Atlantic whitefish young discovered in Bridgewater lake system

There was a rare piece of good news Friday for the endangered Atlantic whitefish after researchers found 15 juveniles in a lake system behind the town of Bridgewater, Nova Scotia, a sign the species is spawning.

"That's really significant," said Andrew Breen of the Bluenose Coastal Action Foundation

It's the largest capture in the three years since the non-government organization installed a rotary trap at the Milipsigate Dam, at Hebb Lake, Lunenburg County.

The three lake watershed is the only place on earth where the Atlantic whitefish - a salmon relative -  still survives in the wild.

Researchers have seen no adults in two years and the landlocked lakes are being rapidly overrun by two voracious predators.

"It does tell us that last year there have been some adult Atlantic whitefish. We are worried about the decline in the population of Atlantic Whitefish and mainly because of the illegal introduction of chain pickerel and smallmouth bass," Breen tells CBC News.

Along with the 2.5 centimetre whitefish pulled from the trap Friday, fisheries technician Phillip Longue also found a plump smallmouth bass.

Smallmouth bass have been in the lakes for many years. The arrival of chain pickerel three years ago may tip the balance.

Reprieve?

So far bass and pickerel have been found in two of the three lakes that make up the whitefish's world.

There are reports chain pickerel are now in Lake Minamkeak, the third lake in the system and until now pickerel free.

"It's a very significant threat," said department of fisheries and oceans biologist Mark Showell, who explained chain pickerel rapidly take over and kill off almost all other fish species in water systems where they are introduced.

This summer Showell will take part in a federal and provincial effort to confirm or deny the presence of chain pickerel in Minamkeak Lake.

They will use a $70,000 electrofishing boat, which uses electricity to stun and capture fish.

"The real problem is there is no clear way to get rid of them once they are in there," Showell said.

He is encouraged by the discovery of juveniles by the Bluenose Coastal Action Foundation.

"That indicates there is a spawning population. The fact we are seeing some kind of numbers is good."

Showell said scientists do not know how many Atlantic whitefish exist in the wild. Estimates range from 500 to 2,000.

High hopes

Researchers were more optimistic in 2014 when they saw dozens of adult Atlantic whitefish feeding just above the Milipsigate dam at Hebb Lake.

"We had high hopes for 2015, and we yet didn't see any (adult) Atlantic whitefish in 2015 or 2016 but at the same time the population of chain pickerel has increased exponentially," said  Breen.

He is particularly concerned that chain pickerel may colonise the last whitefish refuge.

"We've got all our eggs in one basket here, so to speak and with the pickerel in there … it doesn't look good."

He said survival may require the return of a captive breeding program for the Atlantic whitefish.

Conservatives killed breeding program

The previous Conservative government cancelled the captive breeding program for whitefish, fired staff and shutdown the laboratory. In December 2013 it dismantled and demolished the Mersey Centre for Biodiversity in Queens County, N.S. where brood stock was hatched and raised.

At the time, DFO said the facility was unnecessary because the department released hatchery raised whitefish into Anderson Lake in Burnside. DFO has not checked in four years to see how many - if any - have survived there.

A population survey at Anderson Lake is another item on Showell's to-do list later this year.

Department brass, he said, have not taken the return of a captive breeding program off the table.

Showell said DFO will also try to create an "index of abundance" in the Hebb Lake watershed behind Bridgewater.

"We have some idea from several years ago, but nothing since. We have no idea whether the population is going up or down."

Gaspereau run starts

Technicians on Friday were also looking for Atlantic whitefish in a fish ladder at the Hebb Lake dam near Highway 103.

The $700,00 fishway was built to open an ocean route to the sea for the first time in decades.

Whitefish were andramanous - they spent part of their lives at sea. On Friday, technicians found no whitefish.

They did capture three more smallmouth bass - which were destroyed - and the first run of gaspereau in 2016, which were sent along their way.