UPWELLING AND THE PRODUCTION OF FISH
325
estimating secondary production lies in our ignorance of the duration
of invertebrate juvenile stages and the dependence of this upon temperature. Such work is not difficult and could be carried out in small marine
laboratories; without such measurements, the collections of zooplankton
made at sea with costly crews and expensive research ships are really of
very little value.
Smith's (1969) recent review of the physical studies of upwelling is
notable for the demonstration that the theoretical formulations of upwelling are confirmed in general by physical measurements. Hence,
some physical understanding of the processes is available and could be
exploited in a study of upwelling. It is clear from the present study that
the biological study of upwelling is a little primitive. An early stage in
oceanographic research is expressed in the form of surveys; it is a
necessary and exploratory stage which, thanks to the intensive work off
California in the last two decades, is in principle complete. This does
not mean that explorations, particularly in some areas, are no longer
needed, but rather that the nature of the work should change t o some
extent.
The major change in the direction of upwelling research may be in
the time interval of sampling. The best methods used so far have employed surveys of about a month apart. But upwelling is often an intermittent process, periods of wind stress alternating with periods of calm,
and so the time unit of study should be as long aa a period of wind stress
or a period of calm. Unless enormous resources become available, a
major upwelling cannot be described at intervals of 3 or 5 days ; perhaps it should not be so described because of the potential waste of
data. In other words, it might be of advantage to study a smaller area,
for example, the Guinea upwelling, the area off Punta San Eugenio in
California, or that off Somalia. Of course, for a short season, a major
upwelling region may comprise a small enough region to make study
worth while, like that off Oregon. Physical measurements can be taken
by continuous recording, for example of temperature, salinity and
oxygen. Measurements of phosphate, nitrate, silicate, nitrite, chlorophyll and turbidity can be made continuously with Autotechnicon
methods (Armstrong, Stearns and Strickland, 1967). Similarly radiocarbon measurements can be made rapidly and reliably with scintillation counters (Wolfe and Schelske, 1967). Zooplankton hauls above
200 m and below 200 m can be made with high-speed tow nets (Beverton
and Tungate, 1967), and the same gear can be used for eggs and larvae.
High-resolution acoustic gear can be used at all depth strata, together
with means of capture at any depth for identification. It is not of value
to collect very large quantities of data unless a model of the biological
325
estimating secondary production lies in our ignorance of the duration
of invertebrate juvenile stages and the dependence of this upon temperature. Such work is not difficult and could be carried out in small marine
laboratories; without such measurements, the collections of zooplankton
made at sea with costly crews and expensive research ships are really of
very little value.
Smith's (1969) recent review of the physical studies of upwelling is
notable for the demonstration that the theoretical formulations of upwelling are confirmed in general by physical measurements. Hence,
some physical understanding of the processes is available and could be
exploited in a study of upwelling. It is clear from the present study that
the biological study of upwelling is a little primitive. An early stage in
oceanographic research is expressed in the form of surveys; it is a
necessary and exploratory stage which, thanks to the intensive work off
California in the last two decades, is in principle complete. This does
not mean that explorations, particularly in some areas, are no longer
needed, but rather that the nature of the work should change t o some
extent.
The major change in the direction of upwelling research may be in
the time interval of sampling. The best methods used so far have employed surveys of about a month apart. But upwelling is often an intermittent process, periods of wind stress alternating with periods of calm,
and so the time unit of study should be as long aa a period of wind stress
or a period of calm. Unless enormous resources become available, a
major upwelling cannot be described at intervals of 3 or 5 days ; perhaps it should not be so described because of the potential waste of
data. In other words, it might be of advantage to study a smaller area,
for example, the Guinea upwelling, the area off Punta San Eugenio in
California, or that off Somalia. Of course, for a short season, a major
upwelling region may comprise a small enough region to make study
worth while, like that off Oregon. Physical measurements can be taken
by continuous recording, for example of temperature, salinity and
oxygen. Measurements of phosphate, nitrate, silicate, nitrite, chlorophyll and turbidity can be made continuously with Autotechnicon
methods (Armstrong, Stearns and Strickland, 1967). Similarly radiocarbon measurements can be made rapidly and reliably with scintillation counters (Wolfe and Schelske, 1967). Zooplankton hauls above
200 m and below 200 m can be made with high-speed tow nets (Beverton
and Tungate, 1967), and the same gear can be used for eggs and larvae.
High-resolution acoustic gear can be used at all depth strata, together
with means of capture at any depth for identification. It is not of value
to collect very large quantities of data unless a model of the biological