Seabird bycatch in dolphinfish longline and tuna handline fisheries off south-southeasten Brazil

We present new information on the current levels and seasonal variation of seabird bycatch rates in dolphinfish and handline fisheries off south-southeastern Brazil, obtained via extensive port interviews (data self-reported by vessel captains) and scant on-board observation. For dolphinfish longline, 51 trips were reported from 32 vessels, covering 395 sets and 402,260 hooks. In total, 94 seabirds were reported caught, including 68 brownboobies (Sula leucogaster), seven Procellaria petrels, six non-identified albatrosses, two Atlantic yellow-nosed albatrosses (Thalassarche chlororhynchos) and 12 unidentified seabirds, resulting in an overall and maximum BPUE of 0.234 and 1.923 birds/1000 hooks, respectively. Excluding the bycatch of brown-boobies, and considering the ‘unidentified seabirds’ as albatrosses or petrels, seabird bycatch was reported for 13 (25%) of the trips and the overall and maximum BPUE was 0.067 and 0.416, respectively. For handline, a total of 89 trips from 26 vessels were reported, covering 873 fishing days. Seabird bycatch was reported for 31 (35%) fishing trips, totalizing 42 seabird, including 16 Procellaria petrels, 12 non-identified seabirds, seven brown-boobies, four Atlantic yellow-nosed albatrosses and four unidentified albatrosses (BPUE= 0.048 birds/fishing day). Bycath rates were higher during winter months for both fisheries. Considering the bycatch rates and the huge effort of both dolphinfish longline and tuna handline fleets, the total mortality in these fisheries represent a potential unaccounted threat to a number of species already killed by pelagic longline fisheries in the southwestern Atlantic.