A guide for planners and managers - IUCN

28 MARINE AND COASTAL
PROTECTED AREAS
Photo by Erkki Siirila.
FIGURE I-13.
In Dominica these boys do their share by
supplying seafood to the community of Portsmouth.
They carry typical West Indian fish traps.
fisheries are widely considered to be fully
exploited (Brainerd, 1994; Hatziolos et al.,
1994; Insull et al., 1995; Tvedten & Hersoug,
1992), with some already being exploited
beyond the level of sustainability with no
margin for feeding increasing populations.
Because demand is increasing with population
growth and prosperity, fisheries are typically
not managed for sustainability; their contribution
to national diets and income is diminishing
and is likely to continue diminishing.
MPAs can help sustain such fisheries.
Past and present overfishing has caused
many of the world’s most valuable fisheries to
be seriously depleted. Nor can it be assumed
that depleted stocks will recover naturally to
reach their full potential. In fact, this is most
unlikely for several reasons: juvenile fishes
will continue to be caught for the aquarium
trade or as bycatch by “industrial” fisheries and
ground up for animal feed; other species may invade the territories of depleted
species and prevent their return and; habitats essential for spawning or as nurture
areas may be degraded or destroyed and lose power to regenerate stocks. Also many
lucrative and exploitative and destructive fisheries are being accelerated such as
those that catch and transport large live fish and those that stun fish with cyanide.
In addition to depleting fish, crustacean, and mollusc stocks, overfishing has
nearly extinguished some popular species, like whales, dolphins, and sea turtles.
Some are the victims of incidental capture as bycatch along with “target” species and
are killed and discarded. An example of this wasteful practice is the incidental capture
and killing of sea turtles in fishing nets, which threatens the survival of several
species.
Protecting critical habitats may be necessary to maintain high fisheries returns
or even to prevent the “economic extinction” of commercially important species. Many
commercially valuable species are not now threatened with biological extinction, but
because they are heavily exploited they could nevertheless be “commercially threatened.”
Invertebrates are often very important to subsistence and artisanal fishers. For
example, the palolo worm, Eunice viridis, an important food resource in Fiji and Samoa,
is reported to be declining. While the causes of the decline have not been scientifically
determined, they may include a variety of factors, such as destruction of coral reefs,
siltation, and pollution. Reserves to protect its main breeding areas have been
established, for example, the Palolo Deep Reserve in Western Samoa.