In order to make clear the relation between the size of live bait and its activity, mortality and escape in tuna long-line fishery, a comparative test was carried out using the horse mackerels of two different sizes, larger or smaller than those of usually used bait. The methods of the test were the same as previous paper (IV).
The results are as follows.
1) The escape of large fish attains to 20% in slightly hooked bait (b), and to 14% In deeply hooked bait (b'). In the case of b, a lot of branch-lines were entangled. The mortality was only 4-2% in both cases. While in the case of small fish, the mortality and the escape of b, b' was 4% respectively. (Table 1, Fig. 1).
2) As regards the activity of live bait after eight hours on hook, b was found to be excellent than b' in the case of both the large and the small fishes.
Generally speaking, the maintenance of live bait seems to be superior in small fish than that of large fish. (Table2)
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