Feeding Habits of Whitebone Porgy, Calamus leucosteus 

 (Teleostei: Sparidae), Associated with Hard Bottom Reefs off 



the Southeastern United States^ 



George R. Sedberry 



ABSTRACT: The feeding habits of whitebone 

 porgy. Calamus leucosteus, were investigated by 

 examining stomachs of specimens collected from 

 hard bottom reef habitat on the southeastern con- 

 tinental shelf and by comparing stomach samples 

 with benthic samples and with stomach samples 

 from four other sparids collected from the same 

 habitat. Whitebone porgy were found to feed mainly 

 on small hard-shelled species of gastropods, 

 pagurid decapods, and sipunculids. Polychaetes, 

 pelecypods, barnacles, and fishes were also eaten. 

 Fishes and echinoderms were consumed by larger 

 individuals. Whitebone porgy selected invertebrate 

 species that were not abundant in benthic samples 

 from the reef, suggesting that these fish forage on 

 sand bottom fauna. Patterns of diet overlap with 

 other reef-associated sparids appeared to be related 

 to feeding morphology and feeding habitat. Overlap 

 in diet between whitebone porgy and southern 

 porgy, Stenotomus aculeatus, was low, although 

 both species forage on sand bottom organisms. Pin- 

 fish, Lagodon rhomboides. fed mainly on a sessile 

 reef amphipod that was rarely consumed by white- 

 bone porgy. Whitebone porgy had a higher diet over- 

 lap with sheepshead, Archosargus probatocephalus. 

 and with red porgy, Pagrus pagrus. because all 

 three species fed on barnacles not consumed by 

 other sparids examined. 



The whitebone porgy. Calamus leucosteus, dis- 

 tributed from the CaroHnas through the Gulf of 

 Mexico (Randall 1978), is an abundant sparid fish 

 on the continental shelf of the South Atlantic 

 Bight, where it is an important component of 

 trawl and hook-and-line fisheries (Huntsman 

 1976; Waltz et al. 1982). Whitebone porgy are 

 found in depths of 11-88 m on the continental 

 shelf of the southeastern coast of the United 

 States, but they are most abundant in depths 



'Contribution No. 281 from the South Carolina Marine 

 Resources Center. 



George R. Sedberry, South Carolina Marine Resources Re- 

 search Institute, P.O. Bo.x 12.5.59, Charleston, SC 29412- 

 25.59. 



Manuscript accepted April 1989. 

 Fishery Bulletin. U.S. 87: 935-944. 



< 30 m (Waltz et al. 1982). The continental shelf 

 at these depths consists primarily of sandy bot- 

 tom, with occasional scattered outcrops of sedi- 

 mentary rock (Struhsaker 1969), and, although 

 whitebone porgy frequently occur on sand bot- 

 tom, they are much more abundant in rocky reef 

 habitats (Wenner et al. 1980; Waltz et al. 1982). 

 These hard bottom habitats support a greater 

 abundance and biomass of large sessile inverte- 

 brates (e.g., sponges, corals, tunicates) and as- 

 sociated motile organisms than do sand bottom 

 areas of the shelf (Struhsaker 1969; Wenner 

 1983; Wenner et al. 1983; Sedberry and Van 

 Dolah 1984; Wenner et al. 1984; Wendt et al. 

 1985). Many of these invertebrates serve as prey 

 for fishes that are closely associated with the 

 reef habitat (Manooch 1977; Sedberry 1987, 

 1988). Other species of fishes are less closely 

 associated with hard bottom reefs, and, while 

 living on or in proximity to these reefs, do much 

 of their foraging in sand bottom habitats on the 

 shelf (Sedberry 1985). Although whitebone 

 porgy appear to be a reef-associated species, 

 their dependence on reef habitat and the abun- 

 dance of prey provided by these habitats are 

 unknown. Although hard bottom reefs support a 

 high biomass of potential prey for fishes, many 

 species of predatory fish are concentrated in 

 these habitats (Sedberry and Van Dolah 1984), 

 and competition for prey may be intense, partic- 

 ularly among closely related species. Several 

 other sparids are abundant in hard bottom reef 

 communities and competition for food among 

 these species could be as intense. Although the 

 food habits of some of these more common spar- 

 ids have been reported from offshore reef habi- 

 tats (Manooch 1977; Sedberry 1987), overlap in 

 diet among the species has not been investi- 

 gated. 



The purpose of this study is to describe the 

 food habits of whitebone porgy, to determine the 

 importance of hard bottom reef habitat as forag- 

 ing gi'ounds for this species, and to determine 

 diet overlap between whitebone porgy and some 



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