Stretching some 2,300 kilometres over 14 degrees of latitude, the Great Barrier Reef lying off Australia’s east coast is the largest reef system in existence. Hugely complex, the Reef supports among others some 3,000 species of mollusc, 1,625 species of fish, 600 soft and hard corals, 133 species of sharks and rays, and more than 30 species of whales and dolphins. The Reef is also used by people, originally by Aboriginal Australians and Torres Strait Islanders for food and materials, then by Europeans for both its resources and tourism. In response to a political row over mining rights on the Reef, the Great Barrier Reef Marine Park Act was introduced in 1975, its primary objective “to provide for the long-term protection and conservation of the environment, biodiversity and heritage values of the Great Barrier Reef Region”. The introduction of the park was heralded a success, an exemplar of marine protection that allowed well-managed human use of such a complex and delicate ecosystem. In 1981 it received UNESCO World Heritage status for its “outstanding universal value”.
It was the first reef ecosystem to receive World Heritage status, but times have changed for the Reef. In 2012 Dr Glenn De’ath, principal research scientist at the Australian Institute of Marine Science, lead a damming piece of research. Between 1985 and 2012, 50.7% of the Reefs initial hard coral cover had declined, primarily as a result of tropical cyclone activity (48% of the mortality), outbreaks of the carnivorous crown-of-thorns starfish (Acanthaster planci) (42% of the mortality), and bleaching (where the corals lose their symbiotic zooxanthellae, 10% of the mortality).
Crown-of-thorns outbreaks are closely linked to poor water quality and high nutrient loads in the Reef, resulting from the clearing, farming, and urbanization of water catchments, and increasing variability in rainfall associated with climate change. Warming waters increases bleaching events, and ocean acidification reduces coral growth rates. Last year researchers Dr Hampus Eriksson and Dr Maria Byrne from Stockholm University and University of Sydney respectively reported serial depletion of holothurian (sea cucumbers) species taken for the Queensland East Coast beche-de-mer fishery, demonstrating that some of the fisheries allowed in the Park may not be as well-managed as we may hope.
More recently talks of dumping dredge spoil near the Reef, and the development of a series of mega-ports in Queensland, including associated shipping developments and routes through the Reef has garnered public outrage. Next year UNESCO will decide if they will list the Reef as ‘in danger’.
The Australian/Queensland Government’s draft ‘Reef 2050 long-term sustainability plan’ has been debased by the Australian Academy of Science, noting that “while the draft plan acknowledges the greatest risks to the Reef are ‘climate change, poor water quality from land-based run off, impacts from coastal development and some fishing activities’, it fails to effectively address any of these pressures”. “The science is clear”, Professor Terry Hughes, Director of the Australian Research Council (ARC) Centre of Excellence for Coral Reef Studies, “the Reef is degraded and its condition is worsening. This is a plan that won’t restore the Reef, it won’t even maintain it in its already diminished state”.
But does it matter? Sure, the Reef has intrinsic value, but what has the Reef ever done for us?
In today’s capitalist world everything is given an economic value. Deloitte’s Access Economics report estimated that the Reef contributed a little over A$7 billion in 2012 to Australia’s economy through direct expenditure. At just over A$6.7 billion, the bulk of this contribution comes from domestic and international tourism/recreation through activities such as snorkelling, scuba diving, fishing, and wildlife watching. A 2012 study lead by postdoctoral researcher Dr Duan Biggs at the University of Queensland highlighted how nature-based tourism/recreational operators perceive good Reef condition to be vital to their business, so much so that many were actively involved in reef conservation.
Indeed, numerous studies questioning visitors (particularly divers and snorkelers) have indicated that they would be less likely to visit the Reef (and in some cases the region in which they were questioned) if Reef quality was to decline. However in reality the tourism market may accept a great deal of reef degradation before long-term numbers are impacted, such as evidenced in by marine biologists Dr Wera Leujak and Dr Rupert Ormond. Their 2007 study demonstrated how visitors to Egypt’s South Sinai degrading reefs had switched from experienced divers/snorkelers with an interest in marine ecology, to less experienced visitors who had little baseline of what a healthy reef should look like.
Commercial fishing and aquaculture that occurs in and around the Reef also makes an economic contribution – approximately A$193 million in 2012, according to the Access Economics report. Around 15,000 tonnes of seafood is extracted from the Park itself each year via various methods. Capture fisheries include hook and line to target finfish such as coral trout and snappers, netting for shark and mullet, whilst aquaculture includes edible oysters and barramundi.
Fishery benefits extend beyond direct extraction, with mangroves, seagrass, and corals providing critical spawning and nursery habitat for a range of commercially (and indeed recreationally) fished species. Tracking black marlin (Istiompax indica), Dr Michael Domeier from the Marine Conservation Science Institute and Dr Peter Speare from the Australian Institute of Marine Science identified the Reef as a key spawning aggregation, not just for marlin found in Australian waters, but likely for across the Coral Seas, providing benefits to places such as Papua New Guinea, Micronesia, and Fiji.
It is unsurprising that the Reef hosts numerous scientific research endeavours. Some of this research relates to the study of reef ecology and biology, some to oceanography, some for climate research. Some are supporting pharmaceutical development. Dr John Hooper, head of the Natural Environments program at the Queensland Museum has conducted a number of studies demonstrating the medicinal properties of sponge species found across the Reef. These include P2X7 antagonists that may prove useful in the treatment of inflammatory diseases such as osteoarthritis, and gastric bactericide which show potential for treatment and prevention of stomach ulcers. Reef science has also made an economic contribution – approximately A$106.1 million in 2012.
Coral reefs and mangroves (which form a part of the Great Barrier Reef ecosystem) have been demonstrated to act as natural coastal barriers, helping to reduce coastal erosion and reducing the impact of storm waves. A study lead by Dr Shari Gallop of the National Oceanography Centre Southampton just this year used 16 year-worth of satellite altimeter measurements to reveal that the Reef as a whole acts as a very effective wave absorber. The reef has proven its defensive worth for many communities. 10 meter waves created by the 1989 tropical cyclone Aivu were reduced to 6 meters after travelling over the Reef. In 1945, blasting of the reef around Heron Island to provide small boat access resulted in erosion problems that took years of extensive - and expensive -stabilization works and dredging to resolve.
Placing a human value on ocean ecosystems is difficult, not least because our understanding of ecosystems, what they provide, and how they interlink is incomplete. Great Barrier Reef provides many services to humans, and in time we may discover even more. Degradation of the Great Barrier Reef isn’t just a marine organism issue, it is very much a human issue.
This story was written for The Marine Professional, a publication of the Institute of Marine Engineering, Science & Technology (IMarEST).