First data on predation of Eucypris mareotica(Crustacea, Ostracoda) in hypersaline waters

Seed shrimp Eucypris mareoticais a widespread species and can reach high abundance in hypersaline lakes and lagoons of the Crimea and other regions. As an example, the maximum abundance of E. mareoticain the hypersaline Chersonesskoye lake reached 198,500 ind./m3in the plankton, 580,000 ind./m2in the benthos, and 220,000 ind./m2in floating Cladophoramats. The species with such high abundance must play an important role in food webs but this role is not known now. Samples were collected from the different habitats in the lake to conduct gut content analysis of E. mareotica. The proportion of ostracods with food items in guts ranged from 9% to 100% in a sample. In 50% of them, animals found in ostracod gut contents include animals (Copepoda (Calanoida or/and Harpacticoida), Cladocera, or Nematoda). The most abundant food item was Cletocamptus retrogressus(Harpacticoida). Experiments with eggs, cysts and nauplii of Artemia(Anostraca) suggested that ostracods cannot break the cyst shells, but as soon as the nauplii hatched, they could be eaten by ostracods. Non-dormant (summer) Artemiaeggs have weaker outer shells; ostracods break shell integrity with their antennae and then consume them. Animals play an important role in the diets of E. mareoticain the Crimean hypersaline lakes and lagoons, as can be assumed in other regions also.