Seeking a safe place for one of Canada’s most endangered freshwater fish | 24CA News

The effort to avoid wasting one in every of Canada’s most endangered freshwater fish now includes digital monitoring of specimens bred in captivity and launched into the Nova Scotia watershed that holds the world’s solely remaining wild inhabitants.

Last week, a ultimate batch of 30 tagged Atlantic whitefish had been launched in the Petite Rivière system behind the city of Bridgewater on the province’s South Shore.

“We have released fish into different parts of the system, the lake portion, riverine portion and as well into the estuary into salt water,” mentioned Jeremy Broome, a biologist with Fisheries and Oceans Canada assigned to the restoration group.

“So looking at which one of those might produce the best survival is important to us.”

Tags inserted with needle

Tiny transponder tags had been inserted with a hypodermic needle into 150 one-year-old fish spawned on the Dalhousie University Aquatron marine analysis facility in Halifax. 

The fish had been anaesthetized, given one week to get better and launched at varied places throughout the watershed. Fish had been launched into the estuary after acclimatizing to saltwater.

Devices put in at slim factors alongside the river system will ship a sign when a tagged fish swims by.

“We are trialling different approaches, sort of spreading our eggs across different baskets to see what might work best,” Broome mentioned.

“If we can determine that survival is better with releases into the estuary, we’re seeing more fish come back from that strategy that would be indicative that we would want to proceed with that approach.”

Landlocked for a century

This whitefish species is an historical relative of Atlantic salmon and naturally anadromous, which means they’re born in freshwater, journey to the ocean and return to spawn.

They have survived solely within the Petite Rivière watershed, which was landlocked for a century by a dam and serves because the water provide for the Town of Bridgewater.

A fish ladder was constructed there in 2012.

The restoration group hopes to see proof that 1100 untagged juveniles launched final 12 months and people tagged in 2023 return to spawn within the subsequent 12 months or two.

Why the Atlantic whitefish is in hassle

Nearly 40 years in the past, the species was the primary fish in Canada to be assessed as endangered by the Committee on the Status of Endangered Wildlife.

The whitefish faces a number of threats together with warming waters and invasive smallmouth bass and chain pickerel launched into the watershed.

Atlantic whitefish at the moment are so scarce that when discovered, the younger are whisked an hour away to the Aquatron, the place a captive breeding program is underway.

Unlike earlier years, no juvenile or larval whitefish had been captured in traps put in all through the system this spring.

Dalhousie’s Aquatron now holds extra Atlantic whitefish than exist within the wild.

“Without the brood stock that we’ve been able to develop at that facility and the progeny that are coming from there now, we really would be out of options. We’re still not in a great place, but without that facility and without that program we’d be in a very dire place,” mentioned Broome.

Looking for one more residence

The restoration group can also be in search of different watersheds in Nova Scotia the place the critically endangered species may very well be launched and survive.

Several candidate websites have been recognized and surveys are deliberate this summer time. Consultations are the subsequent step.

“I think we’re at a point where we have to make a move and we have to start trying these things,” he mentioned.

A 20-year restoration merry-go-round

After it was first declared a species in danger in 2003, a captive breeding program was established on the Mersey Biodiversity Centre in Nova Scotia as a part of a government-mandated restoration technique.

The program was shut down and the Mersey variety centre actually bulldozed underneath the Harper authorities in 2013.

Several months later, the voracious invasive chain pickerel had been found within the Petite Rivière watershed, which held the remaining wild inhabitants.

Thousands of whitefish reared within the variety centre had been launched right into a holding lake behind the Burnside industrial park in Dartmouth. None survived.

No grownup whitefish had been seen alive between 2014, when the chain pickerel turned established, and 2018.

Dalhousie to the rescue

Since then, Dalhousie intervened to supply its Aquatron facility, first as a Noah’s Ark to avoid wasting the species from threat of extinction and later to host a captive breeding program.

The college has additionally been concerned in constructing a streamside rearing facility — a miniature part of the variety centre that was demolished by the earlier federal authorities.

Even the reintroduction into the Petite Rivière system is a repeat of the work of the cancelled captive breeding program.

Still, Broome stays hopeful.

“This is truly, this is a Nova Scotia species of fish. It’s only found here, only in the province, the only place in the entire world,” he mentioned.

“So it’s ours to do something about. It’s ours to protect and keep on the face of the planet.”