The Effects of Hook Type and Time-On-Line In Shark Catches In A Pelagic Longline Fishery In The Southwestern Atlantic Ocean

The incidental mortality of sharks due to longline fishing has been widely held responsible for declining populations of several species and, therefore, mitigation measures are urgently needed. Gear modifications, such as the use of circle hooks, in particular, are showing promising results in reducing bycatch mortality, not only of sharks but of several species. The amount of time that the fish remains in the line (time-on-line) is likely to be another important factor influencing fish mortality, in general.

To evaluate this, the catch composition, catch rates, hooking location and time, and number of fish alive at haulback were monitored during 12 sets from a commercial vessel operating in the southwestern equatorial Atlantic Ocean. Circle (size 16/0, 0° offset) and J-style (size 9/0, 10° offset) hooks were deployed in an alternating fashion. Hook-time recorders were used to assess time of hooking. Felipe presented results of this research in a poster platform (see below) during the 28th Annual Meeting and Symposium of the Florida Chapter of the American Fisheries Society in Ocala, Florida, and received the Best Student Poster Award. This research is part of a Cooperative International Project, jointly funded by the U.S. and Brazilian Governments, through U.S. National Marine Fisheries Service and the Special Secretariat of Aquaculture and Fisheries, respectively. The authors would like to give special thanks to Dr. David Kerstetter, Dr. John Graves, Mariana Coxey, Tropical Conservation and Development Program, and Fisheries and Aquatic Sciences Department at the University of Florida.

FPSR Carvalho Poster