Evaluation of Fixed-Station Sampling for Lobster Settlement Survey in the Mid-Coast Region of Gulf of Maine

The American lobster (Homarus americanus) supports one of the most valuable fisheries in the northeastern U.S.. Most landings occur in the coastal Gulf of Maine (GOM). A settlement survey has been conducted for monitoring the early life history of lobster and providing abundance indices of newly settled lobster. Using data collected in the GOM from 1989 to 2008, we evaluated the performance of this program in capturing spatio-temporal variability in lobster population. We found that the young-of-year lobster density was closely correlated with older juvenile lobster density, and predicted the distribution of young-of-year lobster density and associated variances based on the older juvenile lobster density distribution. We applied fixed-station and random station sampling designs to the generated population of young-of-year lobsters. Combining the simulation and analytical approach results, we found that fixed-station sampling tends to underestimate the mean of young-of-year lobster density. Fixed-station sampling design is more likely to detect the temporal trend of mean young-of-year density compared to the random sampling design. This study improves our understanding of performance of sampling design used for current lobster settlement surveys in the northeastern U.S..