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Infection and mortality of wild salmon by parasitic sea lice from fish farms

Photo credits: Alexandra Morton.
Click on photo for larger picture.

Marine salmon farming has been associated with parasitic sea lice infestations and concurrent declines of wild salmon populations in Europe and Canada.

To effectively protect wild salmon populations, we need a detailed understanding of how fish farms change the dynamics of natural lice-salmon systems.

There are two components to understanding this relationship:

(1) Quantifying lice transmission from farm salmon to out-migrating wild juvenile salmon;


(2) Quantifying mortality rates of juvenile salmon infected by sea lice.

We are developing mathematical and statistical models to address these questions, and conducting complementary field research in the Broughton Archipelago, BC.

Combining these models and data yields new insights into how the farm salmon - wild salmon - sea lice system works, and how to move towards ecologically sustainable solutions.

This work is being conducted by mathematical biologists Martin Krkosek and Mark Lewis at the Centre for Mathematical Biology, in collaboration with biologist John Volpe at the University of Victoria, biologist Alexandra Morton of the Raincoast Research Society, and physicist Neil Frazer at the University of Hawai’i.

Publications/In Review: 

Krkošek, M., Ford, J., Morton, A., Lele, S., Lewis, M.  2008. Sea lice and pink salmon declines: response to Brooks and Jones. Reviews in Fisheries Science 16:4, 413-420.

Krkošek, M., Ford, J.S., Morton, A., Lele, S., Myers, R.A., Lewis, M.A. 2007. Declining wild salmon populations in relation to parasites from farm salmon. Science 318: 1772-1775.

Krkošek,, M., Gottesfeld, A., Proctor, B., Rolston, D., Carr-Harris, C., Lewis, M.A. 2007. Effects of host migration, diversity, and aquaculture on disease threats to wild fish populations. Proceedings of the Royal Society of London, Series B. 274:3141-3149.

Krkošek, M., Lauzon-Guy, J.S, Lewis, M.A. 2007. Relating dispersal and range expansion of California sea otters. Theoretical Population Biology: 71: 401-407.

Krkošek, M., Lewis, M.A., Volpe, J., Morton, A. 2006. Fish farms and sea lice infestations of wild juvenile salmon in the Broughton Archipelago - A rebuttal to Brooks. Reviews in Fisheries Science: 14(1): 1-11.

Krkošek, M., Lewis, M.A., Morton, A., Frazer, L.N., Volpe, J.P. 2006.  Epizootics of wild fish induced by farm fish. Proceedings of the National Academy of Sciences: 103(42):15506-15510 (2006). Supplemental material

Krkošek, M., M.A. Lewis, & J.P. Volpe. 2005. Transmission dynamics of parasitic sea lice from farm to wild salmon. Proceedings of the Royal Society of London B: 272: 689--696

SeaLice Photos and Results