Sea otter (Enhydra lutris) foraging habitat use in a heterogeneous environment in Kachemak Bay off Alaska

Sea otters, Enhydra lutris (Linnaeus, 1758), forage in a mosaic of habitat types. The relative use of heterogeneous environments by sea otters is largely unknown. Here, we examined whether foraging sea otters selectively use habitats based on substratum grain size and/or prey availability. Use by foraging sea otters was determined by the occurrence of foraging activity documented by VHF radio-tagged otters and by field collected data on substratum types and prey. Selection for substratum type and prey was determined by comparing currently used vs available foraging locations. We found that foraging sea otters used rocky habitats to a greater extent than soft sediment habitats, but did not necessarily use areas with higher prey abundance, biomass, or potential energy density per unit area.