Ocean acidification kills 10 million scallops in waters off BC

By Laine Welch

Just as Nero fiddled while Rome burned, U.S. policymakers 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 climates. 
West coast scallops are the latest bivalves to feel the bite. The Parksville Qualicum Beach News reported that 10 million tiny scallops have died in waters off Victoria, British Columbia.
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 per cent 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,” Saunders told the News. “That level has been so stable that, for many years, no one bothered to measure it because it never changed. It was really startling.”
Early last year, the company counted 3 million scallops seeded in 2010 and 7 million from 2011, and was gearing up for processing. But the shellfish started to die, and by July, the losses reached 95 per cent. Other local growers faced the same fate.
“The high acidity in local waters interferes with everything they do; their basic physiology is affected,” said Chris Harley, 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 said the acidic ocean is increasingly affecting 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 ocean corrosion. In 2005, growers first noticed oyster failures in natural sets in Willapa Bay in southern Puget Sound. 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,” said Bill Dewey of Taylor Shellfish Farms. “So eventually, they lose the race and they die.”
Taylor Shellfish operates an 11,000-acre farm in Shelton, Wash., and 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 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, surveys have been in a depth range of 20 to 275 fathoms, where most fishing takes place. This year, they will 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. 
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 areas in that region, and each one contains 40-50 stations.
Halibut stock surveys occur from late May through August, and take three to four weeks to complete. It’s a chance to make a good chunk of change, said survey manager Claude Dykstra. Typical payouts range between $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.
Fixed-gear vessels using fixed gear can submit a proposal at www.iphc.int /

Fish watch

March 8 is opening day for halibut and sablefish, and fishing continues throughout Alaska for cod, flounder and other ground fish. 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.  

Fish bits

• The Alaska Dept. 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. Sean Parnell. That includes a 10 percent reduction in state funding for the Alaska Seafood Marketing Institute, or about $780,000. 

• 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 sells its products in more than 50 countries. The book is authored by John Van Amerongen. Find it at Trident’s website. 

Contact the writer
Posted by on Mar 4th, 2014 and filed under Fish Factor. You can follow any responses to this entry through the RSS 2.0. Both comments and pings are currently closed.

1 Response for “Ocean acidification kills 10 million scallops in waters off BC”

  1. Wow this is sad. Pacific oysters are one of my favorite foods. Is there any data to understand if this has occurred cyclically in the past?

Comments are closed

Like us on Facebook