The year 2021 was marked by a record number of sightings of humpback whales and fin whales in the Saguenay – St. Lawrence Marine Park. While this is excellent news for cruise passengers and tourists, experts are wondering about this abnormal concentration of cetaceans, especially since several sectors of the St.Lawrence seem to have been neglected by these animals in search. of food.
According to “preliminary” data provided to the To have to by Parks Canada, more than 100 humpback whales were sighted in 2021 in the marine park sector alone. By comparison, for the period from 2008 to 2017, the annual average was five individuals, a figure which reached 26 in 2019, then 21 in 2020. A marked increase was also observed for fin whales, with more 50 individuals in 2021, compared to 29 in 2020 and an annual average of 14 for the period from 2008 to 2017.
“This is an unprecedented growth in the number of whales” in the marine park and in the western portion of the St. Lawrence estuary, summarizes Christian Ramp, researcher specializing in the study of whales at the Scottish Oceans Institute of the University of St Andrews.
A cetacean specialist at Fisheries and Oceans Canada, scientist Véronique Lesage also judges that this year’s results are “impressive”. However, she wonders about the reasons for this concentration of whales in a relatively small region of the estuary.
“This year’s data cannot be explained by population growth alone. The jump this year, which is gigantic compared to other years, must be explained by something else. The trail of explanation may lie on the side of a lack of food elsewhere. “
An ecosystem that is impoverished?
You should know that the whales that frequent the waters of the St. Lawrence are there mainly to feed. Different species also need large amounts of food. Humpback whales and fin whales, for example, can eat several hundred kilograms of fish, such as capelin or sand lance, every day.
In normal times, we therefore find several individuals of these species in different sectors of the estuary and the Gulf of St.Lawrence, which does not seem to have been the case this year, specifies Mr.me The wise man. “We went for a walk in the northwestern gulf and the eastern estuary, but we couldn’t find anything. The whales all seemed to be gathered in the marine park, ”she noted during her research on the waters of the St. Lawrence.
A point of view shared by Christian Ramp, stressing that tourists have surprisingly observed few cetaceans off Gaspé. Humpback whales, well known to researchers in other regions, have also been observed exceptionally in the marine park. This is the case with Fleuret, a female that the Mingan Islands Research Station (MICS) team has known since 1982. She was seen this summer for the first time in the estuary, says Mr. Ramp.
This exceptional situation raises questions that remain unanswered for the moment, adds Véronique Lesage. “If there was food elsewhere, we would see animals there. This is good news for cruise passengers in the Marine Park, but I don’t believe it is an encouraging sign for the ecosystem in general. It is possibly symptomatic of an ecosystem which is impoverished. Was there a food problem in the gulf that caused the animals to move towards the estuary? This is a hypothesis, but I have no data to analyze it. “
A MICS collaborator for several years, René Roy observed that blue whales were very few in number in areas where he observed them systematically. “It’s totally unusual,” he drops. Despite 29 days of sea trips in the estuary and off the tip of the Gaspé, he only observed seven individuals of this species classified as “endangered” in Canada. By comparison, he observed 63 in 2018, 66 in 2019 and 25 last year.
Restless animals
However, Mr. Roy was able to see several dozen humpback whales, most often grouped together in the same sector. He indicates in passing that these whales were usually calm, unlike the more spectacular behaviors observed in the marine park: repeated jumps out of the water, blows given on the water with the fins, episodes of ” trumpeting »(Sounds produced by the expulsion of pressurized air through the closed vent), etc.
While he stresses that it is not possible to determine with precision what explains these behaviors on the part of humpback whales, Christian Ramp believes that it cannot be ruled out that these, observed very often this summer, are linked to “disturbance”. »Suffered by animals throughout the summer season in the marine park. Several observation cruise ships and pleasure boaters circulate there, as well as freighters, container ships and tankers that use the St. Lawrence Seaway.
Mr. Ramp also says that this year he observed various spectacular behaviors during a day when excursion boats were very present near the humpback whales. “In July, I was in the marine park area, and I couldn’t get close to the [cétacés] because the observation industry takes precedence. But you could hear them doing trumpeting and jumps, but also swim quickly and dive quickly. There were about 30 whales in the area. The next day, I[en ai] saw about thirty a little further downstream, all of whom were sleeping. “
“I believe that the constant presence of boats around them, with the noise they cause, can disturb them,” adds Christian Ramp, who has been studying humpback whales in the St. Lawrence for several years. René Roy is also of the opinion that it would be relevant to “reflect” on the consequences of the observation industry, which is omnipresent in the marine park.
Could the increased presence of whales in the marine park justify new protection measures? “We are currently working on the evaluation of measures specific to the lower estuary sector,” replied Parks Canada. A “scientific opinion” should also be published “soon”. It “will provide food for thought on the implementation of new measures”.