Spawning Behavior of Cultured Delta Smelt in a Conservation Hatchery

Abstract

AbstractUnderstanding reproductive behavior of sensitive species is crucial for their conservation. The Delta Smelt Hypomesus transpacificus is a federally threatened, state‐endangered fish whose reproductive behavior is poorly understood. We used genetic techniques to investigate the spawning behavior of cultured Delta Smelt in a conservation hatchery. We conducted a natural tank‐spawning experiment in a total of four separate tanks during two spawning seasons. Delta Smelt were allowed to spawn in order to investigate spawning patterns using genetic parentage analysis of larvae produced. In total, 2,474 larvae were assigned two parents with >80% likelihood. Of the adults that had larvae assigned to them, males spawned on average 2.8 times and females 1.7 times. The mean number of larvae produced by females was 40.7, while males produced a mean number of 19.2 larvae during a single spawning season. Genetic diversity was reduced from the parent population to the offspring population, as indicated by a small but significant reduction in heterozygosity. Finally, we found no evidence that Delta Smelt preferred to mate with unrelated individuals.