WORKING TO SAVE NATURE'S PLAYGROUND David Lloyd and David Wachenfeld ith coral reefs under threat from human pressures ranging from global warming to over-fishing, the international community designated 1997 as the International Year of the Coral Reef. Australian scientists have been reviewing the condition of the Great Barrier Reef, the largest of these complex marine ecosystems. 'There is an old saying that what the eye does not see the heart does not grieve. That is, until it is too late!' says Tamarii Tutangata (Tam) sitting back in his sparsely furnished office in Apia, the capital of Samoa. As Director of the South Pacific Regional Environment Programme (SPREP), Tam has a special concern about the status of coral reefs. 'Reefs feed our families and protect our coast, without them many Pacific nations could simply wash away in the next storm or lose the fish they have relied upon for generations. We can easily see the damage to soils, forests and grasslands; unfortunately damage to our coral reefs is hidden below the surface of the water. By the time the first signs become visible the damage can be extreme.' Similar concerns are being expressed right across the coral belt, the tropical regions which includes Southeast Asia, the Caribbean, Africa and the Middle East. World wide, coral reefs are under threat. Over-fishing, pollution from cities, soil washed down rivers, anchor damage, coral bleaching and uncontrolled tourism are all having an effect upon the world's coral reefs. That is one of the main reasons that scientists around the world declared 1997 the International Year of the Coral Reef. During the International Year of the Reef much attention in Australia was focused on the Great Barrier Reef and the lessons learned in managing competing uses within a World Heritage Area of 35 million hectares. 'It is the sheer size and scale of the Great Barrier Reef World Heritage Area that makes it so important,' Dr Ian McPhail, the Chair of the Great Barrier Reef Marine Park Authority, said. The Authority is responsible for managing the World Heritage Area which stretches 2000 kilometres along Australia's eastern seaboard from Lady Elliot Island in the south to Australia's northern tip at Cape York. With its 2900 individual reefs, rainforests, mangrove forests, seagrass beds, 900 continental islands and coral cays, deep ocean troughs and sandy beaches, the Great Barrier Reef World Heritage Area is one of the richest natural systems on earth. For many animals such as humpback whales, dugongs and turtles, the region is a breeding area critical to their global survival. It is an area as complex and diverse as any rainforest and scientists freely admit they have only scratched the surface of what there is to know about the region. To Ian McPhail, these are the things that make management of the reef a challenge. 'It is a huge and incredibly complex system that we are just beginning to learn about. Significant events, such as the mass spawning of coral that occurs in three days in November on the outer reef, were only discovered ten years ago. 'The possible links of El Niño and decreasing water quality to outbreaks of the crown-of-thorns starfish are still informed speculation. Overall the "outer reef" has suffered little from human impact. Australia is fortunate to have one of the few coral reef ecosystems in the world that is in good health.'

Increased loads of sediment and nutrient resulting from poorly managed land-use activities have the potential to degrade coastal wetlands, mangrove, seagrass and coral reef communities Standing waist deep in a creek that feeds the Herbert River and keeping a sharp eye out for crocodiles, Mr David Haynes, Water Quality Coordinator with the Authority, is taking samples to assess the quality of the water that will eventually find its way into the marine environment. He explained that the ocean currents, that wash across the outer reef, have travelled westerly across vast tracts of the Pacific. By the time the water reaches Australia most of the nutrients have sunk to the ocean depths. The coral communities on the outer reef have adapted to these low nutrient conditions. In comparison the inshore waters, walled-in by barrier reefs, form a shallow lagoon system. This restricts the usual flushing and dilution of contaminants that occur in open seas. The Great Barrier Reef lagoon concentrates the nutrient rich waters flowing in from towns and farms of north Queensland. 'The principal concern is the potentially negative effects of land degradation and land-based sources of pollution on adjacent coastal wetlands, mangroves, seagrasses and coral reef communities,' says Mr Haynes. Recognising this concern the Cane Growers Association has conducted an environmental audit of their industry. Since the 1880s the development of the sugar industry has seen the conversion of much of the wetlands into cane fields. Added to this is a major pastoral industry which has caused a great deal of vegetation clearance. 'Both these industries are absolutely important economically,' says Dr McPhail, 'but increased loads of sediment and nutrients have the greatest potential to degrade coastal ecosystems. We are also concerned about the effect of agricultural pesticides and herbicides together with heavy metals, hydrocarbons and litter, in particular plastics, coming from cities and towns', he added. The melaleuca wetlands and mangrove forests are areas of high biodiversity with 70 per cent of all inshore fishery species being dependent on these areas for some part of their life cycles. At the Australian Institute of Marine Science, Dr Norm Duke has been studying the mangrove environments in the World Heritage Area. 'They are in relatively good condition, although,' he adds, 'there are clear indications that pressures on them are increasing rapidly.' These pressures include the direct removal and damage of mangrove plants, conversion of mangrove lands to other uses, changing water flow and sediment distribution, chronic and catastrophic pollution and the introduction of exotic pests and pathogens. There are good environmental and economic reasons to maintain wetland systems. Wetlands use their nutrient exchange efficiency as a filter for excess nutrients in run-off water. The limiting factor for the growth of mangrove forests is the supply of nitrogen and phosphorus, which are potentially deadly to fringing coral reefs. Mangrove forests can efficiently remove these chemicals converting the nutrient to leaf growth. The leaves drop, and as the leaves decompose they form the base of the food chain. 'This constant supply of food makes a very stable food chain. If we had no mangroves, this rich mud would wash away with the tides and floods. In its place we would have a boom or bust planktonic system dependent upon ocean tides which are simple, highly reactive and unstable', says Andrew Ballard an environmental scientist at the Authority. Following on the findings of the State of the Great Barrier Reef Workshop, a special workshop on wetlands was organised in September 1997 at Babinda, Queensland, Australia in the heart of cane country. Participants at the workshop came from a variety of interest groups including local government, recreational and commercial fishing, conservation, agriculture, indigenous people, tourism, and local coastal communities as well as representatives from various government departments. They heard that less than 10 per cent of the freshwater wetlands remain in the Herbert river catchment and unlike mangrove systems, no controls exist to protect these critical habitats. The outcome was a resolution by all groups to protect the remaining wetlands adjacent to the Great Barrier Reef and measures were suggested to assist in rehabilitating degraded areas. While most people think immediately of coral reefs when they think of the Great Barrier Reef World Heritage Area, the region also contains a number of other important habitats such as mangrove and seagrass communities. There are at least 5000 square kilometres of seagrass habitat in the World Heritage Area which are important to the ecology and the economy of the region. They are an important level in the food chain, directly feeding grazing animals such as turtles and dugong, and indirectly as the decomposing leaves are eaten by invertebrates which in turn are eaten by larger organisms. Seagrasses also provide shelter for juvenile crabs, prawns and fish. They are often called the nursery of the sea. Juvenile brown tiger prawns can live nowhere else but in seagrass beds. Seagrass beds stabilise the sediment with their root and rhizone systems. Their role in converting nutrients into food for other organisms helps filter the water flowing on to the reef. Fishing and tourism are both highly important industries in the Great Barrier Reef. Evaluating the impact of these activities on the ecology of the Reef and adopting strategies to minimise any negative effects is a major focus of scientific activity.

Rapidly swelling numbers of tourists in the last decade has focused the attention of scientists and governments on the need to protect the Reef's ecology Recreational fishing is one of Queensland's most popular past-times. Around 882 000 people or 40 per cent of the State's population wet a line annually. In comparison, there are around 250 commercial 'reef-line' operations, supporting three or four dories each, that harvest between 3000 and 4000 tonnes annually which is roughly equivalent to the recreational catch. Data indicates that current catch levels are sustainable, however most agree that any increased 'effort' will affect this sustainability. This does not necessarily mean that all populations of fish are 'healthy' or 'natural'. Comparisons between reefs where fishing is allowed and those where it is prohibited indicate that fishing can cause localised changes. Studies show decreases in the number and the average size of coral trout and red-throat sweetlip emperor which are specifically targeted by fishermen and heavily exploited. Coral reefs make up only five per cent of the area of the Great Barrier Reef. The region between the edge of the continental shelf and land, that is not coral reef, is known as inter-reef area, or the Great Barrier Reef lagoon. Our knowledge and understanding of these areas is relatively poor, and so management decision making is difficult. The inter-reef communities are an important part of the World Heritage Area with high biodiversity values. The area supports a valuable trawl fishery landing about 7000 tonnes of prawns and 1000 tonnes of scallops per year, as well as sand-crabs, lobsters and some fish. However, during trawling many tonnes of animals (known as by-catch) are caught by accident and discarded by the fishermen. High intensity trawling can have substantial impacts on the animals living on the seabed, with up to 90 per cent of biomass being removed. It is hoped that the introduction of Bycatch Reduction Devices will reduce the impact on fish and turtles as they are introduced into the trawling fleet over the next two years. To date the Great Barrier Reef Marine Park Authority has relied on certain 'no-take' areas or 'green zones' to separate conflicting uses such as fishing and tourism. This has coincidentally provided a refuge for many fish species. Now, the Marine Park Authority is looking at expanding this protection to populations 'representative' of varied communities found in the World Heritage Area. Commercial and recreational fishing groups, understandably, tend to question the motives of marine park managers when valuable fishing reserves are seemingly locked away. Indeed, to outsiders it may seem as yet another case of conservation measures incompatible with industry initiatives. But to the contrary, marine reserves may benefit fisheries, according to Dr Gary Davis, from the United States National Biological Survey. He says fisheries 'refugia' could become the most important tool in the fishery manager's toolbox. The last decade has seen a tourism industry characterised by rapid growth and changing management needs. Tourism in the region has grown from about 150 000 visitor days per year in the early 1980s to about 1.5 million visitor-days in 1994-95. It is currently the main commercial use of the reef and is estimated to generate over $1 billion annually. During this time the industry has altered significantly to meet tourists' demands. 'In 1985, boats were capable of travelling at 10 knots and could reach 20 nautical miles in two hours, which is as long as most "daytrippers" wish to travel,' says Dr McPhail. 'In 1990 they travelled to 50 nautical miles at 25 knots, in 1997 they travel to 70 nautical miles at 35 knots and it is projected that in 2001 they will be able to travel to 100 nautical miles at 50 knots. What this means is that the extent of the World Heritage Area that has become accessible over this period to the "day trip" tourist industry has increased from four per cent to a projected 81 per cent.' Management strategies that relied on remoteness to protect wilderness qualities in some areas of the park in 1985 are not appropriate today. 'Put simply, some areas of the Reef, principally offshore Cairns and the Whitsundays, are starting to fill up and World Heritage and experience values need to be protected. Plans of Management for these areas will address issues such as competition between commercial and recreational interests and the protection of important or vulnerable sites,' Dr McPhail said. But management is also about protecting an industry. 'I think there is little we could do if a major spill occurred but the ecological impacts and effect of the negative publicity on the region's economy could be catastrophic. 'Sometimes I think that Australians forget the asset on their door step. We have one of the healthiest and best managed reefs in the world.' Information from research lead by Professor Helene Marsh of James Cook University shows that while dugong populations in the northern part of the World Heritage Area are stable, those in the south have plummeted. 'Dugong numbers appear to have been stable over the last decade in the Great Barrier Reef Region north of Cape Bedford, however, on the urban coast south of Cooktown, dugong numbers have declined by approximately 50 per cent over the past eight years,' said Professor Marsh. As a result of this decline, Indigenous groups have decided not to hunt along the urban coast of the region and there is now no permitted traditional hunting of dugongs south of Cooktown. Fishers have agreed to support an Endangered Species Education Program and the Queensland shark control program is being reviewed with a view to reducing by-catch. It will be necessary to introduce additional measures to decrease the incidental capture of dugongs in gill nets. Habitat deterioration remains a major unresolved threat to dugongs in the Great Barrier Reef Region. Dugong Protection Areas have been introduced in a number of significant areas along the Queensland coast in the hope of halting, and possibly eventually reversing, this decline. But dugong are not the only marine mammals needing protection in the Great Barrier Reef. Australia is one of the very few countries where the Indo-Pacific humpback dolphin and the Irrawaddy River dolphin are found that does have an effective marine wildlife management program. It is unlikely that these species will survive into the next century outside of Australia. In the Great Barrier Reef region management is focusing on dealing with the physical threats from gill netting and shark netting, and the reduced availability of food from over-fishing, pollution and habitat destruction affecting fish nursery areas such as seagrass and mangroves.

(David Lloyd is currently Manager, Extension Unit with the Great Barrier Reef Marine Park Authority. Dr David Wachenfeld is currently Project Officer - Monitoring with the Authority.) This article previously appeared in 'GEO Australasia', November-December 1997. Please note, however, that some paragraphs from the original article are not included here.

Great Barrier Reef Marine Park Authority
PO Box 1379 TOWNSVILLE QLD 4810. Phone: (07) 4750 0700, Fax: (07) 4772 6093
E-mail: registry@gbrmpa.gov.au