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in on corals: impact of divers and boaters on reefs "Mr Chew emphasised that 'the lagoon isn't just for divers', saying: 'It's for anyone who wants to get wet and enjoy our marine life.'" ST 31 Mar 06 How will the created reef be managed? In particular, will the impact on the reef and surrounding habitats be well managed? "Mr Lewis sees the likelihood of Project Noah developing into a lucrative business" BT 31 Mar 06 What will the environmental impact be if the 'built reef' is run as a commercial enterprise? "The divers, however, face a difficult task because of poor visibility caused by silt suspended in the water. It can be so bad that 'you have to bump into coral to notice them', said Project Noah manager Spencer Lewis." ST 31 Mar 06 Will SUF divers involved in the census be properly trained so as not to damage our reefs as they do their census? Extracts from Coral Reefs: An ecosystem under threat by the UNEP Production and Consumption Branch The tourism-related impacts on coral reefs in the Caribbean are typical of those occurring worldwide. Tourism has both direct and indirect impacts on coral reefs. Snorkeling, diving and boating can cause direct physical damage to reefs. Indirect impacts relate to the development, construction and operation of tourism infrastructure as a whole. Direct physical damage from snorkeling and diving has been the subject of extensive study and is well documented. The damage inflicted by divers and snorkelers consists mostly of breaking fragile, branched corals or causing lesions to massive corals. Most divers and snorkelers cause little damage; only a few cause severe or widespread damage. Research indicates that reef degradation and change of reef community structure occurs once a certain level of use by divers and snorkelers is exceeded. As a rule of thumb it is recommended that the level of 5,000 to 6,000 dives per sites per year should not be exceeded. Training and briefing of divers and snorkelers will greatly help to reduce negative impacts. Physical damage from anchors and especially boat groundings can be severe. Anchor damage is proportional to the size of the boat (i.e. weight of the anchor and length of anchor chain) and is further dependent on the type of coral community. Recovery of coral damage from boat groundings is slow. Anchor damage can be avoided to a large extent by installing permanent moorings, designating anchorages and providing adequate information on anchoring and mooring. Extracts from A coral damage index and its application to diving sites in the Egyptian Red Sea by S. C. Jameson ' M. S. A. Ammar ' E. Saadalla H. M. Mostafa ' B. Riegl on the Nova website As the popularity of recreational scuba diving increases, the physical damage to coral reef organisms caused by anchoring and divers has become a major concern of coral reef managers. Researchers in other parts of the world have also confirmed diver-related impact as a major management concern within marine parks. Coral reef diver carrying capacities are usually very sensitive political and economic subjects because sport diver volume directly impacts local and regional tourist economies, and because understanding of this subject by scientists, managers and politicians is still very limited. Diver carrying capacities are rarely considered "up-front'' by planners and developers. As a result, coral reef managers in many areas have to fight uphill battles to convince authorities to limit sport diving volume. Extracts from Dive Jive: An Underwater View of Ecotourism on www.wildasia.net What do we really know about diver behaviour? Most studies to date indicate that, at present levels, divers don't cause enough damage to compromise ecological functions. But divers can quickly degrade the aesthetics of a reef. Coral cover was not found to be different between dive and non-dive areas; however, species composition changed. The proportion of old and slow-growing massive corals were fewer, as 'weedy' branching corals proliferated. We don't know whether this change is due to diver contact or other stresses. Divers intentionally or inadvertently touch corals an average of 10 times per dive. Fins are the primary culprit. Hence branching corals are the most susceptible to diver damage. Most divers are okay, it's a small minority that cause the problem. In a study by Rouphael Inglis, he observed that 84% of the divers did no damage, while a mere 4% accounted for over 70% of the destruction. Poor buoyancy is the single biggest factor on why divers negatively impact reefs. Gloved divers touch the reef more than those who do not. And women touch the reef far less than men. The environmental impact from snorkelling has yet to be studied, but it is probably greater than that from scuba diving. The biggest culprits causing direct damage to reefs are anchors. Proper mooring of dive boats is essential to minimise the damage from a maximum number of visitors. And how many is too many? Carrying capacities relate to both ecological functions and resource management options. The former depends on how many organisms an area can support, while the latter refers to how many people can use a site without unacceptable changes in the physical environment and quality of experience. PADI does not believe fixed numbers will work; rather that education plays a prominent role. Researchers consistently conclude that education largely determines the level of interaction with coral reefs, and one's attitude toward conservation. Two studies highlight the importance of briefing divers. First, Medio (1996) observed that non-briefed divers make contact with the reef eight times per dive with 80% of those contacts causing damage. After a short talk, contact fell to an average of only 1.5 times per dive with less than 30% damaging. Townsend (2000) counted an average of 26 touches per dive for a control group with no briefing. In contrast, a treatment group - with a proper briefing - averaged less than eight touches per dive. Extracts from Physical Impacts by Scuba Divers on the Reefs around Hoga Island and Strategies for their Reduction on the Operation Wallacea website Observations of diver behaviour: The study has so far accumulated 9,000 minutes of observations making it the largest study ever conducted. Initial analysis shows an overall mean rate for contacting live substratum on the reef of 0.43 contacts per 10 minute segment, compared to a worldwide average of 1.6 per 10 minute segment. This may be due to a number factors including the high level of ecological awareness among divers at Operation Wallacea and the high numbers of women divers, who have been shown by this study and others to do significantly less damage to the reef than men. Other groups who appear from the results to be high risk are camera users, divers in large groups, divers being guided by a divemaster and those engaged in work close up to the reef. There appears to be no correlation between the levels of training and experience of a diver and the rate at which they contact the reef. This confirms earlier studies and is attributed to the willingness of more experienced divers to approach the reef more closely. Novice divers tend to be more wary and hover clear of the substratum. Extracts from Scuba diving from the UN Atlas of the Oceans website Divers may damage coral through direct physical contact with their body or fins, but may also cause harm to colonies by stirring up sediment. Coral reefs at Eilat, northern Red Sea, are among the most heavily used in the world for recreational diving, with >250,000 dives per year on only 12 km of coastline. Field observations of diver behaviour revealed ca 10 incidents of reef contact per dive, mostly via raising of sediments onto the reef, but also involving direct breakage of corals. A study looking at diver impact in Sharm el Sheikh, Egypt, found there were more damaged coral colonies, loose fragments of coral and partially dead or abraded corals in intensely dived areas than control sites. Though the differences between heavily and lightly dived areas may be relatively unimportant biologically they were quite considerable from an aesthetic point of view. Another study in the Caribbean island of Grand Cayman, found that (1) hard and massive coral cover decreased with an increase in number of divers, and (2) when moving away from the dive mooring buoy. High intensity sites also typically exhibited more dead coral and coral rubble. Montastrea annularis seems to be particularly sensitive to diver impact. The health of this massive coral species is important, as these colonies constitute the main reef building corals at the studied sites. Researchers on the Great Barrier Reef found that 32 out of 214 divers caused damage to corals, mostly by kicking the reef with their fins. The study also revealed that divers carrying underwater cameras (non-naïve photographers) and males caused more damage than divers without cameras or females! Despite these results, there seems to be considerable uncertainty surrounding concerns about biological impacts of SCUBA diving on coral reef communities - overall most divers and snorkelers seem to cause little damage. Long term studies will be needed to ascertain such impacts. In the short term however there is a clear concern about the reduced amenity values associated with increased use by divers of certain coral reef areas. Thus the question arises, what is acceptable in terms of damage and what isn't, i.e. what is the carrying capacity - critical threshold level of use - of a particular site. The problem with this approach is that individual divers vary greatly in their behaviour and thus in the amount of damage they can cause to a reef. As a consequence, imposing strict limits on the number of divers allowed to dive a site might unnecessarily deny many the opportunity to experience unique dive sites. However, it does facilitate management of dive sites (mostly marine protected areas) and helps reduce the potential impact of divers on coral communities and marine fauna. Anchoring of diving boats can also cause serious damage to coral communities. However, in most diving locations morring buoys have been deployed and strict regulations exist prohibiting anchoring directly on coral spurs. |