The St. Lawrence beluga population would have at least twice as many individuals as previously thought. This new assessment does not mean, however, that the population has increased, but rather that the analysis of the data has greatly improved, insist the experts consulted by The duty. What is more, this cetacean is still not on the road to recovery and the high mortalities of females and young mortgage its future.
The most recent assessment of this population, presented on Friday as part of the 2023 Beluga Symposium, concludes with an average estimate of 1,850 belugas, with an established interval of between 1,530 and 2,180 individuals. This assessment is much higher than the previous one, published in 2013, which concluded at a population of approximately 880 animals. The goal of the federal government’s “recovery plan” is still a long way off, however, since it aims to bring the workforce to more than 7,000 individuals.
This upward revision does not mean that belugas are more numerous, warns Véronique Lesage, cetacean specialist at Fisheries and Oceans Canada. “Our methods of analysis to estimate the size of the population suggest that, in the past, we underestimated its abundance. It hasn’t doubled, but the methods that allow us to estimate its real size are better,” she explains to the Duty.
Moreover, the population, which numbered about 10,000 individuals at the beginning of the 20the century, shows no signs of increasing or even recovering. It remains rather “stable” underlines Mme The wise man. And it is difficult to predict the “trajectory” of the next few years without scientific evidence.
Scientific Director of the Group for Research and Education on Marine Mammals, Robert Michaud is also very cautious in interpreting the data, which has not yet been officially published by Fisheries and Oceans Canada. . “The portrait we have is a little less worrying, because we have seen a brake on the decline. But, in the long term, we are talking more about a stabilization of the population, ”he summarizes.
In terms of good news, experts have indeed noted that the decline of these resident cetaceans of the St. Lawrence has stopped. The most plausible explanation associates this phenomenon with the reduction, then the disappearance, of cases of cancer in belugas. In the 1980s and 1990s, analyzes of carcasses found on the banks of the St. waters of the river and the Saguenay River.
Thanks to the remediation plans implemented over the past three decades, these cases have gradually decreased and the last case of cancer was reported in 2011. Véronique Lesage sees this as an example of the “benefits” of depollution programs. Robert Michaud adds, however, that “the total load of contaminants remains very high” in belugas, in particular due to the emergence of new contaminants.
Concerns
Scientists remain “very worried”, insists Mme Lesage, because of the marked increase in mortality of females and very young cetaceans. The many cases of females who have died giving birth since 2010 constitute a real “dark series”, according to Mr. Michaud. Concretely, these belugas are no longer able to contribute to the recovery of the population. As for the young found dead in the last decade, they cannot begin to breed. “These premature deaths jeopardize the ability of this isolated population to increase over the next few years,” argues Véronique Lesage.
Added to this are the potential effects of global warming on the St. Lawrence, which remain difficult to predict for the time being. We know, for example, that rising temperatures can have consequences for the fish stocks that belugas feed on. And we are already seeing a marked decrease in the ice cover in winter in the estuary and the gulf. However, these animals from the Arctic need it to protect themselves from winter storms.
The question of the constant “disturbance” suffered by these cetaceans in the estuary also remains topical. Whether it’s merchant shipping, boaters, cruisers, kayakers, or industrial work in the species’ habitat, all of these factors can interfere with feeding, communication, or laying. down.
In short, emphasizes Robert Michaud, “in the long term, the beluga has not emerged from troubled waters”. A healthy population should double every 30 years, says the man who has studied the species for four decades. However, in this case, we speak at most of “a certain stabilization”.
“We had a huge impact on this population, first with hunting, then with contaminants and stressors. And it’s now a fraction of where it should be. She needs our good care. We do not have the luxury of changing the status of the population, which is currently considered endangered. We must show wisdom and caution,” concludes Robert Michaud, recalling the importance of the expansion project for the Saguenay—St. Lawrence Marine Park. Quebec and Ottawa have promised to carry out the project, which will protect all the summer habitat of the small cetacean, by 2025.