Question Period Note: Sea Lice and Aquaculture

• Farmed fish are free of sea lice when they enter open net pens from a hatchery, but they can pick them up in the marine environment.
• If not properly managed, sea lice levels can become elevated and wild juvenile salmon can be exposed to higher than natural levels during the spring out-migration period.
• In January 2023, DFO Science published a Science Response on the association between sea lice from Atlantic salmon farms and sea lice infestations on juvenile wild Pacific salmon in BC. The presence of sea lice on wild migrating juvenile Pacific salmon could not be explained solely by farm infestation pressure.
• Information on sea lice continues to evolve and my Department relies on information from credible and collaborative research to inform best practices in sea lice management.
• Regulatory measures set by Fisheries and Oceans Canada in British Columbia provide oversight of sea lice levels on salmon farms
• Routine sea lice audits and sampling inspections ascertain industry compliance.

• Sea lice are naturally occurring parasites in Canada’s coastal waters. While sea lice generally do not harm adult fish, they can harm small juvenile salmon as they emerge from river systems when they are quite small and without complete scale development for protection.
• Farmed fish are free of sea lice when they enter the ocean, but can pick them up in the marine environment. If not properly managed, sea lice levels can become elevated and wild juvenile salmon can be exposed to higher than natural levels during the spring out-migration period.
• Fisheries and Oceans Canada (DFO) scientists have studied sea lice, their relationship to the marine environment and fish, as well as treatments and methods to reduce their abundance on farmed fish, which inform improvements in management measures.
• One of the methods used to control sea lice is a Health Canada approved drug called SLICE. Due to some localized resistance to this drug, there is a push for the use of alternative methods to manage sea lice, including mechanical, thermal, freshwater, and other non-chemical treatments.
• DFO is exploring options to encourage innovation, including in non-chemical options to treat sea lice.
• In British Columbia (BC), the Department requires sea lice management, treatment, and mitigation measures at farms when sea lice levels are high. These measures have been very effective; most years, more than 90 per cent of sites are below the regulatory thresholds for sea lice during the out-migration period (March 1 to June 30).
• Any evidence of population-level harm to wild salmon resulting from salmon farms would prompt the immediate revision of aquaculture licences to ensure the conservation of wild salmon stocks.
• On the east coast, where the provinces are the lead regulators, information on sea lice management practices is not readily available to DFO. Each province regulates the industry differently and relies on individual companies to submit management plans, which are not made public.

Science Response
• In January 2023, DFO Science published a Science Response on the association between sea lice from Atlantic salmon farms and sea lice infestations on juvenile wild Pacific salmon in BC.
• This study showed that there was a positive trend between sea lice on farmed and wild salmon in all four geographic regions studied (Clayoquot Sound, Quatsino Sound, Discovery Islands, and the Broughton Archipelago). However, a statistically significant association was not observed between infestation pressure attributable to Atlantic salmon farms and the probability of sea lice L. salmonis infestations on wild juvenile Pacific salmon.
• The study used data from multiple Atlantic salmon farms, reported to DFO by industry, and sea lice counts on wild fish sampled at specific distances from nearby farms in the four study areas that were collected and made publicly available by industry.
• This work did not include an assessment of the influence of environmental factors which could potentially impact the relationship between wild and farmed salmon. Further, the report provided recommendations on additional work that would be useful to contribution to further analyses.
• A number of university academics have critiqued the January 2023 science advice including in the media.
• DFO and Carleton University’s Canadian Centre for Evidence-Based Conservation are collaborating to develop a state of knowledge report on the impacts of sea lice from aquaculture on Pacific wild salmon on the west coast of Canada.
• This state of knowledge report will be reviewed at Canadian Science Advisory Secretariat meeting in 2024 by national and international science experts and various stakeholders. Meeting participants will examine the latest information and data on this topic with the goal of ensuring the Department’s science advice continues to inform ongoing decision-making.
 

If pressed on sea lice on the west coast of Canada
• DFO and Carleton University’s Canadian Centre for Evidence-Based Conservation are collaborating to develop a state of knowledge report on the impacts of sea lice from aquaculture on Pacific wild salmon on the west coast of Canada.
• This state of knowledge report will be reviewed at a Canadian Science Advisory Secretariat meeting in late 2024 by national and international science experts and various stakeholders. Meeting participants will examine the latest information and data on this topic with the goal of ensuring the Department’s science advice continues to inform ongoing decision-making.

 
If pressed on sea lice on the east coast of Canada
• In Atlantic Canada, provincial governments are responsible for management of sea lice on salmon farms.
• My department works in close collaboration with provincial partners who have the jurisdiction to manage sea lice.