Bisack KD 1993 Estimates of total U.S. harbor porpoise bycatch in the Gulf of Maine sink gill-net fishery Northeast Fish Sci Cent Ref Doc 93-11; 23 p https://repository.library.noaa.gov/view/noaa/5374 Bisack Kathryn D Division Resource Evaluation & Assessment READ Protected Species Secondary NEFSC Ref or Lab Document Reports