Benthic Polychaeta of the Middle Atlantic Bight: feeding and distribution

Abstract

Data on feeding biology was used to investigate distribution patterns of benthic polychaetes of the Middle Atlantic Bight off the United States East Coast. Feeding biology classifications used in the analyses were based on (1) gut-contents analyses of polychaetes collected in the study area; and (2) recent publications regardmg polychaete feeding. Proportion of carnivorous polychaetes was greatest in coarser sedlments, and decreased significantly with water depth across the continental shelf. Surface-deposit feeders numerically dominated most habitats. Abundance of surface-deposit feeders decreased across the continental shelf and sharply increased at the shelf break, paralleling the pattern of water-column production. Proportion of subsurface-deposit feeders was greatest in finesedlrnent habitats, and increased significantly with depth and percent organic carbon across the continental shelf. Sessile polychaetes generally inhabited physically stable habitats. Proportion of sessile polychaetes was positively correlated with percent silt and clay and percent organic carbon. Feeding and motility categories were generally more useful in distinguishing habitats than were morphology categories. Apparently, distribution and abundance of surface-deposit feeders were regulated by food resources from water-column production, and distnbution of sessile polychaetes was limited primarily by physical disturbance.