ИСТИНА

Algal thicket communities cover 43–55 % of the Dzharylhach Bay area in the Black Sea. Zoobenthos community of the seagrass Zostera marina is the largest of them. Its share of the total area covered by the algal thicket communities is 43–55 %. 51 animal species have been identified to be a part of the said community. In terms of species richness, bivalves (29 %) prevailed, as well as crustaceans (23 %) and polychaetes (22 %). In terms of abundance, the most dominant were polychaetes (20–30 %) and bivalves (16–26 %). Bivalves were also the most dominant in terms of biomass (74–87 %). The most common species were: gastropod Bittium reticulatum, amphipod Ampelisca diadema, polychaete Platynereis dumerilii, bivalve molluscs Mytilaster lineatus and Polititapes aureus. Species density in the community varied from 4 to 17 species/0.025 m2, and was, on the average, 9.88±0.74 species/0.025m2. Zoobenthos abundance ranged from 160 to 8520 ind./m2, and was 2000±380 ind./m2 on the average, and its biomass ranged from 2 to 1438 g/m2, 370±77 g/m2 on the average. The most abundant species were B. reticulatum (15–25 % of the total zoobenthos abundance) and Pl. dumerilii (12–22 %). In some locations, Mytilus galloprovincialis had the largest biomass (32–40 % of the total community biomass); in the other ones, Chamelea gallina (9–15 %) and P. aureus (10–18 %) prevailed. The highest species diversity has been demonstrated by the part of the community, located on sandy shell substrate; the communities, located on sandy and silty sand substrate, were only slightly less diverse. The highest abundance was recorded at the sites with silty sand, sandy silt, sandy shell and silty shell substrates. The sites with silty sand and sandy shell substrates were characterized by the highest biomass.