Migration patterns of endangered North Atlantic Right Whales have changed rapidly in recent years, inspiring waves of research from the oceanic academic community. Credit: Georgia Department of Natural Resources Permit 15488
BAR HARBOR – Todd, a collaborator on a 10-year North Atlantic Right Whale (NARW) study utilizing hundreds of acoustic-based, underwater monitoring devices, says the evidence shows that right whales are rapidly changing their migration habits, and spending more time in unexpected areas along the East Coast and up in Canadian waters.
These new migration patterns explain the recent, sharp increase in fatal human-whale interactions, but also point towards potential solutions, Todd says.
College of the Atlantic Steven K. Katona Chair in Marine Sciences Dr. Sean Todd“These new regions where we find right whales have not yet had time to develop appropriate conservation measures that would otherwise ensure these whales’ protection,” Todd says. “Using this new knowledge, I hope we can work toward legislation that will modify those activities—such as shipping and fishing—in places where whales might be present.”
The study, “Long-term passive acoustic recordings track the changing distribution of North Atlantic right whales (Eubalaena glacialis) from 2004 to 2014” (Nature Scientific Reports), is the first that is large enough to show right whale movements over the entire eastern seaboard of the United States and Canada. Over 20 different sources contributed either expertise or data to this project, which was coordinated by Sofie Van Parijs and Genevieve Davis at the National Oceanic and Atmospheric Administration.
Recent, rapid changes in migration patterns of NARWs, which have accompanied an equally rapid rise in water temperatures in the Gulf of Maine, led to a devastating 17 NAWR deaths in 2017, largely from fishing rope entanglement or ship strikes. While current regulations protect whales by limiting fishing, cargo transport, and other activities in areas where they traditionally live, there are fewer regulations in the areas to which they now migrate.
Real-time acoustic monitoring systems now exist that can send out a signal when right whales
are detected in the area, allowing the Coast Guard and other organizations to request nearby
ships slow down, or avoid the area, Todd says. The acoustic study demonstrates interventions
like this are necessary and urgent, he says.
“Tracking whale migration is progress towards their survival, but we still have not answered the question, ‘Why are these changes taking place?’” - Dr. Sean Todd.
“Whale migration is shifting so rapidly that it is difficult to place preventative measures within an effective time frame,” Todd says. “Hopefully, real-time acoustic monitoring and our improved knowledge of right whale movements will lead to fewer deaths in the future. Luckily, we are seeing this effort expand across borders and institutions. This is a multinational effort, and needs to remain so.”
NARWs have been declining in health and numbers since 2010. Out of the mere 450 in
existence, there were 17 confirmed deaths in 2017, and only 5 new calves born.
The northern Gulf of Maine, which used to see many right whales during the summer, has seen very few in recent years, while the numbers in Cape Cod Bay have risen dramatically. In April 2017, an aerial survey of Cape Cod Bay spotted 206 whales, almost 40% of the population. The Gulf of Saint Lawrence has also seen an increase in right whales.
The Gulf of Maine is one of the fastest warming bodies of water anywhere on the planet,
according to scientific studies, and Todd hypothesizes that the warming may be a significant
contributor to NARW migration pattern shifts.
Advances in technology are helping scientists use recorded data of North Atlantic Right whale vocalizations to track migration patterns. Credit: Georgia Department of Natural Resources Permit 15488The new presence of NARWs in the Gulf of Saint Lawrence has proved detrimental to the
population of the species. From 2009 to 2013, an average of 4.3 whales were killed annually in U.S. and Canadian waters. In 2017, 12 of the 17 deaths occurred in Canadian waters. These
mortalities were caused largely by whales becoming entangled in fishing gear, or getting hit in shipping lanes.
For Davis’ meta-study, data were collected from 2004 through 2014, using 324 recording devices placed up and down the East Coast. These devices perform what is called passive acoustic monitoring (PAM), which uses audio recording to detect whale vocalizations. Once collated, the data can then be used to show right whale movements.
Other tracking techniques include visual surveys but, “you’re dealing with animals that don’t spend a lot of time at the surface. They dive down for long periods of time,” says Bort Thornton, whose Master’s work at COA revolved around passive acoustics and helped confirm the presence of a right whale breeding ground in the central Gulf of Maine.
North Atlantic Right Whale. Browse more maritime art at Matt Messina Illustration. Credit: Matt Messina ’16“Visual surveys are great … but they can only be done when there’s good weather, good visibility. If the sea state is bad, or there is fog, your detection probability goes way down,” she says.
PAM can monitor an area constantly, even when conditions are too rough for humans to observe firsthand, Bort Thornton says. Scientists can thus track whale presence throughout the year, regardless of weather, gaining far more information about their movement patterns.
Nearly three-dozen scientists, including COA alumni Jacqueline Bort Thornton MPhil ’11, Julien Delarue MPhil ’08, and Scott Kraus ’77, helped co-author the PAM study. Previous studies in this field would never have seen so much collaboration, which “allowed the paper to answer some really interesting questions. Genevieve [Davis] did a superb job putting this all together,” Todd says.
Having finished up his work with PAM for now, Todd and his team at Allied Whale, the marine
mammal research program at College of the Atlantic where Todd is the director, are moving
towards a study of the oceanographic conditions in the Gulf of Maine. Todd is worried that the
changing temperatures in the Gulf may be affecting plankton, the whales’ source of food.
“Tracking whale migration is progress towards their survival, but we still have not answered the
question, ‘Why are these changes taking place?’” Todd says. “We are responsible, and I think part of what it is to be human, is to be able to take responsibility for those actions, and to try to change.”
