The influence of contiguous shoreline type, distance from shore, and vegetation biomass on nekton community structure in eelgrass beds

Three factors affecting the structure of nekton communities (fishes and dec apod crustaceans) in eelgrass beds were identified and evaluated: contiguou s shoreline type, distance from shore, and macrophyte biomass. Throw traps (1 m(2)) were used to sample eelgrass nekton at seven locations in Great So uth say (New York, U.S.) dong Fire Island National Seashore from Jig throug h October 1995. Abundances of Gobiosoma ginsburgi, Apeltes quadracus, and O psanus tau were significantly higher in eelgrass beds adjacent to salt mars hes. Menidia menidia, Syngnathus fuscus, Pseudopleuronectes americanus, and Palaemonetes pugio were significantly more abundant in eelgrass adjacent t o beaches. Regression analyses indicated that Syngnathus fuscus, Pseudopleu ronectes americanus, and Anguilla rostrata abundances were positively relat ed to eelgrass biomass, and Apeltes quadracus and Gobiosoma ginsburgi abund ances were highest at moderate levels of macroalgae biomass. The distance o f an eelgrass bed from shore was also important. Species generally associat ed with Salt marshes (Fundulus heteroclitus, Cyprinodon variegatus, Lucania parva, and Palaemonetes pugio) were more abundant in eelgrass near the mar sh shore. Abundances of Apeltes quadracus, Syngnathus fuscus, Menidia menid ia, Hippolyte pleurcanthus, and Crangon septemspinosa increased with distan ce from the shoreline. Shoreline type, distance from share, and macrophyte biomass appear to affect the abundance and distribution of some nekton spec ies. The effect of shoreline type may be related to the distribution of mac rophyte biomass; the biomasses of eelgrass and macroalgae were significantl y higher along beach and marsh shorelines, respectively Explaining within-h abitat variability and identifying microhabitat preferences for nekton will aid in the proper design of future studies and habitat restoration efforts .