Oyster farmers and gardeners not planting in ground use cages, bags or baskets based on their water site. FLUPSY’s are typically as interesting and unique as the oyster farmers who create them.įiberglass containers allow for easy moving and sorting. These are very efficient in moving high volumes of water laterally for circulation and nutrient introduction to oysters before grow-out. Upweller systems allow farmers to grow and sort seed in a concentrated area. These spats are typically sold to and used by farmers who are growing in bags, cages and racks, not those growing on water way bottoms. Used for promoting eyed larvae to attached on similarly sized micro-cultch for spat on tiny shell. These sets of spat shell are typically used by farmers who plant oysters on water way tidal grounds. Setting: Tiny eyed oyster larvae are attached to a cultch (substrate of oyster shell). When shipped out to oyster farms for setting, these millions of eyed larvae appear like lumps of sand and mud. This process helps maximize healthy production of eyed larvae for setting. Nutrient rich algae are circulated in these super-sized tanks to feed oyster larvae. These tanks provide nutrient rich food critical for the early oyster development phases. Once the “eye” appears, the oyster larvae are ready for setting, shipment and sale. Generations of waterman live here.īasketed and bagged oysters are maintained at a proper temperature and salinity to allow good spawning to take place. They are then considered to be competent for metamorphosis, ready for the setting phase.Dorchester county has a long, rich history of aquaculture. When they reach a size of 250 microns, the larvae become eyed, going from the veliger stage to the pediveliger stage.

The water is then changed and feeding is carried out on a daily basis with the different species of phytoplankton specified above. The larvae are regularly harvested on sieves of increasing size to check their growth and separate the biggest from the smallest. The resulting larvae then spend around twenty days growing. In triploid spawning, the eggs are crossed with sperm taken from tetraploid males supplied by IFREMER.Ģ4 hours after fertilisation, the larvae have usually gone from the trochophore stage to the 'D'-larva stage (they are D-shaped). In diploid spawning, the eggs are mixed with the sperm taken from our diploid males. Individual sex is then determined by observation under the microscope and the females are separated from the males. With the latter technique, gametes (sperm and eggs) are obtained by gonad laceration. In the former technique, mature broodstock is placed into small individual spawning units and subjected to a number of shocks to stimulate the spontaneous release of gametes. Spawning can be induced by thermal shock or scarification. After a few days, the algae cells have multiplied and the operation is repeated until enough has been produced to feed the stock. The production process is sequential : every day a small volume of culture, known as inoculum, is diluted in a greater volume of well water. Feed microalgae can either be produced inside lit, temperature-controlled rooms or in outdoor ponds exposed to sunlight. The phytoplankton used to feed the broodstock and larvae is grown using a variety of methods depending on the species. Tetraploid broodstock is produced and kept by IFREMER and its supply for the production of triploid spat is tightly controlled and secure. Each batch is cleaned and fed every day with various species of phytoplankton. In the event of losses or poor analysis results, the batch is discarded. All the batches are monitored and analysed in order to ensure they are healthy from the start. Hot temperature conditions accelerate maturity at the start of the spawning season and colder conditions slow down the maturation process until the start of the autumn. It is thus possible to have spawning throughout the year by adapting the temperature and quantity of food. This staggered approach enables us to prepare mature oysters from January through to September. Once selected, these adult oysters are carefully cleaned and placed in rearing tanks on a two-monthly basis, from November to July. The activities that take place in this unit can be split into three categories: broodstock maturation, the production of phytoplankton and larval growth.įor several years now, diploid broodstock has been selected on the basis of origin and overall performance in terms of growth, shape, robustness, etc. The seawater used is filtered and purified on-site. This first phase takes place in controlled conditions in a purpose-built facility. The oyster hatchery represents the first phase in the oyster spat production process.

Algae species feed for oyster spat