Uncertain future of North Atlantic right whale linked to tiny food source

Scientists believe a change in the ocean caused a drop in the North Atlantic right whale population in recent years as the mammalssought new places to find food.

Nick Record, a senior research scientist at Bigelow Laboratory for Ocean Sciences in Boothbay, Maine, said the downward trend started in 2010.

At that time, researchers started noticing fewer right whales showing up in typical feeding areas in the Gulf of Maine and the Bay of Fundy.

This is because their main source of food was in decline, he said.

North Atlantic right whales began making headlines in2017, when at least 18 were found dead inU.S. and Canadian waters 12 off the Canadian coast.

• Right whales return early to Atlantic Canada while babies seen in U.S. waters

Necropsies found many of the whales had become entangled in fishing gear or were struck by ships, resulting in strict closures of fishing areas and speed limits on vessels.

But Record said the "star of the show" is actually a tiny crustacean smaller than a grain of salt, called calanus, also known as Calanus finmarchicus.

Calanus is the right whale's primary food source. There used to bean abundance of the tiny creatures in the Gulf of Maine and the Bay of Fundy.They float in the water by the billions.

"If you've been swimming in the ocean, you may have swallowed mouthfuls of it and that's what the whales are there doing," he said. "They're swallowing mouthfuls of it."

Record said the calanus is "the battery" of the Gulf of Maine and the Bay of Fundy because ithibernates and packs on a lot of fat for wildlife such as whales, herring and sea birds.

"It's sort of the last big meal before winter," he said.

Calanus like the cold

Record is the lead author of a paper published this month in the journal Oceanography, which links warming in the Gulf of Maine with the life cycle of calanus.

Since 2010, Record said, there have been changes to the ocean's conditions caused by climate change, including warming current systems coming into the Gulf of Maine and Bay of Fundy.

These warmer temperatures aren't good for the calanus, which thrive in cooler temperatures.

Without it, the whales don't have as much energy and have a harder time producing more calves.

• 3rd right whale calf spotted this season excites researchers

"That's what the whales like," he said. "They need to gain a lot of energy before the winter or if they're going to have calves."

The right whales showing up in unusually large numbers in the Gulf of St. Lawrence in the past few years, where the deaths in Canadian waters occurred, were likely trying to find areas with more calanus.

What happens now?

Record said both Canadian and U.S. scientists need to collaborate and look at oceanographic data to determine where the whales are headed next.

Currents are changing year to year and they can either "snap back" or continue to change.

Record said he can't forecast where the whales will be from year to year.

• Measures to protect North Atlantic right whales have been effective, official says

"Climate change isn't just a slow gradual march for future conditions," he said. "There are these fits and bumps and ups and downs along the way."

North Atlantic right whales have returned to Canadian waters early this year, according to the Department of Fisheries and Oceans, who recently spotted them via surveillance planein the Gulf of St. Lawrence.

The whales usually arrive in the region in June. So far, seven calves have been recorded so far south of the border in 2019.

North Atlantic right whales are an endangered species, with a population that has fallen to the low 400s in recent years. Only about 100 are breeding females.