Length at Age, Sexual Maturity and Distribution of Atlantic Halibut, Hippoglossus hippoglossus L., off the Northeast USA

This paper presents first estimates of length at age, size and age at sexual maturity, and depth distributions of Atlantic halibut (Hippoglossus hippoglossus L.) off the Northeast USA. The estimates are based on samples collected from spring and autumn bottom trawl surveys in the Gulf of Maine-Georges Bank region (1976–2000) and an experimental longline fishery off the coast of Maine (2000–2001). Longlines targeted larger, faster growing fish than a bottom trawl indicating gear selectivity. Sexual dimorphism in growth was apparent with females attaining greater sizes after age 4. Median age at maturity was estimated to be 6.0 years for males and 7.3 years for females. Adult halibut (>80 cm) occurred at greater average depths than juveniles (<40 cm), but mean depth of capture differed among seasons for all size-classes of halibut. The results suggest that halibut from the Gulf of Maine-Georges Bank region grow faster than those from the Newfoundland-Labrador region. Median ages at maturity of male and female halibut were lower than in other regions of the Northwest Atlantic; however, lengths at maturity were similar.