32
J. A. GULLAND AND J. E. CARROZ
abundance of fish as yet too small to be fished. Fortunately, a t least
with the longer-lived species, moderate errors in setting the quotas in
one year can be corrected by suitable adjustment in the subsequent
year without appreciable loss, but this does require that the administrative machinery for setting and adjusting the quota is reasonably rapid.
The complexities of regulation are further increased when more
than one species of fish is considered. Apart from the fisheries on
shoaling fish such as anchoveta, herring, etc., few of the other important
fisheries of the world are based exclusively on one species. Within a
large fishing region the proportion caught of different species varies
from ground to ground, and also often from season to season on the
same ground. The needs for regulation of the various species also tend
to vary, possibly very widely; the more valuable species may be
seriously over-exploited, while others be hardly exploited at all.
Proper management must therefore ensure suitable regulation for the
former species, without discouraging fishing on the others, and this is
not easy. Thus the success of the regulation of the Pacific halibut might
be judged by comparing the catches in recent years of ca 15 000 tons of
halibut in the Atlantic (where there are no special regulations to
protect the halibut, which because of its potentially long life, slow
growth, and high value is especially vulnerable to too heavy fishing)
with nearly 40 000 tons in the Pacific, where halibut fishing is strictly
regulated. However, it might possibly equally validly be argued that
the failure of the halibut regulation is measured by the comparison of
the total catches of all species from the areas in which halibut occur in
significant quantities. About 1; million tons of other bottom-living
fish (cods, redfishes and flounders) are caught annually off the east
coast of Canada (T.C.N.A.F. areas 2-4), but until recently only about
60 000 tons were taken off the west coast of Canada and Alaska from
the grounds covered by the Halibut Commission. I n the last few years
very large catches have been taken in the area by trawlers from Japan
and the U.S.R.R. but these countries are not members of the Halibut
Commission.
A most serious failure in a rather different way, through not considering individual stocks but only the overall total, has occurred in
Antarctic whaling, where the stocks of blue, fin and sei whales have
been in succession the main object of the industry (Fig. 11). Attention
did not switch from the preferred to the next most preferred species
(blue to fin, or fin to sei) until the former had been drastically depleted.
Although now only the sei whale stocks (the smallest stock of the three)
are abundant enough to support any appreciable catches, the actual
catches in any one of the past seasons which have so decimated the
J. A. GULLAND AND J. E. CARROZ
abundance of fish as yet too small to be fished. Fortunately, a t least
with the longer-lived species, moderate errors in setting the quotas in
one year can be corrected by suitable adjustment in the subsequent
year without appreciable loss, but this does require that the administrative machinery for setting and adjusting the quota is reasonably rapid.
The complexities of regulation are further increased when more
than one species of fish is considered. Apart from the fisheries on
shoaling fish such as anchoveta, herring, etc., few of the other important
fisheries of the world are based exclusively on one species. Within a
large fishing region the proportion caught of different species varies
from ground to ground, and also often from season to season on the
same ground. The needs for regulation of the various species also tend
to vary, possibly very widely; the more valuable species may be
seriously over-exploited, while others be hardly exploited at all.
Proper management must therefore ensure suitable regulation for the
former species, without discouraging fishing on the others, and this is
not easy. Thus the success of the regulation of the Pacific halibut might
be judged by comparing the catches in recent years of ca 15 000 tons of
halibut in the Atlantic (where there are no special regulations to
protect the halibut, which because of its potentially long life, slow
growth, and high value is especially vulnerable to too heavy fishing)
with nearly 40 000 tons in the Pacific, where halibut fishing is strictly
regulated. However, it might possibly equally validly be argued that
the failure of the halibut regulation is measured by the comparison of
the total catches of all species from the areas in which halibut occur in
significant quantities. About 1; million tons of other bottom-living
fish (cods, redfishes and flounders) are caught annually off the east
coast of Canada (T.C.N.A.F. areas 2-4), but until recently only about
60 000 tons were taken off the west coast of Canada and Alaska from
the grounds covered by the Halibut Commission. I n the last few years
very large catches have been taken in the area by trawlers from Japan
and the U.S.R.R. but these countries are not members of the Halibut
Commission.
A most serious failure in a rather different way, through not considering individual stocks but only the overall total, has occurred in
Antarctic whaling, where the stocks of blue, fin and sei whales have
been in succession the main object of the industry (Fig. 11). Attention
did not switch from the preferred to the next most preferred species
(blue to fin, or fin to sei) until the former had been drastically depleted.
Although now only the sei whale stocks (the smallest stock of the three)
are abundant enough to support any appreciable catches, the actual
catches in any one of the past seasons which have so decimated the