Promiscuous: A mating system where both sexes have multiple partners during the breeding system. In fishes, this is the most common mating system. Breeders make little or no mate choice and spawn with multiple partners, either sequentially or at the same time.
Breeding aggregations of promiscuous spawners can make some fish species particularly vulnerable to fishing. The fish generally assemble according to environmental cues (e.g., temperature, moon phase) that are known to fishermen. Overfishing on spawning aggregations can be particularly devastating to fish populations because the high fecundity (fertility) individuals are readily removed from the population. The Nassau grouper (Epinephelus striatus), for example, once supported an important Caribbean fishery but is currently endangered because of overfishing on these spawning aggregations.