干潟におけるゴカイ(N.japonica)の成長と密度推移について〔英文〕

概要

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The change of population density and growth of the marine polychaetous annelid Neanthes japonica IZUKA were examined in a typical natural habitat in Mikawa Bay. The population change in site of food supply was compared with that in natural site. The powdery or granular foods of appropriate size for worms were supplied by spreading. The substratum of this habitat was composed of soft mud, 45%of which was found to be fine inorganic particles smaller than 60 mesh and 26.6% rion. A tendency was observed that the number of nests in the artificial feeding area was larger than the area under natural conditions. The worms of the earlier stage in April were found in 2-3cm depth of mud. In August, the population density decreased to about 1/8 of that in April. The number of body segments rapidly increased during the period from June through July, and reached full number in August. The body length and weight increased rapidly during the period from April through July. The artificially fed nereids indicated better growth than natural worms in respect to both length and weight. The high death-rate of worms was found at high temperature in summer. The artificial food contributed greatly to the enlargement of each segment of the worm.
日本水産學會の論文