Timing reproduction in teleost fish: cues and mechanisms

• Fish have a variety of systems to determine sex, find mates, and time reproduction.
• Factors that lead to spawning occur across multiple timescales.
• Core mechanisms that control reproduction in fish are conserved across vertebrates.
• The molecular bases for this control can be interrogated with new technologies.
• Fish offer exceptional opportunities for experimental analyses.

Fish comprise half of extant vertebrate species and use a rich variety of reproductive strategies that have yielded insights into the basic mechanisms that evolved for sex. To maximize the chances of fertilization and survival of offspring, fish species time reproduction to occur at optimal times. For years, ethologists have performed painstaking experiments to identify sensory inputs and behavioral outputs of the brain during mating. Here we review known mechanisms that generate sexual behavior, focusing on the factors that govern the timing of these displays. The development of new technologies, including high-throughput sequencing and genome engineering, has the potential to provide novel insights into how the vertebrate brain consummates mating at the appropriate time.