MANAGEMENT OF FISHERY RESOURCES
27
not likely to be ideal ; the fishing mortality may be reduced, but it is
most unlikely that the costs can be reduced in proportion. Initially a
closure of, say, 10% of the normal fishing season will reduce the fishing
mortality and the running costs (but not the capital costs) by about
lo%, but the long-term effects are likely to be the same as for uiiallocated catch quotas, discussed in more detail below, i.e. an increasingly wasteful entry of new vessels, etc., as the catfell per unit effort
rises, necessitating a progressive shortening of the season to maintain
the effort (mortality) at the desired level.
Closed areas or closed seasons can also be used to control the sizes
of fish caught if there are areas where or times when small fish are
particularly common ; for instance, the smaller fish of several species
tend to remain in inshore or shallower areas, and closure of these
nursery areas would give effcctive protection of these smaller fish. In
addition, there nzay be times or places where the fish are in poor
condition (e.g. after spawning), and when closure would allow the
fish to recover and thus give a larger and more valuable catch. Such
closures (other than a closure of all areas to fishing for a season) are
particularly valuable when there are alternative grounds which can be
fished profitably while the nursery areas are closed. Otherwise such
closures would involve temporary lay-up of vessels, or diversion to an
unprofitable fishery, and hence add to the cost of the fishery.
(d) Regulation of the type of gear may be divided Into those banning
or restricting the use of more efficient, or " damaging ", gears, i.e.
aimed a t reducing the fishing mortality, and those, such as mesh
regulations, aimed a t controlling the sizes of fish caught. The former
types have little justification as a permanent feature of fishery management ; they only succeed in reducing the fishing mortality to the extent
that they increase the costs of catching a given proportion of the stock.
They may be necessary when increased fishing effort will severely
reduce the total catch, e.g. by reducing the number of recruits, but
when used they are an implicit admission of failure to achieve any
ketter management.
Regulation of the gear to control the sizes of fish caught, especially
mesh regulation of trawls, are useful and have been introduced widely
in the North Atlantic, and also in other areas, such as the East China
Sea. Generally, they do not affect the cost of fishing, and indeed a trawl
with larger meshes may be cheaper and fish more effectively on the
larger fish. The selectivity of many gears, such as purse seines, cannot
be altered in practice-they catch all the fish in a shoal-while that of
others, e.g. long-lines, can only be altered rather imprecisely-larger
hooks tend to catch larger fish, but the relation is far from exact. Even
27
not likely to be ideal ; the fishing mortality may be reduced, but it is
most unlikely that the costs can be reduced in proportion. Initially a
closure of, say, 10% of the normal fishing season will reduce the fishing
mortality and the running costs (but not the capital costs) by about
lo%, but the long-term effects are likely to be the same as for uiiallocated catch quotas, discussed in more detail below, i.e. an increasingly wasteful entry of new vessels, etc., as the catfell per unit effort
rises, necessitating a progressive shortening of the season to maintain
the effort (mortality) at the desired level.
Closed areas or closed seasons can also be used to control the sizes
of fish caught if there are areas where or times when small fish are
particularly common ; for instance, the smaller fish of several species
tend to remain in inshore or shallower areas, and closure of these
nursery areas would give effcctive protection of these smaller fish. In
addition, there nzay be times or places where the fish are in poor
condition (e.g. after spawning), and when closure would allow the
fish to recover and thus give a larger and more valuable catch. Such
closures (other than a closure of all areas to fishing for a season) are
particularly valuable when there are alternative grounds which can be
fished profitably while the nursery areas are closed. Otherwise such
closures would involve temporary lay-up of vessels, or diversion to an
unprofitable fishery, and hence add to the cost of the fishery.
(d) Regulation of the type of gear may be divided Into those banning
or restricting the use of more efficient, or " damaging ", gears, i.e.
aimed a t reducing the fishing mortality, and those, such as mesh
regulations, aimed a t controlling the sizes of fish caught. The former
types have little justification as a permanent feature of fishery management ; they only succeed in reducing the fishing mortality to the extent
that they increase the costs of catching a given proportion of the stock.
They may be necessary when increased fishing effort will severely
reduce the total catch, e.g. by reducing the number of recruits, but
when used they are an implicit admission of failure to achieve any
ketter management.
Regulation of the gear to control the sizes of fish caught, especially
mesh regulation of trawls, are useful and have been introduced widely
in the North Atlantic, and also in other areas, such as the East China
Sea. Generally, they do not affect the cost of fishing, and indeed a trawl
with larger meshes may be cheaper and fish more effectively on the
larger fish. The selectivity of many gears, such as purse seines, cannot
be altered in practice-they catch all the fish in a shoal-while that of
others, e.g. long-lines, can only be altered rather imprecisely-larger
hooks tend to catch larger fish, but the relation is far from exact. Even