Regional Differences in the Infection of the European Anchovy Engraulis encrasicolus with the Nematode Hysterothylacium aduncum in the Winter Period off the Coasts of Crimea and the Caucasus

Abstract—The main indicators of infection of the European anchovy Engraulis encrasicolus (L.) with larvae of the nematode Hysterothylacium aduncum (Rud, 1802) in winter have been studied in two areas of the Black Sea: off the coast of Crimea and the Caucasus. Regional differences in the indicators of infection intensity and abundance index in second-year and third-year fish are revealed. When analyzing the values of the extensiveness of infection, no significant differences are found. Three main factors that determine regional differences in anchovy infection in the studied areas are analyzed.