Location: National Cold Water Marine Aquaculture Center
Project Number: 8030-10600-001-024-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jun 9, 2025
End Date: May 31, 2026
Objective:
To conduct progeny tests of USDA ARS germplasm intended for genetic improvement as part of the northeast eastern oyster breeding program.
Approach:
The USDA ARS breeding program will spawn wild oysters collected throughout New England to create a genetically diverse base population for a northeast regional breeding program. This population will consist of 100 - 150 single pair crosses (families) combined into 25 – 35 rearing groups (4 families per group). ARS will rear the spat in a land-based nursery system until they reach ~ 4 mm in size. They will be tested for disease-free certification, packaged in labeled mesh spat bags and transferred to the cooperator’s farm for deployment. The cooperator will receive approximately 3000 seed oysters per rearing group (up to 105,000 seed total) in June, coinciding with an on-farm husbandry schedule that maximizes early growth, minimizes disease-related juvenile mortality, and reduces overwintering losses. The cooperator will maintain seed at their farm for up to 36 months using routine on-farm practices with some modification. Modifications include always keeping ARS-provided group labels with the seed, maintaining each group in replicated gear, and keeping replicated groups separate. During the first five months of deployment, the cooperator will tend to the seed by defouling, increasing gear mesh size, and splitting bags to maintain healthy densities on a schedule appropriate for their farm. The cooperator and ARS will communicate regularly during this period and ARS assistance with these tasks will be left to the cooperator’s discretion. To preserve the genetic variation in each rearing group and allow for unbiased assessment of group-specific growth traits that will inform selection of future generations, size grading is not advisable; however, the experimental design allows for ~ 10% loss whenever seed are transferred to larger mesh size gear.
Following the first overwintering, ARS will coordinate access to experimental material to stock replicate (3) bags for performance evaluations. Performance will be evaluated at ~12 and 18 months post-fertilization. The cooperator will continue to maintain the material in replicate bags until data analysis is completed, at which point ARS will pit-tag a subset of oysters from best performing groups to serve as broodstock for future generations. Pit-tagged oysters can be combined into fewer bags. Concurrent with seed deployment, ARS will install a solar-charged cellular data buoy equipped with water quality instrumentation to characterize environmental conditions on the farm. ARS staff will maintain the monitoring equipment and share environmental data with the cooperator. This agreement is intended to cover two overlapping generations of our base-breeding population (36-48 months). The first year class (deployed 2025) will represent a cohort of breeding founders. The second year class (deployed 2026) will be the first selected cohort based on data collected from generation 0 (deployed at a RI farm in 2024). Because the breeding program will consist of overlapping generations, the number of seed/replicate bags deployed at the cooperator’s farm will approximately double during the 2nd year of the project. In subsequent years, the number of see/bags will be relatively stable.