Habitat addition and stock enhancement for American lobsters, Homarus americanus

Six experimental artificial reefs for lobsters were established in Narragansett Bay, Rhode Island, in February 1997. These have been monitored according to a ‘before-after-control-impact’ design since placement by means of visual surveys, traps, tag-recapture, photoquadrats, and airlift sampling. Juvenile and adult lobster density at the reef increased from near zero to >1 lobster m–2, significantly higher than the two control areas. Settlement of young-of-year lobsters has significantly increased. We used microwire tags to mark hatchery-reared lobsters and released over 2000 marked 5th–6th-stage lobsters in each of two years. The density of young-of-year lobsters on enhanced reefs was not different from that on the control reefs. Despite intensive sampling, we have recovered only one of the hatchery-reared animals. Field observations indicate possible behaviour differences in the hatchery-reared lobsters that might make them more susceptible to predation.