Tag: pacific northwest
Changing Sea Chemistry Will Hit Alaska Communities Hard, Study Says

Changing Sea Chemistry Will Hit Alaska Communities Hard, Study Says

By Sandi Doughton, The Seattle Times

SEATTLE — Oyster growers in the Pacific Northwest have already been stung by changes in ocean chemistry linked to greenhouse-gas emissions.

Now, a new study led by Seattle researchers finds communities in Southwest and Southeast Alaska that rely on the sea for food and jobs are also likely to be hit hard over the coming decades.
The analysis, published this week in the journal Progress in Oceanography, is among the first to examine the potential social and economic impacts of ocean acidification — sometimes called global warming’s twin.

Just as carbon dioxide from power plants, factories, and cars diffuses into the atmosphere, the gas is also absorbed by the world’s oceans. As a result, scientists say the average pH of seawater has become slightly lower, or more acidic, since the start of the industrial era.

That effect is expected to intensify in the future — and some places are more vulnerable than others.

The Alaskan waters that yield much of the U.S. commercial-seafood catch are near the top of that list, said lead author Jeremy Mathis, of the National Oceanic and Atmospheric Administration’s Pacific Marine Environmental Lab in Seattle.

Carbon dioxide dissolves more readily in cold water, and the Bering Sea and Gulf of Alaska are already naturally CO2-rich.

“It doesn’t have that far to go before it reaches this critical threshold where the water can become corrosive,” Mathis said.

That’s what scientists say occurred along the Washington and Oregon coasts beginning in the mid-2000s. Naturally low pH levels dropped even further, killing oyster larvae in hatcheries that drew water from the Pacific.

The industry solved the problem by closing intake valves when pH is low, but some companies also shifted operations to Hawaii.

Many Alaskan communities, where people live off the seafood they catch, don’t enjoy that flexibility, Mathis said. If crab or salmon populations crash, people will see their main source of protein, and economic well being, diminish.

In identifying the most vulnerable communities, the researchers examined incomes, educational levels, educational opportunities, and job diversity.

They also looked at which seafood species dominate local economies and diets, and how those species are likely to be affected by changing ocean chemistry.

Red king crab, for example, appear to be very sensitive to small changes in acidity that can make it harder to build shells. In laboratory tests, larvae died at a high rate when exposed to pH levels that now occur some times of the year in the Bering Sea.

By 2100, those conditions are expected to be common. “The waters of the Gulf of Alaska and the Bering Sea and the Arctic Ocean will be corrosive to shellfish throughout the year,” Mathis said.

Salmon are less sensitive to pH, but are still at risk because of possible effects on their food. Tiny creatures called pteropods, which are eaten by a wide range of fish, are already being harmed by water corrosive to their shells along the West Coast and other places.

Many of these problems were detailed last year in a series of stories by The Seattle Times.

Drawing on existing studies of the impacts of changing pH on marine creatures, the researchers used computer models to estimate potential impacts on harvests by the year 2100. In some places, like Dillingham on Bristol Bay, they found some catches could drop by as much as 70 percent.

But Tuesday’s study contains few numbers, and no estimates of potential economic impacts. That’s because there are so many unknowns, said co-author Steve Colt, professor of economics at the University of Alaska Anchorage.

“We just don’t know enough about all the links in the chain, starting with the ocean chemistry and going through the various levels of the food chain and even getting from potential changes in fish abundance and distribution to the economic impact to communities,” he said.

Instead, the researchers calculated a relative risk index. Communities most at risk are colored red on a map — and are concentrated in the southeast and southwest portions of the state.

For example, Petersburg, an island community in Southeast Alaska where many Washington-based fishing boats operate, ranks high in the red category because it is so dependent on seafood and has few other job opportunities.

Even without hard figures, the study is one of the first attempts to bridge the gap between scientific research on ocean acidification and its potential impacts to people, said Scott Doney, chairman of the Marine Chemistry and Geochemistry Department at Woods Hole Oceanographic Institution in Massachusetts.

“This brings it home to the level of talking to community leaders, political leaders and business leaders in Alaska to say here are the areas we think are the most vulnerable,” said Doney, who was not involved in the project.

Photo: Svadilfari via Flickr

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Once-Common Marine Birds Disappearing From Pacific Northwest Coast

Once-Common Marine Birds Disappearing From Pacific Northwest Coast

By Craig Welch, The Seattle Times

ANACORTES, Wash. — The bird-counters stood in the windy bow chattering into headsets and scanning the Strait of Juan de Fuca with binoculars.

“Scoters,” Sherman Anderson said. “Three of them. At 11 o’clock. Look like surfs.”

“Marbled murrelets,” he added seconds later. “I see two.”

Inside the boat’s cabin, another Washington Department of Fish and Wildlife worker listened through a headset of his own so he could record the tally on a computer.

Bird surveys like this and others done by plane are tracking a significant ecological shift in our region — a major decline in once-abundant marine birds. From white-winged scoters and surf scoters to long-tailed ducks, murres, loons, and some seagulls, the number of everyday marine birds here has plummeted dramatically in recent decades.

Scoters are down more than 75 percent from what they were in the late 1970s. Murres have dropped even more. Western grebes have mostly vanished, falling from several hundred thousand birds to about 20,000.

The reasons often vary — from climate change and shoreline development to marine pollution and the rebound of predators such as bald eagles.

But several new studies now also link many dwindling marine bird populations to what they eat — especially herring, anchovies, sand lance, and surf smelt, the tiny swimmers often dubbed forage fish.

The relationship between marine birds and slick, fatty forage fish is complex. Some birds are here year-round while others pass through for just a few months. Some birds key in solely on silvery herring while others can just as easily eat flounder.

Some forage-fish species, such as herring, are a fraction of what they once were. But little information exists about the health of other species. But an exhaustive new analysis of bird diets and population trends found that marine birds relying exclusively on fish like herring were up to 16 times more likely to be in trouble than birds that ate nonschooling bottom-dwellers like sculpin.

“The result was remarkably strong,” said study author Ignacio Vilchis, formerly with the SeaDoc Society at the University of California, Davis. “It showed that it’s the diving birds that go after forage fish which are much more likely to have a declining trend.”

There’s certainly no shortage of crashes to evaluate. Five years ago one study showed the overall bird numbers in Puget Sound and British Columbia’s Georgia Strait were down 30 percent from the late 1970s. In Puget Sound alone, marine bird numbers have been cut in half.

Biologists for years have tried to understand why the change hit so many species at once. But only recently have they really started to examine some of the systemic shifts that may cause or exacerbate declines.

“It’s one thing to have a rare species decline,” said Joe Gaydos, with the SeaDoc Society. “But we’re not talking about a few plovers. We’re talking about big, common species, and a lot of them.”

There is no easier way to view this decline than through the once-ubiquitous Western grebe.

These black and white ducklike birds with their long necks and thin beaks settle in winter in colonies on lakes from southwest Canada to California but gather their food from marine waters.

While the bulk of that population once centered on Washington and lower British Columbia, sightings of larger flocks of grebes are unusual enough that when it happens “birders will talk about it on the Internet for days,” Gaydos said.

At first it wasn’t clear whether this was a local or continental-scale problem, said Scott Wilson, a biologist with Environment Canada. It’s both: Up and down the West Coast, the winter breeding population is half what it was in 1975.

But something else was going on, too.

While Puget Sound and lower B.C. declines top 95 percent, grebe populations in parts of California have tripled. The center of the bird’s range shifted 550 miles south.

“Food is one of the key resources species need to survive,” Wilson said. And grebes rely on forage fish.

In Puget Sound, the biggest stock of herring used to reside at Cherry Point, south of Bellingham. But since 1970 that herring stock has crashed, with more than 90 percent of the population all but gone.

The loss of herring probably drove grebes away, Wilson hypothesized, but it also did so just as sardine stocks were recovering to the south. Down to a few thousand metric tons in 1985, sardine populations in California have since exploded to more than 2 million metric tons, providing an alternative food for hungry grebes.

“The grebes were tracking this very large-scale change — the combined change to herring in the north and sardines in the south,” Wilson said. “And Western grebes are quite mobile.”

Changes in other bird populations, too, could to some degree be related to changes in forage fish.

Surf scoters, which primarily eat mussels and small crabs, also sometimes turn to herring eggs during spring migration. In 1978, bird surveyors counted 40,000 scoters near where herring were spawning. But in 2004 and 2005, surveyors counted fewer than 1,000 birds in the same location.

Some researchers suspect that since the herring spawn moves from year to year, bird counters probably missed quite a few scoters. But experts believe the general trend of decline is real.

“I think the herring absolutely did play a role in the scoter decline, but exactly what that role is, we just don’t know,” said Joe Evenson, of the Washington Department of Fish and Wildlife.”

At that time of year, scoters are eating roe because they’re storing up a lot of fat and that can help determine whether they are successful at breeding. But I think there’s not just one thing that contributed to the scoter collapse.”

Meanwhile, the chief threat to marbled murrelets is still believed to be logging in their breeding grounds high in ancient Douglas fir forests. But some researchers have suggested that along the coast, murrelets are being forced to abandon their fatty fish diets and are eating less-nutritious fish lower in the food chain — especially just before the important period when they mate.

At the same time, some scientists believe the herring problem itself may be far worse than others acknowledge.

Forage fish, particularly herring, are supposed to be so abundant they are eaten by almost everything, including hake, dogfish, and sea lions and whales.

“They are the central node of the marine ecosystem,” said Iain McKechnie, a coastal archaeologist with the University of British Columbia. “They aren’t the base, they aren’t the top, but they are the thing through which everything else flows.”

Photo: Seattle Times/MCT/Steve Ringman

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