4. Dynamics of Reef Fish and Decapod Crustacean Spawning Aggregations: Underlying Mechanisms, Habitat Linkages, and Trophic Interactions

Spawning migrations are an important life-history event for many species of commercially important tropical reef fishes and decapod crustaceans. Spawning aggregations are highly predictable events in which hundreds to thousands of individuals migrate across multiple habitats to converge on specific sites for reproduction. Species that undergo spawning migrations provide a potential mechanism to interlink and possibly influence local food webs along their migratory pathways and at aggregation sites. The rapidly declining condition of many aggregating species world-wide emphasizes the urgency with which we need to increase our under-standing of how spawning aggregations function within complex coral reef and other tropical ecosystems. This chapter provides a comprehensive review of reef fish and decapod crustacean spawning aggregations, including mechanisms under-lying their timing and periodicity, characteristics of spawning aggregation sites, and the spatial and temporal patterns of movement and migration. This overview provides the foundation for a discussion of the habitat linkages and potential trophic interactions that occur during migration and spawning, and highlights the existing gaps in our knowledge of how spawning aggregations function and their importance to ecological processes and fisheries sustainability.