Effects of laboratory salmon louse infection on mortality, growth, and sexual maturation in Atlantic salmon

Abstract Elevated salmon louse infection pressure generated by farming represents a major threat for wild Atlantic (Salmo salar). This study explored the effect of lice on mortality, and body gonad growth in F1 salmon. Mature males (jacks) immature fish were either infected with two different intensities (LIIs, 0.08 or 0.35 g−1) kept as uninfected controls. Fish maturation was thereafter environmentally stimulated seawater, followed transfer to freshwater 38 d simulate river ascendance. No females matured, while 99% initially started puberty. Jacks had high, maturing low, seawater independent lice. The parasites an LII-dependent negative length, weight, condition factor seawater. In freshwater, after detached, that previously reduced length but not weight when compared control. did affect relative size any phenotypes. present results show has complex, unexplored, regulation recovering from under laboratory settings. Further, suggest possible effects reproductive success is most likely governed condition. However, further work semen quality encouraged.