A conservation group is sounding alarms about the discovery of farmed salmon in rivers on the east coast, citing research suggesting that potential crossbreeding could harm the long-term health of wild populations.
Two Atlantic salmon originally from aquaculture sites were among seven adult fish harvested from Nova Scotia’s Gaspereau River this year by the federal Fisheries Department, the Atlantic Salmon Federation said in a press release on Friday.
The New Brunswick-based conservation group said it was the second year in a row, and the third time since 2017, that fugitives had been removed from the Gaspereau River. The fish caught in Nova Scotia were being collected for a Department of Fisheries hatchery, which maintains endangered populations of Atlantic salmon from the Bay of Fundy, the federation said.
The salmon federation cited studies from the past two decades that indicate that when domesticated salmon are bred with wild fish, their offspring are less fit, contributing to population declines. A 2003 study published in a Royal Society journal found that farmed salmon in Ireland consistently showed lower survival in fresh and ocean water compared to wild salmon and that hybrid salmon was weaker than wild salmon.
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Furthermore, the Royal Society article noted that fugitives were larger and tended to consume more resources, “so the competitive effect alone serves to reduce the fitness of the wild population regardless of genetic changes in the population.” .
The salmon federation said that this year, four farmed salmon were caught at a dam on the Union River in Maine and that federation scientists discovered three farmed salmon attempting to enter the Magaguadavic River in New Brunswick.
“We have worked with industry and government for years to implement ways to trace leaks back to their owners in order to address the causes of these events,” said Kris Hunter, director of the federation’s Nova Scotia and Prince Edward Island programs.
Hunter said that overall “progress has been incredibly slow.”
Susan Farquharson, executive director of the Atlantic Fish Producers Association of Canada, said in an email that while her group has discussed the discovery of the two fish collected from the Gaspereau River, she has not had a chance to review the data. about them.
“Escape events are rare and are largely the result of extreme weather events,” he said. “Occasionally a small number of fish escape due to human error when handling fish.”
Farquharson said that farmed salmon are “very poorly adapted” to survive or reproduce in the wild, adding that in the rare event that an escape occurs during the breeding season and the fish survives to maturity, “the research shows that the natural selection process will continue to play an important role, so any genetic impact would be very low. “
Leakage risks are being reduced thanks to “robust” industry efforts to contain farmed salmon, he added. Those measures, Farquharson said, include the use of “predator exclusion” nets, which are made up of high-density polyethylene mesh and stainless steel wire, and the use of frequent inspections of nets and equipment.
This Canadian Press report was first published on December 3, 2021.
© 2021 The Canadian Press
Reference-globalnews.ca