Tourism

With the sun, sea and white sands, tourism has become a major problem to coral reefs by the increase in boating activities and divers.

An estimated 14 million people engage in SCUBA diving every year; with many divers seeking out coral reef ecosystems (Shackley, 1998.). Divers affect coral reef ecosystems by breaking coral and reef dwelling organisms with fins and equipment and by handling and touching the coral. They also stir up sediment with fins increasing surrounding water turbidity (CORAL, 2004.). Chadwick-Furman (2002) estimated that on a typical SCUBA dive of 60 min at 4–8 m depth, each recreational diver broke 1.7 ± 4.9 corals and raised 9.4 ± 11.9 sediment clouds onto the reef (n = 251 divers). This impact can be reduced by pre-dive educational briefings which explain the sensitive nature of coral reef ecosystems (Medio et al., 1997; Townsend, 2000.).

Diver disturbing the coral (CRC Reef Research Centre, 2006.).

Boats use anchors and antifouling paints which directly affect coral reef ecosystems. Anchors and connected chains can break and fragment corals (Dinsdale & Harriott, 2004.). This directly destroys homes of organisms but also indirectly increases the turbidity of the surrounding water; reducing the sunlight available to the zooxanthellae (Pastorok & Bilyard, 1985.) which could lead to coral bleaching. Given the slow growth rate for most coral species, it can take many years, for coral colonies to recover (CORAL, 2004.). However, anchor damage can be prevented by the installation of mooring buoys and simple changes in boating habits and education.

Chain destroying reef topography (University of Western Australia, 2006.).

Antifouling paints are used to prevent organisms from attaching to the bottom of boats. These include TBT; “the most toxic substance ever deliberately introduced to the marine environment by mankind” (Goldberg, 1986.). Marshall et al., 2002 documented a TBT problem in the Great Barrier Reef caused by the grounding of a 21,000-ton container ship. They found that the “highly toxic substance” killed or injured most of the organisms in the surrounding area. Luckily, TBT is now a banned substance for vessels less than 83 feet in length, but other antifouling paints are still being used. These are copper based and have been documented to inhibit some coral larvae from developing into juvenile coral polyps (Young, 2003.).