For their study, biologists captured seal pups during the month of May. They installed a pyramid tag on their head, similar to a small yellow hat. Then another tag on one back palm, and on the other, a three-centimeter-long acoustic transmitter.
The research team weighs the young seals, measures the pups and then releases them into the St. Lawrence. Some individuals will also be equipped with a satellite transmitter that will remain attached to their head for a few months.
During the rest of the summer season, as well as in the fall, researchers go to the São Lourenço River to locate seal pups wearing numbered yellow hats, in particular to quantify the survival rate of populations in the estuary.
The Maurice-Lamontagne Institute team, located in Bas-Saint-Laurent, also collects data collected by acoustic receivers located at Bic and Métis-sur-Mer. With the help of satellite transmitters, biologists will be able to better understand the movements of seal pups.
little studied population
The team is looking for clues about the health of the seal population in the estuary. The researchers are interested in it because it is an emblematic species of São Lourenço, from one shore to the other.
The seal is a very charismatic species.says researcher Xavier Bordeleau, from the Maurice-Lamontagne Institute, who specializes in seal trophic and spatial ecology.
Along with the beluga, it is the only marine mammal species that lives all year in São Lourenço. In addition, it is a species that can be seen as a sentinel of its ecosystem due to its sensitivity to anthropogenic and environmental disturbances.
In addition, the increasing population of gray seals in the Gulf of São Lourenço is increasingly attracting the attention of researchers. Technologies implemented during the study can help document the interaction between the two species.
New technologies under study
The research program also serves to test new technologies, as access to seals in the region is generally easy. The technologies developed during this program could then be used in studies of populations of marine mammals that are more difficult to access.
A new technology is being studied during this research program, 180 kHz acoustic telemetry. This is a device installed on the pup, which emits a frequency that is outside the seals’ hearing capacity.
Using acoustic transmitters and acoustic receivers installed at Bic and Métis-sur-Mer, researchers can obtain data on young seals in real time, 24 hours a day, seven days out of seven.
” This allows us to understand that when an animal is detected in two different seasons, it requires some movement. Therefore, we know that this animal has been alive since the last time it was detected. »
There are animals that went to Forillon Park and are now in New Brunswick. Some spend time in Trois-Pistoles and Baie-Comeau. They move a lot during the summer.observes researcher Xavier Bordeleau.
There is a part of the puppies that stay more locally. They make sea voyages to feed, but still regularly return to the colonies of Bic and Métis.
a growing population
Fisheries and Oceans Canada’s last aerial survey in 2005 reported approximately 650 individuals in the Gulf and Estuary of St. Lawrence. A new aerial inventory took place in 2019.
individus, dont plus de 2000 qui se trouvaient dans l’estuaire”,”text”:”En tout, dans le golfe et dans l’estuaire, on a vu un peu plus de 5500individus, dont plus de 2000 qui se trouvaient dans l’estuaire”}}”>Altogether, in the gulf and estuary, we saw just over 5,500 individuals, including over 2,000 that were in the estuary.comments the researcher specializing in marine mammals at the Maurice-Lamontagne Institute Arnaud Mosnier.
So we can very broadly say that there seems to be an increase in populationhe says.
Data collection will take place throughout the summer, until the researchers retrieve the acoustic receivers in October. The publication of the first year of data collection is scheduled for the end of 2022.