A guide for planners and managers - IUCN

172 MARINE AND COASTAL
PROTECTED AREAS
Pollutants originating offsite have been demonstrated to have a number of
effects: killing mature plants and animals, interfering with physiological—particularly
reproductive—processes, aborting larval development, making areas unsuitable for
recruitment or settlement of new individuals, and smothering or changing the texture
of the habitat. Johannes (1975), Loya & Rinkevich (1987), Marszalek (1987), Brown
(1987) cover this topic in detail. Forms of pollution that should be noted by the
protected area manager are listed in Table II-3. Various methods of discharge that
limit damaging effects to reasonable levels can be established for most pollutants. Initial
assessment and constant monitoring of actual and potential pollutant discharges are
important in selecting, planning, and managing viable coral reef protected areas. Gaining
collaboration of offsite authorities and communities in the adjacent Zones of Influence
could be helpful in controlling sources of pollution.
Table II-3. Pollutants and Their Effects on Coral Reefs
Herbicides
May interfere with basic food chain processes by destroying or damaging zooxanthellae
in coral, free living phytoplankton, algae, or seagrass communities.
Can have serious effects even at very low concentrations.
Pesticides
May selectively destroy or damage elements of zooplankton or reef communities;
planktonic larvae are particularly vulnerable.
May accumulate in animal tissues and affect physiological processes.
Antifouling Paints and Agents
May selectively destroy or damage elements of zooplankton or reef communities.
Not likely to be a major factor except near major harbors, shipping lanes, and industrial
plants cooled by seawater.
Sediments
Smother substrate.
Smother and exceed the clearing capacity of some filter-feeding animals.
Reduce light penetration, which may alter vertical distribution of plants and animals
on reefs.
May absorb and transport other pollutants.
Sewage and Detergents
May interfere with physiological processes.
Sewage, Nutrients, and Fertilizers
May stimulate phytoplankton and other plant productivity beyond the capacity of control
by grazing reef animals and thus modify the community structure of the reef
system.
May cause eutrophication and consequent death of reef organisms.
May favor coral growth if limited in quantity and where water circulation is good.