Susceptibility of Caligus rogercresseyi collected from the native fish species Eleginops maclovinus (Cuvier) to antiparasitics applied by immersion

Abstract

A major challenge for Chilean salmon farming is infestation by the ectoparasite Caligus rogercresseyi. In addition, there is evidence that a loss of chemotherapeutic treatment efficacy against important fish pathogens is occurring in salmon farming, including antiparasitic efficacy. Currently, there are known techniques that allow the determination of the susceptibility profile of parasites to antiparasitic treatment. However, there is scarce information about both threshold values and categorization of antiparasitic susceptibility for C. rogercresseyi. Bioassay technique allowed the determination of both mean values and the natural variation of EC50%, which were contrasted with available susceptibility thresholds. Results allowed to determine that parasites from the native fish host, Eleginops maclovinus, are susceptible to azamethiphos, deltamethrin and cypermethrin treatments, showing a high susceptibility profile to antiparasitics.

A low‐cost screening system for kinetic analysis of Caligus rogercresseyi : New focus on pharmacological study of caligidosis disease

“…The infectivity of Caligus rogercresseyi in natural reservoirs is linked to a variety of environmental, biological and management factors, influencing infestation development (Gonzalez Gomez et al, 2019; Molinet et al, 2011). Temperature plays a major role in copepod cycle development by affecting physiological processes speed and viability (Bravo, 2010; Yatabe et al, 2011).…”