アサリを主とする海産二枚貝の濾水・摂餌に及ぼす濁りの影響

概要

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In natural condition of sea water there are many grades of turbidity originated from varied kinds of particles, and it is important to know the effect of suspending particles on the living processes of bivalves in our technique of shell culture. Some experiments were carried out to test the rate of pumping and feeding of bivalves (Venerupis semidecussata, Mercenaria meretrix, Ostrea gigas and Mytilus edulis) by means of high concentration of particles. The rate of pumping was measured by using the formula of JØrgensen and that of feeding by weighing the dried feces excreted by the bivalves after an hour leaving in the sea water to which bentonite had been added. The results are summarised as follows: (1) In each species of organisms tested the rate of pumping was not reduced due to the high concentration of bentonite. (2) In V. senzidecussata the amount of feeding increased with the growing concentration of the particles up to the time when pseudo-feces were discharged, and the pseudo-feces increased further, whereas the true feces did not increase in the higher concentrations. Nearly same tendency of feeding was observed in M. meretrix. (3) It was found in O. gigas and M. edulis that the amount of feeding increased with the growing concentration of bentonite, but the rate of its increment grew smaller.