Benthic‐pelagic coupling in a temperate inner continental shelf fish assemblage

Abstract

The hypothesis that demersal finfish production dependence on pelagic food webs decreased with seabed habitat affinity and fish size was tested using stable isotope and stomach contents data from 17 finfish species collected during summer months from the inner continental shelf of the U.S. mid‐Atlantic coast. Trophic dependence on pelagic prey was generally lower among species with higher affinities for bottom habitats, but even species morphologically adapted for bottom feeding benefited from pelagic production via diel vertical migration of prey. There was a consistent pattern of declining reliance on pelagic food webs with increasing fish size, although the relationship between size and trophic sources varied among functional groups within the fish community. Overall, pelagic primary production during the summer was an important basal energy source for the demersal finfish community in this coastal ocean habitat (d 20 m depth), particularly during juvenile life phases. These results suggest that these fish communities are sensitive to climate‐related changes in contemporaneous pelagic primary production in addition to the timing and magnitude of spring phytoplankton blooms.