Alternative content
Joth Davis "strip spawns" a female hybrid oyster by using a scalpel to remove the eggs from her gonads
credit:
Ashley Ahearn
At the Taylor Shellfish hatcher in Quilcene, WA brightly colored vats of microalgae line the "cupboards" - ready to be used to feed the oyster larvae.
credit:
Ashley Ahearn
Joth Davis removes sperm from a male hybrid oyster as Dennis Hedgecock observes sperm motility under the microscope.
credit:
Ashley Ahearn
In a quiet inlet of Hood Canal Joth Davis, head scientist for Taylor Shellfish, stands over a large gurgling vat of oysters.
“You hear this bubbling. We’re on a system where the water is flowing through some cylindrical tanks that have mesh screen on the bottom. On top of the mesh screen are juvenile oysters and the water is flowing down through the bed of oysters and supplying them with microalgae that they need to grow.”
Growing these filter feeders isn’t as easy as putting larvae in a vat and feeding them delicious microalgae. Taylor Shellfish - the largest shellfish farming company in the country - has invested about $50,000 in figuring out how to create fast-growing, uniformly-shaped oysters that they hope will blow conventionally farmed and wild oysters out of the water.
Davis walks through rows of red, green and brown tanks of algae to the lab at the back of the hatchery.
There sits Dennis Hedgecock, hunched over a lab notebook looking at oyster family trees. He’s a University of Southern California professor who’s doing genetic experiments using Taylor oysters.
“Ok. We’re about ready to go here,” he announces. “We are crossing brothers and sisters to make a set of families that are useful for genetic mapping.”
Wait. What? Crossing brothers and sisters? Isn’t that oyster incest?
It turns out inbreeding oysters is good for science. By breeding brother and sister oysters, Hedgecock can concentrate the genes and then start to pick apart what gives oysters certain characteristics. Is growth rate linked to this gene? Food uptake linked to that one? How about shell shape and color? Once scientists isolate those desirable genetic qualities, they can use that information in developing future stock. Hedgecock explains, “We inbreed oysters on purpose because when we cross the inbred lines we get this hybrid vigor.”
Ever heard of a Labradoodle – the mix between a Labrador and a poodle? That’s kind of how hybrid vigor works: two concentrated genetic lines come together to make an animal that doesn’t have problems like bad hips, which can result from inbreeding. Dog genetics and oyster genetics don’t work exactly the same way, but Hedgecock says the same concept applies.
“Hybrids are better certainly than their inbred parents and often they’re better than your average wild oyster,” he says. “That’s the idea. We’re looking for these crosses that are even better than the wild oyster.”
Hybrid oyster larvae absorb 40 percent more food than inbred oysters, which makes them grow faster. Scientists don’t know what causes hybrid vigor, which is also seen in corn production. But Hedgecock hopes to unlock that secret, using oysters.
To do that, Hedgecock and Davis are carefully breeding oysters. Today they’re doing what’s called “strip spawning,” Davis explains, as he slides a scalpel into an oyster and cracks it open. He flops the newly exposed phlegm-like creature over to reveal its gonads, and mushes them around until a milky white substance oozes out. “See all the white? Those are eggs.”
Davis then rinses the eggs into a beaker, grabs a male oyster and repeats the process. Males look the same as females but under a microscope you can see hundreds of millions of sperm, instead of eggs.
Then in a highly scientific manner, Davis grabs a beaker and pours the sperm and eggs in together. “I will just grab something and stir them up and we’ll look at them to see if there are now sperm flocking around each egg, as they are wont to do, he says, before proclaiming: “We just made life.”
Taylor Shellfish has now started breeding hybrids to hybrids to produce double hybrids, which are still in the early phases of growth but Davis says they are showing signs of outperforming farmed and wild oysters alike.
“These oysters reached market size after literally 5-6 months of grow-out. Usually it would take, oh, at least 8 months to a year and that translates directly into dollars,” he says.
It’s unclear whether hybrid and double-hybrid oysters are more resilient to changes in ocean temperatures or ocean acidification. For now Hedgecock is trying to get good-looking oysters that grow fast… and taste good. But, Dr. Hedgecock, you’re never tempted to eat the specimens?
Hedgecock grins. “I wouldn’t say that.”
Congrats to David James for his winning submission, 'Annabella smelling the Balsam.'
Share your experiences as part of EarthFix's Public Insight Network.
Oregon/Washington: Is there buzz in your community about coal trains or new export terminals?
Join our Public Insight Network!
EarthFix is a public media project of Oregon Public Broadcasting and Boise State Public Radio, Idaho Public Television, KCTS 9 Seattle, KUOW Puget Sound Public Radio, Northwest Public Radio and Television, Southern Oregon Public Television and the Corporation for Public Broadcasting.
