The effect of emamectin benzoate in the control of Lemanthropus kroyeri (van Beneden, 1851) (Lernanthropidae) infestations in cultured sea bass, Dicentrarchus labrax (Linnaeus, 1758)

Five different dose groups were formed to evaluate the efficacy of emamectin benzoate as a treatment for Lernanthropus kroyeri (van Beneden, 1851) infestation in cultured sea bass Dicentrarchus labrax (L.). Emannectin benzoate was administered in-feed at doses of 0 (control), 10, 25, 50, and 100 mu g kg(-1) biomass day(-1) for 7 consecutive days. Parasites were counted on days 7, 14, and 21, and comparisons were made to untreated control fish. Seawater temperature was 16-16.5 degrees C. Treatment with emamectin benzoate was effective against larval and mature stages of L. kroyeri. The number of L. kroyeri in the control fish increased by 8% during the 21 days of the study, whereas their number decreased in the treated fish by 55%, 50%, 43%, and 74% at the dose of 10, 25, 50, and 100 mu g kg(-1), respectively. No differences were observed with respect to growth between the treatment groups and the control group, and no mortality was observed at the end of the study.