SEASONAL VARIATION OF SWIMMING LAYER OF YELLOWFIN TUNA BY AREA OF DIFFERENT CURRENTS IN MID-WESTERN AND SOUTHWESTERN PARTS OF THE PACIFIC OCEAN
1961 Volume 27 Issue 4 Pages 302-306
Details
1961 Volume 27 Issue 4 Pages 302-306
The present author studied on seasonal variation of swimming layer of yellowfin tuna by area of different currents in the mid and southwestern parts of the Pacific Ocean. The results are as follows:
1) Swimming layer became shallowest (about 110m) in June and deepest (about 145m) in December of a year in areas of the North Equatorial current and the Equatorial Counter current (N). And it tended to rise in the spring and sink in the fall.
2) Swimming layer became shallowest (about 110m) in May and deepest (about 145m) in November in the South Equatorial current area (M) north of the convergency line (10°S). And it tended to rise in winter toward spring and sink in summer toward autumn.
3) Swimming layer in area M was a little shallower than is mentioned in literature No. 1 throughout year and the month when swimming layer was shallowest and deepest respectively in area N came a little later than in area M.
4) Swimming layer became shallowest in March (about 105m) and October (about 90m) and deepest in January (about 130m) and June or July (about 135m) of a year in the South Equatorial current area south of the convergency line. And it tended to rise and fall periodically twice a year.
5) Swimming layer in area S was shallower than in areas N and M throughout year.
