STABLE ISOTOPE ANALYSES DIFFERENTIATE BETWEEN DIFFERENT TROPHIC PATHWAYS SUPPORTING ROCKY-REEF FISHES

Stable isotope analyses of 5 reef-associated fishes, Decapterus punctatus, Diplodus holbrooki, Rhomboplites aurorubens, Pagrus pagrus, and Haemulon aurolineatum, were conducted to determine the ability of stable isotope analysis to distinguish among the species and the trophic pathways that support them. Analyses of deltaC-13, deltaN-15, and deltaS-34 from white swimming muscle yielded significant differences between species. Multiple stable isotope signatures of these 5 species indicated that at least 2 trophic pathways, one planktonic and one benthic, supported these reef-associated species. Variability of isotopic signatures within species was largely a result of collection site differences. DeltaC-13 and deltaN-15 values indicated that all fishes were feeding at similar trophic levels. DeltaS-34 values proved to be useful supplements to carbon and nitrogen isotope values in separating species by signature.