Surface Swarming of Euphausiids — Komaki 
441 
NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV 
Fig. 6 . Average annual changes of water temperature profile 10 miles off (a) Ozaki during 1919-1939, 
and (b) Shioyazaki during 1914-1939. Locations are shown in Figure la. 
at Kyogasaki were the only data available for 
relating temperature to the long-term change 
in swarming in the Sea of Japan shown in 
Figure 7. The monthly mean values of water 
temperatures in a given month from 1943 to 
1957 are plotted in Figure 9. It appears that 
all water temperatures in March, from 1943 
to 1952, were lower than the accumulated av- 
erage value calculated over the years beginning 
with 1915 (dashed lines in Fig. 9). March is 
the month when swarming takes place exten- 
sively in the Wakasawan area. Also, the least 
squares regressions (solid lines in Fig. 9) ob- 
tained from values during these 14 years sug- 
gest an explanation for the disappearance of 
euphausiids from the neritic areas. All regres- 
