Status of Coral Reefs of the World 2000

Status of Coral Reefs of the World: 2000
WESTERN AUSTRALIA
Ashmore Reef, Scott Reef and Rowley Shoals
These isolated oceanic and shelf-edge reefs are far from any mainland influence, being
scattered between 12 o S and 18 o S along a line 400km from the northwest Australian coast.
Ashmore Reef (12 o S) is closer to Indonesia than Australia and is regularly fished by
Indonesians under a joint agreement. Scott Reef (14 o S) is visited less frequently by
Indonesians, and is a prospective site for extraction of liquid natural gas. The three reefs of
the Rowley Shoals (17 o S) are protected as State and Commonwealth marine parks. Trochus,
trepang (sea cucumbers), shark and other fish are harvested, but the effects on the reefs are
unknown. All reefs have hard pavements of coralline algae and low and stunted corals in
exposed high wave-energy areas, and high coral cover and a large variety of growth forms
in sheltered habitats. The NorthWest Shelf and coastline endures many large cyclones. Coral
communities at all reefs were in good condition through most of the 1990s. In 1995, parts
of the Rowley Shoals suffered significant cyclone damage. Scott Reef and the Rowley
Shoals have been monitored by AIMS since 1995. Average cover on reef slope sites
before the cyclone was 47%. In sites at Imperieuse Reef cover of branching Acropora spp.
dropped from 50% to less than 1% after the storm. Then in 1998, Scott Reef was bathed in
warm water for several weeks, resulting in extensive bleaching and subsequent coral
mortality at monitoring sites at 9m. Extensive bleaching was observed to depths of more
than 30m. Average coral cover in exposed sites prior to the bleaching was 54%, but after
there was less than 10% cover of live coral. Recent surveys of the extensive lagoon floor
showed that large areas of live coral survived at 25-60m (see Case study ).
Cocos-Keeling Islands
These are atolls south of Sumatra at about 12 o S. The human population is very low (600-700
people) with low impacts on the reefs, except for some over-harvesting of some molluscs
(Lambis lambis). The Cocos-Keeling Islands are an Australian protected area: To quote from
the Integrated Marine Monitoring Plan: “The waters surrounding Cocos are the responsibility
of the Federal Government. ...The Federal National Parks and Wildlife Conservation Act 1975
was applied to Cocos in 1992 to provide for the protection of all wildlife (both terrestrial
and marine). This legislation is unique in automatically protecting all species unless
specifically unprotected by Ministerial Declaration.” “Commercial fishing is of such a small
scale (and low economic value), that the Australian Fisheries Management Authority
(AFMA) is also unrepresented on the Islands. An AFMA officer visits once a year, and Parks
Australia staff conduct any surveys and monitoring on their behalf.” Thus these reefs are in
virtually pristine condition, but there were reports of two large-scale coral die-offs in the
past, followed by significant recovery of the corals.
The Dampier Archipelago and Monte Bello Islands
These reefs and islands (21 o S) are on inner-shelf and middle-shelf parts of the continental
shelf, respectively. There is high diversity and abundance of corals and fish, and despite
increasing pearl oyster farming, petroleum exploitation, shipping, fishing and tourism
activity, there is no evidence of significant human damage to the reefs. The Monte Bellos
were used for British Nuclear tests from 1952-1956. A program of assessments of marine
resources of each of these areas is in progress.
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