256
D. €1. CUSHING
McEwen (1929) off California, but the scale of the phcnomcnon was first
described thoroughly on the " Meteor ') expedition.
The biologists did not explore the upwelling arcas to any great extent until quite recently. Gunther's (1936) exploration of the Peru
current was the first explicit examination, followed by Steemann
Nielsen's world survey in the " Galathea )' expedition. A fortunate
outcome of this apparent disinterest is that when the upwelling areas
were explored they were examined with standard equipment, the radiocarbon method of measuring primary production and the 1 m plankton
net, or its variants. Since the early fifties many expeditions have sailed,
covering much of the Pacific and Indian Oceans and some continuing
work has been executed in the Atlantic ocean. Most of the expeditions
were designed to study large-scale physical phenomena and at the
stations they occupied, biological observations were also made. The
work off California was aimed at a more specific objective, to discover
why recruitment to the Californian sardine fishery had failed. An
expedition to the Benguela current was carried out by the '' Discovery ')
Investigations/NIO to explore the production there. It would be
churlish for a biologist to describe the Indian Ocean expedition as one
designed to extract physical information only, because much biological
information of great interest emerged, but perhaps a fuller study of upwelling in the Bay of Bengal and upon the Malabar coast of India can
now be carried out.
The present study was made for FA0 as part of its IWP project
(Indicative World Plan). The aim was to make a projection of world fish
production during the decade 1975-85. As the upwelling areas comprise
the most promising ones for exploitation in tropical and subtropical
waters, an attempt was made to estirnatc possible production from
estimates of primary and secondary production. Some areas, such as
that off Peru, arc already well exploited but others, such as that off
Southern Arabia, are not. We may distinguish three forms of production in tropical and subtropical seas, the coastal upwellings (within
100 km of the shore), the offshore divergences round the edges of the
subtropical anticyclones, and the central areas. Here thc first two have
been examined but not the third. This is because the present fisheries
depend primarily upon herring-like and cod-like fishes. To exploit the
whole ocean (in addition to the tuna), the small fishes of the Deep
Scattering Layer, e.g. myctophids, should be caught; they can be
caught, but because they are dispersed they cost too much to exploit at
the moment.
The conclusion to this work is that the catches available in the upwelling areas amount to about 100 million tons, a fair proportion of
D. €1. CUSHING
McEwen (1929) off California, but the scale of the phcnomcnon was first
described thoroughly on the " Meteor ') expedition.
The biologists did not explore the upwelling arcas to any great extent until quite recently. Gunther's (1936) exploration of the Peru
current was the first explicit examination, followed by Steemann
Nielsen's world survey in the " Galathea )' expedition. A fortunate
outcome of this apparent disinterest is that when the upwelling areas
were explored they were examined with standard equipment, the radiocarbon method of measuring primary production and the 1 m plankton
net, or its variants. Since the early fifties many expeditions have sailed,
covering much of the Pacific and Indian Oceans and some continuing
work has been executed in the Atlantic ocean. Most of the expeditions
were designed to study large-scale physical phenomena and at the
stations they occupied, biological observations were also made. The
work off California was aimed at a more specific objective, to discover
why recruitment to the Californian sardine fishery had failed. An
expedition to the Benguela current was carried out by the '' Discovery ')
Investigations/NIO to explore the production there. It would be
churlish for a biologist to describe the Indian Ocean expedition as one
designed to extract physical information only, because much biological
information of great interest emerged, but perhaps a fuller study of upwelling in the Bay of Bengal and upon the Malabar coast of India can
now be carried out.
The present study was made for FA0 as part of its IWP project
(Indicative World Plan). The aim was to make a projection of world fish
production during the decade 1975-85. As the upwelling areas comprise
the most promising ones for exploitation in tropical and subtropical
waters, an attempt was made to estirnatc possible production from
estimates of primary and secondary production. Some areas, such as
that off Peru, arc already well exploited but others, such as that off
Southern Arabia, are not. We may distinguish three forms of production in tropical and subtropical seas, the coastal upwellings (within
100 km of the shore), the offshore divergences round the edges of the
subtropical anticyclones, and the central areas. Here thc first two have
been examined but not the third. This is because the present fisheries
depend primarily upon herring-like and cod-like fishes. To exploit the
whole ocean (in addition to the tuna), the small fishes of the Deep
Scattering Layer, e.g. myctophids, should be caught; they can be
caught, but because they are dispersed they cost too much to exploit at
the moment.
The conclusion to this work is that the catches available in the upwelling areas amount to about 100 million tons, a fair proportion of