The Modern Status of Populations and Feeding Habits of the Longtail Dwarf Goby Knipowitschia longecaudata (Gobiidae) in the Don River Delta and the Eastern Part of Taganrog Bay

Resumo

The size and sex composition and feeding habits of the longtail dwarf goby Knipowitschia longecaudata have been studied in the Don River delta and in the eastern part of Taganrog Bay. The maximum size of specimens has increased compared to the 1950s, which is, probably, caused by a decreasing pressure of predatory fishes. The change in the spectrum of food objects caused by the transformation of the zooplankton species structure and occurrence of marine forms as a result of an increase in water salinity has been found. The specific abundance and biomass of the species have been estimated for the first time: the maximum abundance reaches 36400 ind./ha in the eastern part of Taganrog Bay and 6700 ind./ha in the Don River delta; the biomass is 5.0 and 1.7 kg/ha, respectively. The features of the spatial and temporal distribution of the abundance and biomass of K. longecaudata have been analyzed.