31
J. A. GULLAND AND J. E. CARROZ
species contributing towards this quota with different weighting factors.
For whales these factors were set to give approximately equal economic
value, i.e. one blue whale unit (BWU) is equal to one blue whale, two
fin whales or six sei whales; but they could equally well be set (and
adjusted as necessary) to take into account the need for protection for
each species. Thus in, say, 1955 the blue whde stocks were seriously
over-exploited, the fin whales probably a t about the optimum level,
and the sei whales virtually untouched. Appropriate factors might
then have been
1 BWU = 0.5 blue whales = 2 fin whales = 15 sei whales
so that, provided also that the total quota had been allocated to
countries or expeditions, there would be strong discouragement t o kill
blue whales, and equally a positive inducement t o go after sei whales.
This section cannot include all possible methods of regulation, and
more especially all the problems likely to arise where they are introduced. Certain general conclusions can be made. Regulations controlling the sizes of fish caught can only be used in limited types of fisheries
(e.g. in trawl nets where the mesh size can be changed). I n these
fisheries they can have definite, if limited beneficial effects, but the
benefits tend to be dissipated unless there is also control of the amount
of fishing. The essential step in f ~ d l
management is therefore to control
the amount of fishing and this will, in an overfished stock, produce a
considerable surplus of value of catch above costs. An important
decision should be made as to how, and by whom, this surplus shall be
taken, otherwise it is probable that the surplus will be dissipated in
some form of excessive costs. Rational management usually involves
restriction of free entry into the fishery, which may be relatively easy
in a national fishery or when a nation has been allocated a national
quota, i.e. where there is a central body, having strong authority and
powers of enforcement, but is not so easy in international fisheries.
For these, limitation of entry may involve such questions as the extent
of exclusive fishery limits, and the powers of international commissions,
and these are discussed in the following section.
IV. THE MECHANICS OF MANAGEMENT AND INTERNATIONAL LAW
Nations can approach the problem of making fisheries management
a reality in two ways: first, the national approach, by taking appropriate measures in sea areas off their shores over which they exercise
sovereignty (territorial sea) or over which they claim jurisdiction over
fisheries (fishery zones), fishermen of other countries usually being
completely excluded ; second, the international approach, by setting
J. A. GULLAND AND J. E. CARROZ
species contributing towards this quota with different weighting factors.
For whales these factors were set to give approximately equal economic
value, i.e. one blue whale unit (BWU) is equal to one blue whale, two
fin whales or six sei whales; but they could equally well be set (and
adjusted as necessary) to take into account the need for protection for
each species. Thus in, say, 1955 the blue whde stocks were seriously
over-exploited, the fin whales probably a t about the optimum level,
and the sei whales virtually untouched. Appropriate factors might
then have been
1 BWU = 0.5 blue whales = 2 fin whales = 15 sei whales
so that, provided also that the total quota had been allocated to
countries or expeditions, there would be strong discouragement t o kill
blue whales, and equally a positive inducement t o go after sei whales.
This section cannot include all possible methods of regulation, and
more especially all the problems likely to arise where they are introduced. Certain general conclusions can be made. Regulations controlling the sizes of fish caught can only be used in limited types of fisheries
(e.g. in trawl nets where the mesh size can be changed). I n these
fisheries they can have definite, if limited beneficial effects, but the
benefits tend to be dissipated unless there is also control of the amount
of fishing. The essential step in f ~ d l
management is therefore to control
the amount of fishing and this will, in an overfished stock, produce a
considerable surplus of value of catch above costs. An important
decision should be made as to how, and by whom, this surplus shall be
taken, otherwise it is probable that the surplus will be dissipated in
some form of excessive costs. Rational management usually involves
restriction of free entry into the fishery, which may be relatively easy
in a national fishery or when a nation has been allocated a national
quota, i.e. where there is a central body, having strong authority and
powers of enforcement, but is not so easy in international fisheries.
For these, limitation of entry may involve such questions as the extent
of exclusive fishery limits, and the powers of international commissions,
and these are discussed in the following section.
IV. THE MECHANICS OF MANAGEMENT AND INTERNATIONAL LAW
Nations can approach the problem of making fisheries management
a reality in two ways: first, the national approach, by taking appropriate measures in sea areas off their shores over which they exercise
sovereignty (territorial sea) or over which they claim jurisdiction over
fisheries (fishery zones), fishermen of other countries usually being
completely excluded ; second, the international approach, by setting