内湾性指標種の季節変動について〔播磨灘の底生動物相-1-〕

概要

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Recently, the successive increase of distribution has been observed of the bivalve Theora lubrica and the polychaete annelid Paraprionospio pinnata in polluted environments of the Inland Sea. They are well-known as indicator species of the disharmonic enclosed bay. This paper deals with the relation of the seasonal changes in quantity of these species to the environmental bottom conditions in the offshore and the coastal areas of Central and South Harima-Nada. The surveys were carried out in principle, from March 1978 to February 1979 at monthly intervals. In the bottom layer, the dissolved oxygen values decreased with increasing temperatures. The numbers of individuals and species of the macrobenthic animals also decreased rapidly in this stagnation period. T. lubrica that showed their maxima at May to June also began to decline as well as P. pinnata. After the stagnation period, the former became extinct, while the latter was the only species recover quickly in the temporary semi-azoic areas. These trends were markedly shown in the offshore areas. These indicate that there is a conspicuous seasonality in disharmonic regions. The degrees of bottom pollution in the offshore and the coastal areas of Harima-Nada as compared with other polluted sea regions were discussed.
日本水産學會の論文