UPWELLING AND THE PRODUCTION OF FISH
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Eastern boundary upwelling area
I _ Divergence
1 Convergence
Dome
NEC
North Equatorial Current
, - *
Current
SEC
South Equatorial Current
SECC
South Equatorial Countercurrent
ECC
Equatorial Countercurrent
EUC
Equatorial Undercurrent
FIQ. 2. Diagram of the distribution of upwollings and divergences in the anticyclones
of an ocean.
upwellings (based on Hidaka and Ogawa, 1958). Between the Equatorial Countercurrent and the North Equatorial Current there is a zone
of convergence (Cromwell, 1958; Hidaka and Ogawa, 1958; Wyrtki,
1966). The system is not centred precisely on the equator, but is offset
somewhat to the north, so that the Equatorial Countercurrent occurs
between 5 and 10"N and the northern edge of the South Equatorial
Current lies about 3"N.
At about the equator, the north and south equatorial gyres meet,
forming a westbound North Equatorial Current (at 10-20'N in the
Pacific) and westbound South Equatorial Current (at 3"N to 10's in