Endangered right whales can be found in Gulf of St. Lawrence all year, study finds
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 looked at acoustic data from the distinctive whale calls, from 2015 to 2017, in the hope of mapping the northern-most points of the whales in Canadian waters.
Scientists say the more they are able to learn about the movement and preferred habitats of the whales, the more they will be able to prevent right whale deaths from human activities, such as entanglements in fishing equipment or ship strikes.
Organizations in the United States and Canada have taken extensive measures over the past few years to try to protect the whales from further harm, 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 the right whales are in the Gulf of St. Lawrence almost all year — from May until December, not just in the summer months.
"This continuous presence is really important because it suggests the whales are using ... the Cabot Strait as the migratory corridor in a more continuous fashion," said Durette-Morin, now an assistant scientist at the Canadian Whale Institute. That has implications "for their conservation because that area is an important bottleneck for basically the whales and large ships that are crossing that area."
The habitat, according to Durette-Morin, generally extends from Florida to the Gulf of Saint Lawrence, and before 2015 there was a lack of monitoring efforts in those northern waters. There have also been sightings as far north as Greenland.
Her study used a vast network of underwater microphones called hydrophones from four different Canadian organizations to gather sound recordings of right whales over the two-year period.
Durette-Morin told Information Morning Moncton those hydrophones were on a series of 67 moorings and 13 acoustic glider deployments that ranged from the Bay of Fundy to the coast of Labrador.
The passive recording of the right whale's calls, known as upcalls, was not meant to track how many whales were in the area, but instead find migratory corridors or patterns.
The study involved analyzing audio recordings equivalent to over 20,000 days and was done with some digital assistance from an automated detector.
"When we hear an upcall in a recorder," said Durette-Morin. "We know that there was at least one right whale present at that time, in that location, and that can give us an idea of the distribution through time and space. That can be used as the minimum presence of right whale occurrence."
The population of the North Atlantic right whale, according to the North Atlantic Right Whale Consortium, is estimated to be 340. They generally move south to the coasts of Georgia and Florida during the winter, and further north, along the east coast of the United States and Canada during the summer months.
The breadth of their habitat, and its constant changes, is a challenge for organizations trying to protect the whales.
"It's important to have characterized distribution information about a population," said Durette-Morin. "Especially to know or to identify areas where there's potential overlap with human induced risk."
Various fisheries, shipping lanes and even tourism are all human activities that potentially pose a risk to the right whales.
Jean-Francois Gosselin, a biologist at Fisheries and Oceans Canada, said that based on research showing an increased presence of the North Atlantic right whales in Canadian waters, particularly in the Gulf of St. Lawrence, Fisheries and Oceans Canada has started a "systemic surveillance program" of Canada's east coast in an effort to track the whales.
He said of the approximately 340-350 North Atlantic right whales left, around 130-140 individual whales have been detected in the Gulf of St. Lawrence since 2018.
Fisheries and Oceans Canada sends aircraft to do aerial surveillance of right whales over the southern Gulf of St. Lawrence around 10 times a year, from April to November. They then extend the search across the rest of the east coast, doing one of two regions on alternating years in order to see whether they can find more aggregations of right whales.
Gosselin also said the aerial surveillance is done in combination with acoustic detection methods, and submitted sightings from research vessels or the coast guard, and the data is gathered to add to a database shared among other research and conservation groups.
The detection of right whales near shipping lanes or fishing areas can also trigger management strategies in real time.
"All of these right whales sightings are reported in there like in the central database that is used to identify the areas where sightings have been detected, and then management measures are put in the following day."
If a fishing area is temporarily closed because of the detection of right whales, DFO will do aerial surveillance for the following 15 days in order to ensure the whales have left the area. If they are detected between days nine and 15, Gosselin said, the area could be closed for the remainder of the season.
Amy Knowlton, a senior scientist at the New England Aquarium, said acoustic monitoring of right whales is only one of the tools used by scientists to try to gauge the presence of the whales, but still an important one, and this study highlights the importance of not relying entirely on visual detection, which are often only a snapshot of much larger scale right whale activity.
"Maybe we need to broaden our scope of management," said Knowlton. "So we're not just focused on these aggregation areas for putting in measures, but we're recognizing that the threats are broadly distributed and try to develop ways to sort of tackle that in a more comprehensive fashion."
She gave the example of the Canadian snow crab fishery in the Gulf of St. Lawrence, which she said has started to use on-demand gear or rope-less fishing to avoid having a buoy line in the water all the time, lessening the risk of the whales becoming entangled.
Knowlton hopes that broadening the use of technologies like that can keep the North Atlantic right whale from extinction.