Canadian sea lice study at odds with activists' claims against aquaculture

Latest DFO study finds no link between salmon farms and sea lice on wild salmon; activists’ claims shown to be false
May 11, 2004

A detailed scientific study, released today by Fisheries and Oceans Canada (DFO), found no link between salmon farms and sea lice infections of wild salmon in the Broughton Archipelago.
“This scientific analysis from DFO supports what we’ve been saying all along: Alexandra Morton’s allegations of a link between salmon farms and sea lice infections are just plain wrong,” said Ian Roberts, a spokesman for grassroots-based Positive Aquaculture Awareness (PAA).
“The DFO study sampled 20,000 fish and showed every three out of four fish were lice-free and even those with lice were perfectly healthy,” said Roberts. 
Yet as recently as last Friday, anti-aquaculture activist Alexandra Morton was spreading false alarms in an e-mail by alleging mainland pink and chum salmon stocks in the Broughton were infected with sea lice at the “highest rate” documented to date and that she was witnessing “an extinction.”
“Ms. Morton should be embarrassed by her false allegations of an extinction and should apologize immediately to the hard working communities and First Nations people whose livelihoods she continues to threaten,” said Roberts.
“Ms. Morton won’t be able to use the excuse of lice in order to justify fallowing more salmon farms in the area either, because DFO found pink and chum salmon throughout the Broughton and Knight Inlet. This contradicts her assertion that fallowing a main migration corridor allows juvenile salmon to move uninfected from fresh water to the ocean,” Roberts said.
The peer-reviewed DFO study further contradicted Morton’s allegations by showing that in cases where fish had sea lice, the majority (15%) were infected with Caligus clemensi (a species rarely found on farmed salmon), while a minority (9%) were infected with Lepeophtheirus salmonis (a species commonly found on wild and farmed salmon).
“This again proves Ms. Morton wrong because the majority of lice found on wild fish are not even the same species as those found on farmed fish,” said Roberts.  “We know she’ll keep crying wolf. But this time we think the real science has caught her red-handed,” Roberts said.
Further information:
Fisheries and Oceans Canada News Release

Vancouver - Fisheries and Oceans Canada today announced that results of the sea lice/juvenile salmon research conducted last spring in the Broughton Archipelago show that of almost 20,000 juvenile salmon sampled, 3 out of every 4 were free of lice. Furthermore, all fish studied appeared to be in good health, in spite of the lice present.

The information collected by DFO scientists from March to mid-June 2003 indicates that pink and chum juvenile salmon were found throughout the study areas, and that two species of sea lice were found on the salmon studied. Of the pink salmon examined, approximately 15% were infected with Caligus clemensi (a species rarely found on farmed salmon) and 9% were infected with Lepeophtheirus salmonis (a species commonly found on wild and farmed salmon). The average number of lice per infected fish in the study area was 1.7. All fish captured appeared healthy and no dead or dying fish were observed in the field.

Another observation is that juvenile pink and chum salmon were found throughout the Broughton Archipelago and in Knight Inlet, thus contradicting the hypothesis that a main migration corridor is used by juvenile salmon moving from freshwater to the open ocean.

On April 6, 2004, members of the Pacific Scientific Advice Review Committee, along with external experts met in Nanaimo to judge the methodologies, data analyses, results, conclusions and recommendations from this study on salmon distribution and sea lice prevalence and intensity of infection. The final conclusions and recommendations of this peer-review process are contained in the advisory document released today and available from DFO’s website.

The next phase of the research plan in the Broughton Archipelago will begin May 10th, with further research into the distribution of pink and chum salmon and prevalence and intensity of infection by sea lice species. A minimum of $300,000 has been set aside for more sampling work in an attempt to better understand the full impact of sea lice infection on these juvenile salmon.

The Canadian Journal of Fisheries and Aquatic Sciences is a scientific peer-reviewed journal published by the NRC Research Press. For the complete article, Sea lice (Lepeophtheirus salmonis) infection rates on juvenile pink (Oncorhynchus gorbuscha) and chum (Oncorhynchus keta) salmon in the nearshore marine environment of British Columbia, Canada
Alexandra Morton, Richard Routledge, Corey Peet, and Aleria Ladwig, see

Sea Lice and Salmon: Elevating the Dialogue on the Farmed-wild Salmon Story is
available online (