RECRUITMENT TO AMERICAN LOBSTER POPULATIONS ALONG AN ESTUARINE GRADIENT

This study evaluates patterns in the distribution and abundance of new ly recruited (young-of-the-year) and older American lobster (Homarus a mericanus Milne Edwards) along a 22 km length of the Narragansett Bay estuary, Rhode Island, with particular attention to substratum associa tions. This not only represents the first assessment of benthic recrui tment of this species along an estuary, but it is also the first study of lobster recruitment in southern New England. Censuses were conduct ed by divers in a substratum-specific manner. In cobble-boulder habita t, with the aid of a diver-operated suction sampler, I found newly rec ruited (5-10 mm carapace length) lobsters to be most abundant on the o pen coast, with numbers diminishing to zero in the upper bay. Visual c ensuses of older lobsters in the same habitat revealed a similar patte rn. On featureless sedimentary habitats new recruits were absent and l obster densities were at least two orders of magnitude lower than in r ocky habitats. In Narragansett Bay, rocky habitats comprise a small pr oportion of the bottom. The availability of such habitats, the relativ e importance of larval supply and potential physiological stress in li miting recruitment up-bay remain unclear.