316
D. H. UUSHING
the Peruvian anchoveta spawn near the line of upwelling along the
shore. There is sometimes a very narrow coastal countercurrent during
the season of upwelling both off California (Reid et al., 1958) and off
Peru (Wyrtki, 1963). Because the fish live in the upper half of the
thermocline, the countercurrent below 200m is of little use t o them.
But here is a mechanism by which the fish can move towarde the pole
during the upwelling season, and the Californian sardine in its period of
abundance was caught as far north as British Columbia late in the
season (Marr, 1960). Thus the major components of the community of
fishes, the sardine (or anchovy) and the hake, may well have a system
of retaining themselves within the upwelling area merely in the two
current/countercurrent systems.
86"
83"
80"
71 "
74"
71"
10
3"
6"
9"
12"
15"
18"
20"
FIG. lS(8). The distribution of zooplankton in ml/haul displacement volume (Flom,
1967 ; Guillen and Florea, 1967).