魚の摂餌に関する生態学的研究-10-天然における摂餌量

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The daily ration of fish in nature is estimated from a comparison between the growth rate of fish in nature and in aquaria. The growth rate of 0-year-old jack mackerel, Trachurus japonicus caught off the coast of Koajiro, Kanagawa Prefecture, indicates 0.249 and 0.172g⁄day in 1957 and 1958 respectively. On the other hand, the growth rate of 0-year-old jack mackerel fed to satiation on pieces of jack mackerel meat once a day indicates 0.501g⁄day, and the growth rates of the fish fed on the food of 2⁄3 and 1⁄3 of the satiation amount indicate 0.350 and 0.154g⁄day respectively. The growth rates of the fish in nature in 1957 and 1958 fall between those of the 2⁄3 and 1⁄3 satiation groups. At this water temperature, the satiation amount of the fish for one feeding a day is about 9% of body weight, therefore, in these waters the daily ration of the fish will be estimated at 3-6% of body weight. Juvenile jack mackerel appear from the beginning of April together with juvenile sardines, and they take food and grow until summer in these waters. The growth rate of the fish will be closely connected with the amount of food in these waters. If the above estimation is correct, in these waters there is not sufficient food to satiate the fish even once a day and they will not attain their maximum growth rate.
日本水産學會の論文