gladfelter 1978 Fish community structure as a function of habitatstructure on West Indian patch reefs Revista de Biologica Tropical 26 65-84

--- J Ogden and E H Gladfelter 1980 Similarity and diversity among patch reef fish com-munities a comparison between tropical western Atlantic (Virgin Island) and tropical centralPacific (Marshall Islands) reefs Ecology 61 1156-1168

Luckhurst B E and K Luckhurst 1978 Diurnal space utilization in coral reef fish communitiesMar BioI 49 325-332

McFarland W N 1983 Periodic recruitment of French grunts HaemulonjIavolineatum from theoffshore plankton Abstract Vol 63rd Annual Meeting Amer Soc Ich and Herp TallahasseeHorida P 22

-- J C Ogden and J N Lythgoe 1979 The influence of light on the twilight migrations ofgrunts Env Bio Fishes 4 9-22

Nolan R S 1975 The ecology of patch reef fishes PhD Thesis Univ of California 230 ppRisk M J 1972 Fish diversity on a coral reef in the Virgin Islands Atoll Research Bull 153 1-

6Russell B c F H Talbot and S Domm 1974 Patterns of colonization of artificial reefs by coral

reef fishes Pages 217-225 in Proceedings of the 2nd International Symposium on Coral ReefsVol I Great Barrier Reef Committee Brisbane Australia

Sale P F 1978 Coexistence of coral reef fishes a lottery for living space Envir BioI Fishes 3 85-102

--- 1979 Recruitment loss and coexistence in a guild of territorial coral reef fishes Oecologia42 159-178

--- 1980 Assemblages of fish on patch reefs-predictable or unpredictable Env BioI Fishes5 243-249

--- and R Dybdahl 1975 Determinants of community structure for coral reef fishes in anexperimental habitat Ecology 56 1343-1355

Stone R B H L Pratt R O Parker Jr and G E Davis 1979 A comparison offish populationon an artificial and natural reef in the Florida Keys Mar Fish Rev 41(9) I-II

DATEACCEPTED August 6 1984

ADDRESS Department of Biological Sciences Florida Institute of Technology Melbourne Florida32901

6 BULLETIN OF MARINE SCIENCE VOL 37 NO I 1985

2 UNIT

bullbull1 UNIT

40 eo 120 100 200 20 280 320 380

LITTLE BAHAMA BANK

bullbull UNIT

20

40 eo 120 180 200 2-40 280 320 300

LAGOONAL OAASSBEOS~w 120

~m 100~Wo 80

T1MEIOAYS)

Figure 4 Population growth of target fishes (snappers and grunts) on man-made reefs sited in twohabitats near Deep Water Cay Bahamas

Field investigation of the natural patch reefs involved two distinct aspects censusing of residentfish communities and measuring of reef size and structure Fish censusing was accomplished by asnorkeler who took a single visual count of all fishes found in the immediate vicinity of the reef Fourmeasures of reef size and structure were taken on each reef censused An estimate of surface area wasgenerated by converting a measurement of maximum circumference into the surface area of a hemi-sphere To define vertical development an index was calculated by dividing the maximum height(vertical distance from the substrate to the highest point on the reef) by the total surface area (estimatedas described above) This index reflects differences in reef shape since reefs of the same height butdifferent diameters would generate correspondingly different values A rugosity index indicating thedegree of surface texture was generated after the method of Luckhurst and Luckhurst (1978) Thedegree of undercut reflects the presence of caves and ledges near the base of the reef necessarymicrohabitats for some species It was expressed as the ratio of the circumference at the level of thesubstrate to the maximum circumference The obtained values of each of these measuresindices werefound to approximate a normal distribution within each habitat Thus reefs from the two habitatswere tested for significant differences in these characteristics by Students (-test

RESULTS

Recruitment of marine organisms on the man-made reefs was rapid The firstarrivals (fish and sea urchins) were observed within 48 h of reef installation Majordifferences in the pattern of fish recruitment were apparent between units placedin the two habitats (Fig 3) Whereas fish populations reached maximal levels in50-60 days on the lagoonal grassbed reefs two of the three reefs sited on theLittle Bahama Bank continued to display marked increases in resident fish pop-ulations throughout the 12-month study period The recruitment of sessile plantsand animals as well as mobile invertebrates (eg gastropods sea urchins crabsand spiny lobster) also generally occurred very rapidly throughout the summerand early fall with a decreased rate evident during the late fall and winter Thegrowth of fish populations and epibiota on the structures was photographicallydocumented in Figure 2 Although the prototype reef was not designed with specialprovisions for attracting spiny lobster (Panulurus spp) these were observed oc-casionally on the reefs throughout the study They appeared to take up residencefor a short while and then move on The maximum number observed in a singlecensus was 24 (four-unit reef Little Bahama Bank)

The reefs were highly successful and efficient in attracting the target species(Fig 4) Regardless of location or configuration of the reefs snappers and gruntsformed the overwhelmingly dominant component of the fish fauna observedthroughout the monitoring period Target fishes comprised over 90 of all fishesinhabiting the man-made reefs sited on the Little Bahama Bank at years end andfrom about 45 to 75 on reefs sited in the lagoonal seagrass habitat Bothjuveniles and adults appeared early and were evident throughout

ALEVIZON ET AL MAN-MADE REEFS IN BAHAMAS 7

Table 1 Diversity of fishes observed on natural and man-made reefs near Deep Water Cay Bahamas(data from man-made reefs represents the results of censusing resident fish populations 12 monthsafter installation)

Number species observed

Seaward grass beds Little Bahama Bank

Family

AcanthuridaeApogonidaeBalistidaeCarangidaeChaetodontidaeDiodontidaeHolocentridaeLabridaeLutjanidaeMullidaeMuraenidaeOrectolobidaePomacentridaeHaemulidaeScaridaeScianidaeSerranidaeSparidaeSynodontidaeSphyranidaeTetradontidae

Community parametersSpecies diversity (H)Species richness (S)Species evenness (J)

Natural(N = 28)

2II36II

22I

4I

24528074

Manmiddotmade(N = 3)

I2I

II3I

25I

2

21622070

Natural(N= 14)

I23

I252

16625051

Man-made(N = 3)

2

I2II

1078051

The efficiency of the units in attracting grunt and snapper appeared to be un-related to overall reef size (ie arrangement into one-unit two-unit or four-unitreefs) Grunts recruited were mainly the white grunt Haemulon plumieri and thebluestriped grunt Haemulon sciurus The majority of snapper recruited were thegrey snapper Lutjanus griseus and the lane snapper Lutjanus synagris After Iyear of recruitment the density of target fishes ranged from 40 to 62 per reef unitwith an estimated average weight of 05 to 07 kg per fish The single exceptionto this trend occurred on the one unit reef sited in the lagoonal grassbeds onwhich 113 target fishes were counted in the final census However the discrepancywas due entirely to a school of 51 small (lt 100 mm standard length) lane snapperwhich had taken up residence since the prior (March 1983) census

The location of the reefs resulted in three notable differences in terms of re-cruitment of fishes First the initial recruitment rate was much higher on thelagoonal grassbed reefs although after about 8 months the target fish populationsizes on a per reef-unit basis were equitable on all reefs (Fig 4) Secondly thenumber of species observed on the lagoonal grassbed reefs was considerably higher(Table I) Finally the target species composition differed somewhat with locationwith snappers generally representing a larger proportion of adult target fishes onthe Little Bahama Bank reefs The first two effects of location (more rapid re-cruitment and higher diversity of lagoonal grassbed units) are most likely attrib-utable to the relative proximity of the lagoonal grassbed units to extensive natural

8 BULLETIN OF MARINE SCIENCE VOL 37 NO I 1985

Table 2 Comparison of four structural characteristics of patch reefs in two different habitats nearDeep Water Cay Bahamas (the means of each measure were compared by Students t-test)

Measured values

Structural characteristic

Area (m2)

Surface rugosity indexVertical development indexDegree of undercut index

Lagoonal grassbeds(N = 14)x (plusmnSE)

284 (plusmn0859)128 (plusmn0038)626 (plusmn20l8)085 (plusmn0022)

Lillie Bahama Bank(N = 28)x (plusmnSE)

209 (plusmn0205)126 (plusmn0035)436 (plusmn571)090 (plusmn003I)

109035113106

p

gt010gt010gt010gt010

reef areas which serve as the main source of recruitment The final difference(proportion of snappers) may be due to differences in the behavior andor eco-logical requirements ofthe two families of target species This same general resultwas also evident on the natural reefs (Table I)

The size and structure of the natural patch reefs investigated in both habitatswere found to be highly similar Significant between-habitat differences could notbe detected in any of the four measures utilized for these comparisons (Table 2)The composition and diversity characteristics of the fish communities recruitedto the man-made reefs and those found on the natural patch reefs are comparedin Table 1 In general the community structure and diversity of fishes inhabitingman-made and natural reefs sited in the same habitat appear more similar thando those characteristics of the fish communities associated with either type (man-made or natural) compared among habitats The overall fish diversity (H) andspecies richness (S) appeared considerably higher on the natural (as comparedwith man-made) patch reefs on the Little Bahama Bank However it must bekept in mind that these diversity characteristics were calculated on very differentsample sizes (number of reefs censused) Increased sample size would be expectedto primarily affect the species richness component of diversity which is wherethe major discrepancies occurred The evenness component (1) is identical forboth types of reefs from the Bank habitat and nearly identical for both typesfrom the seagrass habitat despite the differences in sample sizes Similarity in thestructures of the fish communities inhabiting the man-made and natural reefs wasquantified by the Bray-Curtis similarity index (Clifford and Stephenson 1975)which is relatively insensitive to differences in sample size These results (Table3) support the conclusion that the fish communities of man-made and naturalreefs sited in the same habitat were more similar than those of either type com-pared among habitats

DISCUSSION

Man-made reefs suitably sited appear to offer a promising means of substan-tially increasing the availability of high quality protein for islanders throughoutthe western Atlantic region The present investigation was concluded before thesustainable yield of the units could be empirically determined Nonetheless thestanding stock and recruitment data obtained indicate that units sited reasonablyclose to extensive natural recruitment sources (eg fringing reefs) might be ex-pected to sustain harvests of 20 or more adult target fishmonth with an averageweight of 05-07 kgfish The initial cost of raw materials needed to build ourreef units was about $70unit If the cost of whole fresh fish is taken to be $2lb

ALEYIZON ET AL MAN-MADE REEFS IN BAHAMAS 9

Table 3 Similarity of community structures of reef fishes residing on man-made and natural patchreefs near Deep Water Cay Bahamas [similarity compared by habitat and reef type is quantified bythe Bray-Curtis index of similarity (IS)]

Comparison

By habitat (Little Bahama Bank ys grassbed)Natural patch reefsMan-made reef units

By reef type (natural vs man-made)

Lagoonal grassbedsLittle Bahama Bank

IS

055062

065075

(retail) a harvest of 20 Ibmonth would represent a continuing return valued atabout $40month The occasional harvesting of spiny lobster would represent anadditional return

Further research will be required to establish the long term effectiveness of suchman-made reefs deployed in large numbers The dynamic interactions betweennatural and man-made reefs are poorly understood and conflicting informationis present in the current literature For example Stone et a1 (1979) built a 500-tire reef close to a comparably sized natural reef off south Florida and concluded(p 11) that the artificial reef did not diminish the resident population ofthe natural reefby attracting them to the new habitat Most ofthe resident species were recruited to the artificial reef as juveniles In contrast we found thatthe majority of recruits to our man-made units were adults presumably recruited(in the lagoonal grassbed habitat) from the nearby fringing reef andor mangroveareas

It must be kept in mind that the long term productivity of man-made reefs inthe context investigated here is predicted on the unverified assumption that asfishes are recruited the recruitment source is capable of replacing its losses at acomparable rate Large recruitment pools (from areas such as extensive fringingreefs) may be able to sustain high recruitment rates to many man-made unitswhereas more restricted recruitment pools (such as those associated with isolatedpatch reefs) would be expected to sustain correspondingly lower rates of recruit-ment In this context it is worth noting that McFarland (1983) documented thesemi-lunar influx of post-larval grunts (Haemulon flavolineatum) on patch reefsoff St Croix US Virgin Islands If the regular loss of adults from such areascorrespondingly increases the survival and possibly growth rates of this regularsupply of young it seems plausible that for some fishes sizable losses from anatural recruitment source might be quickly replaced in tropical reef situationsClearly this is an area where further research is badly needed

The role of reef structure as a determinant of community structure of residentreef fishes has been emphasized by some authors (Risk 1972 Gladfelter andGladfelter 1978 Gladfelter et a1 1980) Others have tended to view reef structureas playing a relatively minor role in comparison to the process of recruitment(Russell et a1 1974 Sale and Dybdahl 1975 Sale 1978 1979 1980) Our resultsstrongly support the latter view The vast differences in structure between thenatural and man-made units appeared clearly subordinate to siting (ie natureand distance of the major recruitment source) in determining reef fish communitystructure This point is emphasized as it is of major interest to the rapidly in-creasing use of man-made reefs as fish attractants

10 BULLETINOFMARINESCIENCEVOL37 NO I 1985

ACKNOWLEDGMENTS

The authors wish to thank Mr and Mrs Perkins Sams whose generosity made this work possibleWe also thank the Bahamian government for permission to conduct this research

LITERATURE CITED

Bohnsack J A and F H Talbot 1980 Species-packing by reef fishes on Australian and Caribbeanreefs an experimental approach Bull Mar Sci 30 710-723

Clifford H T and W Stephenson 1975 An introduction to numerical classification AcademicPress New York 299 pp

Gladfelter W B and E H Gladfelter 1978 Fish community structure as a function of habitatstructure on West Indian patch reefs Revista de Biologica Tropical 26 65-84

--- J Ogden and E H Gladfelter 1980 Similarity and diversity among patch reef fish com-munities a comparison between tropical western Atlantic (Virgin Island) and tropical centralPacific (Marshall Islands) reefs Ecology 61 1156-1168

Luckhurst B E and K Luckhurst 1978 Diurnal space utilization in coral reef fish communitiesMar BioI 49 325-332

McFarland W N 1983 Periodic recruitment of French grunts HaemulonjIavolineatum from theoffshore plankton Abstract Vol 63rd Annual Meeting Amer Soc Ich and Herp TallahasseeHorida P 22

-- J C Ogden and J N Lythgoe 1979 The influence of light on the twilight migrations ofgrunts Env Bio Fishes 4 9-22

Nolan R S 1975 The ecology of patch reef fishes PhD Thesis Univ of California 230 ppRisk M J 1972 Fish diversity on a coral reef in the Virgin Islands Atoll Research Bull 153 1-

6Russell B c F H Talbot and S Domm 1974 Patterns of colonization of artificial reefs by coral

reef fishes Pages 217-225 in Proceedings of the 2nd International Symposium on Coral ReefsVol I Great Barrier Reef Committee Brisbane Australia

Sale P F 1978 Coexistence of coral reef fishes a lottery for living space Envir BioI Fishes 3 85-102

--- 1979 Recruitment loss and coexistence in a guild of territorial coral reef fishes Oecologia42 159-178

--- 1980 Assemblages of fish on patch reefs-predictable or unpredictable Env BioI Fishes5 243-249

--- and R Dybdahl 1975 Determinants of community structure for coral reef fishes in anexperimental habitat Ecology 56 1343-1355

Stone R B H L Pratt R O Parker Jr and G E Davis 1979 A comparison offish populationon an artificial and natural reef in the Florida Keys Mar Fish Rev 41(9) I-II

DATEACCEPTED August 6 1984

ADDRESS Department of Biological Sciences Florida Institute of Technology Melbourne Florida32901

ALEVIZON ET AL MAN-MADE REEFS IN BAHAMAS 7

Table 1 Diversity of fishes observed on natural and man-made reefs near Deep Water Cay Bahamas(data from man-made reefs represents the results of censusing resident fish populations 12 monthsafter installation)

Number species observed

Seaward grass beds Little Bahama Bank

Family

AcanthuridaeApogonidaeBalistidaeCarangidaeChaetodontidaeDiodontidaeHolocentridaeLabridaeLutjanidaeMullidaeMuraenidaeOrectolobidaePomacentridaeHaemulidaeScaridaeScianidaeSerranidaeSparidaeSynodontidaeSphyranidaeTetradontidae

Community parametersSpecies diversity (H)Species richness (S)Species evenness (J)

Natural(N = 28)

2II36II

22I

4I

24528074

Manmiddotmade(N = 3)

I2I

II3I

25I

2

21622070

Natural(N= 14)

I23

I252

16625051

Man-made(N = 3)

2

I2II

1078051

The efficiency of the units in attracting grunt and snapper appeared to be un-related to overall reef size (ie arrangement into one-unit two-unit or four-unitreefs) Grunts recruited were mainly the white grunt Haemulon plumieri and thebluestriped grunt Haemulon sciurus The majority of snapper recruited were thegrey snapper Lutjanus griseus and the lane snapper Lutjanus synagris After Iyear of recruitment the density of target fishes ranged from 40 to 62 per reef unitwith an estimated average weight of 05 to 07 kg per fish The single exceptionto this trend occurred on the one unit reef sited in the lagoonal grassbeds onwhich 113 target fishes were counted in the final census However the discrepancywas due entirely to a school of 51 small (lt 100 mm standard length) lane snapperwhich had taken up residence since the prior (March 1983) census

The location of the reefs resulted in three notable differences in terms of re-cruitment of fishes First the initial recruitment rate was much higher on thelagoonal grassbed reefs although after about 8 months the target fish populationsizes on a per reef-unit basis were equitable on all reefs (Fig 4) Secondly thenumber of species observed on the lagoonal grassbed reefs was considerably higher(Table I) Finally the target species composition differed somewhat with locationwith snappers generally representing a larger proportion of adult target fishes onthe Little Bahama Bank reefs The first two effects of location (more rapid re-cruitment and higher diversity of lagoonal grassbed units) are most likely attrib-utable to the relative proximity of the lagoonal grassbed units to extensive natural

8 BULLETIN OF MARINE SCIENCE VOL 37 NO I 1985

Table 2 Comparison of four structural characteristics of patch reefs in two different habitats nearDeep Water Cay Bahamas (the means of each measure were compared by Students t-test)

Measured values

Structural characteristic

Area (m2)

Surface rugosity indexVertical development indexDegree of undercut index

Lagoonal grassbeds(N = 14)x (plusmnSE)

284 (plusmn0859)128 (plusmn0038)626 (plusmn20l8)085 (plusmn0022)

Lillie Bahama Bank(N = 28)x (plusmnSE)

209 (plusmn0205)126 (plusmn0035)436 (plusmn571)090 (plusmn003I)

109035113106

p

gt010gt010gt010gt010

reef areas which serve as the main source of recruitment The final difference(proportion of snappers) may be due to differences in the behavior andor eco-logical requirements ofthe two families of target species This same general resultwas also evident on the natural reefs (Table I)

The size and structure of the natural patch reefs investigated in both habitatswere found to be highly similar Significant between-habitat differences could notbe detected in any of the four measures utilized for these comparisons (Table 2)The composition and diversity characteristics of the fish communities recruitedto the man-made reefs and those found on the natural patch reefs are comparedin Table 1 In general the community structure and diversity of fishes inhabitingman-made and natural reefs sited in the same habitat appear more similar thando those characteristics of the fish communities associated with either type (man-made or natural) compared among habitats The overall fish diversity (H) andspecies richness (S) appeared considerably higher on the natural (as comparedwith man-made) patch reefs on the Little Bahama Bank However it must bekept in mind that these diversity characteristics were calculated on very differentsample sizes (number of reefs censused) Increased sample size would be expectedto primarily affect the species richness component of diversity which is wherethe major discrepancies occurred The evenness component (1) is identical forboth types of reefs from the Bank habitat and nearly identical for both typesfrom the seagrass habitat despite the differences in sample sizes Similarity in thestructures of the fish communities inhabiting the man-made and natural reefs wasquantified by the Bray-Curtis similarity index (Clifford and Stephenson 1975)which is relatively insensitive to differences in sample size These results (Table3) support the conclusion that the fish communities of man-made and naturalreefs sited in the same habitat were more similar than those of either type com-pared among habitats

DISCUSSION

Man-made reefs suitably sited appear to offer a promising means of substan-tially increasing the availability of high quality protein for islanders throughoutthe western Atlantic region The present investigation was concluded before thesustainable yield of the units could be empirically determined Nonetheless thestanding stock and recruitment data obtained indicate that units sited reasonablyclose to extensive natural recruitment sources (eg fringing reefs) might be ex-pected to sustain harvests of 20 or more adult target fishmonth with an averageweight of 05-07 kgfish The initial cost of raw materials needed to build ourreef units was about $70unit If the cost of whole fresh fish is taken to be $2lb

ALEYIZON ET AL MAN-MADE REEFS IN BAHAMAS 9

Table 3 Similarity of community structures of reef fishes residing on man-made and natural patchreefs near Deep Water Cay Bahamas [similarity compared by habitat and reef type is quantified bythe Bray-Curtis index of similarity (IS)]

Comparison

By habitat (Little Bahama Bank ys grassbed)Natural patch reefsMan-made reef units

By reef type (natural vs man-made)

Lagoonal grassbedsLittle Bahama Bank

IS

055062

065075

(retail) a harvest of 20 Ibmonth would represent a continuing return valued atabout $40month The occasional harvesting of spiny lobster would represent anadditional return

Further research will be required to establish the long term effectiveness of suchman-made reefs deployed in large numbers The dynamic interactions betweennatural and man-made reefs are poorly understood and conflicting informationis present in the current literature For example Stone et a1 (1979) built a 500-tire reef close to a comparably sized natural reef off south Florida and concluded(p 11) that the artificial reef did not diminish the resident population ofthe natural reefby attracting them to the new habitat Most ofthe resident species were recruited to the artificial reef as juveniles In contrast we found thatthe majority of recruits to our man-made units were adults presumably recruited(in the lagoonal grassbed habitat) from the nearby fringing reef andor mangroveareas

It must be kept in mind that the long term productivity of man-made reefs inthe context investigated here is predicted on the unverified assumption that asfishes are recruited the recruitment source is capable of replacing its losses at acomparable rate Large recruitment pools (from areas such as extensive fringingreefs) may be able to sustain high recruitment rates to many man-made unitswhereas more restricted recruitment pools (such as those associated with isolatedpatch reefs) would be expected to sustain correspondingly lower rates of recruit-ment In this context it is worth noting that McFarland (1983) documented thesemi-lunar influx of post-larval grunts (Haemulon flavolineatum) on patch reefsoff St Croix US Virgin Islands If the regular loss of adults from such areascorrespondingly increases the survival and possibly growth rates of this regularsupply of young it seems plausible that for some fishes sizable losses from anatural recruitment source might be quickly replaced in tropical reef situationsClearly this is an area where further research is badly needed

The role of reef structure as a determinant of community structure of residentreef fishes has been emphasized by some authors (Risk 1972 Gladfelter andGladfelter 1978 Gladfelter et a1 1980) Others have tended to view reef structureas playing a relatively minor role in comparison to the process of recruitment(Russell et a1 1974 Sale and Dybdahl 1975 Sale 1978 1979 1980) Our resultsstrongly support the latter view The vast differences in structure between thenatural and man-made units appeared clearly subordinate to siting (ie natureand distance of the major recruitment source) in determining reef fish communitystructure This point is emphasized as it is of major interest to the rapidly in-creasing use of man-made reefs as fish attractants

10 BULLETINOFMARINESCIENCEVOL37 NO I 1985

ACKNOWLEDGMENTS

The authors wish to thank Mr and Mrs Perkins Sams whose generosity made this work possibleWe also thank the Bahamian government for permission to conduct this research

LITERATURE CITED

Bohnsack J A and F H Talbot 1980 Species-packing by reef fishes on Australian and Caribbeanreefs an experimental approach Bull Mar Sci 30 710-723

Clifford H T and W Stephenson 1975 An introduction to numerical classification AcademicPress New York 299 pp

Gladfelter W B and E H Gladfelter 1978 Fish community structure as a function of habitatstructure on West Indian patch reefs Revista de Biologica Tropical 26 65-84

--- J Ogden and E H Gladfelter 1980 Similarity and diversity among patch reef fish com-munities a comparison between tropical western Atlantic (Virgin Island) and tropical centralPacific (Marshall Islands) reefs Ecology 61 1156-1168

Luckhurst B E and K Luckhurst 1978 Diurnal space utilization in coral reef fish communitiesMar BioI 49 325-332

McFarland W N 1983 Periodic recruitment of French grunts HaemulonjIavolineatum from theoffshore plankton Abstract Vol 63rd Annual Meeting Amer Soc Ich and Herp TallahasseeHorida P 22

-- J C Ogden and J N Lythgoe 1979 The influence of light on the twilight migrations ofgrunts Env Bio Fishes 4 9-22

Nolan R S 1975 The ecology of patch reef fishes PhD Thesis Univ of California 230 ppRisk M J 1972 Fish diversity on a coral reef in the Virgin Islands Atoll Research Bull 153 1-

6Russell B c F H Talbot and S Domm 1974 Patterns of colonization of artificial reefs by coral

reef fishes Pages 217-225 in Proceedings of the 2nd International Symposium on Coral ReefsVol I Great Barrier Reef Committee Brisbane Australia

Sale P F 1978 Coexistence of coral reef fishes a lottery for living space Envir BioI Fishes 3 85-102

--- 1979 Recruitment loss and coexistence in a guild of territorial coral reef fishes Oecologia42 159-178

--- 1980 Assemblages of fish on patch reefs-predictable or unpredictable Env BioI Fishes5 243-249

--- and R Dybdahl 1975 Determinants of community structure for coral reef fishes in anexperimental habitat Ecology 56 1343-1355

Stone R B H L Pratt R O Parker Jr and G E Davis 1979 A comparison offish populationon an artificial and natural reef in the Florida Keys Mar Fish Rev 41(9) I-II

DATEACCEPTED August 6 1984

ADDRESS Department of Biological Sciences Florida Institute of Technology Melbourne Florida32901

8 BULLETIN OF MARINE SCIENCE VOL 37 NO I 1985

Table 2 Comparison of four structural characteristics of patch reefs in two different habitats nearDeep Water Cay Bahamas (the means of each measure were compared by Students t-test)

Measured values

Structural characteristic

Area (m2)

Surface rugosity indexVertical development indexDegree of undercut index

Lagoonal grassbeds(N = 14)x (plusmnSE)

284 (plusmn0859)128 (plusmn0038)626 (plusmn20l8)085 (plusmn0022)

Lillie Bahama Bank(N = 28)x (plusmnSE)

209 (plusmn0205)126 (plusmn0035)436 (plusmn571)090 (plusmn003I)

109035113106

p

gt010gt010gt010gt010

reef areas which serve as the main source of recruitment The final difference(proportion of snappers) may be due to differences in the behavior andor eco-logical requirements ofthe two families of target species This same general resultwas also evident on the natural reefs (Table I)

The size and structure of the natural patch reefs investigated in both habitatswere found to be highly similar Significant between-habitat differences could notbe detected in any of the four measures utilized for these comparisons (Table 2)The composition and diversity characteristics of the fish communities recruitedto the man-made reefs and those found on the natural patch reefs are comparedin Table 1 In general the community structure and diversity of fishes inhabitingman-made and natural reefs sited in the same habitat appear more similar thando those characteristics of the fish communities associated with either type (man-made or natural) compared among habitats The overall fish diversity (H) andspecies richness (S) appeared considerably higher on the natural (as comparedwith man-made) patch reefs on the Little Bahama Bank However it must bekept in mind that these diversity characteristics were calculated on very differentsample sizes (number of reefs censused) Increased sample size would be expectedto primarily affect the species richness component of diversity which is wherethe major discrepancies occurred The evenness component (1) is identical forboth types of reefs from the Bank habitat and nearly identical for both typesfrom the seagrass habitat despite the differences in sample sizes Similarity in thestructures of the fish communities inhabiting the man-made and natural reefs wasquantified by the Bray-Curtis similarity index (Clifford and Stephenson 1975)which is relatively insensitive to differences in sample size These results (Table3) support the conclusion that the fish communities of man-made and naturalreefs sited in the same habitat were more similar than those of either type com-pared among habitats

DISCUSSION

Man-made reefs suitably sited appear to offer a promising means of substan-tially increasing the availability of high quality protein for islanders throughoutthe western Atlantic region The present investigation was concluded before thesustainable yield of the units could be empirically determined Nonetheless thestanding stock and recruitment data obtained indicate that units sited reasonablyclose to extensive natural recruitment sources (eg fringing reefs) might be ex-pected to sustain harvests of 20 or more adult target fishmonth with an averageweight of 05-07 kgfish The initial cost of raw materials needed to build ourreef units was about $70unit If the cost of whole fresh fish is taken to be $2lb

ALEYIZON ET AL MAN-MADE REEFS IN BAHAMAS 9

Table 3 Similarity of community structures of reef fishes residing on man-made and natural patchreefs near Deep Water Cay Bahamas [similarity compared by habitat and reef type is quantified bythe Bray-Curtis index of similarity (IS)]

Comparison

By habitat (Little Bahama Bank ys grassbed)Natural patch reefsMan-made reef units

By reef type (natural vs man-made)

Lagoonal grassbedsLittle Bahama Bank

IS

055062

065075

(retail) a harvest of 20 Ibmonth would represent a continuing return valued atabout $40month The occasional harvesting of spiny lobster would represent anadditional return

Further research will be required to establish the long term effectiveness of suchman-made reefs deployed in large numbers The dynamic interactions betweennatural and man-made reefs are poorly understood and conflicting informationis present in the current literature For example Stone et a1 (1979) built a 500-tire reef close to a comparably sized natural reef off south Florida and concluded(p 11) that the artificial reef did not diminish the resident population ofthe natural reefby attracting them to the new habitat Most ofthe resident species were recruited to the artificial reef as juveniles In contrast we found thatthe majority of recruits to our man-made units were adults presumably recruited(in the lagoonal grassbed habitat) from the nearby fringing reef andor mangroveareas

It must be kept in mind that the long term productivity of man-made reefs inthe context investigated here is predicted on the unverified assumption that asfishes are recruited the recruitment source is capable of replacing its losses at acomparable rate Large recruitment pools (from areas such as extensive fringingreefs) may be able to sustain high recruitment rates to many man-made unitswhereas more restricted recruitment pools (such as those associated with isolatedpatch reefs) would be expected to sustain correspondingly lower rates of recruit-ment In this context it is worth noting that McFarland (1983) documented thesemi-lunar influx of post-larval grunts (Haemulon flavolineatum) on patch reefsoff St Croix US Virgin Islands If the regular loss of adults from such areascorrespondingly increases the survival and possibly growth rates of this regularsupply of young it seems plausible that for some fishes sizable losses from anatural recruitment source might be quickly replaced in tropical reef situationsClearly this is an area where further research is badly needed

The role of reef structure as a determinant of community structure of residentreef fishes has been emphasized by some authors (Risk 1972 Gladfelter andGladfelter 1978 Gladfelter et a1 1980) Others have tended to view reef structureas playing a relatively minor role in comparison to the process of recruitment(Russell et a1 1974 Sale and Dybdahl 1975 Sale 1978 1979 1980) Our resultsstrongly support the latter view The vast differences in structure between thenatural and man-made units appeared clearly subordinate to siting (ie natureand distance of the major recruitment source) in determining reef fish communitystructure This point is emphasized as it is of major interest to the rapidly in-creasing use of man-made reefs as fish attractants

10 BULLETINOFMARINESCIENCEVOL37 NO I 1985

ACKNOWLEDGMENTS

The authors wish to thank Mr and Mrs Perkins Sams whose generosity made this work possibleWe also thank the Bahamian government for permission to conduct this research

LITERATURE CITED

Bohnsack J A and F H Talbot 1980 Species-packing by reef fishes on Australian and Caribbeanreefs an experimental approach Bull Mar Sci 30 710-723

Clifford H T and W Stephenson 1975 An introduction to numerical classification AcademicPress New York 299 pp

Gladfelter W B and E H Gladfelter 1978 Fish community structure as a function of habitatstructure on West Indian patch reefs Revista de Biologica Tropical 26 65-84

--- J Ogden and E H Gladfelter 1980 Similarity and diversity among patch reef fish com-munities a comparison between tropical western Atlantic (Virgin Island) and tropical centralPacific (Marshall Islands) reefs Ecology 61 1156-1168

Luckhurst B E and K Luckhurst 1978 Diurnal space utilization in coral reef fish communitiesMar BioI 49 325-332

McFarland W N 1983 Periodic recruitment of French grunts HaemulonjIavolineatum from theoffshore plankton Abstract Vol 63rd Annual Meeting Amer Soc Ich and Herp TallahasseeHorida P 22

-- J C Ogden and J N Lythgoe 1979 The influence of light on the twilight migrations ofgrunts Env Bio Fishes 4 9-22

Nolan R S 1975 The ecology of patch reef fishes PhD Thesis Univ of California 230 ppRisk M J 1972 Fish diversity on a coral reef in the Virgin Islands Atoll Research Bull 153 1-

6Russell B c F H Talbot and S Domm 1974 Patterns of colonization of artificial reefs by coral

reef fishes Pages 217-225 in Proceedings of the 2nd International Symposium on Coral ReefsVol I Great Barrier Reef Committee Brisbane Australia

Sale P F 1978 Coexistence of coral reef fishes a lottery for living space Envir BioI Fishes 3 85-102

--- 1979 Recruitment loss and coexistence in a guild of territorial coral reef fishes Oecologia42 159-178

--- 1980 Assemblages of fish on patch reefs-predictable or unpredictable Env BioI Fishes5 243-249

--- and R Dybdahl 1975 Determinants of community structure for coral reef fishes in anexperimental habitat Ecology 56 1343-1355

Stone R B H L Pratt R O Parker Jr and G E Davis 1979 A comparison offish populationon an artificial and natural reef in the Florida Keys Mar Fish Rev 41(9) I-II

DATEACCEPTED August 6 1984

ADDRESS Department of Biological Sciences Florida Institute of Technology Melbourne Florida32901

ALEYIZON ET AL MAN-MADE REEFS IN BAHAMAS 9

Table 3 Similarity of community structures of reef fishes residing on man-made and natural patchreefs near Deep Water Cay Bahamas [similarity compared by habitat and reef type is quantified bythe Bray-Curtis index of similarity (IS)]

Comparison

By habitat (Little Bahama Bank ys grassbed)Natural patch reefsMan-made reef units

By reef type (natural vs man-made)

Lagoonal grassbedsLittle Bahama Bank

IS

055062

065075

(retail) a harvest of 20 Ibmonth would represent a continuing return valued atabout $40month The occasional harvesting of spiny lobster would represent anadditional return

Further research will be required to establish the long term effectiveness of suchman-made reefs deployed in large numbers The dynamic interactions betweennatural and man-made reefs are poorly understood and conflicting informationis present in the current literature For example Stone et a1 (1979) built a 500-tire reef close to a comparably sized natural reef off south Florida and concluded(p 11) that the artificial reef did not diminish the resident population ofthe natural reefby attracting them to the new habitat Most ofthe resident species were recruited to the artificial reef as juveniles In contrast we found thatthe majority of recruits to our man-made units were adults presumably recruited(in the lagoonal grassbed habitat) from the nearby fringing reef andor mangroveareas

It must be kept in mind that the long term productivity of man-made reefs inthe context investigated here is predicted on the unverified assumption that asfishes are recruited the recruitment source is capable of replacing its losses at acomparable rate Large recruitment pools (from areas such as extensive fringingreefs) may be able to sustain high recruitment rates to many man-made unitswhereas more restricted recruitment pools (such as those associated with isolatedpatch reefs) would be expected to sustain correspondingly lower rates of recruit-ment In this context it is worth noting that McFarland (1983) documented thesemi-lunar influx of post-larval grunts (Haemulon flavolineatum) on patch reefsoff St Croix US Virgin Islands If the regular loss of adults from such areascorrespondingly increases the survival and possibly growth rates of this regularsupply of young it seems plausible that for some fishes sizable losses from anatural recruitment source might be quickly replaced in tropical reef situationsClearly this is an area where further research is badly needed

The role of reef structure as a determinant of community structure of residentreef fishes has been emphasized by some authors (Risk 1972 Gladfelter andGladfelter 1978 Gladfelter et a1 1980) Others have tended to view reef structureas playing a relatively minor role in comparison to the process of recruitment(Russell et a1 1974 Sale and Dybdahl 1975 Sale 1978 1979 1980) Our resultsstrongly support the latter view The vast differences in structure between thenatural and man-made units appeared clearly subordinate to siting (ie natureand distance of the major recruitment source) in determining reef fish communitystructure This point is emphasized as it is of major interest to the rapidly in-creasing use of man-made reefs as fish attractants

10 BULLETINOFMARINESCIENCEVOL37 NO I 1985

ACKNOWLEDGMENTS

The authors wish to thank Mr and Mrs Perkins Sams whose generosity made this work possibleWe also thank the Bahamian government for permission to conduct this research

LITERATURE CITED

Bohnsack J A and F H Talbot 1980 Species-packing by reef fishes on Australian and Caribbeanreefs an experimental approach Bull Mar Sci 30 710-723

Clifford H T and W Stephenson 1975 An introduction to numerical classification AcademicPress New York 299 pp

Gladfelter W B and E H Gladfelter 1978 Fish community structure as a function of habitatstructure on West Indian patch reefs Revista de Biologica Tropical 26 65-84

--- J Ogden and E H Gladfelter 1980 Similarity and diversity among patch reef fish com-munities a comparison between tropical western Atlantic (Virgin Island) and tropical centralPacific (Marshall Islands) reefs Ecology 61 1156-1168

Luckhurst B E and K Luckhurst 1978 Diurnal space utilization in coral reef fish communitiesMar BioI 49 325-332

McFarland W N 1983 Periodic recruitment of French grunts HaemulonjIavolineatum from theoffshore plankton Abstract Vol 63rd Annual Meeting Amer Soc Ich and Herp TallahasseeHorida P 22

-- J C Ogden and J N Lythgoe 1979 The influence of light on the twilight migrations ofgrunts Env Bio Fishes 4 9-22

Nolan R S 1975 The ecology of patch reef fishes PhD Thesis Univ of California 230 ppRisk M J 1972 Fish diversity on a coral reef in the Virgin Islands Atoll Research Bull 153 1-

6Russell B c F H Talbot and S Domm 1974 Patterns of colonization of artificial reefs by coral

reef fishes Pages 217-225 in Proceedings of the 2nd International Symposium on Coral ReefsVol I Great Barrier Reef Committee Brisbane Australia

Sale P F 1978 Coexistence of coral reef fishes a lottery for living space Envir BioI Fishes 3 85-102

--- 1979 Recruitment loss and coexistence in a guild of territorial coral reef fishes Oecologia42 159-178

--- 1980 Assemblages of fish on patch reefs-predictable or unpredictable Env BioI Fishes5 243-249

--- and R Dybdahl 1975 Determinants of community structure for coral reef fishes in anexperimental habitat Ecology 56 1343-1355

Stone R B H L Pratt R O Parker Jr and G E Davis 1979 A comparison offish populationon an artificial and natural reef in the Florida Keys Mar Fish Rev 41(9) I-II

DATEACCEPTED August 6 1984

ADDRESS Department of Biological Sciences Florida Institute of Technology Melbourne Florida32901

10 BULLETINOFMARINESCIENCEVOL37 NO I 1985

ACKNOWLEDGMENTS

The authors wish to thank Mr and Mrs Perkins Sams whose generosity made this work possibleWe also thank the Bahamian government for permission to conduct this research

LITERATURE CITED

Bohnsack J A and F H Talbot 1980 Species-packing by reef fishes on Australian and Caribbeanreefs an experimental approach Bull Mar Sci 30 710-723

Clifford H T and W Stephenson 1975 An introduction to numerical classification AcademicPress New York 299 pp

Gladfelter W B and E H Gladfelter 1978 Fish community structure as a function of habitatstructure on West Indian patch reefs Revista de Biologica Tropical 26 65-84

--- J Ogden and E H Gladfelter 1980 Similarity and diversity among patch reef fish com-munities a comparison between tropical western Atlantic (Virgin Island) and tropical centralPacific (Marshall Islands) reefs Ecology 61 1156-1168

Luckhurst B E and K Luckhurst 1978 Diurnal space utilization in coral reef fish communitiesMar BioI 49 325-332

McFarland W N 1983 Periodic recruitment of French grunts HaemulonjIavolineatum from theoffshore plankton Abstract Vol 63rd Annual Meeting Amer Soc Ich and Herp TallahasseeHorida P 22

-- J C Ogden and J N Lythgoe 1979 The influence of light on the twilight migrations ofgrunts Env Bio Fishes 4 9-22

Nolan R S 1975 The ecology of patch reef fishes PhD Thesis Univ of California 230 ppRisk M J 1972 Fish diversity on a coral reef in the Virgin Islands Atoll Research Bull 153 1-

6Russell B c F H Talbot and S Domm 1974 Patterns of colonization of artificial reefs by coral

reef fishes Pages 217-225 in Proceedings of the 2nd International Symposium on Coral ReefsVol I Great Barrier Reef Committee Brisbane Australia

Sale P F 1978 Coexistence of coral reef fishes a lottery for living space Envir BioI Fishes 3 85-102

--- 1979 Recruitment loss and coexistence in a guild of territorial coral reef fishes Oecologia42 159-178

--- 1980 Assemblages of fish on patch reefs-predictable or unpredictable Env BioI Fishes5 243-249

--- and R Dybdahl 1975 Determinants of community structure for coral reef fishes in anexperimental habitat Ecology 56 1343-1355

Stone R B H L Pratt R O Parker Jr and G E Davis 1979 A comparison offish populationon an artificial and natural reef in the Florida Keys Mar Fish Rev 41(9) I-II

DATEACCEPTED August 6 1984

ADDRESS Department of Biological Sciences Florida Institute of Technology Melbourne Florida32901