Associations between flatfish abundance and surficial sediments in the eastern Bering Sea

Abstract

Spatially explicit relationships between pleuronectid flatfish abundance and surficial sediments in the eastern Bering Sea were investigated using published sediment descriptions and trawl survey data (1982-1994). Flatfish food habits were also examined because sediment properties are known to affect the distribution and abundance of benthic prey. For six species, we compared sediment textures in areas of highest and lowest abundance (kilograms per hectare). Sand predominated in areas of high yellowfin sole (Pleuronectes asper) (YFS) (p << 0.001) and rock sole (Lepidopsetta spp.) (RS) (p << 0.001) abundance, while mixed sand and mud was most common in areas of lowest abundance. In contrast, mixed sand and mud predominated in areas preferred by flathead sole (Hippoglossoides elassodon) (FHS) (p << 0.001), Alaska plaice (Pleuronectes quadrituberculatus) (AP) (p = 0.002), and arrowtooth flounder (Atheresthes stomias) (ATF) (p = 0.004), with more diverse substrates in low-density areas. Areas of high and low Greenland turbot (Reinhardtius hippoglossoides) (GT) (p = 0.845) abundance had similar sediment textures (primarily mixed sand and mud). Species with highly restricted diets (AP) or piscivores with weak sediment associations (GT, ATF) had relatively inflexible food habits, whereas YFS, RS, and FHS food habits varied considerably with sediment type. Our findings suggest that benthic-feeding pleuronectids prefer certain sediment textures because of adaptive differences in prey availability.