Bass, Gray

Guillory, Vincent

Northeast Gulf Science

English

Gray Bass

Vincent Guillory

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Community Structure and Abundance of Fishes Inhabiting Oceanic Oyster Reefs and Spoil Islands in the Northeastern Gulf of Mexico

Aquila Digital Community (University of Southern Mississippi, USM)

Northeast Gulf ScienceVolume 3Number 2 Number 2 Article 912-1979Community Structure and Abundance of FishesInhabiting Oceanic Oyster Reefs and Spoil Islandsin the Northeastern Gulf of MexicoGray BassFlorida Game and Freshwater Fish CommissionVincent GuilloryFlorida Game and Freshwater Fish CommissionDOI: 10.18785/negs.0302.09Follow this and additional works at: https://aquila.usm.edu/gomsThis Article is brought to you for free and open access by The Aquila Digital Community. It has been accepted for inclusion in Gulf of Mexico Scienceby an authorized editor of The Aquila Digital Community. For more information, please contact Joshua.Cromwell@usm.edu.Recommended CitationBass, G. and V. Guillory. 1979. Community Structure and Abundance of Fishes Inhabiting Oceanic Oyster Reefs and Spoil Islands inthe Northeastern Gulf of Mexico. Northeast Gulf Science 3 (2).Retrieved from https://aquila.usm.edu/goms/vol3/iss2/9116 Northeast Gulf Science Vol. 3, No. 2 December 1979 COMMUNITY STRUCTURE AND ABUN-DANCE OF FISHES INHABITING OCEANIC OYSTER REEFS AND SPOIL ISLANDS IN THE NORTHEASTERN GULF OF MEXICO. This paper is a quantitative compar-ison of the community structure of the fishes associated with oceanic oyster reefs and spoil islands of the· Gulf of Mexico. These oyster reefs (Figure 1) along the northeastern Gulf coast are the only living oyster reefs known in oceanic waters of North America (Price 1954). Although oceanic by exposure to the open sea, this coastal zone is estu-arine in character, receiving freshwater discharges from the Withlacoochee and Crystal Rivers (Grimes 1971; Grimes and Mountain 1971; Carr and Adams 1973). Portions of the oyster reef system have been replaced by spoil islands created by construction of a navigation channel for the proposed Cross-Florida barge canal. Other channels have also been cut through the reefs north and south of the study area. Destruction of oyster reefs has been viewed with concern for several reasons. Reef removal adversely affects sport and commercial oyster harvests. Secondari-ly. the oyster reef maybe valuable to the nearshore ecosystem through produc-tion of food and habitat for other marine organisms. In addition, oyster reefs may also improv~ the potential angler harvest of an estuary (Arve 1960; Sieling 1960; Dahlberg 1972). Quantitative measurements of the fishes associated with oyster reefs are lacking although the ichthyofauna of oyster reefs have been qualitatively evaluated (Pearse and Wharton 1938; Gunter 1945; Arve 1960; Runyan 1961; Wells 1961; and Dahlberg 1972). Many studies have reviewed environmental effects of turbidity and siltation asso-ciated with dredge and fill operations. However, little data, with the exception of Ritchie (1970) and Briggs and O'Connor ( 1971 ), exist copcerning fishes associated with spoil islands. MATERIALS AND METHODS The extremely rough substrate of oyster reefs prevent adequate sampling with conventional techniques such as trawls and seines. In addition. the cryp-tic habits of many benthic fishes makes them difficult to collect. Although large areas of the spoil islands are sand-bot-tomed, there are also areas of rough substrate on the islands. In an effort to overcome sampling difficulties and to obtain quantitative results we employed a Wegener Ring sampler in both habitats. Originally designed by Wegener et al. (1974) for quantitative sampling of shallow lake margins, the sampler con-sists of a floating ring with a fine mesh net suspended between the surface float and a steel ring which acts as a bottom weight. The area enclosed by the sampler is 0.004 ha. our sampler dif-fered from the standard design only in having deeper net sides ( 100 em) to allow use in deeper water. The sampler is thrown over the area to be sampled and emulsified rotenone immediately applied inside the ring. Fishes killed or stunned by the toxicant are then col-lected with dip nets . . During August and September 1975 we obtained fifteen random samples each from oyster reefs and from spoil islands. Sampling was conducted during daytime at slack low tide as water depths over the reefs were too great during high tide to employ the sampler. Sampling could not be accomplished during rising or falling tides because the rotenone did not remain within the enclosure long enough to kill all fishes and also killed fishes outside the net. All 1Bass and Guillory: Community Structure and Abundance of Fishes Inhabiting Oceanic OyPublished by The Aquila Digital Community, 1979fishes collected were immediately pre-served in 10% formalin and later trans-ferred to 45% isopropanol in the lab-oratory. Specimens were later identified and weighed. Scientific nomenclature follows Bailey et al. ( 1970 ). Species associations were determined by a modification of Cole's (1949) index of affinity. The first, or primacy, species group was defined as the largest group in which all species exhibit, as deter-mined by this index, affinity for one another. The species of this primary group were excluded in determination of the second largest species group, and this procedure was repeated until all possible groups were identified. RESULTS Fourteen species were taken from the oyster reefs (Table 1). Number and bio-Gulf of Mexico sampling area Short papers and notes 117 mass per sample ranged from eight to 63 individuals (:X= 35.5) and 2.1 to 39.0 g (}r~ 22.4 g) .. Expanded, these figures pro-vided an estimate of 86,779 fish per ha, and a biomass of 55.5 kg per ha The most abundant oyster reef fish was Gobiosoma bosci, followed by Bath-ygobtus soporator, Chasmodes saburrae, Eucinostomus gula, Gobtesox strumosus and Opsanus beta. These six species comprised 90.7% of the total by number and 92.8% of the biomass. Six species dominated the oyster reef collections. Euctnostomus gula occur-red in every sample, while Gobiosoma bosci appeared in 14 of 15 samples. Chasmodes saburrae, Bathygobius soporator and Opsanus beta were taken in twelve samples while Gobiesox stru-mosus was taken in nine. The remain-ing eight species occurred less than Withlacoochee River Figure 1. Location of the study area 2Gulf of Mexico Science, Vol. 3 [1979], No. 2, Art. 9https://aquila.usm.edu/goms/vol3/iss2/9DOI: 10.18785/negs.0302.09118 Northeast Gulf Science Vol. 3, No. 2, December 1979 three times, except Lucania paroa, which appeared in five collections. Spoil island samples yielded a total of fifteen species (Table 2). Number and biomass per sample ranged from 0 to 251 individuals (x=24.1) and 0 to 42.6 g ('R = 8.4 g). The estimated standing crop consisted of 59,610 fish per ha. with a biomass of 20.7 kg per ha Anchoa mitchilli was the most abundant species of the spoil islands, followed by Eucino-stomus gula, Syngnathus floridae and Lucania paroa. Eucinostomus gula ap-peared in 11 of 15 samples while no other species appeared more than four times. Eight species (see Tables 1 and 2) were taken from both habitats, although most exhibited differences in abun-dance. Fish observed on the oyster reefs alone were Myrophis punctatus, Gobi-esox strumosus, Micrognathus criniger-us, Gobiosoma bosci, and Citharich-thys spilopterus. Species taken only from the spoil islands were Menidia beryllina, Orthopristis chrysoptera, Cynoscion nebulosus, Prionotus scitu-lus, Prionotus tribulus, and Paralich-thys lethostigma. Species associations differed between the two habitats. Species of the primacy species group of both habitats were mutually exclusive: Paralichthys letha-stigma, Symphurus plagiusa, Cynos-scion nebulosus, Lucania paroa, and Syngnathus floridae from the spoil islands; Opsanus beta, Gobiesox strumosus, Eucinostomus gula, Chas-modes saburrae, Bathygobius sopor-ator, and Gobiosoma bosci on the oyster reefs. Spoil island species groups two and three, characterized by Opsanus beta-Prionotus scitulus and Gobiosoma ro-bustum-Prionotus tribulus were also mutually exclusive from the correspond-ing secondacy species groups of the oyster reefs. Species groups two and three of the oyster reefs were composed of Myrophis punctatus-Micrognathus crinigerus and Syngnathus floridae-Citharichthys spilopterus. DISCUSSION Fish communities of the spoil islands and oyster reefs differ both quantita-tively and qualitatively. Although the Wegener Ring cannot be expected to ade-quately sample truly pelagic fishes or large transient species, the character-istic species, especially the cryptic or burrowing forms, of both habitats were adequately collected. TABLE 1. Composition, standing crop and frequency of occurrence of fishes collected from oyster reefs. Standing Crop I Frequency of Total Hectare Occurrence No. % wt.(g) % No. Wt.(kg) No. % Myrophis punctatus 2 0.4 18.7 5.6 329.2 3.08 2 13.33 Anchoa mltchilli 14 2.6 2.2 0.6 2305.2 0.37 3 20.00 Opsanus beta 22 4.2 37.3 11.1 3622.7 6.16 12 80.00 Gobiesox strumosus 37 7.0 36.2 10.7 6043.3 5.95 9 60.00 Lucania paroa 8 0.3 0.7 0.2 1317.2 0.12 5 33.33 Micrognathus crtnigerus 3 0.6 0.3 0.1 494.0 0.04 6.67 Syngnathus jlortdae 1 0.2 0.2 0.1 164.7 0.02 1 6.67 Eucinostomus gula 48 9.0 39.6 11.8 1904.0 6.52 15 100.00 Chasmodes saburrae 69 13.1 50.9 15.1 11362.9 8.37 12 80.00 Bathygobtus soportor 119 22.6 119.1 35.4 19595.3 19.61 12 80.00 Gobtosoma basel 183 34.7 29.4 8.7 30134.0 48.41 14 93.33 Gobtosoma robustum 19 3.6 1.5 0.4 3128.7 0.25 6.67 Cithartchthys spilopterus 0.2 0.6 0.2 164.7 0.10 6.67 Symphurus plagiusa 0.2 0.2 1.1 164.7 0.02 6.67 TOTAL 527 336.8 86779.3 55.57 3Bass and Guillory: Community Structure and Abundance of Fishes Inhabiting Oceanic OyPublished by The Aquila Digital Community, 1979Short papers and notes 119 TABLE 2. Composition, standing crop and frequency of occurrence of fishes collected from spoil Islands. Thtal No. % wt.(g) Anchoa mttchilli 252 69.61 15.6 Opsanus beta 1 0.28 2.3 Lucania parva 9 2.49 1.6 Menidia beryllina 4 1.10 7.7 Syngnathus jloridae 21 5.80 6.3 Eucinostomus gula 49 13.53 30.7 Orihoprtstis chrysoptera 1 0.28 11.3 Cynoscton nebulosus 5 1.38 16.8 Chasmodes saburrae 8 2.21 5.2 Bathygobius soporator 2 0.83 4.9 Goblosoma robustum 4 1.10 0.5 Prionotus scitulus 0.28 3.2 Prionotus tribulus 0.28 0.2 Paralichthys lethostlgma 0.28 18.2 Symphurus plagiusa 3 0.83 1.2 TO'D\L 362 125.7 Biomass and numerical abundance were greater on the oyster reefs than on the spoil islands. The numerical dif-ferential between the habitats is proba-bly greater than our samples suggest because 70% of the total number of fish collected on the spoil islands was taken in one sample dominated by a large school of juvenile Anchoa mitchtlli. The larger standing crop associated with the oyster reefs may be attributed to the dominance of productive oyster bottoms which provide an abundance of cover and food for the associated ichthyofauna. While the spoil islands offer greater habitat variety (sand, rock, and mud substrates, oysters, submer-gent vegetation and emergent plants), an estimated 80% of the submerged area consisted of barren sand where few fishes were collected. On the spoil Islands greatest density of fishes was observed on those areas recolonized by oysters or covered by submergent vege-tation. Age differential between the two habitats may also contribute to the difference in fish production. The spoil islands, constructed between 1960 and 1970, are much younger than the reefs. Over a longer period of time the spoil Islands may develop greater capacity for Standing Crop I Frequency of Hectare Occurrence % No. Wt.(kg) No. % 12.41 16796.0 2.57 2 13.33 1.83 164.7 0.53 t 6.67 1.27 1482.0 0.27 3 13.73 6.12 658.7 1.26 3 13.33 5.01 3458.0 1.02 3 13.33 24.42 8068.7 5.06 11 73.33 8.99 164.7 1.85 6.67 13.36 823.3 2.76 1 6.67 4.41 1317.3 0.86 4 26.67 3.90 329.3 0.82 6.67 0.40 658.4 0.08 6.67 2.55 164.7 0.52 6.67 0.16 164.7 0.02 6.67 14.48 164.7 2.99 6.67 9.55 494.0 0.20 6.67 59610.5 20.7 production. However, it is unlikely that barren sand areas will approach the production of the living oyster reefs. Nine spoil fish species were restricted to collections over oyster shell or sub-mergent vegetation and were collected only once. The presence of these species in relatively minor spoil island habitats may account for the slightly higher numbers of species found there. Despite inferences drawn from the species assemblages derived from math-ematical analysis of our data, a charac-teristic ecological community apparently does not exist on the islands. The five species in the primacy group of the spoil islands were not encountered more than three times. All three species groups were not encountered as a unit more than once. Thus, the species assem-blages of the spoil islands were quite uncommon, and apparently represent fortuitous associations rather than an ecological community. The presence of many spoil island species only once or twice in samples may be simply an indication of transience or ubiquitous-ness. On the other hand, a distinctive as-semblage was observed on the oyster reefs. All six species in the primary 4Gulf of Mexico Science, Vol. 3 [1979], No. 2, Art. 9https://aquila.usm.edu/goms/vol3/iss2/9DOI: 10.18785/negs.0302.09120 Northeast Gulf Science Vol. 3, No. 2, December 1979 species group were collected at least nine times and were the most common fishes taken. As a unit this group was observed together in seven samples. Five of these (Gobtosoma bosci, Bathygobt-us soporator, Chasmodes saburrae, Gobiesox strumosus, Opsanus beta) are cryptic benthic forms which apparently exhibit preference for the oyster reefs. Euctnostomus gula, one of the most common fish of the reefs, was not con-sidered a characteristic element of the reef ichthyofauna despite its constant appearance there because it is ubiquitous and abundant almost every-where else in the nearshore zone (Grimes 1971; Grimes and Mountain 1971; Carr and Adams 1973). Destruction of oceanic oyster reefs in the northeastern Gulf eliminates an ecologically distinctive community. Further studies to better describe this system of oyster reefs are needed. We hope that this study will provide a stimulus to other workers to quanti-tatively investigate community struc-tures in the coastal zone. LITERATURE CITED Arve, J. 1960. Shell plantings in Chinco-teague Bay, Maryland. Ches. Sci., 1 {1-2: 58-63. Bailey, R., I. Fitch, E. Herald, E. Lachner, C. Lindsey, C. Robins, and W. Scott 1970. A list of common and scientific names of fishes from the United States and Canada. Amer. Fish. Soc., Spec. Publ. No. 6, 150 pp. Briggs, P. and J. O'Connor. 1971. Com-parison of shore-zone fishes over naturally vegetated and sand-filled bottoms in Great South Bay. New York Fish Game. Jour., 18(1):15-40. Carr, W. and C. Adams. 1973. Food habits of juvenile marine fishes occupying seagrass beds in the estuarine area near Crystal River, Florida. Trans. Amer. Fish. Soc., 102(3):511-540. Cole, L. 1949. Measurement of inter-specific association. Ecol .. 30:411-424. Dahlberg, M. 1972. An ecological study of Georgia coastal fishes. Fish. Bull. 70(2):323-353. Grimes, C. 1971. Thermal addition stud-ies of the Crystal "River steam electric station. Fl. Dept. Nat. Resour., Mar. Res. Lab. Prof. Pap. Ser. No. 17,54 PP· ---- andJ. Mountain. 1971. Effects of thermal effluent upon marine fishes near the Crystal River steam electric station. Fl. Dept. Nat. Resour .. Mar. Res. Lab. Prof. Pap. Ser. No. 18. 64 PP· Gunter, G. 1945. Studies on marine fishes of Texas. Publ. Inst. Mar. Sci., Univ. Tex., 1(1):1-190. Pearse, A and C. Wharton· 1938. The oyster "leech" StylochVS tntmicus Palomli associated witb oysters on the coast of Florida. Ecol. Monogr .. 8:605-665. Price, W. 1954. Oyster reefs in the Gulf of Mexico. In: Gulf of Mexico, its origin, waters, and marine life, Fish. Bull., 55(89):491. Ritchie, D. 1970. Fish. In: Gross physical and biological effects of overboard spoil disposal in upper Chesapeake Bay. Univ. Md. Nat. Res- Inst., Spec. Rept. No. 3, pp. 50-63. R~nyan, S. 1961. Early development of the clingfish, GobiesoX strumosus Cope. Ches. Sci., 2(3-4):113-141. Sieling, F. 1960. The reso'-.trces of Wor-cester County Coastal waters. Md. Dept Res. Educ., Ref. No. 601-10, 17pp. Wegener, W., D. Holcomb, aJ1-d V. Williams. 197 4. Sampling shallo~ water fish populations using the vvegener Ring. Proc. Southeast. Assoc _ Game Fish Comm., 27:663-674. Wells, H. 1961. The fauna ~f oyster beds, with special reference to the salinity factor. Ecol. Monogr., :31(3):239-266. 5Bass and Guillory: Community Structure and Abundance of Fishes Inhabiting Oceanic OyPublished by The Aquila Digital Community, 1979Gray Bass, Florida Game and Fresh Water Fish Commission, 926 Michi-gan Ave., Pensacola, FL 32505 and Vincent Guillory1, Florida Game and Fresh Water Fish Commission. 1 Present address: Louisiana department of Wild-life and Fisheries, P.O. Box 37, Grande Isle, LA 70358. Review 121 Reviews: L.O. Sorensen, A Guide to the Seaweeds of South Padre Island, Texas. 123 pp. ISBN 0-89787-101-4, Gorsuch Scans-brick, Publishers, Dubuque, Iowa, 1979. 86.95. Various aspects of the morphology, distribution and ecology of marine algae are given in this nontechnical, illus-trated guide for the identification of the algae of South Padre Island, Texas. The spiral bound text, which is small enough to be used as a pocket field guide, contains information on the collection and preservation of marine algae; a map of the study area; systematic lists of green, brown and red algae; keys for identification; figures and descriptions of the most abundant taxa; a glossary; and a bibliography. It is unfortunate that the shortcom-ings of this informative manual detract from its intended use. Several common rules have been violated in the construc-tion of the keys which make them un-satisfactory. For example, the key to the identification of the brown algae does not begin with a dichotomous couplet-a fact that resulted in the exclusion of Giffordia from the key. The phrase "not as described above" is used four times in a key of seven brown algae and 17 times in a key of 29 red algae. Taxonomic names in the keys should have been followed by page numbers to the ap-propriate description and figure. While most errors in the text are not serious, several such as the listing of Rosen-vingea as R. sanctae crncis in the key and as R. orientalis in the text and the omission of Penicillus capitatus and Giffordia mitchelliae from the keys are disconcerting to the reader. I am puzzled by the author's use of the words algae, alga and algal. Although the line 6Gulf of Mexico Science, Vol. 3 [1979], No. 2, Art. 9https://aquila.usm.edu/goms/vol3/iss2/9DOI: 10.18785/negs.0302.09

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Community Structure and Abundance of Fishes Inhabiting Oceanic Oyster Reefs and Spoil Islands in the Northeastern Gulf of Mexico

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