Bycatch penyu, hiu, mamalia laut dan burung laut pada perikanan rawai telah tercatat sebagai salah satu faktor utama penyebab turunnya populasi biota laut tersebut di dunia. Penelitian ini bertujuan untuk mengetahui tingkat bycatch penyu, hiu, mamalia laut dan burung laut dan juga opsi-opsi upaya mitigasinya serta menguji efektifitass circle hook sebagai salah satu teknologi mitigasi bycatch biota-biota laut tersebut pada perikanan rawai tuna Indonesia. Telah dilakukan observasi pada 8.564.858 mata kail dari 5.622 setting pancing rawai tuna Indonesia yang berpangkalan di dua pelabuhan utama armada perikanan rawai tuna Indonesia yaitu Pelabuhan Bitung, Sulawesi Utara dan Pelabuhan Benoa, Bali selama periode Mei 2006 hingga Juni 2014, dan membandingkan circle hook ukuran 16/0 dengan tuna hook berukuran mix (13/0, 14/0 dan 15/0) pada 27 armada rawai tuna yang berpangkalan di pelabuhan Benoa, Bali dan berlokasi tangkap di Samudera Hindia pada tahun 2006 ? 2011 dan 2013 . Hasil penelitian menunjukkan bahwa nilai laju pancing (hook rate) per seribu mata kail bycatch hiu di rawai tuna Indonesia sebesar 0,2446, penyu 0,0732, burung laut 0,0030, lumba-lumba 0,0021, dan paus 0,0009. Circle hook layak di terapkan di rawai tuna di Indonesia karena circle hook terbukti efektif untuk mengurangi jumlah bycatch biota laut dilindungi dan terancam punah dan meningkatkan jumlah tangkapan target utama (tuna). Setting dalam dan setting alat tangkap malam hari telah teruji efektif untuk mengurangi bycatch biota laut. Selain itu beberapa praktek mitigasi bycatch lainya telah dibahas dalam penelitian ini.

---

Bycatch of sea turtles, sharks, marine mammals and seabirds in longline fishery is recorded to be one of the major factors that causes declining populations of those critical species worldwide. This research aims to identify bycatch level of sea turtles, sharks, marine mammals and seabirds as well as to pinpoint the mitigation options and examine the effectiveness of circle hook as one of the bycatch reduction technologies applied in Indonesian tuna longline fisheries. In this study, a total of 8,564,858 hooks were observed from 5,622 gear settings in Indonesian tuna longline fisheries based in two major fishing ports, namely Bitung Fishing Port - North Sulawesi and Benoa Port - Bali from May 2006 to June 2014. The applications of 16/0 circle hook size and mixed tuna hook sizes of 13/0, 14/0 and 15/0 from 2006 to 2011 in 27 tuna longliners based in Benoa - Bali were also compared. Fishing ground of those fleets was mostly in Indian Ocean. The results suggest that hook rate per thousand hooks in Indonesian tuna longline fisheries for shark bycatch is 0.2446, 0.0732 for sea turtle bycatch, 0.0030 for seabird bycatch, 0.0021 for dolphin bycatch and 0.0009 for whale bycatch. Circle hooks are suitable and applicable for Indonesian tuna longline fishery due to circle hooks is proved effective to reduce protected and endangered marine species while still can increased the target catches (tuna). Deep setting system and night setting also proved effective to reduce those bycatch of marine species. Others bycatch mitigation practices has been discussed in this study.