Patterns in abundance and growth of juvenile lobster, Homarus americanus

Abstract

The combined effort of assessing abundance and measuring the time between settlement and recruitment is fundamental to forecasting future recruitment to the lobster fishery. This study represents the first monthly year-round sampling for abundance and in situ growth of juvenile lobster, Homarus americanus. Juvenile lobsters for repeated mark-recapture surveys were tagged in situ, so disturbance to the animals was minimal. From direct measurements of tagged individuals, lobsters up to 17 mm CL were estimated to be within their first two growing seasons. Some juveniles in the study area were recaptured up to four years later, indicating use of this nursery habitat for the first four to five years of benthic life. The purpose of sampling year-round was to detect patterns in abundance and identify the optimal time of year for sampling designed to determine trends in abundance. The relative abundances of young-of-the-year and later juvenile lobsters incorporated significant seasonal cycles (P < 0.0001). No monotonic interannual trend was detected (P > 0.05), indicating no overall increase or decrease in abundance from 1993 to 1999. Year-round monthly sampling of the lobster population is producing valuable information on patterns in abundance and individual growth rates.