Distribution of benthic trophic groups in the Middle and South Caspian Sea

Trophic groups were recognized on the data of the quantitative processing of the samples collected during three seasonal benthic surveys in the Middle and South Caspian Sea. Sestonophages and sediment feeders were divided into epifaunal and infaunal animals. The dominance of sestonophages near the eastern coast of the Middle Caspian Sea is due to the severe wave currents (shelf and inertial), which block the formation of sediments. Infaunal sediment feeders prevail near the western coast of the Middle Caspian and over the major part of the South Caspian, whereas epifaunal organisms are distributed at sea depths more than 70-100 m, where the overall drop in their biomass takes place. Nonselective sediment feeders living in the sediment column are present almost in all the samples, though their biomass is small. Carnivorous organisms are almost entirely absent; their function is covered by sturgeons, which actively feed on benthic organisms.