Diet of the Symbiotic Amphipod, Brandtia parasitica parasitica (Crustacea, Amphipoda), Living on Diseased Baikal Sponges of the Family Lubomirskiidae in Southern Lake Baikal

Resumo

The diet of a symbiont, Brandtia parasitica parasitica (Dybowsky 1874), of Baikal sponges collected during an ecological crisis in the littoral zone of Lake Baikal is analyzed. In June 2015, the main components of the diet of the amphipod that lived on diseased sponges were fine detritus, sedimented chrysophycean algae of the genus Dinobryon, and planktonic diatoms of the genus Synedra. These algae dominate in phytoplankton in the southern part of Baikal during the study period. Abundant blue-green algae were present on the surface of diseased sponges, but B. p. parasitica did not feed on these algae. As toxins secreted by blue-green algae are known to render a negative effect on hydrobionts, mass overgrowth of sponges with blue-green algae should reduce the population of the symbiotic amphipod.