Cooperative Institute for Marine and Atmospheric Studies, Rosentiel School for Marine and Atmospheric Science, University of Miami
Circle hooks and J-style hooks were tested on pelagic longline vessels (US Atlantic) to determine if the use of circle hooks reduced bycatch mortality while maintaining target species catch rates. 00 offset circle hooks were determined to increase the survival of bycatch species at haulback while having little impact on target species catches. Specifically, J-style hooks had a significantly higher total overall catch rate. Catch rates of yellowfin tuna in the fall were higher (significantly) for circle hooks and pelagic stingrays (spring caught) were the only species that had a significantly higher catch rate on J-style hooks. Circle hooks caught four times as many yellowfin tuna in the mouth compared to J-style hooks. Yellowfin tuna and dolphinfish caught on circle hooks in the fall and spring respectively, were significantly larger than those caught on J-style hooks. Survival rates of dolphinfish and escolar were statistically higher at haulback when circle hooks were used in the fall and spring respectively.