Status of Coral Reefs of the World 2000

Status of Southeast and Central Pacific Coral Reefs ‘Polynesia Mana Node’
Global Climate Change
At present there is no definitive evidence that global change effects are impacting more
than direct human stresses, however detailed studies are required to detect any future
impacts of seawater warming and sea level rise on coral reefs. Politicians and scientists in
these countries are aware of the potential impacts from climate scenarios. This was noted
in all of the national reports, particularly in relation to the possibility of more frequent El Niño
changes. In Kiribati, a Climate Change Working Committee has been launched. Models for
Moorea, French Polynesia show that a 1cm a year increase over the next 30 years could
destroy all natural shorelines, which would have to be replaced with modified protecting
walls. Such construction could have negative impacts on the fringing reefs.
ANTHROPOGENIC THREATS TO CORAL REEFS
Human population densities on all islands are relatively low and all archipelagos are remote
from continental influences. Therefore, most of the islands in this region are free of
anthropogenic impacts, with only occasional local damage. There has been some
degradation of coastal zones, lagoons and coral reefs due to human activities in a few areas
near urban centres. Even though there may be some pollution and degradation in lagoons,
the important outer slopes of the reef ecosystems remain healthy.
Over-Fishing
This is a major problem in most countries due to changes in governance from traditional and
ancestral tenure-based fishing rights and practices to more legislation and policies that are
typically common-property based reflecting laws in colonial countries. However, the need
for increasing reliance on cash-based income and products (e.g. petrol) is also eroding
traditional reef-management practices. For example, Polynesians traditionally collected fish
and other food from the lagoons and reefs along their own village ‘coastal zone’ and
collecting was forbidden in other areas. Now individuals and commercial operators can
harvest resources from anywhere, and there is over-fishing due to the increased use of
power boats, nets and other sophisticated gear. Destructive fishing methods (poisons and
dynamite) have only been reported in Tonga, Kiribati (poison) and in Wallis and Futuna
(poison and dynamite use). There are no other reports of dynamite fishing.
Coral, Sand and Mangrove Extraction for Construction
Extraction of material from the lagoon and reef areas (e.g. coral sand, rubble) to build
houses (Kiribati) or for roads, walls, and shoreline construction is a major problem in all
islands with significantly increasing populations. Coral and sand mining have been banned
in Kiribati and French Polynesia, but activities continue. Where mangroves exist, they have
been cut for firewood and construction, even though it is banned in Kiribati and Tonga.
Groynes and Rock Walls
Construction of walls in conjunction with roads, airports, marinas, wharves, markets and
residences to diminish erosion is common everywhere. Often this encroaches on lagoons
and results in the disappearance of beaches. This has been a particular problem in Wallis
and Futuna, and less than 50% of the coastline remains in a natural unaltered state
throughout the Society Islands, French Polynesia. Similar problems have been encountered
on Rarotonga, Cook Islands.
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