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Why Was There a Sudden Population Crash for Rare Whales?


Climate change is the silent force behind the sudden decline in the population of North Atlantic right whales, according to a new study that supports a growing body of research on why critically endangered animals are shifting from slow recovery to alarming decline.

Analysis of data on plankton, ocean conditions and whale sightings, It was published Wednesday in the journal Oceanography.showed that whales left their traditional feeding grounds in the Gulf of Maine in 2010, the same year that warmer waters caused the oily crustaceans they ate to decline in the area.

Most of the whales eventually migrate their food north to St. Lawrence, but protection from fishing gear and the ships protecting them in their previous habitat was not available in the new ones. The leading cause of death for North Atlantic right whales is entanglement in gear, followed by collisions with ships.

“They moved so quickly that our policies didn’t move with them,” said Erin Meyer-Gutbrod, a quantitative marine ecologist at the University of South Carolina and one of the study’s authors. “The environment is not as predictable as it used to be, so I think we all need to think more.”

Worse, the researchers found that the decline in crustaceans led to a decrease in reproductive rates. Dr. “We’re slowing their births and increasing their death,” Meyer-Gutbrod said. “You don’t need to be a super mathematician to predict what this change will lead to.”

Scientists counted only 356 people remaining.

The research helps explain why deaths increased in 2017, and marine mammal officials said:unusual death event“still in effect. Whales tend to get tangled in ropes used for crab and lobster fishing. The ropes can suffocate them, sever parts of their bodies, or cause slow death from malnutrition or swimming.

Canadian officials responded add protection st. Lawrence, including speed restrictions for ships and the temporary closure of certain fishing areas if a whale is spotted. On Tuesday, NOAA Fisheries new rules announced To catch lobster and Jonah crab in American waters, the pointer aims to reduce the number of lines from buoys to traps. They also weaken the lines so that entangled whales can be released.

Conservationists have reacted with disappointment to the long-awaited rules, criticizing them for falling too far behind what the whales need.

According to the authors of the study, the most effective solution would be to switch to ropeless fishing gear. “It would have had a tremendous impact,” said Charles Greene, a senior fellow at Ocean Visions, a research and advocacy group, and one of the study’s authors.

Fishermen worry that such gear is excessively expensive and less efficient. The key, say activists and researchers, is making the equipment attractive to them.

A former professor of earth and atmospheric sciences at Cornell University, Dr. “We have to figure out how to properly fund it so they can make this technological change,” Greene said. “That’s what drives people to put rooftop solar on their homes.”

Various speed restrictions exist in United States waters to protect whales from collisions, but operators often disregard the rules. According to research by the nonprofit Oceana.

Perhaps 10,000 true whales swam in the North Atlantic before widespread whaling arose. Because they move slowly, stay close to shore, and swim when they die, they were considered good hunting targets, and they obtained copious amounts of oil and bales. According to the International Whaling Commission. In the 1890s, the species was hunted to near extinction. But the number of whales slowly recovered after the ban on commercial whaling and reached around 500 before the current decline took place.

Previous research has suggested that: plankton loss and warming water It had encouraged whales to move, but this study provides the strongest example of human-induced climate change causing a reduction in prey, driving whales into new areas and causing a decline in reproductive rates.

“While it is distressing because of the ultimate danger faced by whales, it is not surprising that they seem to be moving north in response to these changes,” said Jaime Palter, professor of oceanography at the University of Rhode Island. study.

The distinctive calluses on the heads of the whales, the researchers said. document each individual.

Although their natural lifespan is around 70 years, the dead are inevitably much younger when found. The most recent victim was an 11-year-old male known as Cottontail. Found dead off the coast of South Carolina in February. The researchers had been tracking him since October, with his head and mouth seen tangled in a line running three or four body lengths behind his back.

Scientists say there is hope for whales. No more than nineteen calves have been born this year since 2013. Dr. Meyer-Gutbrod said she thought their mother had somehow found more food.



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