#Status of Coral Reefs 2002 - International Coral Reef Action Network

Status of Coral Reefs in the Hawaiian Archipelago
LOCAL COMMUNITIES COMBATING INVASIVE ALIEN ALGAE
The coral reefs of Hawai’i have been invaded by alien marine algae, with at least two
species swarming over and killing corals. Now researchers, State and Federal resource
managers, and NGOs have joined forces to galvanise local community volunteer
groups to combat the invaders. The first target was the alien red alga Gracilaria
salicornia that now dominates reefs in front of the world famous Waikiki Beach.
Because this alien species could damage the economy of the local tourism industry, as
well as the ecosystem, the University of Hawai’i, the Waikiki Aquarium, the Hawai’i
Department of Land & Natural Resources, the Hawai’i Coral Reef Initiative, NOAA,
Reef Check and the Nature Conservancy have formed a combined force to control
and reduce the impacts from G. salicornia. Two large-scale community clean-ups were
held with an average of 80 community volunteers removing over 2.5 tonnes of the
alien algae from the reefs during each 4 hour workday. Scuba divers stuffed burlap bags
full of the aliens underwater, and swimmers then paddled the bags to shore on boogie
boards. The beach volunteers then took over, drained the bags, weighed and sorted
the algae. Their role was to help the researchers separate out and return native algae
to the reef, while the remaining aliens were then donated to a composting company to
end their days usefully on Hawaiian gardens. From: Jennifer Smith, jesmith@hawaii.edu
Many species have been introduced into the MHI, either deliberately for algal culture or to
enhance fishing, or inadvertently with ships e.g. 4 of 19 introduced macroalgae are now
prevalent throughout the MHI. Kappaphycus alvarezii, is killing corals in Kane’ohe Bay
and over 5,000kg of Gracilaria salicornia were removed from an area near Waikiki. Key
fishing target species (6 groupers, 4 snappers, and 1 emperor) were introduced with 3
being so successful that they are damaging native fish populations. There are reports of
chlorine being used to capture lobster or fish, and illegal long gill nets are frequently used
in Hawai’i causing depletion of fish stocks, and death of endangered bycatch species. The
amount of marine debris continues to be a problem in MHI, and the major problems in
NWHI are derelict fishing nets entangling coral reefs. Indeed US$3 million was spent to
remove 50 tonnes of debris in 2001. NOAA is attempting to model currents to determine
the sources and concentration points of such debris to be able to remove the material
before it causes reef damage.
Reefs around Kaho’olawe have been damaged by military bombing and amphibious vessels
have smashed reefs on O’ahu. There is also considerable military activity in the NWHI, and
damage does not incur penalties. A major problem for the reefs of Hawai’i are the
numerous small and large vessels passing through the islands. Groundings on coral reefs
are a persistent problem, with direct damage as well as pollution from oil and toxic cargoes.
CURRENT AND POTENTIAL CLIMATE CHANGE IMPACTS
These reefs are remote and have not yet experienced major bleaching events, probably
because of relatively strong currents and deep water around the islands. Some coral
bleaching was observed in the NWHI in October 2002 after a period of sustained hot water
and calm winds. NOAA satellite monitoring, showed warm waters in the NWHI, as far as
Midway Atoll from early August to September 2002. With temperatures at Midway up to
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