@article{oai:ir.kagoshima-u.ac.jp:00007803,
 author = {YUWAKI, Yasutaka and 湯脇, 泰隆 and HENMI, Tomio and 辺見, 富雄},
 journal = {鹿児島大学水産学部紀要, Memoirs of Faculty of Fisheries Kagoshima University},
 month = {Dec},
 note = {Oceanographical observations and biological research in the southern region of
the Hawaiian Islands were carried out on board the Keiten Maru from May to June,
1978.
When the present results are compared with those obtained last year (1977), some
differences are found in the oceanic characteristics and the distribution of zooplankton,
which are summarized as follows.
1) The numerical values of the temperature of the surface water are ca 26.0°C
at 15°N, ca 26.9°C at 12°N and ca 27.7°C at 08°N, respectively. Though the numerical value of the temperature of the surface water is almost equal to that of 1977, it
becomes somewhat higher northward from 12°N.
2) The thermocline exists in a layer at a depth of about 80 m - 200 m around 14°N,
about 50 m - 140 m around 09°-30'N but was shallower than that in 1977. The vertical gradients of temperature in the thermocline are ca 0.10 °C/m at 14°N, ca 0.13 °C/
m at 08°N, and less than that in 1977.
3) The numerical value of surface salinity is ca 34.60%, and ca 0.20% lower
than that in 1977. The salinity maximum, which was found in a layer at a depth
of about 100 m around 14°-30'N in 1977, extended to the south from the north as
far as 09°N in a layer between 90 m - 125 m in 1978.
4) The first salinity minimum is found at a depth of about 250 m at 15°N and is
the same as our research reported in 1977. The depth of the salinity minimum becomes gradually shallower as approaching to the equator from the north. The second salinity minimum, showing the Equatorial Pacific Water, is found at a depth of
about 800 m.
5) The boundary between the North Equatorial Current and the Equatorial Countercurrent
is recognized around 09°N and it seems to have shifted to the south compared with that in 1977.
6) The current axies of the eastward and westward flow are around 08°-45'N and
09°-30'N. The axis of the eastward flow shifts to the south about 100 miles compared with that in 1977 but the axis of the westward flow is almost the same as that
in 1977.
The numerical value of the maximum velocity of the eastward and westward flow
are ca 23 cm/sec and ca 33 cm/sec. These are somewhat higher than that in 1977.
The total flux of the eastward and westward flow are ca 8.0×10^<6> m^<3>/sec and ca
19.3×10^<6> m^<3>/sec. The total flux of the eastward flow is far larger than that in 1977
but the total flux of the westward flow is smaller than that in 1977.
7) The maximum value of the occurrence of zooplankton per cubic meter is 461
individuals at 10°N and the minimum value is 140 individuals at 13°N. The rate of
the occurrence of Copepoda, Radioioria, Ceratium and Appendicularia is 53%, 16%, 11%
and 10%, respectively. The individual number and the rate of occurrence of each
one are almost equal to that in 1977.},
 pages = {215--231},
 title = {The Oceanographical Research in the Southern Region of the Hawaiian Islands II},
 volume = {28},
 year = {1979}
}