A guide for planners and managers - IUCN

320 MARINE AND COASTAL
PROTECTED AREAS
18. Palau: Protection of Reef Fish
Spawning Aggregations
Many different species of coral reef food fish aggregate at specific locations each
year in order to spawn. Groupers are best known for this habit because they
tend to stay at such sites for 1—2 weeks per lunar month during the spawning
season. But snappers, jacks, emperors and surgeonfish are among the food fishes that
also use such sites.
The spawning aggregations of these fishes are less well studied than those of
groupers because they are less conspicuous. The fish tend to aggregate for fewer days
per spawning period and sometimes come to the aggregation site for only a short period
near dusk. Nevertheless, fishers often know the locations and seasonal and lunar timing
of these aggregations, making them, like those of groupers, especially vulnerable to
overfishing.
In the case of groupers, spawning aggregations have been completely obliterated
by overfishing at a number of locations in both the Atlantic and the Pacific (reviewed
by Johannes, et al 1999). In recent years, moreover, fishers in the billion dollar live
reef food fish industry, centered in the Southeast Asia and spreading into the Pacific
and Indian Ocean islands, have taken to targeting spawning aggregations. Some of
their operations focus exclusively on these aggregations, and some use cyanide to stun
the fish.
A growing number of reports reveal that this industry is depleting grouper
spawning aggregations and the stocks they represent at unprecedented rates. Typically
it takes only three to four years for live reef fish operations to deplete an area to the
point where it is no longer economical to fish for groupers there (Johannes and
Riepen, l995; Erdmann and Pet, l999; Bentley, in press). Where cyanide is used, the
collateral destruction of other fish and invertebrates, including corals, is substantial.
Even where this trade does not operate, fishing pressure is heavy and increasing
in many areas due to the demands of growing populations and expanding export
markets. Coastal waters in much of Asia, for example, are severely overfished.
Under such circumstances, the fact that reef fish spawning aggregations have
been ignored by most fisheries managers in the Indo-Pacific is almost as