Endangered right whales can be found year-round in the Gulf of St. Lawrence, a study has found
North Atlantic right whales are spending more time in Canadian waters, according to a recent study, information that could help save the species from extinction.
A group at Dalhousie University studied acoustic data of distinctive whale calls from 2015 to 2017 in hopes of mapping the whales’ northernmost points in Canadian waters.
Scientists say the more they learn about the movement and preferred habitats of whales, the better they can prevent right whale deaths from human activities such as entanglement in fishing gear or ship attacks.
Organizations in the United States and Canada have taken extensive measures to protect the whales from further harm in recent years, but 2023 has already been a tough year for the endangered mammals, with four new entanglements and two deaths.
One of the most surprising findings, said Delphine Durette-Morin, who completed the study as a master’s student at Dalhousie, is how active right whales are in the Gulf of St. Lawrence almost year-round — from May to December, not just in the summer months.
“This continued presence is really important because it suggests that the whales … are using the Cabot Strait as a migratory corridor in a more continuous way,” said Durette-Morin, now an assistant scientist at the Canadian Whale Institute. This has implications “for their conservation because this area is a major choke point for the whales and large ships that transit this area.”
Habitat generally extends from Florida to the Gulf of St. Lawrence, according to Durette-Morin, and prior to 2015 there was a lack of monitoring efforts in these northern waters. There have also been sightings as far away as Greenland.
Their study used a vast network of underwater microphones called hydrophones from four different Canadian organizations to collect audio recordings from right whales over a two-year period.
Durette Morin tells Information tomorrow Moncton These hydrophones were located at a range of 67 moorings and 13 acoustic glider sorties ranging from the Bay of Fundy to the Labrador coast.
The passive recording of the right whale’s calls, known as upcalls, was not intended to track how many whales were in the area, but instead to find migratory corridors or patterns.
The study involved analysis of over 20,000 days of audio recordings and was conducted with the digital assistance of an automated detector.
“When we hear an up call in a recorder,” Durette-Morin said. “We know that there was at least one right whale in this location at the time, and that can give us an idea of the temporal and spatial distribution. That can be used as a minimum occurrence of right whales.”
The population of the North Atlantic right whale is estimated at 340, according to the North Atlantic Right Whale Consortium. They generally migrate south to the coasts of Georgia and Florida in the winter and further north along the east coast of the United States and Canada during the summer months.
The vastness of their habitat and its constant changes pose a challenge for organizations trying to protect the whales.
“It’s important to have information about the distribution of a population,” Durette-Morin said. “Specifically to know or identify areas where there are potential overlaps with man-made risks.”
Various fisheries, shipping lanes, and even tourism are all human activities that potentially pose a risk to right whales.
Jean-Francois Gosselin, biologist at Fisheries and Oceans Canada, said Fisheries and Oceans Canada is implementing a “systemic surveillance program” based on research showing an increasing presence of North Atlantic right whales in Canadian waters, particularly in the Gulf of St. on Canada’s east coast to track the whales.
He said of the approximately 340-350 remaining North Atlantic right whales, around 130-140 individual whales have been spotted in the Gulf of St. Lawrence since 2018.
Fisheries and Oceans Canada dispatches aircraft for aerial surveillance of right whales over the southern Gulf of St. Lawrence about 10 times a year from April to November. They then extend the search to the rest of the East Coast, alternating one of two regions to see if they can find more aggregations of right whales.
Gosselin also said aerial surveillance will be carried out in combination with acoustic detection methods and sightings will be transmitted by research vessels or the Coast Guard, and the data will be collected to add to a database shared by other research and conservation groups.
The detection of right whales near shipping lanes or fishing grounds can also trigger real-time management strategies.
“All of these right whale sightings are reported there as in the central database which is used to identify the areas where sightings were discovered and then management action is taken the next day.”
When a fishing area is temporarily closed due to the discovery of right whales, DFO conducts aerial surveillance for the following 15 days to ensure the whales have cleared the area. If they’re spotted between days nine and 15, the area could be closed for the remainder of the season, Gosselin said.
Amy Knowlton, a senior scientist at the New England Aquarium, said acoustic monitoring of right whales is just one of the tools scientists are using to try to gauge the whales’ presence, but it’s an important one nonetheless, and this study underscores the importance of not being the only one rely on visual detection, which is often just a snapshot of right whale activity on a much larger scale.
“Maybe we need to expand our management scope,” Knowlton said. “So we’re not just focusing on these aggregation areas to take action, but recognizing that the threats are widespread and trying to develop ways to address that in a more comprehensive way.”
She gave the example of the Canadian snow crab fishery in the Gulf of St. Lawrence, which she says has started using on-demand gear or ropeless fishing to avoid having a buoy line in the water all the time, thereby reducing risk will the whales get tangled.
Knowlton hopes that expanding the use of such technologies can save the North Atlantic right whale from extinction.