By Jim Swartzenberg J&B AquaFood and Skip Kemp Carteret Community College -CULTURING OYSTERS- In North Carolina WWhhaatt ttoo ddoo aanndd hhooww ttoo ddoo iitt WWhheerree ttoo ggoo ffoorr hheellpp TThhee rreewwaarrddss aanndd tthhee ppiittffaallllss Table of Contents I Introduction .……………………………………………………..1 II What are cultured oysters? …………….……………………...…5 III Business Requirements …………………………………………..7 IV Raising and Acquiring Seed ………..…………………………..15 V Culture Methods ………………………………………………...21 VI Predators, Pests, Competitors, Diseases, Defense Mechanisms ...35 VII Shellfish Sanitation ………………………………………………45 VIII Markets and Marketing …………………………………………..49 IX Business Investment ……………………………………………...53 X Natural Forces …………………………………………………….61 Appendix A — Dining Room Dermo Testing …………………………….69 Appendix B — Hazard Area Critical Control Point ……………………….75 Appendix C — Lifecycle of an oyster ……………………………………..85 Appendix D — Marine Fisheries Rules and Regulations ………………….87 Appendix E — Sample Lease Management Plan ……..…………………103 Appendix F — Small Business Plan ……………………………………..109 Appendix G — Sources …………………………………………………..111 Appendix H — The Systems at a Glance ………………………………..119 CULTURING OYSTERS IN NORTH CAROLINA Introduction I Years of Research his manual is the result of several years of research and development by many people with varying backgrounds. It draws heavily on the experience of others. So in that TTrespect, few of the ideas are really new. After all, culturing oysters can be traced back to the early Romans who found that broken roof tiles that had fallen in the water made good spat collectors. Since then, various cultures have modified those techniques, so that very little is new in this business — just a lot of adaptation and redesigning from the old ways. For purposes of this manual, oyster culture is distinguished from oyster restoration and rehabilitation. Oyster culture is a sustainable enterprise, requiring a shellfish lease from the state, and is a private, for-profit commercial enterprise. Oyster restoration and rehabilitation can be a private or state effort on public bottom, with no claim of ownership and no intent of economic feasibility. If oyster reefs are harvested, they are not sustainable without additional planting; whereas, oyster culture involves yearly planting and harvesting to maintain a sustained harvest. For North Carolina, you might say, it all started in the early 1990s when Alfred “Al” Evans, a product design specialist from Tipper Tie, Inc. in Apex, NC, telephoned Philip “Skip” Kemp, then an extension specialist from North Carolina Sea Grant Advisory Service, at Members of the that time based at the N.C. Aquarium on Atlantic Beach. Oyster Corps Tipper Tie produces and leases the machines that put carried home aluminum clips on the mesh food bags, called chubs, that hold food products such as sausages and turkeys. the ladders to a Evans had the idea that Tipper Tie’s food packaging total of 30 sites. materials could be used in the aquaculture industry for growing oysters. Although somewhat copied from the mariculture techniques of Washington State and France, he thought his products might be compatible with some sort of new technique and design for growing East Coast oysters. They labored many months with the idea that they could come up with a system that would somehow resemble agricultural techniques used on a farm. This meant they had to design a mechanized plant-to-harvest system that would be user-friendly and adaptable to fairly large numbers. After all, the French, Japanese, and even Americans on the West Coast had been doing this sort of “oyster farming” for many years. So it just seemed natural, that it could be done on the East Coast, USA. 1 CULTURING OYSTERS IN NORTH CAROLINA After about a year, they formed an “Oyster Corps” of volunteer leaseholders who attended several workshops and helped assemble “chub ladders,” which were the final product from the Evans/Kemp research project. Members of the Oyster Corps carried home the ladders to a total of 30 sites. With the blessing of the Division of Marine Fisheries, each participant was granted a 540 square foot research water column sanctuary in which to float their oyster chub ladders. It was a good year for the test. There was ample rainfall and no hurricanes to tear up the chubs. As we’ll see later in this manual, these two factors are vital to the success of a good crop. The oysters were measured at two, five and fourteen-month intervals. At the best sites, up to 68, 76, and 100 percent of the oysters sampled were of market size at the end of the test. Oyster growth varied considerably among the sites. The best sites appeared to be in the mid- to high-salinity ranges. However, the best guess at the time was that the growth was probably more closely related to a combination of the energy level and flow of the water, along with the food supply, than it was to the salinity. That debate still goes on. In any case, the project appeared to be a success, helping to speed up the growth rate of the oysters and to keep them healthy during peak disease seasons. Both Kemp and Evans, along with other marine scientists at Sea Grant, hoped this new method would circumvent the effects of diseases such as dermo that kill oysters in their second year of growth. Ongoing oyster culture research and development projects continue to add to the knowledge base for growing oysters. Now, more than a decade later, after many different configurations, starts and stops, successes and failures, this manual is being compiled to explain the systems, evaluate their strengths and weaknesses, and outline how to implement them successfully. If there is one key lesson to learn as you follow the Farming process from start to finish, it is that farming oysters is not an exact science. It simply does not work the same way at all oysters is not an sites, at all times, under all conditions. Farming oysters is a exact science. very fluid and flexible process that one must master at a It is a very fluid specific place and time. Oyster farmers have to be ready to change midstream and adapt to varying factors. They have to and flexible expect that the same end product will not always be the final process. result and that there will be good years with bumper crops and bad years when the crop is a total loss. The methods described in this manual are not the end-all and be-all of oyster farming but perhaps a beginning. There has been enough research to provide a long list of lessons learned, of what to do and of what not to do, but even with the best of methods, the uncontrollable forces of Mother Nature tend to prevail. Stretches of drought that result in unusually high salinity for prolonged periods of time, for example, can wreak havoc on any system of confinement that oysters are subjected to. During these times, the sea mosses and sea squirts tend to clog up the containers, slow down the growth of the 2 CULTURING OYSTERS IN NORTH CAROLINA oysters, and invite such devastating predators and diseases as mud blisters (polydora) and dermo (Perkinsus marinus). The same forces that allow for a fast-growing oyster most likely have the same effect on the pathogens that spark the disease. When diseases attack in mass, a crop can be lost very quickly. Development of a fast-growing, disease resistant strain of oysters is primary for the advancement of the industry. Even then, the new strain would be effective only in an aquaculture situation — and then only as long as the strain can be maintained. Researchers in Virginia toyed with the idea of a new disease-resistant strain to repopulate unproductive and lost public areas in the Chesapeake Bay, but their attempts so far have ended in failure. They found that their “designer” oyster can augment and enhance the wild population, but then through spawning with wild stocks, it simply reverts to the dominant genetic stock and soon dies out. Aquaculture is not intended to supplant the wild fishery or other techniques such as relay, tonging, and dredging, but rather to provide a sustainable source of seafood for discriminating consumers. With enough people involved in the cultured oyster industry, the benefits should soon spill over to the waters that surround the leases. This manual is a follow-on to one that describes raising the seed titled, “Farm Raising of Oyster Seed.” Whether you raise your own seed or buy it ready to plant, it might be a good idea to look at both manuals before starting a project. There is an accompanying video to “Farm Raising of Oyster Seed” that provides a brief overview of how some systems work. This manual examines several off- bottom techniques for raising oysters, Figure 1: These triploid oyster seed, about including the rack and cage, oyster chub, two months old, will reach maturity and be long-line bag, and bottom/stackable cages. ready for market in about eighteen months. Though it uses the term “off-bottom,” some methods that place the oysters on or very near the bottom, but in confined and controlled environments, adapt well to farming techniques. In addition, this manual presents the tools, techniques, economics, and other business aspects that go into a successful and profitable crop of oysters. 3 CULTURING OYSTERS IN NORTH CAROLINA written in digital format, is intended to be user friendly. It T his interactive manual, may be printed from a personal computer with a CD-ROM drive and printer. The text comes with helpful tools, which expand the scope and add links to many details unavailable in a p rinted text. Though it may be printed out and maintained in a binder for ease of use, to experience the full potential, it needs to be accessed on a computer with an Internet hookup.