[slideshow effect="slide" category="42" width="" height="330" autoplay="5000" speed="1000" pagination="false" prevnext="true"]

About the Industry

Take a Look at Florida Clam Farming

Changing Seas – Farming the Seas, Part 1, Produced by WPBT2 Miami

Cedar Key Clams: Fishermen Farming the Sea, Produced by UF IFAS

Industry Components

The components of clam farming consist of three consecutive biological or cultural stages—production of small seed in a hatchery, rearing of larger seed for field planting in a land-based nursery, and growout on an openwater lease to a marketable size.

Hatchery: Clam culture begins in the hatchery with the production of seed. While hatchery techniques are well defined, they are fairly complex. In addition, a hatchery operation requires a capital investment in property, facilities, equipment, and skilled labor. For these reasons, most growers prefer to purchase seed from a hatchery. There are 8-10 hatcheries in the state, ranging from small backyard operations to commercial-sized facilities, which provide almost a half billion seed annually. In the hatchery, adult clams, or broodstock, are induced to spawn by manipulation of water temperatures. Fertilized eggs and resulting free-swimming larval stages are reared under controlled conditions in large tanks filled with filtered, sterilized seawater. Cultured marine phytoplankton, or microalgae, are fed at increasing densities during the 10 to 14-day larval culture phase. After which, pediveliger larvae begin to settle out of the water column, or metamorphose. Even though a true shell is formed at this time, post-set seed are microscopic and vulnerable to fluctuating environmental conditions. They are maintained in the hatchery for another 30 to 45 days in downwellers until they reach about 1 mm in size.

Nursery: This component serves as an intermediate stage and provides the small clam seed produced in a hatchery with an adequate food supply and protection from predators until they are ready to be planted for growout. Nursery systems built on land usually consist of wellers or raceways. A weller system consists of open-ended cylinders placed in a water reservoir. Seawater circulates through the seed mass, which is suspended on a screen at the bottom of the cylinder. The direction of the water flow defines whether the system is referred to as a downweller or upweller. Raceways consist of shallow tanks or trays with salt water pumped from an adjacent source providing a horizontal flow as opposed to a vertical flow in the wellers. The water flow provides food (naturally occurring phytoplankton) and oxygen to the seed. Many growers are attracted to the nursery option as seed costs are lower and, at times, smaller seed are more available. Further, the systems can be constructed inexpensively and maintained on a part-time basis. Depending on water temperatures, 1-2 mm seed require from 6-12 weeks to reach 5-6 mm in shell length, the minimum size planted in the field. Currently, about 40 land-based nursery facilities are located statewide. These systems can be novel, such as floating upwellers or FLUPYS, which are employed at specific sites, usually marinas.