Journal of the Faculty of Fisheries and Animal Husbandry, Hiroshima University Volume 5 Issue 2
1964-12-20 発行

瀬戸内海のタコの漁況について

Note on the fishing condition of the common octopus, octopus vulgaris CUVIER, in the Inland Sea of Seto, Japan
Nishikawa, Sadaichi
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abstract
1. Examination has been made as to the extent to which the annual catch of octopus in the Seto Inland Sea is affected by the water temperatures of the Kuroshio region off Shiono-misaki and Ashizuri-zaki and by the precipitation in various parts of the Seto Inland Sea.

2. Year-to-year fluctuation of the octopus catch in different parts of the Seto Inland Sea during 1925-60 has been compared with the spring (April-June) and summer (July-September) water temperatures at Shiono-misaki and Ashizuri-zaki in the preceding year. For convenience' sake, water temperatures were expressed in terms of the deviation from long-term (36 years) averages.

3. Analyses of the data for the 36 years suggested a tendency that, when April-June and/or July-September temperatures of the Kuroshio region off Shiono-misaki or Ashizuri-zaki are relatively high in a certain year, octopus catch in the Seto Inland Sea is comparatively rich in the next year. This tendency was especially pronounced when the octopus catches in the innermost parts of the Seto Inland Sea were correlated to the preceding year's spring water temperature of the Kuroshio region. However, it sometimes happened that the octopusc atches in the entrance parts of the Seto Inland Sea were poor in a year immediately following a relatively high summer water temperature in the Kuroshio region.

4. When year-to-year fluctuation of octopus catch in each prefecture on the Seto Inland Sea was compared with the local precipitation during June-October of the preceding year, there showed up a general tendency that octopus catches in the innermost parts of the Seto Inland Sea are rather negatively correlated to the local preciptation of the preceding year. The octopus catches in the entrance parts of the Seto Inland Sea, however, did not show such correlation to local precipitation.