UPWELTAXNO AND THE PRODUCTION OF FISH
31 1
herbivores have to search to some degree for food. Yet where they do
not have t o do so in the coastal upwellings themselves, the transfer
coefficients are lower. Perhaps some form of superfluous feeding takes
place in the rich areas, as Beklemishev (1957) suggested.
Algae and herbivores are drifted out of the upwelling areas. But the
fish populations are retained within the coastal upwelling areas and so
provide a means by which the energy of the transitory plankton populations is extracted. In temperate seas, the abundant fish stocks tend
to spawn at a season and position which allows the larvae to exploit the
food available in the production cycle. In the tropical and subtropical
seas, the abundant fish stocks have located themselves in the coastal
upwelling areas and exploit the production cycle there as it passes
through.
VII. THE BIOLOGY OF AN UPWELLING AREA
Wooster and Reid (1963) have estimated the Ekman offshore transport by 5' sectors and by quarters of the year according t o the wind
stresses. Their figures show that the offshore transport was most intense in winter in the Peru Current and for most of the year between
Liideritz and the Orange River in the Benguela Current. In the Canary
Current the highest values in spring and summer are about two-thirds
of those in the two southern currents and a little more than twice that
in the California Current. This order (Peru, Benguela, Canary, California) is that observed in total primary production and in total secondary production and so in a very general way the production of living
material is dependent upon the rate of upwelling. But there is no
correlation between the Ekman transports (which are roughly assumed
to be related to the rate of upwelling) and the intensities of primary
production, in gC/ma per day, or the stocks of zooplankton, in
ml/l 000 m3. The Peru Current upwelling has a high total production
in plants and animals because it lasts a long time, but the intensities in
gC/m2 per day and the zooplankton stocks appear to be low.
Strickland et al. (1969) have published four radiocarbon observations
from " brown water '' off Pisco, and their average value amounted to
2.4 gC/m2 per day, which is considerably greater than the average of
0.67 gC/m2 per day; however, there are only a few observations and
many have been taken in the upwelling water ; indeed only a few patches
of brown water were found by Strickland et al. in upwelling water.
The Peru Current upwelling and that in the California Current were
sampled by the same equipment, by the same people at about the same
period: but there is no difference in the radiocarbon measurements in
subarea 1 in the Peru system and all three subareas in the California
31 1
herbivores have to search to some degree for food. Yet where they do
not have t o do so in the coastal upwellings themselves, the transfer
coefficients are lower. Perhaps some form of superfluous feeding takes
place in the rich areas, as Beklemishev (1957) suggested.
Algae and herbivores are drifted out of the upwelling areas. But the
fish populations are retained within the coastal upwelling areas and so
provide a means by which the energy of the transitory plankton populations is extracted. In temperate seas, the abundant fish stocks tend
to spawn at a season and position which allows the larvae to exploit the
food available in the production cycle. In the tropical and subtropical
seas, the abundant fish stocks have located themselves in the coastal
upwelling areas and exploit the production cycle there as it passes
through.
VII. THE BIOLOGY OF AN UPWELLING AREA
Wooster and Reid (1963) have estimated the Ekman offshore transport by 5' sectors and by quarters of the year according t o the wind
stresses. Their figures show that the offshore transport was most intense in winter in the Peru Current and for most of the year between
Liideritz and the Orange River in the Benguela Current. In the Canary
Current the highest values in spring and summer are about two-thirds
of those in the two southern currents and a little more than twice that
in the California Current. This order (Peru, Benguela, Canary, California) is that observed in total primary production and in total secondary production and so in a very general way the production of living
material is dependent upon the rate of upwelling. But there is no
correlation between the Ekman transports (which are roughly assumed
to be related to the rate of upwelling) and the intensities of primary
production, in gC/ma per day, or the stocks of zooplankton, in
ml/l 000 m3. The Peru Current upwelling has a high total production
in plants and animals because it lasts a long time, but the intensities in
gC/m2 per day and the zooplankton stocks appear to be low.
Strickland et al. (1969) have published four radiocarbon observations
from " brown water '' off Pisco, and their average value amounted to
2.4 gC/m2 per day, which is considerably greater than the average of
0.67 gC/m2 per day; however, there are only a few observations and
many have been taken in the upwelling water ; indeed only a few patches
of brown water were found by Strickland et al. in upwelling water.
The Peru Current upwelling and that in the California Current were
sampled by the same equipment, by the same people at about the same
period: but there is no difference in the radiocarbon measurements in
subarea 1 in the Peru system and all three subareas in the California