The effects of single and repeat Lepeophtheirus salmonis (sea lice) infections on the health of juvenile Pacific salmon

Description

There is evidence that different species of Pacific salmon differ in their susceptibility to infections with sea lice, Lepeophtheirus salmonis, under laboratory conditions. For example, pink and coho salmon have been shown to be less susceptible to sea lice infections than chinook or chum salmon. This multi-year project examined the susceptibility and lethal infection level of juvenile sockeye, coho, pink, and chum salmon to L. salmonis. In addition, the effects of previous exposure to L. salmonis on susceptibility to infection and the physiological and immunological responses was determined for these species.

Findings

The immune responses to exposure to L. salmonis were very different among fish sizes. Harmful effects of the sea lice infection were identified in the smaller fish. Larger sized fish responses indicated greater immunity to infection. Just over 80 percent of the exposed pink and chum salmon died. While sockeye salmon had no deaths, there was clear evidence of declining health and weight, particularly at 21 and 28 days.

Publications

DFO. 2014. Sea lice monitoring and non-chemical measures. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2014/006.

Jakob, E., Sweeten, T., Bennett, W., and Jones, S.R.M. 2013. Development of the salmon louse Lepeophtheirus salmonis and its effects on juvenile sockeye salmon Oncorhynchus nerka. Diseases of Aquatic Organisms 106(3): 217-227.

Johnson, S.C. and Jones S.R.M. 2015. Monitoring for sea lice on wild salmon in western and eastern Canada. DFO Can. Sci. Advis. Sec. Res. Doc. 2014/060. vi + 33 p+ Appendices.

Jones, S. and Johnson, S. 2015. Sea lice monitoring and non-chemical measures A: Biology of sea lice, Lepeophtheirus salmonis and Caligus spp., in western and eastern Canada. DFO Can. Sci. Advis. Sec. Res. Doc. 2014/019. v + 18 p.

Jones, S.R., Bruno, D.W., Madsen, L., and Peeler, E.J. 2015. Disease management mitigates risk of pathogen transmission from maricultured salmonids. Aquaculture Environment Interactions 6(2):119-134.

Jones, S., Kim, E., and Bennett, W. 2008. Early development of resistance to the salmon louse, Lepeophtheirus salmonis (Krøyer), in juvenile pink salmon, Oncorhynchus gorbuscha (Walbaum). Journal of Fish Diseases 31(8): 591-600.

Saksida, S., Bricknell, I., Robinson, S. and Jones, S. 2015. Population ecology and epidemiology of sea lice in Canadian waters. DFO Can. Sci. Advis. Sec. Res. Doc. 2015/004. v + 34 p.

Sutherland, B.J., Jantzen, S.G., Sanderson, D.S., Koop, B.F., and Jones, S.R. 2011. Differentiating size-dependent responses of juvenile pink salmon (Oncorhynchus gorbuscha) to sea lice (Lepeophtheirus salmonis) infections. Comparative Biochemistry and Physiology Part D: Genomics and Proteomics 6(2):213-223.

Program Name

Program for Aquaculture Regulatory Research (PARR)

Year(s)

2010 to 2014

Principal Investigator(s)

Simon Jones, Research Scientist, Fisheries and Oceans Canada, Pacific Biological Station, Pacific Region
Email: Simon.Jones@dfo-mpo.gc.ca

Stewart Johnson, Research Scientist, Fisheries and Oceans Canada, Pacific Biological Station, Pacific Region
Email: Stewart.Johnson@dfo-mpo.gc.ca

Team Member(s)

Eva Jakob, Fisheries and Oceans Canada,  Pacific Biological Station, Pacific Region

Laura Braden, Fisheries and Oceans Canada,  Pacific Biological Station, Pacific Region