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Fishery Bulletin 91(4), 1993 



feed, molt, reproduce or disperse (Alldredge and King, 

 1985). This behavior makes them subject to intense 

 predation by vermilion snapper or other specialized 

 nocturnal predators (Robertson and Howard, 1978). 



Demersal zooplankton are approximately as abun- 

 dant as holozooplankton on the continental shelf off 

 North Carolina (Cahoon and Tronzo, 1992), and the 

 nocturnal emergence of demersal zooplankton prob- 

 ably increases overall food availability at night, while 

 allowing planktivorous fishes to feed under the cover 

 of darkness. Small vermilion snapper are prey for di- 

 urnal lutjanids and crepuscular serranids (South Caro- 

 lina Wildlife and Marine Resources Department 1 ; 

 Parrish, 1987; Sedberry, 1988) and would be subject to 

 predation during the day. 



Vermilion snapper also consumes holoplanktonic spe- 

 cies such as copepods, hyperiids, Lucifer faxoni, and 

 doliolids, as well as nektonic squids and fishes. As 

 noted by Grimes (1979), squids were especially impor- 

 tant in the diet of large juveniles and adults. These 

 larger size classes of vermilion snapper also fed more 

 on fishes, which included schooling pelagic species such 

 as Spanish sardine, Sardinella aurita. Spanish sar- 

 dine makes up 9.4% of fishes caught in trawls on the 

 southeastern continental shelf 2 . Predation by vermil- 

 ion snapper on nektonic foragers such as squids and 

 Spanish sardine provides a trophic link between the 

 pelagic nekton and the reef. In the role as an abun- 

 dant consumer of nekton, holoplankton, and demersal 

 zooplankton, vermilion snapper may be important in 

 transferring energy from benthic sand habitats and 

 the water column to the reef, in the form of feces. 

 Feces that disintegrate just above the reef provide fine 

 particles and nutrients for filter- and suspension- 

 feeders, and fecal pellets that are less refractile can be 

 used directly by small crustaceans and other organ- 

 isms living in the reef (Rothans and Miller, 1991). Ver- 

 milion snapper appear to be relatively inactive during 

 the day, hovering or moving slowly in large schools 

 along the reefs within a meter of the bottom (pers. 

 observ. by GRS from Sea Link I). By feeding in the 

 water column at night and swimming just above the 

 reef during the day, vermilion snapper enhances the 

 transfer of this organic matter to the benthos. During 

 these diurnal resting periods, vermilion snapper prob- 

 ably deposit feces, derived from water column noctur- 



'South Carolina Wildlife and Marine Resources Department. 1984. 

 Final Report. South Atlantic OCS area living marine resources study. 

 Phase III. Volume 1. Prepared by Marine Resources Research Insti- 

 tute, SCVVMRD, for Minerals Management Service, Washington. D.C.. 

 under contract No 14-12-0001-29185. 223 p. 



-Sedberry. G. R.. C. A. Barans, C. A. Wenner, and V. G. Burrell Jr. 

 The ichthyofauna of sandy bottom habitat on the continental shelf 

 off the southeastern U.S. Manuscr. in prep. 



nal foraging, onto the reef. Bray et al. (1981) also found 

 that a planktivorous reef fish functioned as a trophic 

 link between the plankton and benthos by importing 

 organic carbon to the reef in the form of feces. Meyer 

 and Schultz ( 1985) found that grunts (Haemulon spp.) 

 feeding on sand flats transferred significant amounts 

 of nutrient and organic matter to reefs, thus enhanc- 

 ing coral growth. 



Benthic polychaetes ranking high in relative abun- 

 dance in the suction and grab samples were not im- 

 portant in the diet of vermilion snapper, and electivity 

 values for all dominant species in the benthic samples 

 were negative. The dominant crustaceans in benthic 

 samples were epibenthic species such as the corophoid 

 amphipod, Eriehthonius brasiliensis, and the caprellid 

 amphipod Luconacia incerta which attach to sessile 

 invertebrates and are usually closely associated with 

 the reef substratum (McCain, 1968; Bousfield, 1973). 

 Because E. brasiliensis and caprellid amphipods have 

 also been found in nocturnal zooplankton samples (Wil- 

 liams and Bynum. 1972; Hobson and Chess, 1976), 

 they may be consumed by predators at night in the 

 water column. Some motile benthic crustaceans such 

 as mysids, cumaceans, and decapods that were com- 

 mon in vermilion snapper stomachs were much higher 

 in relative abundance in stomachs than in benthic 

 samples. Vermilion snapper apparently prey on these 

 benthic crustaceans during their periodic migrations 

 into the water column. The polychaetes that dominated 

 benthic samples apparently do not undertake such 

 migrations. 



Vermilion snapper feed on many of the same prey 

 species as the benthic-feeding sparid Stenotomus 

 chrysops, an abundant demersal fish of the continen- 

 tal shelf (Sedberry and Van Dolah, 1984; Sedberry, 

 1988; Sedberry et al. 2 ). Submersible observations indi- 

 cate that S. chrysops feeds during the day on the 

 benthos, living in sand adjacent to reef habitat, whereas 

 vermilion snapper were not observed to forage in this 

 manner. Vermilion snapper apparently consumes sand- 

 dwelling benthos at night, when they emerge from the 

 bottom, while S. chrysops feeds on benthos during the 

 day when demersal zooplankton has burrowed in the 

 bottom. This provides a temporal partitioning of prey 

 resources between these two dominant species of reef- 

 associated fish. 



For reef fishes of the southeastern shelf, there is 

 large variation in the degree of dependence on hard 

 substrate as a habitat for prey (Sedberry, 1985, 1987, 

 1988). Of the three most abundant species in our reef 

 trawl catches (S. chrysops, Haemulon aurolineatum, 

 and R. aurorubens), all occur over sand bottom, al- 

 though they are much more abundant over reefs 

 (Wenner, 1983; Sedberry and Van Dolah, 1984). The 



