Aquaculture steps up to save endangered salmon species

A decade-long project in New Brunswick is using adapted ocean aquaculture systems to raise wild salmon to adulthood and return them to rivers where returns had nearly disappeared.

By Fabian Dawson
SeaWestNews

A new peer-reviewed study has documented how a modified salmon aquaculture site in New Brunswick is helping revive one of Canada’s most endangered wild Atlantic salmon populations by rearing young fish at sea and returning them to spawn in their home river.

The study, led by Parks Canada biologist Corey N. Clarke and published in Fisheries Research, examined a decade of work at a Wild Salmon Marine Farm near Grand Manan Island. The site uses adapted sea pens to raise juvenile salmon sourced from Fundy National Park streams through the high-mortality ocean phase of their lifecycle.

“We document the first known marine aquaculture farm established and dedicated to rearing wild-origin Atlantic salmon for population restoration,” reported Clarke, the study’s lead author with Fundy National Park.

The project focuses on the Inner Bay of Fundy Atlantic salmon population, listed as endangered under Canada’s Species at Risk Act.

Historic returns dropped from roughly 40,000 adult salmon to fewer than 200, with adults nearly absent from some rivers.

Traditional hatchery releases failed to bring back returning adults. The new program changed strategy by releasing fully mature salmon back into the Upper Salmon River to spawn naturally.

“To our knowledge, this is the first published account documenting a marine aquaculture farm being established, adapted, and dedicated to rearing wild Atlantic salmon for population restoration purposes,” the study states.

From 2015 to 2024, the program released between 67 and 804 adult salmon each year into the river. Monitoring data show those fish are returning from the ocean on their own.

The study reports that between 2016 and 2024, 10 to 48 returning adults were detected each year. Returns had been “mostly absent” from 2000 to 2012.

“We detected released adults returning naturally in all subsequent years and some years in numbers unseen since this population collapsed in the mid-1980s, ” the authors wrote.

Returning salmon have been observed spawning, producing juveniles, and contributing marine nutrients that support river food webs. Juvenile migration events have occurred every year since adult releases began.

Co-authors John M. Whitelaw and John W. Robinson of Fundy National Park worked on monitoring and river assessments, while Matthew J. Ingersoll of Kelly Cove Salmon, based on Grand Manan Island, supported marine husbandry operations. The study notes that the marine facility operated under separate protocols from commercial salmon farms.

The authors emphasize that this approach is intended for populations where ocean survival failure prevents recovery, and where local genetic stocks can be preserved. The method combines aquaculture infrastructure with natural spawning in the river, meaning the next generation develops under natural conditions.

“This work provides a practical conservation tool for salmon populations where ocean-phase survival limits recovery,” the study concludes.

While the study is based in Eastern Canada, its findings are likely to draw interest in British Columbia, where several wild salmon populations are at risk and where the role of aquaculture in salmon recovery remains a central policy debate.

The authors do not argue that aquaculture replaces habitat restoration or climate measures but show that aquaculture technology can be adapted to support endangered wild stocks when marine survival is the limiting factor.

Image courtesy of www.fundysalmonrecovery.com