UPWELLING AND THE PRODUCTION OF FISH
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River, but do extend for a considerable distance eastward of the Cape
of Good Hope. Of the lesser upwellings those off Somalia, southern
Arabia, the Malabar coast of India and off the southern coasts of Ceylon
are shown ; of these, the Somali upwelling, like that south of Ceylon,
appears t o have generated more extensive deposits than would be
expected from the present extent of the upwelling areas. The deposits
off Ghana correspond to the area of the Guinea upwelling, but those off
north-west Australia are much more extensive than might be expected
and lie west of the present upwelling area. With the exception of the
last area, the phosphatic deposits show the presence of the major upwellings and the intermediate ones, but not the minor ones or the
equatorial ones.
Figure 19B shows the distribution of guano islands (Hutchinson,
1950). There is a concentration off Baja California and in the Gulf of
California, all the way down the coast of Peru, on the south-west coast
of South Africa, off southern Arabia, off Somalia, off northern Madagascar, off north-west Australia, off Vietnam and north of New Guinea.
The major upwelling which is not recorded by this method is that in
the Canary Current. But minor ones, like those in the Flores Sea and
Banda Sea, are recorded. Perhaps the method is a little too sensitive
to the presence or absence of birds or suitable islands. It is extraordinary that although the upwelling off the coast of Venezuela and off
Puerto Rico appears on the chart, those on the north coast of Yucatan,
on the coast near the delta of the Mississippi and off the west coast of
Florida are absent.
The best representation of the upwelling areas throughout the world
is shown in Fig. 19C; it is a chart of the positions of capture of sperm
whales by Nantucket whalers between 1726 and 1919 (Townsend, 1935).
In the northern summer, or southern winter, catches were prominent in
the southern upwellings, in the Peru Current and in the Benguela
Current, but they appeared there also in the southern summer. No
catches at all were made in the California Current and only light catches
were made in the Canary Current; in the northern winter, however,
some catches were made off Baja California and some off Casablanca.
The first was really the beginning of the Californian upwelling and the
second the end of that in the Canary Current. The most prominent
feature of this chart is the band of captures along the Line in the
Pacific, effectively in the divergences of the South Equatorial Current ;
those off the Marquesas Islands are noticeable, as are those further east.
The same structures occur in the other two oceans, but for some reason
they did not attract catches of sperm whales. A particular region which
appears in both charts is the area north of Madagascar, the Madagascar
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River, but do extend for a considerable distance eastward of the Cape
of Good Hope. Of the lesser upwellings those off Somalia, southern
Arabia, the Malabar coast of India and off the southern coasts of Ceylon
are shown ; of these, the Somali upwelling, like that south of Ceylon,
appears t o have generated more extensive deposits than would be
expected from the present extent of the upwelling areas. The deposits
off Ghana correspond to the area of the Guinea upwelling, but those off
north-west Australia are much more extensive than might be expected
and lie west of the present upwelling area. With the exception of the
last area, the phosphatic deposits show the presence of the major upwellings and the intermediate ones, but not the minor ones or the
equatorial ones.
Figure 19B shows the distribution of guano islands (Hutchinson,
1950). There is a concentration off Baja California and in the Gulf of
California, all the way down the coast of Peru, on the south-west coast
of South Africa, off southern Arabia, off Somalia, off northern Madagascar, off north-west Australia, off Vietnam and north of New Guinea.
The major upwelling which is not recorded by this method is that in
the Canary Current. But minor ones, like those in the Flores Sea and
Banda Sea, are recorded. Perhaps the method is a little too sensitive
to the presence or absence of birds or suitable islands. It is extraordinary that although the upwelling off the coast of Venezuela and off
Puerto Rico appears on the chart, those on the north coast of Yucatan,
on the coast near the delta of the Mississippi and off the west coast of
Florida are absent.
The best representation of the upwelling areas throughout the world
is shown in Fig. 19C; it is a chart of the positions of capture of sperm
whales by Nantucket whalers between 1726 and 1919 (Townsend, 1935).
In the northern summer, or southern winter, catches were prominent in
the southern upwellings, in the Peru Current and in the Benguela
Current, but they appeared there also in the southern summer. No
catches at all were made in the California Current and only light catches
were made in the Canary Current; in the northern winter, however,
some catches were made off Baja California and some off Casablanca.
The first was really the beginning of the Californian upwelling and the
second the end of that in the Canary Current. The most prominent
feature of this chart is the band of captures along the Line in the
Pacific, effectively in the divergences of the South Equatorial Current ;
those off the Marquesas Islands are noticeable, as are those further east.
The same structures occur in the other two oceans, but for some reason
they did not attract catches of sperm whales. A particular region which
appears in both charts is the area north of Madagascar, the Madagascar