Abstract

The potential for large scale aquaculture of the calico scallop, Argopecten gibbus, has been investigated in Bermuda since 1997. An initial broodstock of 100 mature individuals was collected from Cape Canaveral, Florida, and transferred to a quarantine system at the Bermuda Biological Station for Research Inc. (BBSR). Hatchery and nursery facilities at BBSR are housed in two 20' insulated fiberglass 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 optimallarval rearing. Insulated 1,000 litre tanks are available for larval rearing; post-larval rearing is conducted in 450 L round tanks, and raceways. Using a 4,600 L larval tankage capacity 40,000 5 mm juveniles are generally produced during one spawn. The facilities are compact and efficient, and they may moreover be easily duplicated in any location. A. gibbus is a hermaphrodite species, spawning during the winter months. Larval culture for this species was developed, investigating optimal temperature and food ration. The length of larvallife is 12 days, and approximately 30% pediveligers are obtained from Day 2 larvae. Settlement is performed either by the use of polyethylene mesh or on 150 µm sieves in the raceway; the former method allows for transfer at sea within 20 - 30 days of settlement, minimizing labour during the nursery phase. Juvenile scallops, 10 - 15 mm shell length, are there after grown in suspended cultures. Shell growth rate is rapid, averaging 5 - 7 mm/month, and survival rate from 15 mm to 65 mm shell height is high ranging between 70% and 90%. Reproductively mature and market size individuals are obtained 12 months after fertilization. Market demand for fresh local seafood is high in Bermuda, and supply to selected restaurants has received positive feedback. Further assessment of the market demand is conducted at presento The techniques developed for calico scallop culture in subtropical waters are relatively simple and have yielded a high percentage of mature market size individuals; furthermore, the custom designed facilities have proved flexible in use and efficient. In brief, the technology for A. gibbus aquaculture may be easily transferred to other sub-tropical and tropical locations, providing a reliable supply of shellfish to tourist-oriented areas.

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