CRC REEF RESEARCH CENTRE TECHNICAL REPORT No. 4

The Effects Of Qualified Recreational Scuba Divers On Coral Reefs.

Tony Rouphael, James Cook University
Graham Inglis, James Cook University

EXECUTIVE SUMMARY

The primary objectives of this study were to:

• determine the type and amount of damage done to coral reef habitats by qualified SCUBA divers;

• develop an effective technique for assessing diver damage that can be used to survey dive sites and categorise them according to degree of damage;

• and provide preliminary recommendations to the diving industry on how best to minimise diver related damage on coral reefs.

A study on the behaviour of SCUBA divers was carried out to determine the effects of divers on corals and to examine if the topography of coral reef dive sites influences the type and amount of damage caused by divers. Direct observations were made on 214 qualified SCUBA divers at Agincourt Reef, in the Cairns section of the Great Barrier Reef Marine Park. Most subjects (70%) had completed fewer than 40 dives since gaining their diving certification.

Eighty-five per cent of divers caused no discernible damage to reef benthos. Damage caused by the remaining divers normally consisted of the loss of one or two small fragments per coral colony. Kicks by divers' fins were the major cause of coral injury. With the exception of two soft corals, all damage was sustained by branching hard corals (including the hydrozoan Millepora sp.). A small number of divers (4%) were responsible for more than seventy per cent of damage observed during this study. Most of these were underwater photographers, but more research is needed to determine more conclusively if divers with cameras cause more damage than those without. Our limited data from this study show that there was no significant difference in the mean number of damaging incidents caused by divers with cameras compared to divers without cameras. There was no relationship between the rate at which divers caused damage to, or came into contact with corals and the experience of the diver (number of logged dives). Topography of the dive site did not influence the rate of contact SCUBA divers had with the substratum. There was evidence, however, to suggest that the amount of damage caused by divers is related to the relative abundance of branching coral found at the site.

We suggest two strategies that may reduce impacts of SCUBA divers on coral reefs. These include managing the behaviour of divers to minimise contact with the substratum and managing impacts through appropriate selection of dive sites.

Dive tourism operators can promote 'environmentally friendly' diver behaviour at their sites by;

• presenting a short commentary to visiting divers about the vulnerability of corals to physical stress,

• encouraging divers to stay at least 1 metre above or away from corals, and

• encouraging underwater photographers to be more aware of their actions when taking photographs.

Operators can also minimise diver impacts by selecting dive sites that have minimal cover of branching corals. We also highlight a number of issues, such as the selection of appropriate control sites and damage indicator variables, which should be considered in any monitoring studies. An experiment is currently underway to investigate the long-term effects of divers on corals at sites that had not previously been used as dive sites.

THIS PUBLICATION IS CITED AS:
Rouphael, T. and Inglis, G. (1995).
The effects of qualified recreational SCUBA divers on coral reefs.
CRC Reef Research Centre Ltd
Technical Report No. 4
Townsville; CRC Reef Research Centre Ltd, 39 pp.

ISBN 1 876054 03 4

A full copy of this report may be obtained from the author(s), and through the following libraries: