釣漁業における餌料の研究-II

Abstract

On the effect of aliving fish for tuna long-line bait, the rate of death and hooking off are, comparatively tested under different conditions as the position of hooking (Fig. 1) and the kinds of fish for bait. The results obtained are as follows: 1) In three kinds of bait fish, young yellow tail, Seriola quinqueradiata (TEMMINCK and SCHLEGEL), shows small number of death but large number of hooking off, mackerel, Scomber tapeinocephalus BLEEKER, shows large number of both death and hooking off and horse mackerel, Trachurus trachurus (LINNÉ), is seemed to be best for aliving bait showing small in number of both death and hooking off which are shown in Table 1. 2) The number of death and hooking off increase with almost same rate with elapsed time in every kinds of bait respectively. The position of hooking c and d are comparatively large number of both death and hooking off as shown in Fig.2. 3) The survival rate after six hours hooking, the position of hooking a is nearly 75 percent, b is over 60 percent and c and d are under 50 percent except horse macherel as shown in Fig.3.