State of World Fisheries and Aquaculture 2004 - Library

World review of fisheries and aquaculture
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jack mackerel, Alaska pollock, Japanese anchovy, blue whiting, capelin and Atlantic
herring). Major increases in catches cannot therefore be expected from these. Two
species could probably support higher fishing pressure in some areas (skipjack tuna and
chub mackerel) and the status of the remaining species (largehead hairtail) is unknown.
In the Southeast Pacific, a combination of high fishing pressure and adverse
environmental conditions, including the severe El Niño event of 1997–98, led to a sharp
decline in catches of the two leading species (anchoveta and Chilean jack mackerel)
during the late 1990s. While the stock of anchoveta has shown signs of recovery, with
catches in the order of 10 million tonnes since 2000, catches of Chilean jack mackerel
totalled 1.7 million tonnes in 2002, representing less than 50 percent of the fishery’s
historical peak production reached in 1994. In the North Pacific large changes in
catches occurred in response to heavy fishing and to natural decadal oscillations in the
productivity of pilchard (or sardine), anchovy and pollock. Following record catches in
the 1980s, the Japanese sardine (or pilchard) fishery collapsed in the mid-1990s and was
followed by a strong rebuild of the anchovy population, which has been supporting
catches of close to 2 million tonnes since 1998. This alternation between sardine and
anchovy stocks follows a pattern observed in many other regions of the world and
seems to be mainly governed by climatic regimes affecting stock production. The
stocks of pollock in the Northwest Pacific are considered overexploited, while those
in the Northeast Pacific are considered fully exploited. Pollock catches peaked in the
late 1980s in both areas and have been declining since then, although a recent modest
recovery is evident in the Northeast Pacific. In the Northeast Atlantic, catches of blue
whiting reached record levels (1.8 million tonnes) in 2001 and declined slightly in 2002.
The stock is currently under heavy fishing and requires more restrictive management
measures. Capelin and herring are exploited to their full potential and are currently
considered within safe biological limits. Catches of skipjack tuna have increased steadily
since 1950 and reached their highest reported value of around 2 million tonnes in 2002,
representing about half of the total capture of market tunas. The status of skipjack
tuna stocks is highly uncertain but there are indications that some potential remains for
increases in catches in the Eastern, Western and Central Pacific and in the Indian Ocean,
provided that these increases in skipjack catches will not lead to parallel increases in
catches of other species that are presently fully exploited or overexploited, for example
bigeye and yellowfin tunas.
The percentage of stocks exploited at or beyond their maximum sustainable levels
varies greatly by area. In the Eastern Central Pacific, only 33 percent of the stocks
for which assessment information is available are recorded as fully exploited, with
the remainder being either underexploited or moderately exploited, whereas in the
Western Central and Northeast Atlantic and the Western Indian Ocean, all the stocks
for which information is available are reported as being fully exploited (73 percent,
59 percent and 75 percent respectively) or as being exploited beyond this level
(Figure 20). In 12 of the 16 FAO statistical regions at least 70 percent of stocks are
already fully exploited or overexploited, suggesting that that the maximum fishing
potential has been reached and that more cautious and restrictive management
measures are needed. This conclusion is also supported by analysis of the trend in
fisheries production of the regions. Four of the 16 regions are at their maximum
historical level of production, while in 12 regions production has declined slightly and
in four the declines have been sharper, including the Northwest Atlantic (50 percent
decline from a peak in 1968), Southeast Atlantic (47 percent decline from a peak
in 1978) and Southeast Pacific (31 percent decline from a peak in 1994). In most
cases overfishing has been a main contributory factor and in some cases this has
been associated with adverse or highly variable environmental conditions. All the
information available tends to confirm the estimates made by FAO in the early 1970s
that the global potential for marine capture fisheries is about 100 million tonnes, of
which only 80 million tonnes are probably achievable. It also confirms that, despite
local differences, overall, this limit has been reached. These conclusions lend support
to the call for more rigorous stock recovery plans to rebuild stocks that have been