A guide for planners and managers - IUCN

170 MARINE AND COASTAL
PROTECTED AREAS
Table II-1. Impacts of Commercial and Recreational Activities on Coral Reefs
and Possible Management Responses
Construction (tourist facilities, research facilities, navigation aids, etc.)
Has immediate mechanical impact.
May alter water flow around the reef and thus change a major ecological factor.
May shade reef locally, reducing photosynthesis.
May become a point source of pollution and littering.
Should be the subject of prior environmental assessment.
Anchor Damage
Breaks or damages corals.
Some designs, notably plough anchors, are particularly destructive.
For small boats a sandbag can be an effective and relatively non-damaging temporary anchor.
At intensively used reefs compulsory anchoring areas or compulsory moorings may
be necessary.
Diver Damage
Almost all diving results in minor unintentional damage to corals and other reef
biota; at frequently dived sites this damage can become significant and can lead
to local loss of fragile species.
On intensively used reefs periodic closure to allow recuperation of dive areas may be
needed.
Small Boat Damage
Small boats and inexperienced boat handlers grounding on reefs can cause considerable
physical damage to shallow areas, particularly at low tide.
On intensively used reefs a system of designated boat channels and moorings to keep
boats away from shallow, fragile areas may be necessary.
Reef Walking
Walking on reefs at low tide is a popular method of reef viewing that inevitably causes
some physical damage.
In areas with a highly developed cover of fragile corals, severe damage to corals can occur.
Reef walking should be controlled and a system of periodic closure for recuperation
may be necessary.
Boulder Moving
Reef walkers move or overturn boulders to view animals beneath them; if the boulders
are not replaced these animals are likely to die.
Boulder replacement is an essential element of education and interpretation.
Shell collectors may use crowbars and hammers to break away pieces of reef when
hunting shells.
Boulder movement and damage to corals should be regulated.
Conservation staff should supervise education and interpretation activities.
Destructive shell collecting should be banned.
Introduction of Species for Commercial Purposes
Introduction of a commercially valuable species may offer temporary economic gain,
but may have a substantial impact on the preexisting natural system by displacing
original species from their earlier habitats and increasing competition for food.
The need for and the environmental impacts of introductions should be carefully
evaluated before they are permitted.