26
October
2011
|
08:00
America/Tegucigalpa

Sturgeon surgeon

(Edmonton) Owen Watkins is skilled at deftly sewing radio transmitters into lake sturgeon, one of Alberta’s most ancient fish. He jokingly calls it “sturgery,” but, wordplay aside, his research project is addressing a serious problem.

The lake sturgeon, classified as an endangered species in Canada, has been in existence for 200 million years, but their numbers are dangerously low—about 1,700 fish— in Alberta’s North Saskatchewan River.

Watkins, a master’s student in the U of A Department of Renewable Resources, is working in collaboration with Alberta Sustainable Resource Development to find out why the population is low, and what can be done to manage the situation. Currently, there are four to six lake sturgeon per river kilometre, compared to a healthy population in for instance, Wisconsin, where the sturgeon are managed to 150 per river kilometre.

“Right now, five per cent of those 1,700 fish are mature, and if we assume a ratio population of 50:50 male to female in any given year, there are only about eight female fish that are spawning,” said Watkins, who also works as a woodlands area fisheries biologist with Alberta Sustainable Resource Development.

Female fish can take upwards of 25 years to mature and can live up to 154 years. The overall sturgeon population should be showing a wide age variety in the river, but the oldest sturgeon his research team has been able to find is 64.

“There is a possibility of losing the species completely,” he says.

Popular with sport fishermen, the sturgeon historically was commercially harvested and shipped to Europe as a food source, and today could be an indicator of river health, Watkins said.

Spanning 500 kilometres of the river between Drayton Valley in west-central Alberta and the Onion Lake bridge on the Saskatchewan border, Watkins’ study is testing three theories on the population: first, that the fish population is now slowly recovering from low oxygen levels that existed prior to the 1960s before Edmonton began treating its sewage; second, that the fish use the river only seasonally to spawn, forage and then leave; and third, the possibility that the population is being overfished, even with a catch-and-release regulation, there is an associated mortality factor.

By implanting transmitters, tagging, measuring and collecting age data on the fish, the researchers are tracking their habitat movements, deriving population estimates and collecting other data to get a snapshot of what the sturgeon population has been doing for the past 20 years.

“We want to get an idea of whether the population is up, down or unchanged.”

Fishermen on the river are also being surveyed as part of the study.

Initial positive findings indicate that young sturgeon, aged two and three, are being found, which means the fish are reproducing, Watkins noted.

The team’s final findings will be presented to the provincial government and will “guide a recovery plan and help manage the North Saskatchewan River not just for sturgeon, but for the benefit of other river fish,” he added.

Watkins’ research is funded through Alberta Sustainable Resource Development and through Environment Canada’s Habitat Stewardship Program.