Fish aggregations often form at the same places and times each year.
Fishers know this by experience and often target spawning aggregations of commercially valuable species. Aggregations represent a unique opportunity to catch many fish in a short period of time.
Unfortunately, because coral reef fisheries are often poorly managed, and as populations of many of the larger reef fishes that form spawning aggregations are slow to replenish following fishing, many spawning aggregations are decreasing in number and some have completely disappeared.
Coral reefs in the Indian, Pacific and Atlantic Oceans are so extensive that it is essentially only within the past decade that scientists have realized that the declines in spawning aggregations seen on their reefs were not unique, but a global phenomenon.
The vastness of the world's oceans is no longer enough to ensure the continued survival of fishes that aggregate.