In order to clarify the relation between the characteristics of the branch line of the tuna long line and the activity, mortality and escape of the live bait (horse mackerel), a comparative test was carried out using three kinds of synthetic fibers and a wire as snods.
The results are as follows;
1) In the case of the synthetic fibers, few fish died and many escaped, while in the case of the wire, many fish died and few escaped. (Table 1.)
2) As for the fish which had survived eight hours on hook, there were few showing high activity among many less active fish in the case of both the wire with its large specific gravity and hardness and the hizex with its especially small specific gravity and hardness. On the other hand, there were many active and few less active fish in the case of both the tetoron cord and the cremona which are medium in specific gravity and hardness. (Table 2; Fig. 1, 2, 3.)