Data from: Variance in reproductive success is driven by environmental factors not mating system in Bonytail (Gila elegans)

Studying the reproductive ecology of aggregate broadcast spawning fishes is difficult because it generally is not feasible to sample all potential parents and unambiguously assign their offspring. We used molecular‐based parentage analysis to gain insights into the reproductive ecology of the endangered Bonytail, and to evaluate whether protected off‐channel habitats could be used as an alternative to hatchery production. By genotyping adults and offspring stocked (n = 4130) into two experimental backwaters across three years, we determined that most adults (82‐97%) contributed to progeny production across years and backwaters, with one exception. Both sexes mated multiply and the number of mates and family size were positively correlated. There was also a positive correlation between adult size and metrics of reproductive success. There were strong interactions between sample years and backwaters suggesting that environmental factors are the primary driver of variance in reproductive success. Knowledge of mating systems and sources of variance in reproductive success is important for management of endangered fish because high variance in reproductive success leads to substantial losses of genetic variation when few individuals reproduce successfully. Although variance in reproductive success was observed, most adults contributed to genetically diverse progeny in experimental backwaters. These results support the use of predator‐free, but otherwise natural, backwaters as an effective conservation tool for reintroducing Bonytail to its native habitat.

研究集群体外产卵鱼类的繁殖生态学颇具挑战，因为通常难以采集到全部潜在亲本，亦无法明确地将子代与其亲本进行匹配。本研究采用基于分子技术的亲权分析方法，解析濒危骨尾鱼（Bonytail）的繁殖生态学特征，并评估受保护的河道外栖息地能否替代孵化场繁育方案。通过对三年内放养至两个实验回水湾的成体与子代（共计4130尾）开展基因分型，本研究发现：多数成体（82%~97%）在不同年份与回水湾中均可产生子代，仅存在一个例外情形。两性均存在多次交配行为，交配伴侣数量与家系规模呈正相关；成体体型与繁殖成功相关指标亦呈显著正相关。样本年份与回水湾间存在较强的交互效应，表明环境因素是繁殖成功变异的主要驱动因子。明晰交配系统与繁殖成功变异的来源，对濒危鱼类的保育管理至关重要——当仅有少数个体成功繁殖时，繁殖成功的高度变异会造成遗传变异的大量流失。尽管观测到繁殖成功存在变异，但在实验回水湾中，多数成体均可产生遗传多样性丰富的子代。本研究结果证实，无捕食者且其余条件自然的回水湾可作为有效保育手段，用于将骨尾鱼重新引入其原生栖息地。