Océans en santé. Communautés en santé

Escaped farmed salmon invading Canada’s rivers

May 12, 2014

SOINTULA, B.C.—Farmed Atlantic salmon were estimated to be present in over half of surveyed rivers and streams according to modeling conducted for an article recently published online in the journal Biological Invasions. Living Oceans is calling on Minister of Fisheries and Oceans Gail Shea to stop approving new net-cage salmon farms until she can provide the public with clear evidence that Canada’s rivers are not being colonized by invasive species.

The study, Occupancy dynamics of escaped farmed Atlantic salmon in Canadian Pacific coastal salmon streams: implications for sustained invasions, cited previous research indicating that the number of escaped fish reported by the B.C. salmon farming industry is greatly underestimated.

“There is simply no way to verify the industry’s data,” said Will Soltau, Salmon Farming Campaign Manager for Living Oceans. “Salmon farmers self-report escapes and at the same time, Fisheries and Oceans Canada (DFO) does not publicly share data from the Atlantic Salmon Watch Program it operates to receive reports from fishermen, field researchers and hatchery workers.”

“We are quite concerned about the implications of what we found,” said Alina Fisher, the report’s lead author. “The fact that Atlantic salmon invasion was stable between years either implies that Atlantics have effectively naturalized or that chronic net-cage leakage is significantly and consistently high. Either case has significant implications for Pacific salmon.”

Atlantic salmon are farmed on Canada’s east and west coasts and escaped fish pose a number of risks to wild salmon, including the transmission of diseases and competition for food and habitat. Last fall on the East Coast—where escaped farmed Atlantic salmon can also interbreed, polluting the wild gene pool—91 escapees were counted in a single fish trap monitored by the Atlantic Salmon Federation (ASF) on the Magaguadavic River in New Brunswick. The significant number of escapees indicates that a large escape in the Bay of Fundy had gone unreported by the salmon farming industry.

“In its Assessment and Status Report on Atlantic Salmon in 2010, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) noted that the growth of the salmon aquaculture industry has coincided with a severe decline in wild populations in the nearby rivers in the Bay of Fundy,” said Sue Scott, VP of Communications for ASF. “COSEWIC also noted that in North America, farm-origin salmon have been reported in 87 percent of the rivers investigated within 300 km of aquaculture sites.”

The Occupancy dynamics report also found that escaped Atlantics on the B.C. coast show a marked preference for rivers with the highest diversity of native salmonid species: 97 percent of the surveyed rivers with high salmon diversity were occupied by Atlantics. Impacts may accordingly be affecting all five species of Pacific salmon as well as steelhead and trout.

“When salmon farming was introduced in Canada, fishermen and environmentalists protested that fish escaping from the net-cages posed a threat to wild stock,” said Soltau. “First DFO said escaped Atlantics couldn’t survive. Then they said they wouldn’t enter river systems. Then they said they wouldn’t spawn, but they found feral juveniles. Since then, DFO has done nothing to ease public concerns about escaped farmed Atlantics’ impact on wild salmon in Canadian rivers.”



Will Soltau
Salmon Farming Campaign Manager
Living Oceans Society

Alina Fisher
Lead author of report

Sue Scott
Atlantic Salmon Federation


Fisher AC, Volpe JP, Fisher JT (2014) Occupancy dynamics of escaped farmed Atlantic salmon in Canadian Pacific coastal salmon streams: implications for sustained invasions.Biological Invasions. Published online 13Feb2014, doi: 10.1007/s10530-014-0653-x

The report examined data collected in snorkel surveys of 41 B.C. rivers over a period of 3 years, 1997-1999. Virtually no monitoring has been conducted since that time or if it has the data have not been shared. New modeling techniques allowed researchers to use the data available to predict the number of impacted streams, as well as assess potential impacts by cross-referencing impacted streams with known habitat for native species.

While Atlantic salmon cannot breed with Pacific salmon, in 1998 escaped farmed Atlantic salmon were found to have produced young in the Tsitika River on Vancouver Island. Atlantic salmon have been spotted in over 80 B.C. rivers and have been caught by fishermen in Alaska over 250 kilometres from the nearest salmon farm.

Open net-cages can tear and when they do, farmed salmon escape through the holes. Over one million farmed salmon escaped into B.C. waters between 1987 and 1996. There has been a dramatic reduction in the number of farmed Atlantic escapes since regulations changed and the industry began self-reporting its losses:

  • 2008 - 111,000 escapes
  • 2009 - 47,000*
  • 2010 - 15,700**
  • 2011 - 12
  • 2012 - 8
  • 2013 - 0

* not reported to the public until after fishermen began catching Atlantic salmon in their nets.
** only made public in the parent company’s quarterly report.

Atlantic Canada

Since ASF began monitoring escapes in the Bay of Fundy salmon aquaculture industry using New Brunswick’s Magaguadavic River at its index river, salmon escapees have outnumbered wild returns in all but four of the last 21 years. The wild salmon run has dwindled from an average of 800 in the 1980s to 293 in 1992 and, by 2012, to two, despite an active restoration program. The Magaguadavic River salmon run has essentially been wiped out.

In 2013 a large escape from net-cages in the Bay of Fundy went unreported by the aquaculture industry; 91 farmed salmon were found in a fish trap in Magaguadavic River.

That same year, between 20,000 and 50,000 mature farmed salmon escaped from a net-cage on the south coast of Newfoundland. The government indicates that 750,000 salmon escapees have been reported in Newfoundland since the industry began; aquaculture salmon have been confirmed in nine rivers on the south coast.


  • This juvenile Atlantic salmon was found in the Amor de Cosmos River, Vancouver Island. Subsequent analyses showed this fish was wild-reared progeny of Atlantic salmon escaped from salmon farms. The Amor de Cosmos River supports numerous native Pacific salmon species. Photo: John Volpe
  •  	  Researchers surveyed the occurrence of Atlantic salmon that had escaped from fish farms (yellow dots), and native Pacific salmon, in 41 Pacific coast rivers and creeks (red diamonds) between 1997 and 1999 on Vancouver Island and the adjacent mainland of British Columbia, Canada.
  • An open net-cage salmon farm on the British Columbia coast. Most salmon farms hold more than one-half million fish penned in open net-cages. There are over 100 open net-cage farms growing farmed salmon in sheltered bays along B.C.'s coast.