Pacific oyster hybridization put to the test


SeafoodSource staff

Published on
March 24, 2011

Dennis Hedgecock is dreaming of bigger, better Pacific oysters, and the University of Southern California biology professor is determined to find out if it’s possible to produce them in the future. Recently, he and USC colleague Donal Manahan received a $394,000 NOAA Sea Grant that will allow the pair to determine which genes and metabolic processes are responsible for hybrid vigor in the oyster, and to develop a tag for identifying offspring with desired traits within hours of their birth.

“I’m very interested in the genetic improvement of aquaculture species,” says Hedgecock. “We have to do this, because we can’t keep returning to nature to get breed stock, which is what a lot of aquaculture does globally.”

The West Coast oyster industry is worth $72 million a year, and based on his initial, small-scale experiments funded by the U.S. Department of Agriculture in the 1990s, Hedgecock believes that growing hybrid Pacific oysters could be transformational. In those experiments, the first generation hybrid oyster grew twice as fast as the industry standard. That means West Coast oyster farm yields could potentially double.

Hedgecock and his team noticed that when you create inbred lines in Pacific oysters, they suffer from inbreeding depression. “The parent stocks of inbred oysters are small and don’t have many eggs,” he explains. “Cross those inbred lines, however, and you create a hybrid oyster that performs far better.”

Until now, translating this research into industry gains has been difficult. One challenge has been the insufficient supply of inbred broodstock required for routine commercial spawns. Hedgecock’s answer is to use large, robust, first-generation hybrids as the commercial broodstock. When two hybrid oysters are crossed, the result is a double hybrid, which should also perform better than wild oysters.

“We hope to show that the double hybrid is better,” says Hedgecock. “But we also just want to get the industry used to working with us, and to get information from the farms about the economics of oyster production in commercial farms. Without detailed data on production, it will be very difficult to say whether the double hybrids are an improvement.”

Click here to view the rest of the feature on Pacific oyster hybridization. Written by SeaFood Business Contributing Editor Lauren Kramer, the story ran in the March issue of SeaFood Business magazine.

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