Daily dynamics of the spatial distribution of mobile invertebrates in the fouling community of the Odessa Bay, Black Sea

Abstract

The daily variability of the quantitative indices of four mass species of mobile invertebrates at different depths within the fouling community of the shore protection structures of the Odessa Bay, Black Sea was shown. Two species of errant polychaetes Platynereis dumerilii (Audouin et M.-Ed., 1834) and Nereis zonata Malmgren, 1867 and two species of isopod crustaceans Lekanesphaera monodi (Arcangeli, 1934) and Idotea balthica basteri (Pallas, 1772) were selected as model objects for the study. The opposite character of the change in the quantitative parameters of polychaetes and crustaceans during the day on different horizons of the community was noted. In the daytime the abundance of polychaetes was maximal on the lower horizon of the community at a depth of2 m. The maximum quantitative parameters of crustaceans were noted at the end of daylight hours on the upper horizon of the community at a depth of0.5 m. During the day most of the crustaceans were concentrated on the upper horizon, and polychaetes – the lower one. It was noted that daily variability of the spatial distribution of invertebrates within the fouling community was related to their trophic behavior. The distribution of juveniles and adult animals on different horizons during the light and dark hours of the day was considered.