[Infestation rates of the main commercial fish species with larvae of contracaecum osculatum (Rudolphi, 1802) (Nematoda: Anisakidae) in Russian waters of the SoutH Baltic in 2000-2012].

The infestation dynamic of the sprat (Sprattus sprattus balticus), the Baltic herring (Clupea harengus membras), and the Baltic cod (Gadus morhua callaris) with nematodes Contracaecum osculatum 1 (Anisakidae) from Russian waters of the South Baltic were studied in 2000-2012. Peculiarities of larval growth in different hosts were analyzed. A total of 6233 fish specimens were investigated, including 1420, 3867, and 946 specimens of sprat, herring, and cod, respectively. The prevalence and mean intensity indices of sprat, herring, and cod constituted 1.27 ± 1 0.3% and 1.0, 1.4 ± 0.19% and 1.13 ± 0.38, and 11.63 ± 1.04% and 5.62 ± 8.00, respectively. The increasing of infection indices was observed in recent years. It was associated with the increase in the number of grey seals, definitive hosts of C. osculatum in the Baltic Sea. The growth of helminthes larvae in sprats, Baltic herrings, and cods was revealed. The important role of the sprat in the cod infestation with C. osculatum and in the transmission of this parasite was demonstrated for the first time.