Oyster Domestication and Seed Production to Support the Industry on Florida's East Coast

Commodities

Practices

This proposed project will address the “SARE on-farm research focus areas” of “Alternative crops/animals”, and “Increasing sustainability of existing farming practices”. Oyster seed will be an alternative product for the collaborating hatchery farm to increase the sustainability of the current existing production of hard clam seeds. Developing this alternative product (capacity of oyster seed production) will meet the desperate needs of grow-out oyster farms to pave the way for a more resilient and sustainable oyster aquaculture industry in Florida.

The proposed on-farm research project will benefit the oyster aquaculture industry and provide solutions to overcome the biggest barrier - seed production, which is recognized as the top priority by the industry community.    

1. The wild oysters (over the harvested size) from the oyster beds on Florida’s east coast will be collected as the founder populations in this project. This approach will ensure the compliance of FDACS policy for oyster germplasm management. Meanwhile, the local stocks may have beneficial traits to the environments for long-term oyster domestication. The genetic structure and broodstock number will be monitored to ensure the proper diversity in the founder population for future domestication and seed quality.  
2. The capacity of oyster seed production in the collaborating hatchery farm will be developed. This action will bring many benefits to the Florida oyster industry – increasing an alternative product (oyster seed) that has a guaranteed local market; training and education of the farm staff for oyster seed production techniques (broodstock conditioning, spawning, fertilization, larval culture, setting, and nursery); meeting the demands for oyster seeds by oyster grow-out farms (20 oyster farms with 115.03 acres of leases) for their business sustainability.
3. The proposed project will lay the foundation for further generation of oyster seed production and could yield a well-managed breeding program for seed quality. Despite the rapid growth of the oyster farming industry in Florida, there is no oyster breeding exists to support this growing industry. Broodstock oysters for seed production in most hatchery farms are randomly obtained from wild or aquaculture populations, and accordingly, the seed may have quality issues depending on the parentage’s genetic origin. In other states, such as Virginia and New Jersey, oyster breeding has been ongoing for decades, and specific strains or lines for disease resistance or tolerance of high/low salinity have been developed and widely used by hatchery farms for seed production. Florida has no such a program, considering the long coastline and booming oyster aquaculture industry, it is urgent and highly required to establish a basis for an oyster breeding program in Florida. The growth and performance of oyster seeds in this project will be evaluated by collaborating with at least one grow-out farm (Treasure Coast Shellfish, LLC) and assessed with the parental genetic background for inheritability analysis.   
4. Triploid oyster seeds have become preferred farming products due to their fast growth (8-10 months to reach market size in Florida from nursery seed) and better meat quality. With special approval of FDACS, the triploid oyster seed must be produced using oocytes (also called eggs by farms) from Florida diploids fertilized with sperm from tetraploids. Currently, tetraploid oysters with Florida germplasm are unavailable. Only the tetraploid stocks originating from the Gulf region with proof of health certification can be used for triploid seed production in 1-2 Florida hatchery farms. Therefore, it is urgent to create tetraploid lines with 100% Florida oyster germplasm to support the booming oyster industry. The domestication of Florida wild oysters in this proposed project could be used to create and establish tetraploid lines.   
5. The seed production activities will be conducted in a private hatchery farm (Premium Seafood Inc.), and the oyster seeds from the wild stocks could be used for the oyster reef restoration programs which are actively ongoing on Florida’s east coast.
6. Although the project research activity will be conducted in two collaborating farms, one extension demonstration/workshop with educational materials will be developed for the transfer of techniques and learning of the knowledge of the whole project.

Project Approach

The goal of this project is to develop a program in farms for oyster domestication and seed production to support the aquaculture industry on Florida's East Coast. The supporting objectives are to:

1. Collect wild oysters along the Florida East Coast as a base broodstock and understand the genetic structures.
2. Demonstrate and train the hatchery staff about oyster sex determination, spawning, and fertilization, larval culture, and larval setting.
3. Produce oyster seed by settling eye-stage larvae with chemical induction or addition of cultch (shell pieces) and subsequent nursery.     
4. Evaluate the growth and survival of seeds in grow-out farms to market size for harvest and assess the genetic inheritance.   

The project approach is to conduct all research activities on the collaborating farms, and the farm staff will participate in and get educated about the research techniques. Through this project, it is expected that the hatchery farm will be able to produce oyster seeds independently as an alternative product (besides hard clam seeds), the grow-out farms will have access to oyster seeds originating from local broodstock as their crop, and the oyster aquaculture communication on the Florida West Coast will achieve self-sustainability. Additionally, the F1 oysters from this project could be used for continued selection breeding and triploid-tetraploid breeding. 

The methodologies to be used in the proposed project

Collection of wild oysters on Florida's east coast. 

Wild oysters will be collected from two oyster bed sites with a special research permit or purchased from the oyster dealers. From each site, a total of 150-200 wild oysters will be collected to ensure that 30 males and 30 females will be obtained as broodstock for gamete collection. After collection, oysters will be cleaned and conditioned in the hatchery farm for sexual maturity.

Gamete collection, fertilization, and cohort production with genetic diversity.

For hard clam seed production, natural spawning must be conducted for gamete collection in hatchery farms. For oysters, gamete collection could be conducted by strip spawning (dissection of gonad) or natural spawning. In this project, strip spawning and natural spawning will be conducted for gamete collection, and sex determination will be made by the presence of sperm or oocytes. Sperm will be suspended in 25-ppt sea water, and motility will be examined as quality control. Oocytes will be collected on a 20-µm screen and examined through microscopic observation for size, color, and morphology. The adduct muscle tissue (~1 cm³) from each parental oyster will be sampled and fixed in 96% ethanol for further genetic analysis. Fertilization will be conducted by mixing sperm and oocytes with a sperm-oocyte ratio of 10:1 by microscopic observation. At least, gametes from 26 males and 26 females will be included in the cohort of fertilized eggs for genetic diversity, and if possible, 2x2 factorial crosses will be conducted to produce 52 sibling and half-sibling families. Fertilized eggs will be examined for release of polar bodies and at 2-hr post-fertilization, fertilized eggs (at 2-cell stage) and total eggs will be counted. A total of 50 million fertilized eggs will be produced from this project.

Larval culture, eye-larval setting, and seed nursery.

Generally, the protocol for hard clam larval culture will be applied to oyster larval culture (usually about 2-3 weeks) with feeding and water change. However, due to the different lifestyles of clams (bottom burrowing) and oysters (substrate attachment), the metamorphosis (commonly called setting by farms) needs to be managed differently. The eye-stage larvae (ready for the metamorphosis) will be harvested and separated through a screen, and the “setting” will be conducted by adding clutch sands or chemical induction. After setting, the metamorphosized oysters (commonly called spat by farms) will be cultured in a down-weller/up-weller indoor and then in the land-based nursery system until reaching 2 mm height. A total of 500,000 seeds (at 2 mm) will be produced as single oysters.  

Growth and survival of oyster seed in grow-out farms.

The oyster seed will be distributed to two oyster grow-out farms (Treasure Coast Shellfish LLC at Sebastian and grow-out lease of Premium Seafood Inc) for field culture to market size. During this period (10-12 months), oysters will be sampled every 3-4 months for survival and growth measurement, and the environmental conditions such as temperature and salinity will be monitored accordingly. Sampled oysters (n = 100) will be dissected and tissue will be fixed in 96% ethanol for further pedigree assignment and genetic inheritance analysis.

Production of extension education material

The project activities will be videoed and edited with narrative scripts. These videos will be used as extension materials for training, and education to other hatcheries and grow-out farmers. One workshop will be organized in the collaborating hatchery farm and UF to demonstrate the steps in person. In the long run, the education materials will be posted on the UF shellfish website for the continuation of extension education.