444 
PACIFIC SCIENCE, VoL XXI, October 1967 
Fig. 9. Monthly mean temperature in each of four 
spring months from 1943 through 1957 at Kyogasaki. 
Dashed lines show mean temperatures, 1915-1957; 
solid lines show least squares regressions for 1943- 
1957. 
Comparing Table 3 with Table 2, it is obvious 
that annual yields of both euphausiids and sand 
eel from the area fluctuate in parallel. 
In addition to the sand eel, the sea gull, 
Larus crassirostris, and a small blackish bird, 
Cerorhinca monocerata, can be considered pred- 
ators on euphausiids in the Kinkazan waters. 
According to local fishermen, C. monocerata 
can dive into the deep, and it probably attacks 
submerged euphausiids from the bottom and 
drives them up to the surface. 
DISCUSSION 
It has been clearly demonstrated here that 
the swarming of Euphausia pacifica in the 
nearshore waters of Japan is closely related to 
Fig. 10 . Annual yield of Japanese mackerel. 
Scomber japonicus, from the Wakasawan area. 
cold water temperatures. This may be expected, 
since the species is a boreal form, occurring 
commonly north of the subarctic convergence, 
as shown by Banner (1949), Boden et al. 
(1955), Nemoto (1957), Brinton (1962^), 
and Ponomareva (1963). The habitat is cres- 
cent in shape, covering the northern part of 
the North Pacific. E. pacifica occurs in the cold 
water lying under the upper strata in the Sea 
of Japan (Komaki and Matsue, 1958). 
Inasmuch as the branches of the warm 
Kuroshio wash the Japanese coasts, E. pacifica 
may be excluded from the coastal areas except 
during the coldest season, while it is more 
commonly concentrated in the nearshore and 
inshore waters of the eastern North Pacific 
(Banner, 1949; Boden et al., 1955; Brinton, 
1962^, b\ Banse and Semon, 1963; Regan, 
1963). Except during its swarming season. 
TABLE 3 
Annual Yield of Sand Eel, Ammodytes 
personaius, from the Kinkazan Area* 
YEAR 
YIELD (TONS) 
1953 
741.7 
1954 
349.6 
1955 
580.8 
1956 
4,029.1 
* From the statistics of the Onagawa fish market. 
