Physiological condition (hereafter shortened to “condition”) influences survival, spawning schedules, and reproductive effort in salmonids. In iteroparous females, the effects of first spawning on condition could result in trade‐offs with future reproduction, mediated by postspawning survival, repeat spawning schedule (i.e., consecutive or skip spawning), or reproductive effort. However, which aspects of condition affect these outcomes and when they are sensitive to condition are not well understood. These issues were examined in highly energy‐depleted hatchery‐origin female summer steelhead Oncorhynchus mykiss that were undergoing postspawning reconditioning in captivity. Measures of condition and reproductive characteristics (i.e., fecundity, egg size, and total egg mass [TEM]) at first spawning were examined for their effects on postspawning survival and future spawning schedules, and condition was tracked during reconditioning to examine effects on reproductive characteristics at repeat spawning. The levels of plasma osmolality and triglycerides measured at first spawning were positively correlated with survival probability, suggesting that survival depends on the ability to maintain homeostasis and access stored energy. Surprisingly, size‐standardized TEM measured at first spawning was positively correlated with the probability of consecutive spawning, providing no support for the hypothesized trade‐off between current and future reproduction. This finding instead suggests that both first‐spawning reproductive effort and consecutive spawning may be influenced by condition at earlier points. Plasma triglycerides and growth rates at sampling points 10–20 weeks after first spawning were strongly correlated with size‐standardized egg size and TEM at consecutive spawning, suggesting that reproductive effort and its allocation to egg size and fecundity depend on energetic status during early oogenesis. These results indicate that condition influences survival, repeat spawning schedules, and reproductive characteristics in female steelhead up to a year or more before repeat spawning. If more broadly applicable, these relationships could provide insight into the mechanisms that link environmental conditions with reproductive characteristics in salmonids and other species.

中文翻译：

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生理条件对圈养条件下雌性头鱼重复产卵的影响

生理状况（以下简称为“状况”）会影响鲑鱼的存活，产卵时间表和生殖力。在有雌性的雌性中，初次产卵的条件可能会导致与未来繁殖的权衡取舍，这是由产卵后的存活，重复产卵的时间表（即连续产卵或跳过产卵）或生殖努力所介导的。然而，人们对条件的哪些方面影响这些结果以及何时对条件敏感尚不清楚。这些问题已在高耗能孵化场的雌性夏季硬头steel Oncorhynchus mykiss中进行了研究正在囚禁中进行后期典当修复的人员。检查初次产卵条件和生殖特征（即繁殖力，卵大小和总卵质量[TEM]）的量度对产卵后存活和未来产卵时间表的影响，并在重整过程中跟踪条件以检查对生殖特征的影响在重复产卵。第一次产卵时测得的血浆渗透压和甘油三酸酯水平与生存概率呈正相关，这表明生存取决于维持体内稳态和获取能量的能力。令人惊讶的是，第一次产卵时测量的尺寸标准化TEM与连续产卵的概率呈正相关，没有为当前和未来繁殖之间的假定折衷提供支持。相反，该发现表明，初产生殖力和连续产卵都可能受早期状况的影响。首次产卵后10–20周的血浆甘油三酸酯和生长速率与连续产卵的标准化卵大小和TEM密切相关，这表明生殖力及其对卵大小和繁殖力的分配取决于早期卵子形成过程中的能量状态。这些结果表明，条件会影响雌性杆头的存活，重复产卵计划和生殖特性，直到一年或一年以上才可以重复产卵。如果更广泛地适用，这些关系可以使人们深入了解将环境条件与鲑鱼和其他物种的生殖特征联系起来的机制。