Vdodovich I. Species diversity and feeding of larvae of summer spawning fish in the coastal area of the Black Sea

Long-term changes (1960-2008) in feeding of dominating fish larvae of the families Gobiidae and Blenniidae in the coastal waters near Sevastopol have been analyzed using data of the electronic database "Feeding of fish larvae of the Black Sea". Larvae of goby and blenny have been shown to have similar feeding concerning both species composition of items and the items length. Feeding selectivity is thought to be due to physiological characteristics of fish larvae and food abundance. Availability of food items in the larvae guts depended on their abundance in the sea. Difference in diet have been found only in quantitative consumption of items. Match of time of Mnemiopsis leidyi appearance and fish larvae in the sea and long Mnemiopsis leidyi growing if there is no Beroe ovate still have a negative effect on feeding base of fish larvae and as a consequence on fish larvae survival. Similar feeding behavior of fish larvae of the families Blenniidae and Gobiidae was observed in the periods of the 1960s and 2000s (the level of similarity was 69%). In the periods of the 1990s and 2000s the decrease of this value to 59% was observed, but the value was high enough and showed a considerable similarity of larvae feeding behavior. In the 1960s and 1990s this value was as low as 40%. Extremely low abundance of fish larvae observed from the 1990s up to the present, availability of considerable share of fish larvae with empty guts, considerable decrease of food items in fish larvae guts (2 - 4 times) in comparison with the 1960s with a generally decrease of abundance of food zooplankton in the sea allow to draw a conclusion about a direct dependence of fish larvae abundance and survival on concentration of food items in the sea. The database "Feeding of fish larvae of the Black Sea" is an absolutely necessary resource for estimating biodiversity and the biota ecological condition the coastal waters of the Black Sea.