Recovery of critically endangered Atlantic whitefish hits milestone

A program to save critically endangered Atlantic whitefish in Nova Scotia takes an important step Thursday.

Juvenile Atlantic whitefish raised in captivity at Dalhousie University in Halifax will be released on a large scale into the Petite Rivière watershed in the Bridgewater area. It is where the wild population remains.

The 150 fish released will be the first in a series. Hundreds of fish will be placed into the wild by year's end.

"It definitely feels like a milestone, like we're getting somewhere," said Jeremy Broome, a Department of Fisheries and Oceans biologist working on the project.

"We're making really good progress and it's exciting."

An ancient relative of salmon, the Atlantic whitefish is seriously threatened in the wild. The last population on the planet exists in three lakes in the Petite Rivière watershed.

Genetic analysis by Dalhousie University's Marine Gene Probe Lab has indicated as few as 13 females capable of reproducing remain.

To save the species, larval whitefish have been taken from the wild to Dalhousie University starting in 2018.

Those fish have grown into a broodstock. They spawned this winter.

Offspring have been driven to the watershed and placed in tanks. Following a week of experimental acclimation to lake water and to wean from pellet feed to wild food, the fish are moved to an in-lake enclosure for further monitoring and adjust to local conditions.  

"The results have been very promising thus far," said Broome. "Survival has been very high and … better than I even expected."

Federal government axed first breeding program

On June 16, a test of protocols and procedures concluded with 22 juveniles released into Milipsigate Lake, one of the three lakes in the system.

It marked the first use of captive breeding for Atlantic whitefish in nearly a decade.

Dalhousie University is filling a gap created when the federal government axed the DFO captive breeding program in 2013.

A few months after the buildings used by DFO were demolished, invasive chain pickerel were discovered inside the watershed.

There were concerns the predator's arrival doomed the Atlantic whitefish. Sightings of adult whitefish have since plummeted.

Dalhousie steps in

But the presence of larval whitefish every year shows at least some breeding adults remain.

Earlier this year, DFO awarded Dalhousie a five-year contract worth $420,750 for "holding, raising and captive breeding" of Atlantic whitefish.

The program offers a prospect not considered for many years — moving beyond survival to rebuilding the population.

About 1,500 fish will be released this year. Five hundred will go in Milipsigate Lake. Another 1,000 will go in the lower part of the Petite Rivière system, which is separated from the three lakes by a dam. 

The lower part of the system is accessible to the ocean and could measure the fish's instinct to return to the sea. A fishway in the system allows fish to return or migrate upstream. 

Broome said all of this will take time.

"This is not something [where] we're going to be able to necessarily detect results immediately," he said. "We're going to be looking for two to three years out to eventually be seeing the results or the impacts of the releases we're doing."