We examined cultured Delta Smelt Hypomesus transpacificus under laboratory settings to provide the first formal characterization of spawning behavior, which included the quantification of participants and diel spawning patterns. We video recorded behavioral observation trials in which four mature males and four ripe females interacted freely for 9–11 d. We found that three behaviors were consistently associated with egg release: (1) two or more fish swam in close proximity to one another just above the substrate or tank floor, (2) fish swam together synchronously during fast, forward‐swimming movements (bouts) while in tandem and in close proximity to one another, and (3) female(s) released eggs and male(s) presumably released milt during one or more bouts. We also found that two to five fish participated in any given spawn and that spawning occurred at night. Furthermore, spawns were observed across three consecutive nights within a trial and up to 17 times within one night, indicating that individuals spawned serially within and across nights within a single clutch cycle. This study enhances our understanding of the Delta Smelt mating system and informs ongoing conservation efforts.

中文翻译：

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养殖三角洲熔炼中产卵行为的表征

我们检查了培养的Delta Smelt Hypomesus transpacificus在实验室环境下提供产卵行为的第一个正式表征，其中包括对参与者和diel产卵模式的量化。我们录制了行为观察试验的视频，其中四名成熟的男性和四名成熟的女性自由互动了9-11天。我们发现三种行为与卵的释放始终相关：（1）两条或更多条鱼在底物或水箱底部上方彼此靠近游泳；（2）鱼在快速向前游泳运动中同时游动（回合） ）并排且紧挨着，并且（3）雌性在一次或多次发作期间释放了卵，而雄性则释放了蜕皮。我们还发现，有2至5条鱼参与了任何给定的产卵，并且产卵发生在夜间。此外，在试验中连续三个晚上观察到产卵，在一晚内观察到多达17次产卵，这表明个体在单个离合器周期内和整个夜晚连续产卵。这项研究增强了我们对Delta Smelt交配系统的理解，并为正在进行的保护工作提供了信息。