Domesticating Shellfish for Future Generations

Pacific Hybreed is using advanced scientific and practical knowledge to help secure a stable and sustainable supply of shellfish in the face of global challenges that affect the shellfish industry, including climate change, warmer and more acidic oceans, and the threat of emerging diseases.

For thousands of years, humans have been domesticating land plants and animals for food production. Our domesticated crops and livestock bear little resemblance to their wild ancestors, to the enormous benefit of human food supply. This has not been the case with aquaculture. To date, on a worldwide basis, shellfish aquaculture depends on the collection and propagation of wild animals and therefore cannot benefit from the sort of structured, data-driven, long-term breeding programs that characterize modern agriculture.


The Promise of Hybrids

About 100 years ago, agricultural scientists in the US discovered the advantages of inbreeding naturally outcrossing (wind-pollinated) crops, such as maize or corn, and then crossing the inbred lines to produce vigorous, high-yielding, uniform hybrid plants. Crossbreeding of corn in the US resulted in a 7-fold increase in yield for the maize industry and is the basis for most crop and even some livestock (poultry and swine) improvement. High-yielding hybrids cannot be achieved by simply selecting higher-yielding parents, because hybrid vigor depends not on the general effects of the parents’ genes, but instead on the specific combination of parental genomes in their offspring.

Having demonstrated that shellfish show hybrid vigor as many plants do, Pacific Hybreed’s founders expect crossbreeding to increase harvest yields and improve resilience to changing ocean temperature and chemistry. Hybrid shellfish will positively impact the success and security of shellfish farmers in the Pacific Northwest and around the world. 

Pacific Hybreed is the only company specializing in the commercial development of hybrid shellfish. We combine traditional quantitative breeding methods with modern, genomic-scale analyses of commercially important traits.


Photo courtesy of Professor Colleen Burge

Resistance to POMS

Pacific Oyster Mortality Syndrome (POMS) is a virulent, transmissible and deadly disease that affects Pacific oysters. It is caused by the Ostreid herpesvirus-1 microvariant (OsHV-1 μVar) virus, and it has devastated oyster industries throughout the world. So far, only one bay along the U.S. West Coast has experienced a much less virulent form of this virus. However, the virulent microvariant has been detected in San Diego Bay, enhancing the already high level of concern that the industry has over this existential threat.

Fortunately, research shows that Pacific oyster populations harbor genetic resistance to this virus and the disease that it causes, although much remains unknown about its ecology and etiology. It is critical, therefore, to develop resistant populations in a manner that won’t compromise other desirable traits or the increases in yield that are already being achieved. Pacific Hybreed is actively collaborating with top shellfish pathologists to understand the mechanisms of POMS resistance, to identify the genes involved, and to breed resistant but otherwise genetically diverse stocks, using this information. We have mapped regions of the genome that distinguished survivors from non-survivors, which will help us to collect oysters carrying POMS-resistant genes, from natural populations.

Much still remains unknown about how POMS spreads or how to mitigate its effects, although we have mapped regions of the genome that distinguished survivors from non-survivors. Pacific Hybreed is continuing research with top shellfish pathologists to understand the mechanisms of POMS resistance, to identify the genes involved, and to breed resistant stocks, using this information.   


Polyploids - "Seedless Shellfish"

An oyster’s natural genetic makeup, like that of most animals, comprises two sets of chromosomes, which contain the DNA that determines how it lives, grows and reproduces. Some animals and plants are polyploid, carrying three or more sets of chromosomes. In agriculture, including shellfish aquaculture, triploids, carrying three sets of chromosomes, are often desirable because they are reproductively sterile or seedless, which means that they are incapable of breeding with wild stocks. Triploid oysters are widely grown in shellfish aquaculture because they offer year-round product quality, often grow faster, and command a premium price. However, in warm-water environments, growers generally do not want to farm triploid oysters because they are more susceptible to sudden mortalities, which can devastate a harvest. To meet this challenge, Pacific Hybreed will focus on the development of triploids that survive better in warm-water environments.

Pacific Hybreed is testing a variety of triploid combinations in different environments, to find those that survive better in warm-water growing conditions.


Photo courtesy of William Dewey

Manila Clams

Reproductively mature clams harvested during warm, summer low tides are likely to spawn, either before or during shipment to customers. This ruins the quality of the clams, which must be discarded, causing significant economic and reputational losses to the farmer. To reduce or eliminate this industry issue, Pacific Hybreed is focusing on the development of Manila clams that are incapable of spawning under these conditions.


Precision Shellfish Farming

In extensive interviews with over 100 shellfish growers along the US West Coast, we discovered that different growers have different needs, often depending on their location. For example farmers in warmer-water environments do not necessarily want oysters that grow too fast and impact harvest by passing too quickly through the ideal market size.
Pacific Hybreed has a program to test stocks in different environments in order to produce the ideal stock for each major growing region.  We call this precision shellfish farming. To aid in optimizing shellfish farming for our customers, Pacific Hybreed can advise growers on situating production and nursery areas for optimal growth and survivorship based on local tidal currents, tidal exposure, food availability, temperature and a host of other environmental parameters. 
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