Many commercially valuable reef fishes are especially vulnerable to overexploitation because they form short-term spawning aggregations that are highly predictable in time and location. These aggregations, and in some cases migration routes to the spawning site are easy to find and target by fishers. The evidence is unequivocal that spawning aggregations can be decimated within a few years by heavy fishing, resulting in serious declines in the fish populations they serve. An extreme, and now well-known, example is the Nassau grouper, Epinephelus striatus, a species seriously threatened by aggregation-fishing. A significant number of Nassau grouper aggregations are depleted in the tropical western Atlantic, and some have disappeared completely. The species is listed as Endangered on the IUCN Red List. Evidence is growing of similar cases for other reef fish species throughout the tropics.
Management and conservation initiatives must specifically address protection measures for times and sites at which spawning aggregations occur. It is vital to ensure successful reproduction and recruitment of aggregating fishes. Protection and management of aggregation sites and aggregating reef fish species are essential, as well as for the long-term well-being of the coastal communities that depend on them for food and livelihoods.
- Ideally, fishing of aggregations should be avoided unless part of important local traditional or subsistence fisheries
- If spawning aggregations are fished for subsistence, they should be closely monitored and carefully managed
- Fishing of spawning aggregations should not be permitted for export/commercial markets
- Spawning aggregations should be included routinely in fishery management plans and marine protected area design
- The potential impacts and benefits of tourism on fish aggregations should be evaluated, especially to determine the possible disturbance caused by tourism activities
- Education is needed to increase understanding of the biological and fishery importance of spawning aggregations and their vulnerability to fishing
- Extreme caution should be exercised not to make public information on the specific locations of aggregation sites that cannot be adequately protected from exploitation