Population biology of a data poor species, offshore hake ( Merluccius albidus) in the northwest Atlantic, United States

Abstract

Offshore hake ( Merluccius albidus) is a data-poor stock and very little is known about its biology and life history. This paper provides a general synopsis of the data acquired during the National Marine Fisheries Service bottom trawl surveys between 1963 and 2008 for offshore hake in the northeast United States and is limited to those fish found in the northwestern Atlantic. Offshore hake are commonly distributed from southern Georges Bank through the Mid-Atlantic Bight, at depths of 160–550 m and temperatures ranging between 11 and 13 °C. They are known to co-occur with silver hake ( Merluccius bilinearis) on the outer continental slopes of the Atlantic Ocean and are easily confused with silver hake because of their strong morphological resemblance. Spawning generally occurs between April and July. Maximum observed size was approximately 43 cm for males and 56 cm for females, and fish greater than 40 cm consist mainly of females, suggesting that they are sexually dimorphic. Length at 50% maturity ( L 50) also differed significantly between sexes with females maturing at larger sizes (28 cm) relative to males (23 cm). This basic life history information is critical to conserving the offshore hake population and managing sustainable fisheries.