UPWELLING AND THE PRODUCTION OF FISH
315
night. On the bottom live flatfish in rather shallow water, and near the
bottom in deeper water live hake and rosefish. The hake probably
migrate upwards at night and feed on euphausids. Between the anchoveta and the hake live the horse mackerel, possibly in the lower
parts of the thermocline and below. At the surface live guano birds
which are surprisingly abundant. In the Peru Current, thcre are 30
million birds, mainly pelicans, boobies and cormorants ; during El Niiio,
the numbers are sharply reduced, because some migrate southwards out
of the area when the fish are no longer accessible and some die of
starvation. In 1958, during El Nifio, the bird populations were sharply
reduced, but by 1962 the numbers of birds had fully recovered. So
they must eat very large numbers of anchoveta. In the Benguela
current, Davies (1958) has estimated that the cormorants off SouthWest Africa take 1 000 tons of horse mackerel and 6 000 tons of
pilchard, that the gannets (or boobies) take 5 000 tons of horse mackerel
and 16 000 tons of pilchards, and that the penguins take 1 000 tons of
horse mackerel and 21 000 tons of pilchards. It is no accident that in
many of the upwelling areas there is a Cab0 Blanco, Cap Blanc or Cape
Blanc. In addition to the birds there are tuna-like fishes and whales.
Nakamura’s (1969) atlas of the catches of tuna by the Japanese longline fleet is really a chart of the divergences in the oceanic subtropical
anticyclones. But the coastal upwellings are less important to the tuna
than the offshore divergences : it is no accident that the eastern tropical
ocean, particularly the eastern tropical Pacific, is an important area for
tuna fishermen. Although tuna may be caught in the area of coastal
upwelling, it is likely that they pass 100 km or more offshore.
The community of fishes in an upwelling area is a specialized onc, as
pointed out earlier, with some analogies to a temperate community of
fishes. The fish characteristic of an upwelling area are not caught much
outside it; hake occur between Cape San Lucas and Kodiak Island,
according to Alverson and Larkins (1969), but their area of abundance
is the California Current upwelling system. The possible dependence of
hake upon the current/countercurrent system has already been noted.
The Californian sardine spawns right in the coastal upwelling zone, as
physically defined ; indeed the points of upwelling, south of Point Conception, off San Diego and off Punta San Eugenio, are recurrent centres
of intense spawning (Ahlstrom, 1966). The Peruvian anchoveta spawns
between Punta Aguja and San Juan in late winter to early summer
when the Ekman transport is most intense (Wooster and Reid, 1963)
and the greatest densities of eggs are found within 100 km of the coast
(Flores, 1967 ; Flores and Elias, 1967) where the radiocarbon values are
highest (Forsbergh and Joseph, 1964). So the Californian sardine and
315
night. On the bottom live flatfish in rather shallow water, and near the
bottom in deeper water live hake and rosefish. The hake probably
migrate upwards at night and feed on euphausids. Between the anchoveta and the hake live the horse mackerel, possibly in the lower
parts of the thermocline and below. At the surface live guano birds
which are surprisingly abundant. In the Peru Current, thcre are 30
million birds, mainly pelicans, boobies and cormorants ; during El Niiio,
the numbers are sharply reduced, because some migrate southwards out
of the area when the fish are no longer accessible and some die of
starvation. In 1958, during El Nifio, the bird populations were sharply
reduced, but by 1962 the numbers of birds had fully recovered. So
they must eat very large numbers of anchoveta. In the Benguela
current, Davies (1958) has estimated that the cormorants off SouthWest Africa take 1 000 tons of horse mackerel and 6 000 tons of
pilchard, that the gannets (or boobies) take 5 000 tons of horse mackerel
and 16 000 tons of pilchards, and that the penguins take 1 000 tons of
horse mackerel and 21 000 tons of pilchards. It is no accident that in
many of the upwelling areas there is a Cab0 Blanco, Cap Blanc or Cape
Blanc. In addition to the birds there are tuna-like fishes and whales.
Nakamura’s (1969) atlas of the catches of tuna by the Japanese longline fleet is really a chart of the divergences in the oceanic subtropical
anticyclones. But the coastal upwellings are less important to the tuna
than the offshore divergences : it is no accident that the eastern tropical
ocean, particularly the eastern tropical Pacific, is an important area for
tuna fishermen. Although tuna may be caught in the area of coastal
upwelling, it is likely that they pass 100 km or more offshore.
The community of fishes in an upwelling area is a specialized onc, as
pointed out earlier, with some analogies to a temperate community of
fishes. The fish characteristic of an upwelling area are not caught much
outside it; hake occur between Cape San Lucas and Kodiak Island,
according to Alverson and Larkins (1969), but their area of abundance
is the California Current upwelling system. The possible dependence of
hake upon the current/countercurrent system has already been noted.
The Californian sardine spawns right in the coastal upwelling zone, as
physically defined ; indeed the points of upwelling, south of Point Conception, off San Diego and off Punta San Eugenio, are recurrent centres
of intense spawning (Ahlstrom, 1966). The Peruvian anchoveta spawns
between Punta Aguja and San Juan in late winter to early summer
when the Ekman transport is most intense (Wooster and Reid, 1963)
and the greatest densities of eggs are found within 100 km of the coast
(Flores, 1967 ; Flores and Elias, 1967) where the radiocarbon values are
highest (Forsbergh and Joseph, 1964). So the Californian sardine and