Seasonal Distribution of Gelatinous Macrozooplankton in the Hamsilos Bay, Southern Black Sea, Turkey

Abstract

The present study describes the abundance and biomass distribution of gelatinous macrozooplankton in relation to physical parameters in Hamsilos Bay. Gelatinous macrozooplankton samples were collected monthly from four stations between July 2015 and June 2016 using a plankton net with a 112 μm mesh size and a 50 cm diameter mouth opening by vertical hauls. Four gelatinous macrozooplankton species were identified: Aurelia aurita (Linnaeus, 1758); Mnemiopsis leidyi A. Agassiz, 1865; Beroe ovata Bruguière, 1789; and, Pleurobrachia pileus (O.F. Müller, 1776). The maximum mean abundance of gelatinous macrozooplankton was recorded in August 2015 (24.58 ind. m-2), whereas the maximum mean biomass was recorded in April 2016 (147.79 g m-2) from four sampling stations. The abundance and biomass of gelatinous macrozooplankton increased in the summer and spring. M. leidyi and P. pileus were primarily responsible for the increase in total gelatinous macrozooplankton abundance in the summer, whereas A. aurita and B. ovata were primarily responsible for the increase in total abundance in the spring and autumn. The abundance and biomass of M. leidyi were positively correlated with temperature and negatively correlated with dissolved oxygen.