Sea Lice Research

2011, February – Price M.H.H., Proboszcz S.L., Routledge R.D., Gottesfeld A.S., Orr C., et al. Sea louse Infection of juvenile sockeye salmon in relation to marine salmon farms on Canada’s West Coast. PLoS ONE 6(2): e16851. doi:10.1371/journal.pone.0016851.
Pathogens are growing threats to wildlife. The rapid growth of marine salmon farms over the past two decades has increased host abundance for pathogenic sea lice in coastal waters, and wild juvenile salmon swimming past farms are frequently infected with lice. Here we report the first investigation of the potential role of salmon farms in transmitting sea lice to juvenile sockeye salmon (Oncorhynchus nerka).


2010, December – Martin Krkosek, Andrew Bateman, Stan Proboszcz, Craig Orr. Dynamics of outbreak and control of salmon lice on two salmon farms in the Broughton Archipelago, British Columbia.
A new scientific study published this week in the on‐line journal, Aquaculture Environment Interactions, confirms that farmed salmon can significantly amplify sea lice in coastal waters of BC, and that controlling lice outbreaks presents substantial challenges to industry, regulators, and salmon conservationists.


2010, November – M. H.H. Price, A. Morton, and J. D. Reynolds. Evidence of farm-induced parasite infestations on wild juvenile salmon in multiple regions of coastal British Columbia, Canada.
Published in the peer-reviewed Canadian Journal of Fisheries and Aquatic Sciences, and conducted in 2007 and 2008, concludes that sea lice levels on wild juvenile salmon are significantly higher in net-cage salmon farming areas and highest in the Discovery Islands where salmon farming is most intense.


2010, November – P.A. Mages and L.M. Dill. The effects of sea lice on juvenile pink salmon predation susceptibility.


2010, October – Brendan M. Connors, N. Brent Hargreaves, Simon R. M. Jones, Lawrence M. Dill. Predation intensifies parasite exposure in a salmonid food chain. Brendan M. Connors, Martin Krkošek, Jennifer Ford, Lawrence M. Dill. Coho salmon productivity in relation to salmon lice from infected prey and salmon farms.
Two new sea lice papers published online in the Journal of Applied Ecology suggest that sea lice from salmon farms may be dramatically affecting the health of coho salmon populations in the Broughton Archipelago.


2009, September – R. Beamish, J. Wade, W. Pennell, E. Gordon, S. Jones, C. Neville, K. Lange, and R. Sweeting. A large, natural infection of sea lice on juvenile Pacific salmon in the Gulf Islands area of British Columbia, Canada.
During two sampling episodes in June and July 2008, 502 juvenile salmon were examined for sea lice via purse seine along the southern Gulf Islands (primarily Salt Spring Island). Abundant lice levels were found and since there were no active fish farms in the area, this paper provides evidence that high levels of louse infestation on juvenile salmon can and do occur naturally. The majority of lice were Caligus clemensi—a generalist louse species—with herring a likely source (as has been shown in Europe and the subsequent infestations of salmon farms).

It is important to note that the data gathered in this paper cannot be assumed to represent the population as a whole because the sample size and number of collection periods are small (i.e., 502 juvenile salmon examined over 5 days in a single year). In addition, the Gulf Islands region is known to harbour higher lice levels than other ‘natural areas’ of BC’s coast.


2009, July – Costello, Mark J. How sea lice from salmon farms may cause wild salmonid declines in Europe and North America and be a threat to fishes elsewhere. Proceedings of the Royal Society of London Series B.
Dr. Mark Costello from the University of Auckland published a review paper summarizing declines in wild salmon populations and the link to sea lice from salmon farms in Europe and North America. It is believed that Lepeophtheirus salmonis (salmon louse) may be transported to intercept migrating salmonid hosts by swimming to the surface during daylight where the onshore wind moves the surface water towards the shore and into estuaries. Countries that produce the most farmed salmonids have a problem with sea lice on farms whereas countries not producing high volumes do not, This suggests a relationship exists between the number of farms and/or farmed fishes, and the development of sea lice infestations on farms. He concludes the evidence that salmon farms are the most significant source of the epizootics of sea lice on juvenile wild salmonids in Europe and North America is now convincing.


2009, May – M. Krkosek, Morton, A., Volpe, J. and Lewis, M. 2009. Sea lice and salmon population dynamics: Effects of exposure time for migratory fish. Proceedings of the Royal Society of London Series B.
The authors examined the process of sea louse transfer to wild juvenile salmon, specifically the period of time the salmon were exposed to infective stages of lice and the importance of the exposure period with regards to interpreting experimental field results and lab results. Fish exposure time to lice is important. The lab studies conducted by Fisheries and Oceans Canada only expose fish to infective stages of lice for hours; however, in real life (as more accurately described by the field sampling studies) the wild salmon in the Broughton Archipelago are exposed to lice for weeks and sometimes months. Hours vs. months makes a big difference (of 2 to 3 orders of magnitude).


2008, February – Ford JS, Myers RA. A global assessment of salmon aquaculture impacts on wild salmonids. PLoS Biology 6(2): e33.
This study compared marine survival of salmon in areas with salmon farming to adjacent areas without farms in Scotland, Ireland, Atlantic Canada, and Pacific Canada to estimate changes in marine survival concurrent with the growth of salmon aquaculture. Through a meta-analysis they show a reduction in survival or abundance of Atlantic salmon; sea trout; and pink, chum, and coho salmon in association with increased production of farmed salmon. In many cases, these reductions in survival or abundance are greater than 50%.


2008, November – Sea Lice and Salmon: A Science Primer.
Watershed Watch Salmon Society produced this summary explaining the sea lice issue and the implications for wild salmon in BC. The summary highlights the fact that salmon farm problems are not isolated to the Broughton Archipelago; Fraser River salmon may be at risk during their outmigration through Georgia Strait.


2008, August – A Brief Response to the January 2008 Report “Overview of Sea Lice Issues and Risks to Farmed and Wild Salmon” prepared for Cermaq.
Stan Proboszcz and Dr. Craig Orr from Watershed Watch Salmon Society review an “Overview of Sea Lice Issues and Risks to Farmed and Wild Salmon” prepared by Saksida and Downey for Cermaq (Mainstream). The response addresses the lack of publicly available data in the form needed to effectively evaluate sea lice impacts as well as key published research and management details that Saksida and Downey failed to include in their review.


2008, June – Map Of Juvenile Pink and Chum Salmon Swimming Near Salmon farms Suffer Higher Levels of Sea Lice Infestation Than Juveniles In Fish Farm-Free Areas Of the BC Coast.
A new map, produced by the Living Oceans Society, compiles all the available sea lice sampling from recent years into one geographic representation. The map locates the sampling sites for each study throughout the BC coast in relation to fish farms that were active at the time of the sampling. It separates the sites into three distinct areas where wild juvenile pink and chum salmon were either exposed to, peripheral to or not exposed to active farms and displays the results in pie charts. The size of each pie is based on the size of the samples in each study. The size of each slice of pie shows the prevalence of sea lice infestation found on the wild juvenile salmon by species. “Prevalence” means the percentage of the total sample that has sea lice. Download PDF | JPG


2008, March – Morton, A., R. Routledge, and M. Krkosek. 2008. Sea louse infestation in wild juvenile salmon and Pacific herring associated with fish farms off the east-central coast of Vancouver Island, British Columbia. North American Journal of Fisheries Management. Published online March 31, 2008.
The authors report on 2 years of sea louse field surveys of wild juvenile pink and chum salmon, as well as wild sockeye salmon O. nerka and larval Pacific herring Clupea pallasii, in another salmon farming region, the Discovery Islands region of British Columbia. These results suggest that the association of salmon farms with sea lice infestations of wild juvenile fish in Pacific Canada now extends beyond juvenile pink and chum salmon in the Broughton Archipelago.


2008, February – CAAR Review of PSF Sea Lice Science Report.
The CAAR review of “Science and Sea Lice: What do we know?” a report released by the BC Pacific Salmon Forum prepared by Brian Harvey, February 2008, reveals the lack of effective evaluation or synthesis of the science. Instead of resolving the “sea lice question,” the review muddies the waters of what is clearly a relevant ecological and sociological topic.


2008, January – Andrew A. Rosenberg. The Price of Lice. NATURE. 451:23-24.
Wild salmon stocks in Canadian coastal waters are being severely affected by parasites from fish farms. So intense are these infestations that some populations of salmon are at risk of extinction.


2007, December – Salmon Farms Drive Wild Salmon Towards Extinction.
A study appearing in the December 14 issue of the journal Science shows, for the first time, that parasitic sea lice infestations caused by salmon farms are driving nearby populations of wild salmon toward extinction.


2005, October – Sea Lice and Salmon: BC Briefing Note. Coastal Alliance for Aquaculture Reform (CAAR).
A succinct, 11-page analysis of the problem of sea lice including references for further reading.


2005, September 28 – Backgrounder: Pink Salmon and Sea Lice Chronology of Events. Coastal Alliance for Aquaculture Reform.


2005, September 28 – Backgrounder: Science Summary: Facts About Sea Lice, Fish Farms and Wild Salmon. Coastal Alliance for Aquaculture Reform.


2005, March – Transmission dynamics of parasitic sea lice from farm to wild salmon. Proceedings of Royal Society B March 30, 2005 Transmission dynamics of parasitic sea lice from farm to wild salmon. Authors: Martin Krkosek, Mark A. Lewis, John P. Volpe


2004, November 18 – Simon Fraser University Convenors Report: Scientists Roundtable on Sea Lice and Salmon in the Broughton Archipelago Area of British Columbia. Part of the Speaking for the Salmon Dialogue Series that includes sections on recommended research and future management.


2004, April – Sea Lice and Salmon: Elevating the dialogue on the farmed-wild salmon story.
This Watershed Watch report provides overviews of aquaculture, the biology and ecology of sea lice, links between sea lice and salmon farms, the Broughton Archipelago pink salmon collapse, current sea-lice treatments, roles of governments, the people involved, and the merits of conserving the biodiversity of wild salmon. And it does so with a science underpinning and easy-to-read language.


2004, March – Sea lice infection rates on juvenile pink and chum salmon in the nearshore marine environment of British Columbia, Canada. Published in the Canadian Journal of Fisheries and Aquatic Sciences (Vol. 61: 147-157). This study compared sea lice infestation rates on juvenile pink and chum salmon in five nearshore areas of the British Columbia coast selected on the basis of proximity to salmon farms. The authors: Alexandra Morton, Richard Routledge, Corey Peet, and Aleria Ladwig conducted a 10-week study in the Broughton Archipelago that found sea lice were 8.8 times more abundant on wild fish near farms holding adult salmon and 5.0 times more abundant on wild fish near farms holding smolts than in areas distant from salmon farms.


2003 – UBC Science Forum: Sea Lice Review and Summary of Research Priorities (Sea Lice White Paper). Authors: R.S. McKinley, B. Finstad, P.A. Bjørn and K.J. Hunter.


2003, October 15 – CAAR Critique of Sea Lice White Paper.


2001, December – Salmon Farms, Sea Lice and Wild Salmon: Risk, Responsibility and the Public Interest. Watershed Watch Salmon Society.