Lake Sturgeon Risks Extinction - Canada Researchers
Author: Jonathan Spicer
The lake sturgeon, one of North America's oldest and largest fish, could disappear completely unless conservation efforts are redoubled, the Committee on the Status of Endangered Wildlife in Canada said this week.
The committee, which compiled existing research on plants, animals and other organisms, identified 520 other wildlife species in Canada that are also "at risk", but not as imminently as the lake sturgeon.
The fish, a "living fossil", is particularly sensitive to outside threats because of its long lifespan and the fact that it doesn't reach sexual maturity until its third decade, said Robert Campbell, a retired wildlife biologist and co-chair of the committee's fresh water team.
"If you do something to disturb that natural population -- for example, fishing them -- it will very quickly reduce the number of larger individuals that are capable of reproduction," he said in an interview.
"It takes a long time for that population to recover."
For the same reasons, the species would take about 150 years -- or three generations -- to go extinct, Campbell said.
The committee has no overall estimate for the number of lake sturgeon in Canada, but like most of the world's 23 sturgeon species, populations are shrinking and mostly dependent on conservation practices.
The fish has a shark-like appearance but no teeth, feeding on worms, leeches, larvae and small fish. It can grow as large as 185 kilograms (400 pounds) to a maximum recorded age of 154 years.
It was once very abundant in the Great Lakes, the North Saskatchewan River and elsewhere in North America, but is now rarely seen because of over-fishing, pollution, and habitat loss due to dams, which fragment the populations and change river flows, Campbell said.
"Exploitation began in the 1800s and very quickly the populations were decimated."
The lake sturgeon were a valuable resource for native Indians and early European settlers who used the fish as a source of smoked meat and oils. More recently, people have harvested many of the sturgeon species, including lake sturgeon, for caviar.
Canadian provinces and several US states protect the giant fish, which has already vanished from some regions.
In August, the committee will recommend that the Canadian government protect the lake sturgeon and other species deemed at risk of extinction under the federal Species at Risk Act.