Laboratory exposure studies to assess impacts of sea lice Caligus clemensi infections on juvenile Sockeye salmon



Sea lice, a naturally occurring parasite, are managed by the Atlantic salmon aquaculture industry in British Columbia according to requirements set out by Fisheries and Oceans Canada (DFO) in the conditions of their aquaculture licence. The Department’s management goal to ensure that infection levels on farms are below a set minimum, is aimed at minimizing the potential exposure of wild and farmed fish to sea lice. Recent research shows that in the Strait of Georgia, over 70% of juvenile Sockeye and other salmon are infected with sea lice of two species: Lepeophtheirus salmonis and Caligus clemensi. Comparative laboratory experiments confirmed that juvenile Sockeye salmon are susceptible to infection with L. salmonis. Compared to other species of salmon, Sockeye salmon are more likely to develop severe skin lesions, osmoregulatory, imbalance and increased susceptibility to virus infections – all of which is related to their inability to mount an adequate defense response in the skin following infection with sea lice.

The majority of previous research has focused on susceptibility and defense responses to L. salmonis, with comparatively little known about the relative susceptibility of Sockeye salmon to C. clemensi. The present study further investigates the physiological effects of single and mixed infections in order to establish a lethal threshold of C. clemensi infection, and to characterise defense response mechanisms in Sockeye salmon. The results of this study will provide data in support of a more balanced assessment of the impact of sea lice on juvenile Pacific salmon, in particular Sockeye salmon.





Program Name

Program for Aquaculture Regulatory Research (PARR)


2015 - 2016


Pacific: Vancouver Island West Coast

Principal Investigator(s)

Simon Jones
Research Scientist, Pacific Biological Station
3190 Hammond Bay Rd., Nanaimo, British Columbia

Team Member(s)

Steve Cho

Amelia Mahony