A new study claims that the climate crisis was to blame for whales getting stuck in crab fishing lines in 2015 and 2016 off the California coast, resulting in death or injury to the marine mammals in at least 50 instances.
The report, "Habitat compression and ecosystem shifts as potential links between marine heatwave and record whale entanglements," was published in the science journal Nature Communications on January 27.
"Increasing climate variability means increased uncertainty," study lead author Jarrod Santora told the Guardian.
Why were whales increasingly caught in crab lines? Because of the climate crisis https://t.co/0lVWrkjqXn— The Guardian (@guardian) February 1, 2020
Santora, a University of California Santa Cruz ecologist, told the paper that the marine heatwave nicknamed the "blob" that warmed waters off the California coast pushed the whales closer to the shoreline and into the nets. The blob heatwave laster from 2013 to 2016.
As the Guardian reported:
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The upwelling in 2015 and 2016 shrunk to just a narrow band along the coast, causing organisms to cluster there. Due to a heatwave-related decline in krill, whales switched to feeding on anchovies in shallower and shallower waters. In addition, the crab fishing season—an $88m industry on the US west coast—had been delayed from November to April, and came to coincide with the whales' presence.
"There were thousands of whales and thousands of crab pots going out, so [this] was a perfect set of events to cause entanglements," said Santora.
The increase in whales off the coast is also the result of "successful management and acts put in place in the 1960s and 1970s like the Endangered Species Act and the Marine Mammal Protection Act," said Santora.
"The grey whales are the highest they've ever been," Santora said, "and humpback whales have remarkably rebounded."
The study's authors argue that with that rise in populations in mind and the climate crisis continuing to warm the oceans, whales should be protected. And the protection need not come at the cost of California's fishing industry.
"Cooperation of fishers, resource managers, and scientists could mitigate future entanglement risk by developing climate-ready fisheries approaches, while supporting thriving fishing communities," reads the study.