Tourism's Impact on Reefs

An ecosystem under threat

Coral reefs are under threat, suffering from decline and degradation due to a combination of natural and anthropogenic factors. The scientific community is in agreement about it and the press talks about it. Fifty-eight percent of the world's reefs are potentially threatened by human activity. Overexploitation and coastal development pose the greatest potential threat (WRI, Bryant et al. 1998).

Assessments made in late 2000 show that 27% of the world's reefs have been effectively lost, with the largest single cause being the massive climate-related coral bleaching event of 1998. This destroyed about 16% of the coral reefs of the world in 9 months during the largest El Niño and La Niña climate events ever recorded.
Source: GCRMN

Some of the man-made damage is related to tourism. At the same time, tourism is of great economic importance to countries with significant areas of coral reef, such as the Caribbean states and territories. For some smaller island territories, tourism is the mainstay of the local economy. Because tourism in the Caribbean is dependent almost entirely on coastal resources, most development takes place in the coastal zone and most of the impacts occur in the coastal zone. Impacts from tourism activities include both direct physical impacts (such as diver damage and anchor damage), as well as indirect impacts from resort development and operation, and development of tourism infrastructure in general.

Impacts from tourism can often be reduced by raising awareness and changing behaviour among both tourists and local tourism industry workers.

Tourism impacts on Coral Reefs: the Caribbean example

The tourism-related impacts on coral reefs in the Caribbean are typical of those occurring worldwide. The tourism sector is of major economic importance in the Caribbean region, both for foreign exchange earnings and for employment. Since Caribbean tourism is primarily associated with beaches and the sea, there have been - and continue to be - impacts from tourism on the coastal environment, including the coral reefs.

Tourism has both direct and indirect impacts on coral reefs. Snorkeling, diving and boating can cause direct physical damage to reefs, and fishing and collecting can contribute to over-exploitation of reef species and threaten local survival of endangered species. Indirect impacts relate to the development, construction and operation of tourism infrastructure as a whole (resorts, marinas, ports, airports, etc.).

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.

Although fishing has caused declines in reef fish stocks throughout the Caribbean, the direct role of tourism in fishing-related decline is most likely not significant. Indirectly, however, tourism increases the demand for seafood and does have an impact of on reef fish resources. Collecting of marine souvenirs by tourists is probably insignificant but there still is a market for marine curiosities in response to a certain tourist demand. This demand can definitely be decreased by increased awareness.

Tourism-related sources of sewage pollution include resorts and, to a much lesser extent, recreational vessels. There is evidence that a very large percentage of the sewage generated by hotels is discharged in coastal waters without adequate treatment. The main impact of sewage pollution is nutrient enrichment, which favours certain species (algae in particular) at the expense of corals. The impacts of nutrient enrichment from sewage pollution on corals in general have been well studied, but those specifically from sewage pollution from hotels and recreational vessels have not been quantified. The studies indicate that the impact of sewage pollution depends on the level of treatment before discharge and the degree of natural flushing by tides and currents at the point of discharge.

Tourism is not generally a source of petroleum hydrocarbon pollution, other than on a small scale when oil or fuel spills from recreational vessels and marinas occur. The effects of petroleum hydrocarbons on corals has been studied for quite some time, producing evidence that chronic oil pollution is more harmful than a single exposure, and that dispersants and emulsifiers used to combat spills are more toxic to corals than oil alone.

Coastal development and the construction and operation of related tourism infrastructure cause increased runoff and sedimentation. Sedimentation is one of the main reasons for reef degradation. Increased sediment loading of coastal waters increases turbidity, reduces light levels and leads to stress on corals, usually expressed by "bleaching" of corals. Heavy sediment loading may also cause corals to suffocate and die. Other documented impacts of sedimentation on corals include lower growth rates, reduced productivity and reduced recruitment.

Tourism is obviously a source of large amounts of solid waste, the impacts of which depend very much on the method of disposal. If disposed of inappropriately, leaching of toxic substances may harm corals. Of particular concern is the "accidental" waste - plastics in particular - that is blown into the ocean from beaches or vessels and has a detrimental effect on corals and other marine life.

Tourism-related impacts on coral reefs are significant, but they are also compounded by other impacts that are not easily distinguished from those of tourism. This does not mean that we must disregard the impacts of tourism activities. On the contrary, the tourism sector and government agencies involved in tourism development must try to eliminate or reduce those impacts that can be controlled, even if there is no 100% proof that a certain impact is directly related to a tourist activity.

Activities with direct impacts Actual and/or potential impacts
Snorkeling Physical damage (breakage, lesions)
Kicking up sediment
SCUBA diving Physical damage (breakage, lesions)
Motor boating and yachting Physical damage from anchoring
Physical damage from boat groundings
Fishing Contribute to over-exploitation of reef fish stocks 
Compete with local fishers
Collecting (shells, lobsters, conch, coral) Threatening local survival of rare species 
Contributing to over-exploitation and competing with local fishers

Activities with indirect impacts Actual and/or potential impacts
Resort development and construction Increased sedimentation
Resort operation Sewage disposal
Fertilizer runoff 
Irrigation
Nutrient enrichment
Solid waste disposal Leaching of toxic substances from inappropriate waste disposal
Litter (especially plastics)
Seafood consumption Over-exploitation of high-priced resource species (snapper, grouper, spiny lobster, conch)
Demand for marine curiosities Exploitation of rare/ endangered/ vulnerable species such as shells, black coral, turtles
Construction of artificial beaches and beach replenishment Increased sedimentation (from sand removal or from beach instability)
Airport construction or extension Increased sedimentation from dredging and infilling
Marina construction Increased sedimentation from dredging
Marina operation Pollution from inappropriate disposal of oils and paint residues 
Pollution from fueling
Motor boating and yachting Nutrient enrichment from sewage disposal
Pollution from fueling
Cruise ships Nutrient enrichment from illegal sewage disposal 
Litter from illegal or accidental solid waste disposal

Links to other sources of information

The United Nations Environment Programme Coral Reef Unit is part of the Division of Environmental Conventions, in close association with the Division of Early Warning and Assessment. With six coral reef specialists, the unit has what is probably the largest concentration of coral reef expertise in the United Nations system.

The Coral Reef Unit works actively with international partners around the world in a concerted effort to reverse coral reef degradation and to increase international, national and local support for coral reef conservation and sustainable use. It is responsible for UNEP's participation in the International Coral Reef Action Network (ICRAN) and other international programmes, and provides the administrative base for the ICRAN Coordinating Unit. 
Web site: www.unep.ch/coral.html

The UNEP-World Conservation Monitoring Centre has prepared the World Atlas of Coral Reefs, a detailed global map of coral reefs that compiles data on a broad range of coral reef related topics. It contains 94 maps, including global maps of biodiversity and reef stresses, regional maps showing 3-D bathymetry and high resolution maps showing reefs, mangroves, population centres, dive centres and protected areas. Colour photographs show reefs, wildlife, people and places. Introductory texts explaining the formation, structure and ecology of coral reefs; their various uses and abuses at the hands of humans; and the techniques used in coral reef mapping. Detailed texts describe the distribution and status of coral reefs in every country. Data tables list information on biodiversity, human use, and protected areas. These include statistics on coral reef area, biodiversity, fish consumption, and threats. 
Web site: www.unep-wcmc.org

The International Coral Reef Initiative (ICRI) is a partnership among nations and organization seeking to implement the marine- and coastal-related provisions of Agenda 21, and other international Conventions and agreements for the benefit of coral reefs and related ecosystems. The Initiative was established to stop and reverse the global degradation of coral reefs and related ecosystems. The ICRI partnership and approach thus far has been to mobilize governments and a wide range of other stakeholders in an effort to improve management practices, increase capacity and political support, and share information on the health of these ecosystems. 
Web site: www.icriforum.org

The International Coral Reef Information Network (ICRIN) is designed to support ICRI's goals of sustainable protection for coral reefs and related ecosystems, by providing an integrated system of public information distribution. ICRIN acts as a central source of information on coral reef outreach and education materials and techniques, and as a catalyst for more effective public awareness activities. ICRIN's primary objectives are to communicate effectively to the public the value and importance of the world's coral reefs and the threats to the reefs' sustainability, and to motivate target audiences to take action to protect coral reefs. 
Web site: www.icriforum.org/icrin/icrin.htm

The International Coral Reef Action Network (ICRAN) is a collaborative effort designed to reverse the decline of the world's coral reefs. Supported by the United Nations Foundation (UNF), ICRAN consists of a set of inter-linked, complementary activities that will facilitate the proliferation of good practices for coral reef management and conservation. The project consists of a one-year startup phase, now ongoing, and a four-year action phase from 2001 to 2005. 
Web site: www.icran.org

UNESCO - World Heritage Centre 
UNESCO's World Heritage Convention aims to preserve the Earth's natural and cultural heritage. Several coral reef areas, including Australia's Great Barrier Reef, are included in the World Heritage List of sites of outstanding interest.
Web site: www.unesco.org/whc