Seasonal dynamics of parasite Lernanthropus kroyeri (van Beneden, 1851) on cultured sea bass Dicentrarchus labrax (Linnaeus, 1758) from the Adriatic Sea

Due to the great economic importance of sea bass Dicentrarchus labrax (Linnaeus, 1758) in Mediterranean mariculture, the aim of this study was to explore the seasonal dynamics of the copepod parasite Lernanthropus kroyeri (van Beneden, 1851) on the gills of cultured sea bass. This is the first study of L. kroyeri on cultured sea bass from the Adriatic Sea. Sea bass (N = 457) samples were taken monthly from October 2012 to October 2014, from the same floating net cage. A significant positive correlation (r = 0.24; P < 0.0001), was found between the sea bass length and the total number of parasites, and between the fish length and egg string length of L. kroyeri (r = 0.647; P < 0.0001). Prevalence of L. kroyeri ranged from 94.4% to 100%. Female parasites dominated the population throughout the research period (72.6%), followed by males (25%) and immature parasites (2.4%). Gravid females were most dominant during the summer season, with their numbers significantly dropping in the winter. Observed seasonal dynamics of L. kroyeri reproductive patterns suggest that the winter season may be the best period for control and treatment of the infection. Furthermore, this new data may provide a basis for the development of epidemiological models with a focus on preventive measures in order to improve health management of mariculture in the Adriatic Sea, as well as in the whole Mediterranean area.

Automated summary

This study investigated the seasonal dynamics of the copepod parasite Lernanthropus kroyeri on cultured sea bass in the Mediterranean mariculture, finding a positive correlation between sea bass length and total number of parasites. Gravid females were most dominant in the summer season, suggesting that winter may be the best period for infection control and treatment. The data may contribute to the development of epidemiological models for preventive measures to improve health management of mariculture in the Adriatic Sea and the Mediterranean area as a whole.