Lobster use of eelgrass habitat in the Piscataqua River on the New Hampshire/Maine Border, USA

The relationship between lobsters and eelgrass beds was investigated in the Piscataqua River, which constitutes the lower portion of the Great Bay Estuary, New Hampshire and Maine. The goals of the study were to assess the numbers, size distribution, and sex distribution of lobsters in eelgrass beds, to determine whether lobsters in the eelgrass beds were transients or residents, and to investigate eelgrass density preferences among adolescent lobsters. Eighty percent of the lobsters collected from eelgrass beds were adolescents, measuring >40 to 70 mm carapace length (CL). Of the 295 lobsters collected at four different eelgrass beds, we found an average male-to-female ratio of 1.2. Tag/recapture efforts in eelgrass beds (1.5 to 4 mo interim period) yielded an average recapture of 5.5%. Twenty transects, each 10 m in length, sampled at two eelgrass sites revealed a lobster density of 0.1 m⁻². In mesocosm experiments, lobsters (53–73 mm CL) showed a clear preference for eelgrass over bare mud. Our investigations showed that adolescent lobsters burrow in eelgrass beds, utilize eelgrass as an overwintering habitat, and prefer eelgrass to bare mud.