集魚灯に集まる魚類の網膜運動反応の前・後半夜での比較
1991 年 57 巻 3 号 p. 425-431
詳細
1991 年 57 巻 3 号 p. 425-431
In order to investigate the differences in retinomotor responses between pre- and post-midnight phases, the responses in chub mackerel angled under a fishing lamp and those in sardine caught by nighttime purse seining were examined.
The adaptation ratio determined in the cone and pigment layers of chub mackerel indicated no direct relationship to illuminance at angling point, but showed a large variation.
Chub mackerel were mostly angled at a light intensity ranging from 10-1 to 10-3 lx, and were angled more frequently in darker areas post-midnight than pre-midnight.
The correlation between cone migration and pigment migtation was high previous to midnight, but was low subsequent to midnight. This tendency was observed in both species.
If these results are due to circadian rhythms corresponding to retinomotor responses, operating time in lamp fishing operations should be considered in commercial endeavors.
