Event causing alarming number of whales to die and wash up on Bay Area beaches is over: scientists

Some of the images in this story could be disturbing to some viewers

ByTim Johns KGO logo
Thursday, March 28, 2024
Event causing Bay Area whale mortalities is over, scientists say
The number of gray whales dying and washing ashore hit alarming rates. After first declaring an unusual mortality event, scientists believe it's over.

SAN FRANCISCO (KGO) -- For the past several years, the number of gray whales dying and washing ashore along the West Coast has hit alarming rates.

But now, after first declaring an "unusual mortality event" or UME back in 2019, scientists believe it's finally over.

"I wasn't surprised by the closure because we've been collecting the data and we've been involved in all the meetings discussing the decline and then the stabilization of the population," said Moe Flannery.

Some of the images in this story could be disturbing to some viewers

RELATED: Scientists hope necropsy data will reveal cause of gray whale deaths

Flannery works with the California Academy of Sciences and was one of the local scientists who would do necropsies on dead whales that washed ashore.

MORE: Whale spends record 10 weeks in SF Bay. Here's why it's concerning scientists

Moe and her partners at the Marine Mammal Center say they think climate change was one of the main reasons driving the UME.

"In the arctic where there's been all this change in the amount of ice coverage and warming there, it looks like it's affected their food supply," said The Marine Mammal Center's Bill Keener.

Researchers think with less food available for the whales in their normal feeding grounds, many didn't have the strength to make their annual migration and ultimately died.

MORE: Gray whale that spent at least 75 days in SF Bay dies after hit by vessel, malnutrition, experts say

Recently, though, they say the whales have adapted.

"We saw for the first time, gray whales switching their prey and feeding on fish," Kenner said.

The UME may be over but local experts say there are still risks to the gray whale population. They tell us things like ship strikes remain a real and dangerous threat to the creatures.

MORE: Scientists hope warning system along NorCal coast will protect whales from ship strikes

Scientists hope a newly implemented warning system along the California coast will protect passing whales from deadly ship strikes.

Beyond ship strikes, scientists say the risk of the UME reoccurring is also a possibility.

That's why they'll continue to monitor the animals and be on high alert for any changes.

"We've moved from the unusual mortality event to a post UME, or a post unusual mortality event monitoring phase. So the high numbers have decreased but we will likely still see dead animals," Flannery said.

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