FISH FACTOR: West coast scallops are suffering from ocean acidification


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Just as Nero fiddled while Rome burned, U.S. policy makers are quibbling over climate issues as bivalves dissolve in an increasingly corrosive Pacific Ocean.

Any kid’s chemistry set will show that big changes are occurring in seawater throughout the world. As the oceans absorb more carbon dioxide from fossil-fuel burning outputs (primarily coal), it increases acidity to a point where shellfish can’t survive. It is referred to as ocean acidification and results in sea creatures’ inability to grow skeletons and protective shells. The process occurs much faster in colder climes.

West coast scallops are the latest bivalves to feel the bite. Ten million tiny scallops have died in waters off Victoria, British Columbia, reported the Parksville Qualicum Beach News.

Nanaimo-based Island Scallops, a grow-out hatchery with 1,235 acres in production, has shut down its processing plant and laid off a third of its workforce. That accounts for about 16 percent of B.C.’s total shellfish aquaculture valued at $10 million.

Island Scallops started seeing problems in 2009 along with other Washington hatcheries, said CEO Rob Saunders.

“Suddenly we were getting these low pH values. That level has been so stable that for many years no one bothered to measure it because it never changed. It was really startling,” he told the News.

Early last year the company counted three million scallops seeded in 2010 and seven million from 2011, and was gearing up for processing. But the shellfish started to die and by July the losses reached 95 percent. Other local growers faced the same fate.

“The high acidity in the local waters interferes with everything they do, their basic physiology is affected,” said Chris Harley, a marine ecologist at the University of B.C.

Growers are artificially increasing the pH levels of the water that circulates through the hatcheries to protect the larvae, but that is little help to the shellfish once they are moved to the sea.

The B.C. Shellfish Growers Association stated that the acidic ocean is increasingly having an effect on survival and growth of shellfish during grow out in the ocean, and that last year mortalities reached 90 percent in all year classes.

Pacific oysters also are one of the most vulnerable to the ocean corrosion. In 2005, growers first noticed oyster failures in natural sets in Willapa Bay in southern Puget Sound, and production was off by 80 percent by 2009. 

“The oysters still grow a shell; it’s just that it dissolves from the outside faster than they can grow it. So eventually they lose the race and they die,” said Bill Dewey of Taylor Shellfish Farms with 11,000 acre in Shelton, Wash. It is the nation’s largest shellfish producer with 500 employees.

Growers there have learned that wind direction tells them when to plug intake pipes to the shellfish holding tanks. When the wind shifts from south to north, they know they have about a 24-hour window before corrosive waters show up. Meanwhile, Taylor is planning to move more of its oyster operations to Hawaii.

Closer to home, researchers are seeing signs of corrosion in tiny shrimp-like pteropods — which make up 45 percent of the diet of Alaska pink salmon.

Carbon dioxide has passed 400 parts per million, or ppm, in the Earth’s atmosphere, according to measurements taken at the Mauna Loa Observatory. That’s up from 280 ppm in the pre-industrial era.

Halibut help

Halibut researchers will test deeper and shallower water depths to get better data on the dwindling stocks, and more fishing boats are needed to help.

Each summer up to 15 boats are contracted to help halibut scientists survey 1,300 stations from Oregon to the Bering Sea. Since 1998 the surveys have been done in a depth range of 20 to 275 fathoms where most of the fishing takes place. This year they want to check out different depths. 

“We use the area from zero to 400 fathoms as halibut habitat, but our surveys cover the area from 20 to 275 fathoms,” said Bruce Leaman, executive director of the International Pacific Halibut Commission. “So we’re using the catch rates from our existing survey depths to extend into those areas. We know we are ignoring some habitat where fishing is going on, but we don’t have the data so we are extrapolating from our known survey areas into the unknown.”

Leaman said researchers plan to expand the surveys from 275 to 400 fathoms and from 20 down to 10 fathoms along the Pacific Coast and in area 4A — the Bering Sea edge and eastern Aleutians region near Unalaska. There are four survey regions in that region and each one contains 40 to 50 stations.

“That’s one of the areas where we are seeing an increasing amount of fishing going on below 275 fathoms,” Leaman said. “Actually, all of the Bering Sea has a significant number of survey stations that are in depths that we don’t currently occupy.”

The halibut stock surveys occur from late May through August, and it takes three to four weeks to get the job done. It’s a chance to make a good chunk of change, said survey manager Claude Dykstra. Typical payouts range from $70,000 to $120,000 depending on survey regions. Boats also get 10 percent of the halibut sales and 50 percent of any other fish retained and sold.

Vessels using fixed gear can submit a proposal at www.iphc.int.

Fish watch

March 8 was opening day for halibut and sablefish. Fishing continues throughout Alaska for cod, flounder and other groundfish. In a few weeks, the jig fleet will be the first to take part in a new small boat pollock fishery, and managers report lots of interest. The Bering Sea pollock fishery will wrap up in a few weeks with a half-million-ton catch for the winter season. Trawlers will be back on the water in June with a total pollock catch this year of nearly three billion pounds.

Crabbing continues in the Bering Sea for golden kings, Tanners and snow crab. Seiners will soon head to Sitka for the mid- to late-March arrival of roe herring. They will compete for a nice haul of more than 17,000 tons. Small boats wanting to drop dredges for the new state water scallop fishery must register by April 1. The Board of Fish will hold its final meeting for this cycle from March 17 to 21 in Anchorage. Statewide king and Tanner crab and supplemental items are on the agenda.

Fish bits

The Alaska Department of Fish and Game will get a $2.5 million cut if recommendations by a House Finance Subcommittee are accepted by the full Legislature and approved by Gov. Parnell. That includes a 10 percent reduction in state funding for the Alaska Seafood Marketing Institute, or about $780,000. The ADFG subcommittee is chaired by Rep. Bill Stoltze of Chugiak, who recommended cuts by division and not specific programs, said Juneau watch dog Bob Tkacz in Laws for the Sea.

The long awaited book — “Catching a Deckload of Dreams” — recounts the journey of Chuck Bundrant from deckhand to chairman and founder of Trident Seafoods, the largest seafood harvesting and processing company in North America. When he arrived in Seattle in 1961, Bundrant had $80 in his pocket. Currently, Trident has sales topping $1 billion, employs more than 10,000 people and its products are sold in over 50 countries. The book is authored by John Van Amerongen. Find it at Trident’s website.

Laine Welch lives in Kodiak. Visit www.alaskafishradio.com or contact msfish@alaska.com for information.

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