Longline terminal gear identification guide

This guide will help observers, researchers, and captains of longline boats to correctly identify hooks, swivels, trace lines, and baits used in pelagic longline fishing. It is important that longline terminal gear is correctly identified as it has an effect, not only on target species catch rates, but on catch rates and post-release survival of bycatch species including marine turtles. The guide is divided into four sections: hooks used in longline fishing, swivels, trace lines, and baits (including lightsticks). Of these, the most important are longline hooks, as past and current research is showing that the use of large circle hooks reduces the catch rate of some bycatch species while improving (or not affecting) the catch of target species. Circle hooks also improve the chances of post-capture survival of released bycatch species. Standardization of hook types and sizes is therefore very important for data recording and analysis for observer logsheets, wheelhouse logsheets, and for scientific studies on the effects of terminal gear on catch rates and post-capture survival. Japan tuna hooks and Teracima hooks are measured in 'sun', a Japanese measurement equivalent to just over 3 cm. This refers to the length of material in the hook from eye to point. Circle hooks and J hooks are sequentially numbered - the larger the number, the larger the hook-, but circle hooks and J hooks with the same number are not the same size. Spanish hooks (a type of J hook) are numbered in a descending order - the larger the hook, the smaller the number.