Spawning aggregations in reef fishes; ecological and evolutionary processes

Abstract

What factors have been important in the evolution of reef fish spawning aggregations? Surprisingly, basic biological features such as size, trophic ecology and anatomy are more predictive than life history features. As long as the different groups (Resident and Transient aggregators) shared basic properties of body size, nutritional ecology and anatomy they manifest similar spawning behaviours regardless of whether they are protogynous or gonochoristic, exhibit short or long generation times or have slow or fast population turnover rates. A critical element in the evolution of spawning aggregations is proposed to be the rapid advection of eggs and larvae away from the reef environment. In addition the timing of spawning episodes may be linked to specific seasonal and climatic features of the ocean environment, a variant of the match/mismatch hypothesis developed to explain spawning patterns in clupeoid fishes. Neither larval retention nor broad dispersal are seen as critical elements in the evolution of spawning aggregations. It is hypothesized that differences in aggregate spawning patterns and their underlying processes will occur in the Pacific and Atlantic oceans, a reflection of the different histories, oceanic environments and habitat structures of these two ocean basins.