Incidental catch of seabirds and sea turtles by Taiwanese longline fleets in the Indian Ocean between 2009 and 2015 x

Observers data collected from 149 Taiwanese tuna longline vessel trips, including 14 albacore large-scale tuna longline vessel (LTLV) trips, 41 bigeye LTLVs trips, 57 trips of southern bluefin tuna(SBF) LTLV, 2 trips for part-time-SBF LTLV, and 35 small-scale tuna longline vessel (STLV) trips between 2009 and 2015 were analyzed. Four hundred and forty-four seabirds and 55 sea turtles were incidental caught. Most seabird bycatch was from the SBF LTLVs (64.6%) and 30.4% from albacore LTLVs. There were limited seabird bycatch in the north of 30 S. The highest rate was 0.201 bird per thousand hooks in the south of 30 S Indian Ocean in the first quarter by albacore LSLVs, followed by the same area, last quarter by SBF LTLVs (0.087 bird per thousand hooks). For bycatch species, 64.4% were albatrosses, including yellow-nosed, wandering, sooty, and shy-type, northern royal, white-capped, light-mantle, black-browed, and grey-headed albatrosses. Other seabird included white-chinned petrel, giant petrel and others. Regarding sea turtles, the high bycatch areas were between 10° N ~15° S, 60° ~90° E. The bycatch rate peaked in the third quarter by STLVs (0.0108 turtle per thousand hooks), followed by same fleet in the first quarter (0.0099 turtle per thousand hooks). The major bycatch species was olive ridley (71.0%). The numbers of other species are very limited.