Recipient Organization
PACIFIC HYBREED, INC.
10610 NE MANITOU PARK BLVD
BAINBRIDGE ISLAND,WA 981103375
Performing Department
(N/A)
Non Technical Summary
For generations, oyster farming has provided significant social and economic value in coastal communities. More recently, there is growing awareness of its environmental value. Farmed oysters require minimal energy and feed, filter a significant volume of water, and remove carbon and nutrients from the sea at harvest. At the same time, growers face increasingly urgent threats from environmental change and stressors, directly or indirectly attributable to climate change, that will likely become more significant in the future. These environmental stressors create the potential for significant reductions in shellfish yields in the years ahead. Breeding programs can improve yields of oysters, especially in regions such as the U.S. West Coast where growers reply on hatchery-produced seed. The primary goal of this SBIR project for Pacific Hybreed, Inc. is to increase production of farmed Pacific oysters through crossbreeding.Crossbreeding to produce within-species hybrid lines has provided massive improvements to yields for corn and other land crops. This project, focused on the Pacific oyster, the largest crop for the shellfish industry on the U.S. West Coast (from California to Alaska) will support the development of hybrid oysters. Published research shows that hybrids can have significantly higher yields. Research efforts have been proposed to utilize crossbreeding and produce distinct hybrid lines optimized for specific growing conditions in different geographies and ocean conditions, now and as they change in the future. The project includes critical field testing of many different genetic lines developed for the project, in multiple locations, to find the correlation among higher performances, specific genetics and local environmental conditions.
Animal Health Component
60%
Research Effort Categories
Basic
20%
Applied
60%
Developmental
20%
Goals / Objectives
The major goal of this Phase I, SBIR proposal is development of genetically improved Pacific oyster, Crassostrea gigas, through crossbreeding and field trials. We propose to conduct rigorous field trials on different, within-species hybrid lines, produced by diallel crosses of partially inbred lines of C. gigas. Yield performances (the product of survivorship and growth rate) of hybrid C. gigas will be measured at multiple field sites, in collaboration with our industry partners. A secondary goal is focused on expanding the current repository of inbred lines for an increased capacity to produce new hybrid lines.The specific objectives of the research effort includeselecting hybrid lines for better field performances, estimating components of genetic variances, and expanding our repository of inbred lines using selected wild-type families. The research has two technical goals that can be accomplished within a Phase I research window,1. Make diallelcrosses of first-generation inbred lines to produce many unique hybrid lines for field testing, to estimate the contribution of different inbred lines to variability in growth and survival at the early-seed stage across different environments.2. Make additional inbred lines from pair-mated, wild-type families that have been selected for better field performance to expand the repository of inbred lines. These new inbred lines will allow multiple diallel crosses for yearly production of new hybrids.The technical question that needs to be answered is: Do better-performing hybrid lines maintain yield performances across different environments? If the results of the research provide a positive answer, breeding program could be made substantially more efficient.
Project Methods
Genotyping to confirm pedigree. Before crossing the genetic lines, we will tissue biopsies from about 10 prospective brood oysters per genetic line to ensure that at least one male and one female will be confirmed. Oyster DNA will be extracted from alcohol-preserved tissues and used for PCR amplification of DNA sequences containing single-nucleotide polymorphic markers. Roche Light Cycler 480 and the corresponding analytical software will be used for determination of genotypes. The parentage and sibship results are tabulated and returned to the hatchery within a week to allow selection of brood stocks for genetic crosses.Spawning and controlled crosses. Brood oysters will be conditioned in our hatchery and artificially spawned using standard protocols to collect gametes. For each female oyster, eggs will be allocated to several beakers each at 1 million eggs per liter. A full factorial, diallel mating scheme will be employed, whereby a male and a female brood oyster from each of seven genetic lines will be crossed in all possible 49 pairwise combinations. This cross-scheme will produce 49 larval families, including seven within-line mating and 42 between-line hybrid combinations.Larval rearing. Larval rearing will be carried out in flow-through tanks. Each 50-l cylindrical culture vessel is equipped with inflow and outflow tubing and a modified "banjo" screen of varying porosities appropriate for holding Pacific oyster larvae of different sizes over the larval period. Microalgal feeds consisting of multiple species will be metered into each culture vessel. Larvae will be fed the alga T-Isochrysis starting at 1-day post-fertilization. As larval growth progresses, algae Chaetoceros mulleri will be added, and feeds will be augmented by additional species Tetracelmis sp. as needed during later larval stages. Algal feed will be supplied via the header tank to larval culture vessels where individual valves control the flow rate to ensure that algal density will be between 30,000 and 80,000 cells per ml seawater on a continuous basis. Every two days, a complete water change will be conducted for all larval cultures. For qualitative assessments of larval health, survival will be estimated based on counts and larval sizes will be measured on calibrated microscope photographic images.Juvenile nursery. When the pediveliger stage of development is reached, larvae will be collected and held out of seawater at 4°C until a sufficient number of competent larvae have been collected. Pediveligers will be induced to settle by exposing competent larvae for one hour to 25 μM epinephrine in 25°C seawater. Larvae will subsequently be screened out of the epinephrine solution and placed into a down-welling setting silo. Each silo is fit with a stream of filtered seawater, containing microalgae for feed during metamorphosis. After newly set spat have reached the size to be retained on a 1-mm mesh screen, they will be transferred to up-welling silos, supplied continuously with filtered seawater and algal feeds. Oysters will be maintained in this nursery until 3 mm in shell height at which size they will be outplanted in the field for yield performance assessments.Field work. Prior research at Pacific Hybreed has developed rotating cylinders for seed grow-out in the field. For this project, each seed cage will be stocked with 100 oysters and placed into field culture at multiple test sites to compare effects of environmental conditions (such as tidal position, water temperature, disease) on yield performances. Different individuals from the same families will be outplanted in a randomized block design at each farm location. Temperature loggers will be attached to cages to record in-situ temperature profiles. Counts, group live weight, and morphometric measurements will be taken on animals at the beginning and the end of field trials.Data analysis, efforts, and evaluation. Data from this project will be analyzed using standard statistical models to examine the impact of genetics and the environment on phenotypic variances. The results will advance the knowledge of genotype-dependent performances of farmed oysters and test the hypothesis whether such performances are consistent across different field sites. Measurable success and key milestones include production of many hybrid lines, deployment of the hybrid lines across different commercial farms, and collection of yield data throughout the period of deployment. We will maintain close communication with the industry partners who host the field work to deliver and interpret the results. This will help translate the research findings into potential improvement of oyster production and facilitate continuing breeding work with different shellfish growers on the US West Coast.