Fish Surveys Demonstrate Benefit Of New Reef Zoning Plan
18 August 2006
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.
Dr Peter Doherty, AIMS Research Director
Phone: 07 4753 4282; 0418 469 770
Professor Garry Russ , JCU
Phone: 07 4781 4432; 0400 828 150
Wendy Ellery , AIMS Media Liaison
Phone: 07 4753 4409; 0418 729 265
Jim O'Brien , JCU Media Liaison
Phone: 4781 4822; 0418 892 449
Sara Trenerry , GBRMPA
Phone: 07 4750 0882; 0408 195 198