Bird flu slams seals and sea lions at the bottom of the world but spares Pacific Coast so far

For the past twelvemonth and a half, Americans person watched and disquieted arsenic H5N1 vertebrate flu racked dairy herds and killed hundreds of millions of commercially raised chickens, turkeys and ducks.

But acold little wide known is that the microorganism has devastated wildlife crossed the globe, sidesplitting millions of chaotic birds and mammals.

Few animals person been harder deed than elephant seals, oversea lions and fur seals successful the Southern Hemisphere. In immoderate places thousands of carcasses and orphaned pups person littered the beaches.

On Thursday, a probe squad led by Connor Bamford, a marine ecologist with the British Antarctic Survey, reported a 47% driblet successful breeding females betwixt 2022 and 2024 successful the 3 largest elephant seal colonies connected South Georgia Island.

Elephant seals stricken with avian flu astatine 1 of South Georgia’s largest colonies.

(British Antarctic Survey)

The elephant seals of South Georgia Island, located betwixt South America and Antarctica successful the South Atlantic, are the largest breeding colony connected the planet.

The microorganism deed determination successful 2023, Bamford said, and researchers were determination to spot it. But it was their sojourn successful 2024 that truly drove the devastation home.

“Normally there’s astir 6,000 seals connected St. Andrews Bay,” helium said, describing a two-mile portion of formation on the northeastern broadside of the island. Usually it’s hard to marque your mode done the animals, it’s truthful jam-packed.

But successful 2024, “it was easy. There were monolithic gaps. There were truthful fewer of them,” helium said.

Other ample breeding colonies — including on the Argentinian coast, arsenic good arsenic respective different islands northbound of the Antarctic ellipse — person besides been hit. In 2023, UC Davis researchers reported that astir 97% of elephant seal pups died astatine Argentina’s Peninsula Valdes, the astir deaths ever recorded for this species.

According to Ralph Vanstreels, a marine ecologist with UC Davis who is researching the animals successful Argentina, two-thirds of confederate elephant seal colonies are present infected. Only those adjacent New Zealand and Australia person been spared.

“We’re conscionable holding our breath,” successful hopes the microorganism doesn’t get there, helium said.

Vanstreels said familial analyses amusement the strain of microorganism circulating successful Argentina acquired mutations allowing it to walk easy betwixt mammals. He said it’s not yet wide whether the microorganism that has deed different elephant seals and pinnipeds successful the portion carries the aforesaid mutations.

Nor does anyone cognize whether the microorganism volition determination northbound to populations on the California seashore — oregon into people.

But it’s near a deadly wake.

Reports of confederate oversea lions, fur seals and crabeater seals dying en masse person travel successful from crossed the region.

Vanstreels and Bamford accidental there’s nary mode to cognize the afloat grade of the virus’ toll connected these animals. Many of these species, specified arsenic crabeater seals, are truthful distant that determination are few, if immoderate quality observers to witnesser the devastation.

More than 30,000 oversea lions successful Peru and Chile died betwixt 2022 and 2024. In Argentina, astir 1,300 oversea lions and fur seals perished.

A researcher launches a drone connected the land of South Georgia, location to the world’s largest confederate elephant seal population.

(British Antarctic Survey)

Vanstreels said researchers don’t yet person immoderate wide thought astir wherefore bluish elephant seals and marine mammals successful the northbound Pacific, including those that breed on the California coast, person been spared.

He said the strain circulating disconnected the North American Pacific seashore doesn’t transportation the mutations seen successful South America, truthful that whitethorn beryllium why. There whitethorn besides beryllium differences successful colonisation densities oregon successful the section marine ecosystem.

“We deliberation the South American oversea lion played a large relation successful transmission, carrying the microorganism on the seashore and possibly introducing it to the elephant seal population,” helium said. “Maybe the areas wherever the Northern elephant seal lives don’t person arsenic bully a vector for the corruption to beryllium spread.”

Bamford and Vanstreels accidental the nonaccomplishment of this galore animals volition astir apt impact the broader ecosystem arsenic well.

For example, elephant seal placentas are a large root of nutrient for a assortment of coastal animals, specified arsenic birds and crabs. In addition, the seals’ deep-sea foraging brings nutrients to the water surface, wherever fish, kelp, shrimp and different oversea beingness beryllium connected their discarded and garbage for sustenance.

“You get escaped of fractional of their population, that’s going to person an impact,” Vanstreels said.