查看文章

The foraging ecology of elasmobranchs (sharks, skates, and rays) is difficult to study because species have spatially and temporally diverse diets. Many diet and habitat preference studies for mammals, birds, and teleosts use stable isotope analysis, but interpretations are limited for elasmobranch studies because taxon-specific isotope discrimination factors from a controlled experiment are unavailable. Trophic discrimination factors for plasma, red blood cells, and muscle were determined from an experiment with leopard sharks (Triakis semifasciata) fed a constant diet of squid over 1000 days. The δ¹³C values for shark tissues at equilibrium with the squid diet did not vary significantly among individuals, but plasma and red blood cell δ¹⁵N values differed significantly among individuals and sampling day. Individual variation of muscle δ¹⁵N averages was observed and likely related to growth. Overall …