440 
PACIFIC SCIENCE, Vol. XXI, October 1967 
TABLE 2 
Annual Yields of Euphausia pacifica from the 
Kinkazan Area* 
YEAR 
YIELD (TONS) 
1953 
431.8 
1954 
0.0 
1955 
887.1 
1956 
1,029.2 
1957 
274.0 
1958 
404.1 
1959 
1,419-1 
* From the statistics of the Onagawa fish market. 
are available, the information at hand indicates 
that the disappearance of swarms from near- 
shore waters continued at least until 1958. 
In order to relate the annual change in the 
euphausiid swarming to the surface water tem- 
perature, examination of water temperatures 
during the first six months of the year at 
Enoshima (Fig. 5a) are plotted in Figures 
5b (1954) to 5 g (1959) with 10-day inter- 
vals. Each point represents the mean values of 
10 daily measurements. 
Upon relating Figure 5 to Table 2, it is 
quite obvious that the temperature was abnor- 
mally higher than the mean throughout the 
winter and spring of 1954, when absolutely 
no euphausiids were caught. On the other hand, 
in 1956 and 1959, when more than 1,000 tons 
of euphausiids were captured, the temperature 
was a little lower than the mean in February 
and March 1956, and it was a little higher 
than, but close to, the mean in April and May 
1959. Euphausiids were fished mainly in the 
early spring of 1956, while they were caught 
more abundantly late in the spring of 1959 
than earlier (Fig. 2). 
The peculiarity of the water temperature in 
the winter and spring months of 1954 also 
can be learned from Figure 8. Figure 8 is 
based on the monthly observations at the sta- 
tion 10 miles off Tsubakishima (Fig. la), 
which is located closer to Kinkazan than is 
Ozaki. Figure 8a shows the water temperature 
profile down to a depth of 200 m during the 
period from November 1953 to November 
1954. Figure 8b shows the temperature profile 
at the same station for the following year. It 
is obvious that a remarkable temperature gra- 
dient was present during the winter and spring 
months of 1954, when no euphausiids were 
Fig. 5. Surface water temperatures at Enoshima. 
(a), Average temperatures for 1910-1944 and 1953- 
1959; {b)-{g), deviations from the mean for 1954- 
1959. 
captured. Considerable warm water occupied 
the surface layers in the spring of 1954, espe- 
cially in April, which corresponds to the middle 
of the swarming season in the Kinkazan wa- 
ters. The temperature profile for the next year 
(Fig. 8b) shows normal seasonal change in the 
area, as is indicated by the temperature profiles 
at the stations off Ozaki and Shioyazaki (Fig. 
6 ). 
The records of water temperatures observed 
