Irina V. Vdodovich's scientific contributions

During a number of years juveniles and larvae of Atherina boyeri Risso, 1810 and Knipowitschia caucasica (Berg, 1916) were caught in the hypersaline waters of Sivash at salinity up to 70-75%. Once the larvae of Atherina hepsetus Linnaeus, 1758 at a salinity of 54% and A. boyeri at a salinity of 90% were caught. New data on the expansion of the salinity range of the survival of A. boyeri are presented. Keywords: Sea of Azov, Siwash Bay, Atherina boyeri, Knipowitschia caucasica.

Seed shrimp Eucypris mareotica is 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. mareotica in the hypersaline Chersonesskoye lake reached 198,500 ind./m³ in the plankton, 580,000 ind./m² in the benthos, and 220,000 ind./m² in floating Cladophora mats. 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) Artemia eggs 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. mareotica in the Crimean hypersaline lakes and lagoons, as can be assumed in other regions also.

In the Crimea, there are many hypersaline lakes and lagoons, where Eucypris mareotica (Ostracoda), high halotolerant species, inhabit. Despite the wide distribution of the species and the abundance of its populations, little is known about the biology of E. mareotica, including its nutrition. Diversity of microalgae in gut of E. mareotica in Lake Chersonesskoye was studied. The crustaceans ate both phytoplankton and alga, which growth on cladophora filaments, as well as various small animals, but microalgae played a main role in their nutrition. The proportion of individuals, which had algae in intestines, ranged in a sample from 0 to 93%. In 335 analyzed individuals, 22 species of microalgae were found, which belong to 4 types, 4 classes and 11 orders. Of these, 4 species belong to the type Cyanobacteria, 3-to Myzozoa, 4-to Haptophyta, 11-to Ochrophyta. The most common species was Peridinium cinctum. Given the availability of a wide variety of consumed microalgae, ostracod gut content analysis can be used to assess species diversity of microalgae in the lakes.