Autumnal Fishing of Skipper and Bonito Influenced by the Rapid Hydrographic Change after the Pass of Cyclones
1938; Springer Science+Business Media; Volume: 6; Issue: 5 Linguagem: Inglês
10.2331/suisan.6.240
ISSN1349-998X
Autores Tópico(s)Food Industry and Aquatic Biology
ResumoThe materials were obtained from the report of the commercial fishing-boats in the fishing-season of skipper from September to December in 1936. Figs. 1 and 2 show the distribution of catch and the displacement of the fishing-centre in addition to the tracks of cyclones. We can see at once that in late December and early October the fishing regions of bonito and of skipper are located in coupled positions face to face with each other off the east of Kinkazan, the former lying near the 20°C isothermal line and the latter near the 18°C isothermal line. Owing to the pass of cyclones in autumn, the sea water is cooled rapidly almost 1°-2° in a few days and shows a conspicuous southward growth of Oyasio Cold Current (Figs. 4 and 5). Corresponding to this hydrographical change, fishing locality of skipper moves quickly to the SW (Fig. 3). Two offshore and coastal branches in early October are of skipper-fishing locality united into a coastal one in mid October, and at the same time the bonito fishing ends.
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