State of the ichthyo, meso - and macroplankton complexes off the Crimean peninsula in connection with the hydrological regime eatures in october 2016

Abstract

Data on the Black sea ichthyo-, meso- and macroplankton species composition and spatial distribution, nutrition of fish larvae near the Crimean Peninsula in October 2016 are analyzed.  The survey period corresponded to the initial phase of the autumn hydrological season.  Ichthyoplankton was represented by eggs and larvae of 9 warm water and 6 temperate fish species. The average number of fish eggs were 2.92 and larvae – 3.56 ind./m-2.  The low proportion (30%) of the warm water anchovy Engraulis encrasicolus dead eggs, as well as the presence of its different-sized larvae in the sea, indicated the continuation of productive spawning. Zooplankton biomass increased from the shelf to deep-water areas. Small-sized fractions of planktonic organisms prevailed on the shelf, providing the best feeding conditions for the survival of fish larvae. Despite the significant biomass of gelatinous planktophages in October 2016, their influence on the ichthyoplankton complexes of the Black sea seems to have remained insignificant.

Keywords: ichthyoplankton, mesoplankton, gelatinous macroplankton, fish larvae nutrition, species diversity, spatial distribution, the Black Sea