Fresh Oysters

Fresh Oysters header image
Good breeding is at the heart of the West Coast oyster industry.

When you think of good breeding stock you might think of racehorses or show dogs. But good breeding is at the heart of the West Coast oyster industry, and it all happens at the Molluscan Broodstock Program in Newport.

Oysters have been grown commercially on the West Coast for more than 100 years,
and today the industry contributes about $85 million a year to the regional
economy. But it’s only been since 1996 that research has been focused on breeding
the highest quality oysters. That’s when the Molluscan Broodstock Program began
as a partnership among the industry, the U.S. Department of Agriculture, and
OSU’s Coastal Oregon Marine Experiment Station.

Chris Langdon
Chris Langdon, OSU’s oyster breeder, keeps track of the progress of males and females in dozens of families and generations of Kumamoto oysters. Photo by Lynn Ketchum.

Chris Langdon has overseen the broodstock program from its beginning. Starting
with 600 wild oysters collected from Alaska to California, he has worked to
breed the plumpest, tastiest, and healthiest oysters for the industry. The
work begins in a facility at OSU’s Hatfield Marine Science Center, in a laboratory
full of bubbling incubators of highly filtered seawater, where the nearly microscopic
young oysters begin their life. Next door, in a room full of various sized
flasks, researchers tend a garden of colorful algae that they grow as food
for the larval oysters.

When the swimming larvae develop into sedentary baby oysters, called spat,
researchers transfer them to an upweller nursery, where upward flowing water
passes over them. After several months, when each is about the size of a pea,
the oysters are transported to commercial locations along the West Coast where
industry partners plant comparable groups of oysters in different environments,
including some suspended in deep water and others in intertidal beds. Partners
in the field help identify oyster groups with the highest survival rates and
meat weights for researchers to breed the next generation of improved stock.

Brian Arnold
Baby oysters in the upweller nursery get clean, filtered seawater, a rich diet of algae, and careful attention from research technician Brian Arnold.
oyster spat
Brian Arnold, an OSU research assistant, peers in on the Kumamoto oyster “spat” from the broodstock program at Hatfield Marine Science Center in Newport. Photos by Lynn Ketchum.

Each year, Langdon breeds two new groups of 50 or 60 oyster families, using
DNA fingerprinting to check the pedigrees and avoid genetic contamination.
As a result of this work, yields of top-performing oyster families are on average
77 percent greater than the yields of progeny from nonselected industry broodstock.
In addition to increasing yield, Langdon is developing oyster breeds with various
colors and shell shape, including oysters with deeply cupped black shells and
dark mantles (meat) inside.

Until recently, the broodstock program has focused on improving one variety,
the Pacific oyster introduced from Japan in 1912. Langdon is expanding the
breeding program to include another import, the Kumamoto oyster, prized for
its flavor but slow growing. He is working to introduce new broodstock from
Japan in order to re-vitalize existing inbred broodstock and expects to release
an improved and certified disease-free Kumamoto broodstock in 2009.

Despite advances in broodstock development, something mysterious has been
killing larval oysters in the Oregon and Washington hatcheries. At first it
was thought to be a strain of bacteria that is harmless to humans but lethal
to baby oysters. When researchers sampled seawater pumped into coastal hatcheries,
they found evidence of a species of pathogenic bacteria, Vibrio tubiashii,
to be much higher than normal. However, installation of bacteria-killing ultraviolet
water-treatment systems did not prevent the larval mortalities.

oysters in net
OSU’s broodstock program selects the largest individual oysters from the highest yielding families to serve as parents for future generations. The remaining oysters from the highest yield families are set aside for industry use. Photo by Lynn Ketchum.

Researchers also noticed that the seawater was occasionally more acidic than
usual, often in conjunction with strong offshore winds. And with the strong
winds and acidic water came die-offs of larval oysters. Now, it seems the chemistry
of the ocean may be changing. Scientists suspect that water rising from deep
in the Pacific Ocean and pumped into seaside hatcheries may have become corrosive
enough to dissolve the shells and reduce survival of larval oysters.

“These seawater conditions have led to dire economic consequences for two
of the four hatchery operators that produce oyster seed for farmers, including
Whiskey Creek Hatchery in Netarts Bay, that accounts for approximately three-quarters
of all larvae used by West Coast oyster farms,” Langdon said. In response,
he is working to help restore seed production in West Coast oyster hatcheries
by developing selected broodstock that can produce larvae to better survive
these seawater conditions and by developing ways to improve the quality of
ocean water that is pumped into hatcheries.

Miguel Ruiz
Oregon Oyster Farms foreman Miguel Ruiz holds a handful of open Olympia oysters. Photo by Lynn Ketchum.

Native oysters set to rebound

The native Olympia oyster, smaller than the commercially produced Pacific oyster, was harvested in abundance 100 years ago, to the point that it nearly disappeared from Oregon and Washington estuaries. But that could change. During the winter of 2006, OSU researchers, working with The Nature Conservancy, planted Olympia oyster spat in Oregon estuaries. The oysters have survived through three full years and larval oysters have established themselves on shells placed in the bay, which suggests that natural colonization of the Northwest native oyster has begun.

Web resources

Molluscan Broodstock Program