Question Period Note: Mouth rot Tenacibaculum maritimum in Pacific Salmon

• The protection of wild Pacific salmon is a priority for this Government.
• My Department recognizes that the future of aquaculture in the Discovery Islands area is of great interest to many people in British Columbia.
• Mouthrot has not been reported in any wild fish species in British Columbia.
• The Department continues to conduct research, undertake risk assessments and provide advice to managers on an ongoing basis to inform their decisions. As new peer-reviewed information becomes available, the Department will continue to review and incorporate the information as part of its risk-based, science-informed adaptive management process.

• On May 13, 2021, The Narwal published an article, ‘They never said a word’: DFO told B.C. salmon farmers, but not First Nations, about mouth rot infestation, which reports on details of a recent Access to Information and Privacy (ATIP) release concerning Tenacibaculum maritimum.
• Tenacibaculum maritimum is a bacterium with global distribution that occurs naturally in the marine environment and has been found on fish surfaces with and without signs of disease. It is commonly found in the ocean in coastal British Columbia (BC).
• Under the right conditions, the bacterium may cause a disease called “mouth rot” or “yellow mouth” in farmed Atlantic salmon in BC.
• Mouth rot is a treatable disease for farmed Atlantic salmon that generally does not cause high mortality. This bacterium has not been demonstrated to cause disease in wild Pacific salmon. It can be present on or in an animal without causing harm or disease.
• A recently published article by Bateman et al. reports new results from a multi-year infectious-agent screening program of farmed salmon in BC.
• Recent research has confirmed the presence of the bacterium on juvenile wild salmon species, but not the presence of the disease. This research helps to improve our understanding of the bacterium; the Department will continue to consider the growing base of evidence in decision making.
• A recent Canadian Science Advisory Secretariat (CSAS) peer reviewed risk assessment determined that T. maritimum attributable to Atlantic salmon farms in the Discovery Islands area poses minimal risk to Fraser River sockeye salmon abundance and diversity under the current farm practices.
• This conclusion was reached given:
o evidence that mouthrot mainly affects farmed Atlantic salmon smolts recently transferred to seawater;
o the disease has rarely been reported in farmed Pacific salmon suggesting a relatively low susceptibility;
o Fraser River sockeye salmon have limited and short interaction with Atlantic salmon farms in the Discovery Islands.
o infection with the bacterium attributable to Atlantic salmon farms in the Discovery Islands area is expected to result in negligible impacts to Fraser River sockeye salmon abundance and diversity.

None