Can scallop farming expand in the
Inland Water Resources and Aquaculture Service (FIRI)
FAO Fisheries Department, Rome
Alessandro.Lovatelli@fao.org Last February 2002, Mr Alessandro Lovatelli, Fishery Resources Officer (FAO, FIRI), visited the Bermuda Biological Station for Research (BBSR) to investigate the possibility for FAO and BBSR to collaborate in the transfer of farming technology developed for two scallop species in the Caribbean Region. The BBSR has successfully developed and commercially tested the culture techniques for all stages of the Bermuda sand scallop (Pecten ziczac) and the Calico scallop (Argopecten gibbus). These two species are native to the Caribbean Sea, but the natural fisheries have been heavily exploited and are currently depleted. Both species are considered suitable aquaculture candidates from both the farming and marketing prospective. The Calico scallop supports a fishery off the east coast of Florida (Cape Canaveral) and has a northernmost distribution off Cape Hatteras (North Carolina) and Bermuda. This scallop species is also found in the Gulf of Mexico and in the Caribbean along the coasts from Cuba to Puerto Rico.
The BBSR has designed and developed a low-cost hatchery for larval and postlarval production. This facility is housed in 2’ x 20’ second-hand insulated fibreglass containers; an independent seawater system allows for the continuous supply of filtered seawater; a temperature control system for seawater further allows for broodstock conditioning and optimal larval rearing. Insulated 1000 L tanks are used for larval rearing, while postlarval rearing is conducted in 450 L round tanks and raceways. Phytoplankton culture is carried out in a separate container, which is fitted with an independent filtration and UV disinfection system. The output of 100 L per day is sufficient for the hatchery requirements. The current set-up allow for the production of 250 000 5 mm spat.
Spawning of the Calico scallop is induced during the natural reproductive cycle (January to May in Bermuda), while larvae and postlarvae are reared under controlled conditions in the hatchery/nursery facility. The length of larval life is 12 days, and approximately 30 percent pediveligers are obtained from 2-day larvae. Settlement is performed either by the use of polyethylene mesh or on 150 µm sieves. The 10-15 mm juveniles are then grown in pearl nets suspended on long-lines. Shell growth rate off Bermuda is rapid, averaging 5-7 mm/month, while the recorded survival rates from 15 mm to 65 mm shell height have also been high, ranging between 70 and 90 per cent. Reproductively mature and market-size individuals are obtained 12 months after fertilization.
The farming techniques for the two scallop species, and in particular those for the Calico scallop, can be transferred to the Caribbean Region; however, the BBSR does not have a mechanism in place for extending the technology to neighbouring countries. One possible role envisaged for FAO is to inform the Caribbean countries on these recent developments and provide them with technical assistance, if requested. In this respect, the BBSR favourably expressed its interest in collaborating in the transfer of the farming technology developed through technical cooperation projects in the region.