魚の摂餌に関する生態学的研究-VII

投餌回数と飽食量との関係

抄録

In the previous reports^{1 ?? 6)} the amount of food sufficient to satiate a school of fish in a single feeding was given and conditions affecting the satiation amount were discussed. In the present investigation, the relationships between the frequency of feeding and the daily ration, and between the frequency of feeding and the satiation amount at each feeding, are examined. The results obtained are summarized as follows:
As the frequency of feedings increases, the daily ration increases but the maximum value is soon reached (Figs. 1 and 2). The relationship between the frequency of feeding and the mean ration per day per fish can be expressed by the formula,
F=F'T(1-α)^T-1
where F=mean ration per day per fish (grams), F'=mean ration per day per fish for one feeding (grams), T=frequency of feeding per day, α=rate of decrease. These constants obtained are shown in Table 5.
The satiation amount at each feeding is greatest with one feeding per day, and decreases with increase in frequency of feeding. With fishes that do not feed at night the satiation amount in the morning compared with those in the daytime and the evening is not necessarily the largest, in spite of the fact that no food is taken for the previous 12 hours (Fig. 1).