243
nation thus fl uctuates along with the abundance
of the anchoveta. In contrast to above, Norway
has a traditional dependence upon fi sh and fi sh
products. This has been creating a steady demand.
This, in turn, has enabled Norway to modernise
and expand its fi shing fl eet.
Contrary to the situation in Europe, longestablished, but static, fi shing industry in extensive highly productive coastal waters has helped
the USA to attain a high position in aquaculture.
However, advancement was limited mainly to
certain high-value fi sheries like tuna and shrimp.
It may be possible for the value of a catch to
increase substantially from year to year mainly
due to burgeoning demand. This may happen
even though the weight of the catch remains
almost the same.
15.5.8.3 Long-Term Trend
in the World Aquatic Harvest
It is said that the global harvest of aquatic biota
increased steadily from the end of the World War
II until the early 1970s. This pattern of increased
growth was possible mainly due to the blending
of different factors, like development of technologically improved mechanised fi shing vessels,
advances in fi shing gears and fi sh catching strategies, expansion of new fi shing grounds, the
extension of fi shing effort to species which formerly were not harvested and, above all, an
increased demand and higher market value for
fi sh. To the contrary, the depletion of catch in
some parts of the world during the mid-1970s
could be attributed to many causes. Move towards
‘enclosure’ or the adoption of 200-mile fi sheries
jurisdictions or the Exclusive Economic Zone
(EEZ) is a signifi cant reason in addition to other
causes like decline of the major fi sheries, such as
the Peruvian anchoveta.
15.5.8.4 Potential Future Harvests:
What Is the Upper Limit?
On perusal of world’s conventional fi sheries with
regard to MSY, it could be revealed surprisingly
that most of them either nearing MSY or have
reached MSY. However, quite a large number of
them are found to be overexploited. Wild fi sh
stocks are common property resources. They can
be exploited by anyone. This is one of the main
reasons of overexploitation.
In view of the above, one may wonder whether
the total yield from oceans is also approaching an
upper limit, considering the fact that many
individual fi sheries are fully exploited. There had
been much efforts, during the last two decades, to
answer this question from a theoretical point of
view. Two basic approaches had been used:
(a) The fi rst approach could be called the ‘food
web approach’. It has the following main
features:
(i) Estimation of primary production of all
sections of the world’s oceans
(ii) Estimation of secondary production of
fi shery organisms at that trophic level
by converting from the net primary production estimate
(iii) Estimation of what percentage of the secondary production of fi shery organisms
can feasibly be harvested by man
It may be possible to obtain an estimate of
potential world annual yield by summing up
estimates from all sections of the oceans.
(b) The second approach is principally an
‘extrapolation technique’. It consists of
three main steps:
(i) All conventional and potential fi sheries
are to be identifi ed.
(ii) The potential MSY from each fi shery is
to be estimated.
(iii) Finally, all these estimates are summed
up to obtain a potential estimate of the
world.
15.6 Aquaculture
Of late, there has been a growing focus and
interest on controlled ‘fi sh farming’ or ‘aquaculture’. It is mainly because the world fi sh
catch seems to be approaching an upper limit,
at least for the foreseeable future. Further, the
potential for substantially increased production
in aquaculture is very encouraging and promising, although there are a number of inherent
biological, technological and socio-economic
problems associated with it. Certainly, the ulti15.6 Aquaculture
nation thus fl uctuates along with the abundance
of the anchoveta. In contrast to above, Norway
has a traditional dependence upon fi sh and fi sh
products. This has been creating a steady demand.
This, in turn, has enabled Norway to modernise
and expand its fi shing fl eet.
Contrary to the situation in Europe, longestablished, but static, fi shing industry in extensive highly productive coastal waters has helped
the USA to attain a high position in aquaculture.
However, advancement was limited mainly to
certain high-value fi sheries like tuna and shrimp.
It may be possible for the value of a catch to
increase substantially from year to year mainly
due to burgeoning demand. This may happen
even though the weight of the catch remains
almost the same.
15.5.8.3 Long-Term Trend
in the World Aquatic Harvest
It is said that the global harvest of aquatic biota
increased steadily from the end of the World War
II until the early 1970s. This pattern of increased
growth was possible mainly due to the blending
of different factors, like development of technologically improved mechanised fi shing vessels,
advances in fi shing gears and fi sh catching strategies, expansion of new fi shing grounds, the
extension of fi shing effort to species which formerly were not harvested and, above all, an
increased demand and higher market value for
fi sh. To the contrary, the depletion of catch in
some parts of the world during the mid-1970s
could be attributed to many causes. Move towards
‘enclosure’ or the adoption of 200-mile fi sheries
jurisdictions or the Exclusive Economic Zone
(EEZ) is a signifi cant reason in addition to other
causes like decline of the major fi sheries, such as
the Peruvian anchoveta.
15.5.8.4 Potential Future Harvests:
What Is the Upper Limit?
On perusal of world’s conventional fi sheries with
regard to MSY, it could be revealed surprisingly
that most of them either nearing MSY or have
reached MSY. However, quite a large number of
them are found to be overexploited. Wild fi sh
stocks are common property resources. They can
be exploited by anyone. This is one of the main
reasons of overexploitation.
In view of the above, one may wonder whether
the total yield from oceans is also approaching an
upper limit, considering the fact that many
individual fi sheries are fully exploited. There had
been much efforts, during the last two decades, to
answer this question from a theoretical point of
view. Two basic approaches had been used:
(a) The fi rst approach could be called the ‘food
web approach’. It has the following main
features:
(i) Estimation of primary production of all
sections of the world’s oceans
(ii) Estimation of secondary production of
fi shery organisms at that trophic level
by converting from the net primary production estimate
(iii) Estimation of what percentage of the secondary production of fi shery organisms
can feasibly be harvested by man
It may be possible to obtain an estimate of
potential world annual yield by summing up
estimates from all sections of the oceans.
(b) The second approach is principally an
‘extrapolation technique’. It consists of
three main steps:
(i) All conventional and potential fi sheries
are to be identifi ed.
(ii) The potential MSY from each fi shery is
to be estimated.
(iii) Finally, all these estimates are summed
up to obtain a potential estimate of the
world.
15.6 Aquaculture
Of late, there has been a growing focus and
interest on controlled ‘fi sh farming’ or ‘aquaculture’. It is mainly because the world fi sh
catch seems to be approaching an upper limit,
at least for the foreseeable future. Further, the
potential for substantially increased production
in aquaculture is very encouraging and promising, although there are a number of inherent
biological, technological and socio-economic
problems associated with it. Certainly, the ulti15.6 Aquaculture