ABSTRACT
Many coral reef fishes migrate to form short-lived aggregations at predictable sites and times in order to spawn. For the purposes of this review, such
spawning aggregations
are defined as any temporary aggregations formed by fishes that have migrated for the specific purpose of spawning. Spawning aggregations are known to be formed by 164 species from 26 families of coral reef fishes, but the actual number is likely to be much higher. Aggregative spawners share a number of common features. (1) All except one species release pelagic eggs. (2) They tend to have large body sizes. (3) They are more abundant in some phylogenetic groups, such as the Labridae, Scaridae, Serranidae, Acanthuridae, and Lutjanidae, although they are relatively uncommon in all but the least speciose families of Albulidae, Chanidae, Gerreidae, and Scombridae. (4) They are more likely to come from large populations with high densities. However, these features are not independent and their relative importance is not easily assessed. Known spawning aggregations form at the same sites over successive, predictable spawning seasons. However, from the limited data presently available, spawning aggregations do not appear to form consistently on predictable reef structures. The periodicity of spawning aggregations can differ greatly for the same species with relatively small degrees of spatial separation.
