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The year 2023 marks the 40th anniversary of the listing of the St. Lawrence beluga on the list of species at risk in Canada. However, despite the abundance of scientific work on this cetacean and the implementation of a recovery program, its decline continues. A symposium is taking place this week in Montreal to try to foresee the future of this environmental sentinel.
This scientific meeting takes place 35 years after the International Forum for the Future of the Beluga, which had made it possible to “sound the alarm”, recalls the scientific director and co-founder of the Research and Education Group on marine mammals (GREMM), Robert Michaud.
“The beluga drew our attention to the poor state of the St. Lawrence and it was used as leverage to start initiatives to clean it up. His tragic situation mobilized us in the face of the urgency of the situation,” he explains, on the eve of the Beluga Symposium 2023, which takes place from Wednesday to Friday at UQAM.
It should be remembered that at the time, this species, first decimated by decades of hunting, was now a victim of industrial pollution, omnipresent in the St. Lawrence and the Saguenay, and therefore at the heart of its habitat.
Cancer
The cases of cancer were particularly numerous. A study published in 2002 in Environmental Health Perspective had also shown that cancer was the cause of the death of 18% of young belugas and 27% of adults found dead between 1983 and 1999 whose carcasses had been analyzed at the Faculty of Veterinary Medicine of the University from Montreal.
“Such a percentage has never been observed in any wild animal population anywhere in the world. To our knowledge, this is the first time that a cancer rate comparable to that prevailing in humans has been documented in wild mammals,” explained co-author Daniel Martineau, from the Faculty of Veterinary Medicine of the Montreal university.
The researchers had also established a link between these data and polycyclic aromatic hydrocarbons (PAHs), which contain powerful carcinogens, found in the sediments of the Saguenay. It has been shown that these compounds were emitted by aluminum smelters located at the source of the Saguenay River. And in the region, workers and citizens were also suffering from high rates of cancer.
The reduction in this type of contamination has gradually eliminated cases of cancer in beluga whales, animals that can live for sixty years. The last case was observed in 2011. But since then, female mortalities, especially during birthing, and those of young belugas have been a real black series.
“PAHs, PCBs and DDT have been replaced by other toxic products that are suspected of contributing to beluga whale deaths. The game is not won”, summarizes Robert Michaud. The population, which would number less than 880 animals, continues to decline year after year. From 2018 to 2022, for example, 74 carcasses were found. However, these individuals do not represent an exhaustive death toll.
Beluga Magic
“We have done things for belugas, but have we really changed? I wonder today what could motivate us. Beyond presenting the tragedy of the beluga, we could also talk about the magic of the beluga. Perhaps that could motivate us, because even today, they are still contaminated,” adds the scientific director of GREMM.
“They are absolutely fascinating social beings and we need a paradigm shift,” he continues, hoping that the Beluga Symposium will also highlight the richness of this social life. “We know, thanks to 40 years of research, that these are animals that have complex social behaviors, that can provide alloparental care, that have vocal repertoires that would confirm the existence of different communities of females, etc. »
The only cetacean residing year-round in Quebec waters also continues to “challenge us about the impacts of human activities” on the fragile ecosystem of the St. Lawrence. Presence of ships, dredging of sediments, contaminants in the water, variation in the abundance of prey and climate change, the factors that affect the beluga are numerous, emphasizes Robert Michaud. “Scientific vigilance remains essential.