The Pacific Ocean
301
dominate to the north of the equator, and are
particularly strong from November to May. Along the
equator itself there are easterly winds. These
are strongest in the Eastern Pacific, and tend to be
generally light to variable further west.
Tropical storms or cyclones are a regular disturbance in areas away from the equator, and become
more numerous in the western parts of the Pacific. The
general westward flow of the surface waters, which are
heated as they flow, sets up a number of gradients,
including an important pressure gradient. Occasionally
this system undergoes reversal in a process known as
the El Nifio Southern Oscillation Ian "El Nino event"].
Such processes are typified by warm water upwellings
in the Eastern Pacific and considerable changes in the
"normal" patterns of currents and upwellings across
the region and even around the globe. The impacts
of such events on coral reefs can be considerable, as
witnessed by the mass bleaching events of recent years
(see Chapter 2).
In terms of biodiversity this is a very important,
though still little studied, region. In the far west it
encompasses the edges of the Indonesian-Philippine
center of coral diversity, and there is evidence to
suggest that biodiversity on reefs in Papua New Guinea
may be at least as high as in these countries. I^oving
east across the region there is a clear gradient of
diminishing diversity which appears to be reflected in
all of the major groups of coral reef organisms, as well
as in mangroves and seagrasses. There are some ^5
mangrove species recorded from Australia and Papua
New Guinea, but only three from Samoa, with none
occurring east of Samoa. Knowledge of the reefs in
this region is still extremely limited. Australia's Great
Barrier Reef has been extensively studied, but its
vast size means that, even here, many reefs are only
occasionally visited by scientists. French Polynesia is
another relatively well studied territory, but it has been
estimated that only about half of the reef systems have
even been visited by scientists, and there is published
material on less than a quarter of them.
This was one of the last regions on Earth to have
been settled by humans. While there is some evidence
of early arrivals in Papua New Guinea and the nearby
islands up to 30 000 years ago, the movement of
peoples out to oceanic islands is largely the result of
more recent journeys. The great Polynesian voyages
probably began some 3 000-4 000 years ago, and continued until about 1 000 years ago. European arrival
in the region had considerable impacts on the native
people. In many islands, "new" diseases decimated
populations, such that, although there are now high
growth rates, many nations still have lower populations than existed before European arrival.
In the Reefs at Risk analysis this region was
assessed as being one of the least threatened ir the
world. Population densities are generally low, and
there are large areas of coral reefs which are far from
any human populations. Despite this, human reliance
on the coral reefs of the region is considerable. For
many of the small island nations they are a critical
source of food, as well as offering protection from
storms, tvjany areas, and some entire nations, are comprised solely of small atoll cays, entirely the product
of reef development, and only a few meters above sea
level at their highest point.
Western-style development is limited in many
countries, and wide areas of reef still fall under some
form of customary marine tenure. Artisanal fishing
predominates in coastal waters, and traditional
systems for controlling this fishing often include
relatively complex and effective management regimes
Isee Chapter 21
Environmental problems do occur in some areas.
There is evidence of target species overfishing in
many countries, and populations of clams and trochus
have collapsed in several nations, even before export
fisheries for these species had begun. Modern fishing
methods have allowed access to more remote reefs,
and more thorough harvesting. As traditional systems
break down, some areas have seen considerable
overexploitation, and also destructive fishing. These
problems do not affect wide areas, but are important,
particularly because they are focussed close to high
population densities and are clearly diminishing the
potential of the reefs as a renewable source of food.
Tourism is important for the economy of many
countries, and is almost entirely focussed on the
coastal zone, with diving and snorkelling being
key activities. In general, however, tourist numbers
remain low compared to other parts of the world, and
they are usually restricted to those islands with more
developed infrastructures.
Pollution and sedimentation are generally not
widespread, but are clearly a concern in localized
areas, especially where there is urban development.
On the high islands sediment runoff and pollution
from agriculture and mining can be a problem.
The transition from traditional to Western society
presents a number of interesting difficulties. The
desire to establish legally designated marine protected
areas has run into conflict with local "owners" of reef
resources. In many countries this has prevented
the establishment of Western-style protected area
systems. While traditional management regimes
remain effective this is unproblematic, but as or when
such systems are undermined there is considerable
potential for overexploitation and damage.
301
dominate to the north of the equator, and are
particularly strong from November to May. Along the
equator itself there are easterly winds. These
are strongest in the Eastern Pacific, and tend to be
generally light to variable further west.
Tropical storms or cyclones are a regular disturbance in areas away from the equator, and become
more numerous in the western parts of the Pacific. The
general westward flow of the surface waters, which are
heated as they flow, sets up a number of gradients,
including an important pressure gradient. Occasionally
this system undergoes reversal in a process known as
the El Nifio Southern Oscillation Ian "El Nino event"].
Such processes are typified by warm water upwellings
in the Eastern Pacific and considerable changes in the
"normal" patterns of currents and upwellings across
the region and even around the globe. The impacts
of such events on coral reefs can be considerable, as
witnessed by the mass bleaching events of recent years
(see Chapter 2).
In terms of biodiversity this is a very important,
though still little studied, region. In the far west it
encompasses the edges of the Indonesian-Philippine
center of coral diversity, and there is evidence to
suggest that biodiversity on reefs in Papua New Guinea
may be at least as high as in these countries. I^oving
east across the region there is a clear gradient of
diminishing diversity which appears to be reflected in
all of the major groups of coral reef organisms, as well
as in mangroves and seagrasses. There are some ^5
mangrove species recorded from Australia and Papua
New Guinea, but only three from Samoa, with none
occurring east of Samoa. Knowledge of the reefs in
this region is still extremely limited. Australia's Great
Barrier Reef has been extensively studied, but its
vast size means that, even here, many reefs are only
occasionally visited by scientists. French Polynesia is
another relatively well studied territory, but it has been
estimated that only about half of the reef systems have
even been visited by scientists, and there is published
material on less than a quarter of them.
This was one of the last regions on Earth to have
been settled by humans. While there is some evidence
of early arrivals in Papua New Guinea and the nearby
islands up to 30 000 years ago, the movement of
peoples out to oceanic islands is largely the result of
more recent journeys. The great Polynesian voyages
probably began some 3 000-4 000 years ago, and continued until about 1 000 years ago. European arrival
in the region had considerable impacts on the native
people. In many islands, "new" diseases decimated
populations, such that, although there are now high
growth rates, many nations still have lower populations than existed before European arrival.
In the Reefs at Risk analysis this region was
assessed as being one of the least threatened ir the
world. Population densities are generally low, and
there are large areas of coral reefs which are far from
any human populations. Despite this, human reliance
on the coral reefs of the region is considerable. For
many of the small island nations they are a critical
source of food, as well as offering protection from
storms, tvjany areas, and some entire nations, are comprised solely of small atoll cays, entirely the product
of reef development, and only a few meters above sea
level at their highest point.
Western-style development is limited in many
countries, and wide areas of reef still fall under some
form of customary marine tenure. Artisanal fishing
predominates in coastal waters, and traditional
systems for controlling this fishing often include
relatively complex and effective management regimes
Isee Chapter 21
Environmental problems do occur in some areas.
There is evidence of target species overfishing in
many countries, and populations of clams and trochus
have collapsed in several nations, even before export
fisheries for these species had begun. Modern fishing
methods have allowed access to more remote reefs,
and more thorough harvesting. As traditional systems
break down, some areas have seen considerable
overexploitation, and also destructive fishing. These
problems do not affect wide areas, but are important,
particularly because they are focussed close to high
population densities and are clearly diminishing the
potential of the reefs as a renewable source of food.
Tourism is important for the economy of many
countries, and is almost entirely focussed on the
coastal zone, with diving and snorkelling being
key activities. In general, however, tourist numbers
remain low compared to other parts of the world, and
they are usually restricted to those islands with more
developed infrastructures.
Pollution and sedimentation are generally not
widespread, but are clearly a concern in localized
areas, especially where there is urban development.
On the high islands sediment runoff and pollution
from agriculture and mining can be a problem.
The transition from traditional to Western society
presents a number of interesting difficulties. The
desire to establish legally designated marine protected
areas has run into conflict with local "owners" of reef
resources. In many countries this has prevented
the establishment of Western-style protected area
systems. While traditional management regimes
remain effective this is unproblematic, but as or when
such systems are undermined there is considerable
potential for overexploitation and damage.