真珠養殖の貝掃除に関する研究-III. : 付着生物がアコヤガイの酸素消費量におよぼす影響

抄録

MIYAUTI, Tetuo (Laboratory of Takashima Pearl Farm Inc., Sasebo). Studies on the effect of shell cleaning in pearl culture-III. The influence of fouling organisms upon the oxygen consumption in the Japanese pearl oysters. Jap.J.Ecol. 18,40-45 (1968). In the Preceding papers, it was reported that the activity of shell movement, the amount of feces, the shell regeneration and the byssus secretion in the Japanese pearl oysters, Pteria (Pinctada) martensii (DUNKER) were decreased by the presence of fouling organisms. In order to clarify whether the work of shell cleaning is effective for increasing the growth of the bivalve and the quality of the pearl, the harmful influence of the presence of fouling organisms upon the oxygen consumption of the Japanese pearl oysters was studied in the present paper. Fouled pearl oysters were reared in three pearl farms in Sasebo Bay and their oxygen consumption before and after shell cleaning was measured. The apparatus employed was similar to Hall's experimental apparatus using the running water system. The results obtained are as follows : 1. The oxygen consumption in fouled pearl oysters changes by cleaning the shell; the rate of oxygen consumption in the cleaned pearl oysters amounted to nearly constant (0.07-0.10cc/g wet tissue/hour) for 14 days after shell cleaning. It seems that the rate of oxygen consumption was relatively slow in recovery. The recovery of the rate of oxygen consumption changes by the degree of the ill-effect of fouling organisms in fouled pearl oysters. 2. The rate of oxygen consumption in pearl oysters has close relation to the weight of the fouling organisms in fouled pearl oysters ; the greater the weight of fouling organisms is, the less the rate of oxygen consumption is liberated. 3. The degree of the ill-effect of fouling organisms upon the fouled pearl oysters varies with species of fouling organisms; the greater degree of the ill-effect of fouling organisms is seen with Balanus amphitrite communis DARWIN; and the less degree of the ill-effect is with Ciona intestinalis LINNE. The results mentioned above together with the outcome of the preceding paper suggests that the activity of the pearl oysters is harmfully influenced by the presence of fouling organisms, and the work of shell cleaning is effective for the production of pearls.