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North Atlantic right whale population drops to about 340, worrying scientists

A North Atlantic right whale entangled in fishing rope with a newborn calf near Cumberland Island, Ga., last year. (Georgia Department of Natural Resources/AP)
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For more than 40 years, a group of researchers in New England have kept tabs on hundreds of critically endangered North Atlantic right whales they’ve come to know by name. They’ve taken millions of photographs of these whales by sky and sea, often tracking when they have given birth, been injured and who their mothers, siblings, cousins and grandparents are.

But, much to their dismay, the North Atlantic right whale population has slid to a low not seen since about 2001 — a steady decline that has continued for more than a decade, according to the North Atlantic Right Whale Consortium. That’s largely due to climate change and lethal, human-caused accidents, the experts say.

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New numbers from the group, released Monday, suggest that only about 340 of the whales were alive as of 2021, a sharp decline from the nearly 500 recorded in 2010. (Researchers track the whales by photographing them year-round, and their estimates are often released with a small range of error.)

“These whales have been plying these waters for tens of thousands of years, and they have an inalienable right to continue to be able to do so,” said Philip Hamilton, a senior scientist at the New England Aquarium who has been tracking North Atlantic right whales for more than three decades. “A lot has happened in the last decade — increased mortality, decreased reproduction, and they’re having to change when and where they’re feeding due to climate change.”

As the story goes, right whales were given their names because they were the “right” whales to hunt hundreds of years ago, when blubber was a key good for trade. Members of the North Atlantic species weigh up to 70 tons, grow as long as 55 feet and are thought to live for up to 70 years.

The whales are “iconic” in New England, Hamilton said, and they can be found anywhere along the coast from eastern Canada to Florida. Their population rebounded from fewer than 300 in 1990 to nearly 500 in 2010, though it’s not entirely clear why; the population could have fluctuated because of natural cyclical patterns that affected the supply of zooplankton, their primary diet, he said.

“It’s a very, very complex ecosystem that changes with temperature, primarily, but also salinity,” he said. “We expect to see some of those cyclic fluctuations in food abundance in different areas.”

Nevertheless, Hamilton said this pattern has not been “bouncing back” since 2010.

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Warming water temperatures caused by climate change are affecting where zooplankton multiply in abundance, which has in turn been driving North Atlantic right whales into areas with fewer regulatory protections in recent years. For example, many whales were killed by entanglements and vessel strikes in the Gulf of St. Lawrence, Hamilton said, spurring Canada to begin adopting measures to manage ship traffic during certain parts of the year. Meanwhile, it is illegal to get closer than 500 yards from right whales in U.S. waters.

About 85 percent of North Atlantic right whales have been entangled at least once, and researchers are able to tell when one has been injured by fishing ropes because of the scars. According to Hamilton, female whales in this species often stop reproducing if they’ve suffered severe entanglements, or they may produce calves once every six to seven years instead of the usual three.

Just 15 calves were born in 2022, the North Atlantic Right Whale Consortium said in the report, a substantial decline from the average of 24 per year in the early 2000s.

“We need to enhance their health and survival by slowing and rerouting vessels to minimize vessel trauma,” said Michael Moore, a senior scientist in the biology department at the Woods Hole Oceanographic Institution in Massachusetts. “To avoid the risk of entanglement trauma, we must remove fishing lines from the water column,” he added, referring to the vertical expanse between the ocean surface and floor.

Scientists around the world have begun developing ropeless fishing systems that would eliminate the lines that connect crab or lobster fishing gear to buoys marking their location on the ocean’s surface. In Massachusetts, researchers have begun testing “virtual buoys” that track the location of fishing traps and trigger them to rise to the surface using acoustic signals.

“There are legislative, financial and technical hurdles that have to be overcome before it can be used on a really broad scale,” Hamilton said. “But it has advanced really quickly in the last four to five years in response to the dire situation for whales.”