Habitat Composition Influences Residency and Seasonal Lobster Movements in the Great Bay Estuary, New Hampshire

Estuaries are unique and challenging environments that are often inhabited by American lobster (Homarus americanus). While a portion of the lobsters in the Great Bay Estuary (GBE, New Hampshire) undertake directed, seasonal movements into and out of the estuary, a proportion remain year-round in the GBE. The goal of this study was to determine if habitat composition in certain areas within the GBE influences their distribution and residency, particularly ovigerous females. We used underwater videography surveys along with acoustic telemetry data (from two previous studies) to assess and compare habitats of resident lobsters, as well as habitats where lobsters tended to be less abundant. We found that habitats where lobsters were more abundant were similar to nearshore, coastal marine habitats; more than 70% of these areas were comprised of rocky complexes interspersed with macroalgae. By contrast, habitats where lobsters were less abundant were primarily comprised of sandy, soft sediment (~ 45%). The strong relationship between complex, rocky habitats, and lobster residency in the GBE indicates that high-quality habitat impacts the abundance and distribution of lobsters in the GBE and may help to support a year-round resident lobster population.