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Scientists Report Rare Sightings Of Tropical Species Off West Coast

Scientists with the National Marine Fisheries Service spotted tropical pygmy killer whales off the coast of California for the first time this year.

Scientists with the National Marine Fisheries Service spotted tropical pygmy killer whales off the coast of California for the first time this year.

Courtesy of National Oceanic and Atmospheric Administration

Scientists surveying whales and dolphins on the West Coast have discovered unusual species of birds and marine mammals far north of their normal ranges. Experts say fish and wildlife are being drawn northward by unusually warm ocean water.

Every few years, scientists with the National Oceanic and Atmospheric Administration take a head count of whales, dolphins and porpoises in the ocean off California, Oregon and Washington.

Survey Leader Jay Barlow says this year’s team returned from the four-month trip last week with good news for whales – many populations are growing – but also a host of strange sightings.

“We had a lot of sightings of fairly tropical and warm water species that we wouldn’t see in this abundance and one species that has never been seen in California waters before – the pygmy killer whale,” Barlow said.

Pygmy killer whales are normally found in the waters around Hawaii and farther south. And they weren’t the only tropical visitors to the West Coast.

Scientists also saw tropical birds way up in the Pacific Northwest. They noted what may be first sighting of a band-rumped storm-petrel off the coast of Oregon. They also saw what they called an “unprecedented northward dispersal” of a warm-water seabird called the brown booby, which was spotted off the central coast of Washington.

Brown Booby
A tropical brown booby. Credit: Klaus Stiefel/Flickr

“That’s amazing,” Barlow said. “It’s rare in San Diego, so to see it off Washington is really, really unusual.”

NOAA research scientist Nate Mantua studies changes in ocean conditions. He says the survey findings aren’t all that surprising given how warm the West Coast ocean water has been. He and other scientists have been watching a blob of warm water in the Pacific all year.

“By October, the entire Northeast Pacific from Alaska all the way down to Mexico had temperatures that were 5 to 6 degrees Fahrenheit warmer than usual,” Mantua said. “This is a really large change in ocean conditions.”

Normally, water that warm would be tied to a strong episode of the cyclical ocean condition known as El Niño.

“This condition isn’t unprecedented,” he said. “It’s something that has happened mostly during extreme El Niño years. What’s unusual about this year is there’s no big El Niño in the tropics to point to as a cause.”

Mantua says he attributes the surge of warm water to a change in wind patterns. He’s not making a connection to climate change because scientists expect that kind of warming to happen more gradually.

But if the pattern continues, he says, the warm water will likely have a negative effect on West Coast salmon headed to the ocean next spring and summer.

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