308
b. #. CUSHINU
Peru and the Benguela Currents. The figure of 278.106 tons C/year in
the Benguela may not differ much from that of 155.106 tons C/year in
the Peru Current, but both are markedly different from the figures of
30. loe tons C/year in the California Current and 35. lo6 tons C/year off
southern Arabia. It will be seen that the production in the Canary
Current amounts to 139.106 tons C/year, but that the bulk of it is based
on the recent small number of observations made by Lloyd (1970) off
Cap Blanc. However, it is certainly likely that the Canary Current is
in the second group, comparable to the California Current and the
south-west monsoon off southern Arabia, even if subsequent observations do not confirm its possible place in the first group. The intermediate areas are the California Current, the southern Arabia upwelling,
that off the Malabar coast of India, and those off Chile, New Guinea,
Java and Vietnam. The minor upwellings are those in the Somali
Current, the Costa Rica Dome, the Guinea Dome, the Java Dome, the
Gulf of Thailand, the north-west Australia upwelling and those in
Indonesia, in the Banda, Flores and east Arafura Seas, the Madagascar
wedge and off the Indian coast of Orissa. The greatest production takes
place in the eastern tropical Pacific and in the area of the Marquesas
divergences, but the intensity in both regions is low over a very broad
area. Because both areas are in the open ocean, where the only present
fish catch is tuna, they are not comparable with the true coastal upwellings, from the point of view of fish production. So a rich upwelling
which yields high fish stocks is to be quite intense (in gC/m2 per day)
over a fairly extensive region for long periods; it is this which distinguishes the Peru and Benguela upwellings (and perhaps that in the
Canary Current) from all the others.
The point may be made in another way, by comparing upwellings
by intensity only. The first group (> 1 gC/m2 per day) comprises one
subarea in each of the Peru and Canary Currents and two in the Benguela, the southern Arabia upwelling and those off Vietnam and in the
Gulf of Thailand ; the difference between the first three and the latter
three is really in the extensive areas and long seasons in the major upwelling areas. A second group (0.3-1.0gC/ma per day) includes one
subarea from the Peru Current, three from the Canary Current and one
from the Benguela Current, the Somali Current, the Guinea Dome, the
Madagascar wedge, the Orissa coast, the Java coast, the coast of west
Ceylon and the three Indonesian areas, the Banda, Flores and east
Arafura Seas. The third group (<0*3 gC/m2 per day) includes all subareas in the California Current, the Costa Rica Dome, the two subareas
off Chile, one in the Benguela Current, that in the Marquesas divergence,
off New Guinea, off the Andaman Islands and off north-west Australia.
b. #. CUSHINU
Peru and the Benguela Currents. The figure of 278.106 tons C/year in
the Benguela may not differ much from that of 155.106 tons C/year in
the Peru Current, but both are markedly different from the figures of
30. loe tons C/year in the California Current and 35. lo6 tons C/year off
southern Arabia. It will be seen that the production in the Canary
Current amounts to 139.106 tons C/year, but that the bulk of it is based
on the recent small number of observations made by Lloyd (1970) off
Cap Blanc. However, it is certainly likely that the Canary Current is
in the second group, comparable to the California Current and the
south-west monsoon off southern Arabia, even if subsequent observations do not confirm its possible place in the first group. The intermediate areas are the California Current, the southern Arabia upwelling,
that off the Malabar coast of India, and those off Chile, New Guinea,
Java and Vietnam. The minor upwellings are those in the Somali
Current, the Costa Rica Dome, the Guinea Dome, the Java Dome, the
Gulf of Thailand, the north-west Australia upwelling and those in
Indonesia, in the Banda, Flores and east Arafura Seas, the Madagascar
wedge and off the Indian coast of Orissa. The greatest production takes
place in the eastern tropical Pacific and in the area of the Marquesas
divergences, but the intensity in both regions is low over a very broad
area. Because both areas are in the open ocean, where the only present
fish catch is tuna, they are not comparable with the true coastal upwellings, from the point of view of fish production. So a rich upwelling
which yields high fish stocks is to be quite intense (in gC/m2 per day)
over a fairly extensive region for long periods; it is this which distinguishes the Peru and Benguela upwellings (and perhaps that in the
Canary Current) from all the others.
The point may be made in another way, by comparing upwellings
by intensity only. The first group (> 1 gC/m2 per day) comprises one
subarea in each of the Peru and Canary Currents and two in the Benguela, the southern Arabia upwelling and those off Vietnam and in the
Gulf of Thailand ; the difference between the first three and the latter
three is really in the extensive areas and long seasons in the major upwelling areas. A second group (0.3-1.0gC/ma per day) includes one
subarea from the Peru Current, three from the Canary Current and one
from the Benguela Current, the Somali Current, the Guinea Dome, the
Madagascar wedge, the Orissa coast, the Java coast, the coast of west
Ceylon and the three Indonesian areas, the Banda, Flores and east
Arafura Seas. The third group (<0*3 gC/m2 per day) includes all subareas in the California Current, the Costa Rica Dome, the two subareas
off Chile, one in the Benguela Current, that in the Marquesas divergence,
off New Guinea, off the Andaman Islands and off north-west Australia.