Salmon lice infection in wild salmonids in marine protected areas: Comment on Serra-Llinares et al. (2014)

Serra-Llinares et al. (2014; Aquacult Environ Interact 5: 1-16) analysed the association between the estimated production of salmon louse copepodites in salmon farms and lice infection levels in wild salmonids. The authors argued that 41% of the variance observed in the number of salmon lice on wild fish is explained by lice production in nearby salmon farms. The correlation identified by Serra-Llinares et al. (2014; their Fig. 3) could, however, be explained by an effect of temperature variation in time and space, rather than a causal relationship between salmon farming and lice infection in wild salmonids.