MANAGEMENT OF FISHERY RESOURCES
31
and if the othcrs do not change, its share would go up t o about 33%) the
share of the others going down accordingly, Quotas allocated in these
proportions would then be equitable in the sense that with regulation
each country would take the same share of catch as it would have done
in the absence of regulation. As the stocks build up under good
management the allocation will become more difficult, since fishing will
become more attractive and more countries will desire t o increase their
fishery.
I n whatever way the limit is set, either as a single overall quota or
allocated to groups of fishermen, it must be defined either in terms of
catch or amount of fishing, e.g. number of days at sea. The objective, in
biological terms, is t o achieve a certain fishing mortality, i.e. t o capture
a certain proportion of the stock each year. Neither the catch nor the
amount of fishing (at least in readily measurable physical terms) will
bear an absolutely constant relation to the fishing mortality. The
catch corresponding to a desired fishing mortality will depend on the
stock abundance, while the amount of fishing effort required to exert a
given fishing mortality will depend on the efficiency of the operation
chosen as the unit of effort (e.g. a day at sea by a vessel of a certain size)
and whether the distribution and behaviour of the fish make them more
or less catchable. The catch is readily definable in standard terms
(though the increasing numbers of vessels freezing and processing at
sea will complicate the precise measurement of the catch in terms of
round fresh (live) weight). The definition of fishing effort in standard
terms is much more difficult, especially if a limit is set as a single quota
requiring the efforts exerted by all the vessels engaged in the fishery t o
be expressed in the same terms. The difficulties of effort measurement
are less if there is allocation of quota, explicitly or implicitly ; e.g. if all
countries agree to reduce their amount of fishing (as measured in various
national units) by a certain percentage, or if limitation is set by issuing
licences. I n the latter case the problem of standard measurement of
effort may only become serious when a licensed fisherman wishes to
improve his efficiency by getting a bigger or newer vessel, or by
changing his type of gear.
The measurement of the amount of fishing in terms of catch also
has its difficulties, chiefly through the need to have a measure of the
abundance of the fish stock. Many fish stocks fluctuate widely in
abundance due to varying strengths of year-classes, while the quota for
a year or a season must be set reasonably in advance of the season.
Some system of forecasting the stock is required, and this can usually
be done with a varying degree of precision, though sometimes requiring
special rescarch effort, e.g. the use of research vessels to survey the
2'
31
and if the othcrs do not change, its share would go up t o about 33%) the
share of the others going down accordingly, Quotas allocated in these
proportions would then be equitable in the sense that with regulation
each country would take the same share of catch as it would have done
in the absence of regulation. As the stocks build up under good
management the allocation will become more difficult, since fishing will
become more attractive and more countries will desire t o increase their
fishery.
I n whatever way the limit is set, either as a single overall quota or
allocated to groups of fishermen, it must be defined either in terms of
catch or amount of fishing, e.g. number of days at sea. The objective, in
biological terms, is t o achieve a certain fishing mortality, i.e. t o capture
a certain proportion of the stock each year. Neither the catch nor the
amount of fishing (at least in readily measurable physical terms) will
bear an absolutely constant relation to the fishing mortality. The
catch corresponding to a desired fishing mortality will depend on the
stock abundance, while the amount of fishing effort required to exert a
given fishing mortality will depend on the efficiency of the operation
chosen as the unit of effort (e.g. a day at sea by a vessel of a certain size)
and whether the distribution and behaviour of the fish make them more
or less catchable. The catch is readily definable in standard terms
(though the increasing numbers of vessels freezing and processing at
sea will complicate the precise measurement of the catch in terms of
round fresh (live) weight). The definition of fishing effort in standard
terms is much more difficult, especially if a limit is set as a single quota
requiring the efforts exerted by all the vessels engaged in the fishery t o
be expressed in the same terms. The difficulties of effort measurement
are less if there is allocation of quota, explicitly or implicitly ; e.g. if all
countries agree to reduce their amount of fishing (as measured in various
national units) by a certain percentage, or if limitation is set by issuing
licences. I n the latter case the problem of standard measurement of
effort may only become serious when a licensed fisherman wishes to
improve his efficiency by getting a bigger or newer vessel, or by
changing his type of gear.
The measurement of the amount of fishing in terms of catch also
has its difficulties, chiefly through the need to have a measure of the
abundance of the fish stock. Many fish stocks fluctuate widely in
abundance due to varying strengths of year-classes, while the quota for
a year or a season must be set reasonably in advance of the season.
Some system of forecasting the stock is required, and this can usually
be done with a varying degree of precision, though sometimes requiring
special rescarch effort, e.g. the use of research vessels to survey the
2'