Many useless benthic animals are contained in the catches of small trawlers. Small crabs are one of these unutilized resources. Attempt was made to use these animals as food in rearing of the Kuruma prawn, Penaeus japonicus BATE. The experiment was carried out using these small crabs and clam meat during low-temperature season from late October to late December, 1964.
Comparison of the growth between the two groups fed on clam meat only and on the mixture of clam and crabs, respectively, clarified that the latter group grew more rapidly than the former. Molting was observed only at temperatures above 15°C. in both groups.
A positive correlation was shown between the feeding rate per day and the mean temperature of 10-day period; namely, at 12°C., the feeding rate was as low as about 2%, and with the elevation of temperature, especially above 16-17°C., increased remarkably.
Furthermore, the correlation between the feeding rate per day and the growth rate was also positive, revealing that the daily ration necessary for the maintenance of body might be 2-3 % of the body weight.
The prawn fed with the mixture of clam and crab meat took the two kinds of food in approximately the same clam/crab ratio as was given. This fact seems to show that in the feeding of the prawn there is no selectivity as to the two kinds of food.