Damage on south african coral reefs and an assessment of their sustainable diving capacity using a fisheries approach

Coral reefs in a marine reserve at Sodwana Bay (27°30'S) make it a premier dive resort. Corals are at the southern limits of their African distribution on these reefs which are dominated by soft corals. The coastline is exposed and turbulent. An assessment of the degree to which sport diving damages the reefs is needed for their management. This study showed that recognizable diver damage is generally concentrated in heavily dived areas. This damage and that of unknown cause probably attributable to divers exceeded natural damage on the reefs, despite the normally rough seas. Fishing line discarded in angling areas also caused considerable damage by tangling around branching corals which become algal fouled and die. Heaviest damage was caused in isolated areas by a minor crown-of-thorns outbreak. A linear regression indicated that 10% diver damage occurs at 9000 dives per dive site p.a. Taking uncertainty into account, a precautionary limit of 7000 dives per dive site p.a. was recommended. Further recommendations are that the reefs be zoned in terms of their sensitivity to diver damage, depth and use by divers according to qualification, and a ban be placed on the use of diving gloves to reduce handling of the reefs.