Spring feeding of Atlantic wolffish (Anarhichas lupus) on Stellwagen Bank, Massachusetts

Full life history information is lacking for Atlantic wolffish (Anarhichas lupus), a species of concern in U.S. waters. Scientific studies indicate that Atlantic wolffish are found in low densities-either solitary or, during spawning season, paired. Groundfish surveys show wolffish abundance in U.S. waters is highest in the Gulf of Maine-Georges Bank region, especially in the southwestern portion at depths of 80-120 m. Contrary to these data, commercial fishermen have reported, and we have validated, that high concentrations of Atlantic wolffish are found in specific shallow locations and at specific times on the Stellwagen Bank National Marine Sanctuary (SBNMS) in Massachusetts Bay. From 53 tows conducted during May-June 2011, 395 Atlantic wolffish were captured on the SBNMS. Average daily catch per unit of effort ranged from 0.6 to 37.8 fish h(-1) in an area characterized by shallow (depths: 27-46 m), cold (5-7 degrees C) water, and a sand and gravel substrate. At this site, wolffish were mature (mean age: 20 years; range: 7-33 years) and in prespawning condition, both sexes were equally represented, and 99% of the fish were feeding actively. Total mortality (Z) estimated from the age frequency was 0.35. Considering the observed wolffish abundance and their feeding intensity, it appears that this area of the SBNMS is a foraging area used collectively by a large group of wolffish during May-June.