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For the two decades following 1950 world marine
and inland capture fisheries production increased
on average by as much as 6 percent per annum,
trebling from 18 million tonnes in 1950 to 56
million tonnes in 1969. During the 1970s and 1980s,
the average rate of increase declined to 2 percent
per year, falling to almost zero in the 1990s. This
levelling off of the total catch follows the
general trend of most of the world's fishing areas,
which have apparently reached their maximum
potential for capture fisheries production, with
the majority of stocks being fully exploited.
World marine catch totals continue to flatten
off following the general trend of most major
fishing areas of the world were fisheries have
evolved from a developing to a more mature and in
some cases senescent phase. When known and
traditional fish stocks and fisheries are taken
into account, the total marine catches from most of
the main fishing areas in the Atlantic Ocean and
some in the Pacific Ocean seem to have reached
their maximum potential years ago and, therefore,
substantial total catch increases from these areas
are unlikely. In contrast, growth in aquaculture
production has shown the opposite tendency.
Starting from an insignificant total production,
inland and marine aquaculture production grew by
about 5 percent per year between 1950 and 1969 and
by about 8 percent per year during the 1970s and
1980s, and it has further increased to 10 percent
per year since 1990.
In 1997 FAO published the results of an analysis
of the landings of 200 species from particular
oceanic areas (species-area combinations referred
to as "resources") which account for 77% of world
marine production. This analysis offers an
important additional perspective to the levelling
off of the growth in capture fisheries production.
Four examples of the 12 groups used in the analysis
are presented, reflecting phases in the development
of a fishery, namely: the undeveloped, developing,
mature and senescent phases. These phases reflect
the evolution of a fishery from stable, as yet
undeveloped, to the rapidly rising level of
productivity during which landing rates rise and
then fall until a point of maximum landings are
reached. Finally, in the senescent stage, the rate
becomes negative as the level of landings
falls.
Results showed that 35% of these 200 major
fisheries resources were senescent, that is,
showing declining yields. A further 25% were mature
(or fully exploited), 40% were still developing and
there were none that remained at a low-exploitation
level. Thus about 60% of the world's major
fisheries resources were found to be either fully
exploited or experiencing declining yields. As few
countries have effective control over fishing
capacity, these resources are in urgent need of
management to end overfishing or to restore
depleted stocks.
In addition, FAO holds information on the state
of 392 of the 696 stock items recorded in their
database, representing a wider set of resource
items than mentioned above. A more recent analysis
of these 392 items, summarized in Figure
1, shows that 6% of these stocks appear to
be underexploited, 20% moderately exploited, 50%
fully exploited, 15% overfished, 6% depleted and 2%
are recovering.
While some 76% of these stocks are at or greater
than a biomass level approximating that needed to
harvest at an optimal level, some 73% are in need
of management if they are to avoid becoming
overfished or, in the case of those already
overfished, if they are to be rebuilt. Some
fisheries in this position are under effective
management, where access to the fisheries has been
limited, thus limiting pressure on stocks. But many
fully fished resources are not adequately managed
and are therefore vulnerable to rapidly moving into
decline, becoming overfished or depleted.
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