Seeking a safe place for one of Canada's most endangered freshwater fish
CBC
The effort to save one of Canada's most endangered freshwater fish now involves electronic tracking of specimens bred in captivity and released into the Nova Scotia watershed that holds the world's only remaining wild population.
Last week, a final batch of 30 tagged Atlantic whitefish were released in the Petite Rivière system behind the town 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," said Jeremy Broome, a biologist with Fisheries and Oceans Canada assigned to the recovery team.
"So looking at which one of those might produce the best survival is important to us."
Tiny transponder tags were inserted with a hypodermic needle into 150 one-year-old fish spawned at the Dalhousie University Aquatron marine research facility in Halifax.
The fish were anesthetized, given one week to recover and released at various locations within the watershed. Fish were released into the estuary after acclimatizing to saltwater.
Devices installed at narrow points along the river system will send a signal 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 said.
"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."
This whitefish species is an ancient relative of Atlantic salmon and naturally anadromous, meaning they're born in freshwater, travel to the ocean and return to spawn.
They have survived only in the Petite Rivière watershed, which was landlocked for a century by a dam and serves as the water supply for the Town of Bridgewater.
A fish ladder was built there in 2012.
The recovery team hopes to see evidence that 1,100 untagged juveniles released last year and those tagged in 2023 return to spawn in the next year or two.
Nearly 40 years ago, the species was the first fish in Canada to be assessed as endangered by the Committee on the Status of Endangered Wildlife.
Researchers say there's been a dramatic rise in the number of people going on medications to treat attention deficit/hyperactivity disorder in Ontario, suggesting factors such as more time spent online and the rise of private assessments for the mental condition could be behind the increase.
Baby, it’s cold outside — but it’s worth putting on that heavy winter coat, scarf and boots and heading out for one of the best meteor showers of the year: the Geminids.
Health officials are reminding Canadians to maintain healthy habits during the holiday season, as influenza leads to more school absences and hospitalizations.
For 40 years, staff at Nova Scotia's Annapolis Royal Historic Gardens thought their ginkgo tree was male.
Health Canada has authorized a new drug to treat postpartum depression.
A website selling moccasins with what looks like Haudenosaunee-style beadwork but with no attribution to an artist or community has sparked conversation online about how to identify authentic Indigenous crafts.
More Canadians have a family doctor or nurse practitioner compared with three years ago, but satisfaction remains low, a comprehensive new survey suggests.
This could be an unusually good year to spot snowy owls in southern Canada.
Over five dozen items belonging to First Nations, Inuit, and Métis are one step closer to returning home.
After Canada announced Tuesday it wouldn’t list the American eel under the Species at Risk Act (SARA) some First Nations people with cultural and spiritual ties to the species are questioning the decision.
The B.C. government is issuing new guidance for physicians when it comes to treating youth with overlapping cases of mental health and substance use challenges, clarifying the use of involuntary care in the process.
Former Assembly of First Nations national chief RoseAnne Archibald says her lawsuit against the national advocacy organization is moving forward, after settlement talks “were stalled and stonewalled” for 18 months.
An early start to Canada’s flu season is hitting children hard, sending a flood of young patients into multiple pediatric hospitals as medical teams warn that emergency visits and admissions could keep climbing in the weeks ahead.