Book Description

"This report presents the 1998 estimates of the bycatch of marine mammal and sea turtle taken by the part of the U.S. Atlantic pelagic longline fleet that lands tuna and Atlantic swordfish. The information is required by NOAA Fisheries to meet its responsibility for management of interactions between protected species and commercial fisheries based on the level of incidental serious injury and mortality. Serious injury is defined under proposed guidelines drafted by the NOAA Office of Protected Resources, and is equated to mortality for the purpose of bycatch estimation. Estimates were based on bycatch rates from a representative sample of the fleet recorded by scientific observers, and fishing effort reported by the fleet. Bycatch rates reported by the fleet were omitted. Estimates were constructed using the Delta-lognormal method. Robustness of the estimates to geographical and temporal effects was examined by pooling across strata (calendar quarters, fishing areas, and groups of species). Point estimates of bycatch were relatively insensitive to pooling treatments, but gains in precision of estimates (coefficient of variation) were attained in cases where bycatch numbers were relatively high. The total observed bycatch in 1998 amounted to six for marine mammals and 20 for marine turtles. Extrapolated to total fleet effort, the most precise estimate (pooling within years, within the three major fishing areas, and grouping of species) indicates that the US pelagic longline fleet operating in the Atlantic caught a total of 205 (57-828, 95%CI) marine mammals in 1998. Of these, the estimated number of marine mammals that were dead or seriously injured and thus presumed dead is 54 (10-277, 95% CI). For marine turtles, an estimated total of 728 (337-1824, 95%CI) were caught by the fleet in 1998. Of these, the estimated number that were dead or seriously injured and presumed dead is 708 (324-1788, 95% CI). Both marine mammals and turtles were mostly caught from the Grand Banks (Northeast Coastal region) fishing area of the US Atlantic EEZ"--Summary.