The AIMS Long-term Monitoring Team has been monitoring the health
of reefs in the Great Barrier Reef World Heritage Area for more than a
decade.
Researchers from the Australian Institute of Marine Science have
surveyed 100 reefs each year for the last 15 years to track the
impacts and recovery of coral reefs from disturbances such as
cyclones, bleaching events, crown-of-thorns starfish, and coral
disease, within an area larger than England.
When the GBR Zoning Plan was introduced on 1 July 2004, it
significantly increased the amount of habitat protected from fishing
and provided a unique opportunity to determine how quickly reef fish
stocks respond to reduced fishing pressure. The ‘no-take’ Green zones
established in the Zoning Plan are designed to create protected areas
where fish can grow and mature to their full potential. As the oldest
and largest fish produce far more offspring than smaller individuals,
the adults living in Green zones are expected to add to the
replenishment of populations on nearby reefs that remain open to
fishing.
The AIMS Long-term Monitoring Team has formed a partnership with
researchers from James Cook University to assess changes in the
abundance of biodiversity arising from the new Zoning Plan. The JCU
team is surveying fish and corals on near-shore reefs. The LTMT is
making complementary surveys on mid- and outer- shelf reefs.
In the last 12 months, AIMS surveyed fish populations on 26 reefs
closed to fishing by the rezoning and 25 matched reefs that remained
open to fishing, representing five geographic regions adjacent to
coastal communities between Cairns and Gladstone. Although 5 reefs in
the Townsville region will not be surveyed until September 2006,
preliminary results from the offshore reefs have shown that an
important fish species, coral trout, is now about 50% more abundant in
the new ‘no-take’ Green zones.
JCU scientists surveyed fish and coral populations on fringing
reefs of the Whitsunday Islands. Before the rezoning in 2004 abundance
of fish like coral trout and stripey sea perch were approximately the
same on reefs open to fishing with those earmarked to be closed to
fishing under the new zoning. Just under 2 years after the rezoning,
both of these fish species targeted by fisheries were almost 60% more
abundant on reefs closed than open to fishing.
AIMS Research Director, Dr Peter Doherty, is excited to see such
clear results within two years of the changed management arrangements.
"The extent of the difference is quite surprising at this early
stage but the consistency of the differences between zones in all of
the places that were examined last year leaves me in no doubt that
this is a real result".
JCU Professor Garry Russ was equally excited and surprised by such
a rapid response of fish populations to the new zoning.
"The fact that we had data from sites in the Whitsundays before the
zoning was implemented, and observed the differences in fish abundance
between zones closed and open to fishing develop through time, is
critical. The complementary results from both JCU and AIMS suggest a
consistent result both offshore and inshore"
This finding adds to other demonstrations in Australia and
elsewhere that marine protected areas can deliver direct benefits to a
regional fish stock, assisting managers to keep fishing pressure at
levels that are ecologically sustainable. In developing countries,
where the human pressures are much greater, marine protected areas
appear to be the most cost-effective form of management to arrest a
global trend towards over-harvesting of food fish stocks.
Great Barrier Reef Marine Park Authority Chairman the Hon Virginia
Chadwick said the results are very encouraging.
"These increases will benefit fish stocks, through both increased
spill-over of adult and juvenile fish from green zones to zones open
to fishing and through improved health of the reef ecosystem.
"This is positive news for both the tourism and fishing industries.
"This monitoring has shown the importance of green zones and why
they are vital to the future of the reef."
Mrs Chadwick said the ongoing monitoring is a great example of
collaboration between managers and researchers.
This collaborative project was supported by GBRMPA, Australian
Research Council, JCU, and MTSRF (Marine and Tropical Sciences
Research Facility), which replaces the very successful Co-operative
Research Centres for coral reefs and tropical rainforests that
operated in North Queensland from 1993 to 2006.
