Orcas from pod J in Puget Sound just west of Seattle. The number of orcas in the area, listed as endangered since 2005, has dwindled to a 30-year low. Photo: Elaine Thompson / Associated Press

By Jim Robbins
9 July 2018

SEATTLE (The New York Times) – For the last three years, not one calf has been born to the dwindling pods of black-and-white killer whales spouting geysers of mist off the coast in the Pacific Northwest.

Normally four or five calves would be born each year among this fairly unique urban population of whales — pods named J, K, and L. But most recently, the number of orcas here has dwindled to just 75, a 30-year-low in what seems to be an inexorable, perplexing decline.

Listed as endangered since 2005, the orcas are essentially starving, as their primary prey, the Chinook, or king salmon, are dying off. Just last month, another one of the Southern Resident killer whales — one nicknamed “Crewser” that hadn’t been seen since last November — was presumed dead by the Center for Whale Research.

In March, Gov. Jay Inslee issued an executive order directing state agencies to do more to protect the whales, and in May he convened the Southern Resident Orca Task Force, a group of state, tribal, provincial and federal officials, to devise ways to stem the loss of the beloved regional creature. “I believe we have orcas in our soul in this state,” he said. At another point, he wrote of the whales and Chinook salmon that “the impacts of letting these two species disappear would be felt for generations.”

The orcas are also facing a new threat. The recent agreement between the Canadian government and Kinder Morgan to expand the Trans Mountain Pipeline would multiply oil tanker traffic through the orcas’ habitat by seven times, according to some estimates, and expose them to excessive noise and potential spills. Construction is set to begin in August, despite opposition from Governor Inslee and many environmentalists.

In the late 1990s, there were nearly 100 of these giant whales in the population. Following the salmon, they migrate in the Salish Sea to the northern coast of British Columbia and often surface in the south at Puget Sound within sight of downtown Seattle, especially during the spring and summer months. The males, which can weigh up to 22,000 pounds, typically live about 30 years, and females, up to 16,000 pounds, survive longer — up to 50 or 60 years, although one J-pod member, Granny, lived to be 105 years old.

Not only are there fewer calves in recent years, but signs of inbreeding also point to a weakening population. In the 1970s and 80s, theme parks like Sea World captured nearly 4 dozen orcas from the region, possibly shrinking the pods’ gene pool. In the last three decades, just two males fathered half the calves in the last three decades, and only a third of the females are breeding, just once every decade instead of every five years. Researchers worry that reproducing females are aging out of the population, and won’t be replaced.

Some conservationists are concerned that the orcas’ decline is another sign of a marine ecosystem in collapse. Beginning in 2013, something known as “The Blob” — a gigantic mass of nutrient poor, extremely warm water — warmed the Pacific from Mexico to Alaska, as much as six degrees above normal. Several years ago, starfish succumbed to a wasting disease and vanished from tide pools.

Much is still unknown about the plight of these orcas, but biologists and conservation managers have zeroed in on several main factors — and they are all connected.

The biggest contributing factor may be the disappearance of big king salmon — fish more than 40 inches long. “They are Chinook salmon specialists,” said Brad Hanson, team leader for research at the Northwest Fisheries Science Center here, part of NOAA. “If they could, they would eat Chinook salmon 24/7.” Orcas gobble 30 a day. Hunting enough smaller prey requires a lot more energy. […]

Another factor is the pollution in Puget Sound. Whales that live off the coast of Seattle, Tacoma and other cities are effectively urban whales buffeted by municipal and industrial waste, and the occasional spillage from wastewater treatment plants into the ocean. Killer whales carry some of the highest levels of pollution of any marine animal. […]

“It’s an ecosystem-wide problem,” Dr. Hanson said. “Things are out of whack and we have to get them back to where we can sustain killer whales. And the clock is ticking.” [more]

Orcas of the Pacific Northwest Are Starving and Disappearing

0 comments :

 

Blog Template by Adam Every . Sponsored by Business Web Hosting Reviews