UPWELLINQ AND THE PRODUCTION OF FISH
285
coast (Posner, 1957); it comes at Christmas time, which is why it is
called El Niiio (the Little Boy), and is accompanied by northerly winds
and heavy rain. It lasts until March and has occurred in particular
years 1891, 1925, 1941, 1953, 1957-8, 1965-6 (Smith, 1969); as the
period of heavy fishing in the anchoveta fishery starts at about this
time, El Niiio is not welcomed because the fish are not accessible when it
flows. The cause of the phenomenon is not known exactly, but Bjerknes
(1961) has suggested that it is associated with changesin the atmospheric
fluctuations which cause a transequatorial flow from the Equatorial
Countercurrent. Thus there are two differences in the Peru Current
from the common pattern, the more prominent countercurrent and the
periodic occurrence of El Niiio.
Canary Current
Until very recently, the Canary Current had not been very well
described. The charts of surface temperature (U.S. Navy Hydrographic
Office, 1944) summarize much of the early historical data. Furnestin
(1959) examined the area between Cap Jubi, in the latitude of the
Canary Islands, and north of Casablanca ; quarterly cruises and some
sections show upwelling to some extent between Cap Ghir, just north of
Agadir, and Mazagan, just south of Casablanca. A further upwelling
appears late, north of Casablanca, and in late summer it occurs on the
Iberian coast as far north as Vigo in north-western Spain. But the upwelling off Portugal has not been explicitly studied. Jones and Folkard
(1968) have published sections of the whole current and show that upwelling is limited to the top 200 m, as in other areas. Surveys were
made in March, June and October in the area ; that in March extended
from Cap Blanc, halfway between Dakar and the Canary Islands and
Cap Juby, that in June from the Gulf of Cintra, just south of Cap Blanc,
to Cap Juby and that in October/November from Dakar to Cap Ghir.
There is enough information t o show that there is a seasonal shift of
upwelling to the north, and near Cap Blanc it is possible that the water
rises from depths a little greater than 200 m and perhaps there is some
evidence of a countercurrent. A remarkable point from their sections is
the apparently slow rate of mixture of various properties and the upwelling tongue sometimes bends downwards t o seaward. The region
between Freetown and Dakar has been examined by Berrit (1958, 1961,
1962), who has shown the shift with season from Cape Vergas in Guinea
northwards as winter gives way to spring. It is in this region that the
Canary Current turns westward into the North Equatorial Current ;
south-eastwards, the Guinea Current and, to seaward, the Equatorial
Countercurrent flows into the Gulf of Guinea. The latter will be
285
coast (Posner, 1957); it comes at Christmas time, which is why it is
called El Niiio (the Little Boy), and is accompanied by northerly winds
and heavy rain. It lasts until March and has occurred in particular
years 1891, 1925, 1941, 1953, 1957-8, 1965-6 (Smith, 1969); as the
period of heavy fishing in the anchoveta fishery starts at about this
time, El Niiio is not welcomed because the fish are not accessible when it
flows. The cause of the phenomenon is not known exactly, but Bjerknes
(1961) has suggested that it is associated with changesin the atmospheric
fluctuations which cause a transequatorial flow from the Equatorial
Countercurrent. Thus there are two differences in the Peru Current
from the common pattern, the more prominent countercurrent and the
periodic occurrence of El Niiio.
Canary Current
Until very recently, the Canary Current had not been very well
described. The charts of surface temperature (U.S. Navy Hydrographic
Office, 1944) summarize much of the early historical data. Furnestin
(1959) examined the area between Cap Jubi, in the latitude of the
Canary Islands, and north of Casablanca ; quarterly cruises and some
sections show upwelling to some extent between Cap Ghir, just north of
Agadir, and Mazagan, just south of Casablanca. A further upwelling
appears late, north of Casablanca, and in late summer it occurs on the
Iberian coast as far north as Vigo in north-western Spain. But the upwelling off Portugal has not been explicitly studied. Jones and Folkard
(1968) have published sections of the whole current and show that upwelling is limited to the top 200 m, as in other areas. Surveys were
made in March, June and October in the area ; that in March extended
from Cap Blanc, halfway between Dakar and the Canary Islands and
Cap Juby, that in June from the Gulf of Cintra, just south of Cap Blanc,
to Cap Juby and that in October/November from Dakar to Cap Ghir.
There is enough information t o show that there is a seasonal shift of
upwelling to the north, and near Cap Blanc it is possible that the water
rises from depths a little greater than 200 m and perhaps there is some
evidence of a countercurrent. A remarkable point from their sections is
the apparently slow rate of mixture of various properties and the upwelling tongue sometimes bends downwards t o seaward. The region
between Freetown and Dakar has been examined by Berrit (1958, 1961,
1962), who has shown the shift with season from Cape Vergas in Guinea
northwards as winter gives way to spring. It is in this region that the
Canary Current turns westward into the North Equatorial Current ;
south-eastwards, the Guinea Current and, to seaward, the Equatorial
Countercurrent flows into the Gulf of Guinea. The latter will be