Fishermen and scientists compete on the number of walleye in Lake Winnipeg

In response to scientists' fears about the number of walleye in Lake Winnipeg, the provincial government has recently begun buying back fishing quotas for walleye.

The province also announced that fishing nets will become larger to allow yellow walleye and other fish species to pass through and breed.

However, members of the fishing industry, who have long disagreed with biologists, responded with an unexpected decision: they voted to dissolve a co-management council with the province.

They also intend to create their own collective and do their own research with the hope that it will serve as a counter-argument to the opinion that Walleye is in trouble.

"We can have our own scientists and have our own research and data," says Einar Sveinson, a fourth-generation Gimli-based fisherman by the lake and president of Manitoba's Pioneer Commercial Fishers.

Its fishing nets have been filled throughout the spring commercial fishing season, which ends Wednesday.

"Overall, the season was fantastic, as were the 10 or 15 last years. There was no noticeable difference from other [seasons], "he says.

Walleye, treasure for fishermen

One week before the end of the season, on Einar Sveinson's boat, there are more walleye than any other species.

"I feel that the industry is really good and I'm optimistic for the future," he says.

Walleye is the cornerstone of Einar Sveinson's business model, but this resource is being reduced, according to provincial fisheries regulators and independent biologists concerned about the future of the stock.

Einar Sveinson has been part of a fishing family on Lake Winnipeg for four generations.

Photo: Radio-Canada

In a dynamic world-wide, commercial fishers and scientists have very different ideas about what goes on beneath the surface of the water and how stocks should be managed.

Einar Sveinson, like many commercial fishers on Lake Winnipeg, says he does not trust the scientists who, he says, spend their days sitting at their desks.

Invasive species pointed out

On average each year, Manitoba's commercial fishermen deliver 4,6 million kilos of walleye to the Federal Freshwater Fish Marketing Board, which exports a large portion of the catch to the United States.

Still, the Manitoba Department of Sustainable Development, responsible for regulating the province's fishery, lists stocks of walleye as satisfactory but deteriorating.

Scientists in the province say that walleye take longer to mature, end up being smaller in adulthood, and are fished at an unsustainable rate.

Biologists argue that commercial fishing is not the main reason for the decline in walleye stocks. In addition, they do not report any of the interrelated environmental issues affecting Lake Winnipeg, including the presence of too many nutrients in its waters, the resulting growth of algal blooms, or the recent arrival of invasive zebra mussels.

Instead, biologists point to the near extinction of another invasive species on Lake Winnipeg: the rainbow smelt.

For nearly two decades, the Lake Winnipeg walleye has thrived on a diet composed of rainbow smelt, a European species first seen in the lake in 1991.

This oily fish prey allowed the walleye to grow considerably in size and number until the smelt population collapsed, possibly due to warming of the lake waters.

There are so few smelts in Lake Winnipeg now that they do not even appear in the trawl surveys conducted by federal scientists, says Rob Olson, director of wildlife and fisheries for the Department of Sustainable Development.

"We do not find literally any trace in the northern basin," he says, adding that smelt has not yet been replaced by native species of prey such as cisco and emerald shiner.

"From a peak in 2008 and 2009, [Golden] catches have been steadily declining," says Rob Olson.

"So that's a concern for us, and that's part of the reason we've introduced some of the changes we've proposed for next spring. "

Insufficient measures

Quota buybacks and increased mesh sizes are good first steps, but they are not enough to prevent further declines in fish numbers, says University of Winnipeg biologist Scott Forbes.

A man in front of a castle.

Scott Forbes, a biologist at the University of Winnipeg, believes stocks of walleye in Lake Winnipeg could collapse.

Photo: Radio-Canada

For years, he has warned of an imminent collapse of walleye stocks and is critical of a quota system that allows commercial fishermen to target one of three species - walleye, walleye or lake whitefish - to maximize their catch. and their profits.

"There are really a lot of fish in the lake, but it's just knowing what fish are in the lake," says the biologist.

"Currently, we harvest about 60% of the exploitable walleye population. The sustainable harvest is just over half of it, "he says.

"If we continue to do what we do, we will lead to the collapse of the population, as was done in the late 1960," says Scott Forbes.

This article appeared first on https://ici.radio-canada.ca/nouvelle/1214985/peche-poisson-developpement-durable-manitoba