A guide for planners and managers - IUCN

PART I
The Roles of Protected Areas
The coconut crab, Birgus latro, is another invertebrate species that is an
important food resource for many island peoples (Figure I-14). Although still abundant
on islands like Aldabra, where exploitation is negligible, populations declined on many
others, including the Chagos Archipelago and Guam (Sheppard, 1979; Amesbury, 1980).
Giant clams (family Tridacnidae)
have been overexploited
throughout much of their range.
Mariculture may prove a major
tool in conserving and managing
these resources (Munro and
Heslinga, 1982), but in the meantime
MPAs are probably the only
way of preserving the remaining
stocks in some countries. In
Australia, giant clam populations
are protected by the Great Barrier
Reef Marine Park. These reserves
may play important roles with
the development of mariculture
operations. Programmes are well
under way for the queen conch,
giant clams, and commercial trochus Trochus niloticus (Berg, 1981; Munro and
Heslinga, 1982; Heslinga and Hillman, 1980). One of the objectives of such programmes
is restocking overexploited areas. The areas will have to be protected to establish the
new populations.
In Indonesia and the Philippines some invertebrate populations are declining
at alarming rates. In Indonesia, sites were sought for reserves specifically to protect
certain species. For example, a marine reserve was delineated for an area off Irian
Jaya, which is still rich in one species, Tridacna gigas, and another reserve was
identified for the species T. derasa in the Flores Sea. In the Philippines, there is little
protection for clams. One exception is the marine reserve along the west side of Sumilon
Island, Cebu, which protects substantial numbers of the clam species T. crocea,
T. maxima, T. squamosa, and Hippopus hippopus (Alcala, 1982).
1.8 Replenishing Depleted Stocks
FIGURE I-14.
The rare coconut or robber crab (Birgus latro) is a tasty, easily
caught creature in desperate need of protection (Aldabra Atoll Strict
Nature Reserve and World Heritage Site).
Protected areas can contribute to the replenishment of threatened marine resources
through creation of No-Fishing Zones (No-Take Zones, Sanctuaries). They can
safeguard breeding sanctuaries from which individuals can disperse to stock exploited
areas. Other MPA protections may be necessary to safeguard recognized nurture
areas (nursery areas) for juvenile stages (Clark, 1996).
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Photo by R. Salm.