Cryogenic Preservation of Oyster Gametes to Improve Hawaii and West Coast Oyster Stocks
All startup and organizational activities have been completed, including making arrangements for the visit of Dr. Terrence Tiersch (Louisiana State University Agricultural Center) to provide training in the process of cryogenic preservation to the staff of the Pacific Aquaculture and Coastal Resources Center (PACRC) at the University of Hawaii Hilo and Hawaiian Shellfish, LLC.
Dr. Tiersch made his first visit in early July 1016 where he visited the Pacific Aquaculture and Coastal Resources Center (PACRC) at the University of Hawaii Hilo and Hawaiian Shellfish, and gave lectures on the cryogenic preservation process for mammals as well as oysters. Approximately 15 staff and students attended the lectures. Large amounts of research data and genetic material is available for domestic mammals but very little has been done for fish and other invertebrates. He also advised on the materials and equipment that would be needed for the training visit by Bill Childress 9/30/2016. With these materials purchased, Hawaiian Shellfish and PACRC created the capacity for cryopreservation work to begin in Hawaii.
Bill Childress visited Hawaiian Shellfish LLC and trained PACRC and Hawaiian Shellfish staff on the use of his “Cryogenic Cooler Kit” for freezing and thawing oyster sperm. Liquid nitrogen was added to the Styrofoam cooler, and his “Straw Rack” held twenty straws of liquid sperm that were extracted from male Pacific Oysters. The “Straw Rack” was created using a 3D printer, and can be adjusted to keep the straws higher above the liquid nitrogen for slower cooling. Staff were also trained on safety measures and the mixing of cryopreservants to be added to the oyster sperm.
To date, the work has focused on accomplishing Project Objective 1: Develop reliable and replicable sperm collection, handling, and shipping methods. Work also focused on Project Objective 3: Evaluate the materials, equipment, and training needs for the hatcheries to collect, freeze, and store sperm on-site in remote locations.
Broodstock oysters were sent from Hawaiian Shellfish on the 5/22/2016 and the 9/14/2016 to LSU Aquatic Germplasm and Genetic Resource Center for cryopreservation experiments and the collection of genetic material.
We have made progress towards accomplishing Project Objective 5: Conduct outreach and training for hatchery and farm personnel, students and the wider aquaculture stakeholders. A draft of cryogenic freezing and thawing methods has been written and will be further refined based on future results of the cryogenic trials. Photos and research data was collected during Dr. Tiersch and Bill Childress’ visits to be used for training purposes.
During the trainings, we successfully froze and thawed diploid oyster sperm and it became active again. Methods were improved as training went on, and we had more success in later freezing and thawing runs. Fertilization was not successful but with the reactivation success of the sperm we hope to achieve fertilization in the coming year.
Impacts and Contributions/Outcomes
If successful, Cryogenic preservation can be crucial to preserving genetic stocks of West Coast Oysters. If disease or climate change were to suddenly impact areas where oysters are living, complete lines could be lost forever. If this were to happen however, the surviving oysters which may be resistant to these effects could be preserved and used in other effected areas to create resistant lines to keep the industry going.