Gulf of Maine Data-Poor Species Assessments Enhanced By a Cooperative Bottom Longline Survey

A cooperative bottom longline survey (LLS) was initiated to sample complex rocky habitats that are less available to bottom trawl surveys (BTS). One objective was to collect distribution, length-frequency, and life history data on data-poor species not well represented in BTS catches. The LLS captured seven data-poor species (including barndoor skate, smooth skate, tilefish), of which four are NOAA species of concern (Atlantic wolffish, Atlantic halibut, cusk, thorny skate), and two are candidates for listing by NMFS under the Endangered Species Act (cusk, thorny skate). Catches differed between the surveys for some data-poor species, particularly cusk and thorny skate which were more common in the LLS. For these two frequently captured species, the additional LLS data will help identify preferred habitat, including within two closed areas, and a better understanding of seasonal distributions. Some species (e.g. halibut, wolffish) were rarely captured in either the BTS or LLS; therefore, the LLS provided valuable supplemental size distribution and life history data. Size distributions differed for some species between surveys, but combined to provide a more complete size distribution for the survey region. Furthermore, samples of data-poor species from the cooperative LLS allowed improved analysis of sex ratios, maturity schedules, and age structure.