Spawning Aggregation

Spawning aggregations occur when fish that are otherwise dispersed across a large area congregate at predictable locations (often reef promontories, seamounts, or river mouths) and specific times (often lunar-linked) for mass spawning. They can involve thousands to millions of individuals and represent critical reproductive events. Because of their predictability and concentration, spawning aggregations are extremely vulnerable to targeted fishing — many have been depleted or eliminated. Key examples: Nassau grouper, humphead wrasse, and Atlantic cod spawning aggregations.

Nassau grouper (Epinephelus striatus) spawning aggregations in the Caribbean once drew 30,000+ fish; many aggregation sites have been fished out, contributing to the species' Endangered status.