Reproductive parameters of 168 franciscana dolphins, Pontoporia blainvillei (73 females and 95 males) incidentally caught (n = 163) or stranded (n = 5) between 2005 and 2016 in southeastern Brazil are presented. Ovarian macroscopic analysis revealed 55 immature (75.3%) and 18 mature (24.7%) females. Annual pregnancy rate was estimated to be 0.36, with a calving interval of 2.8 years. Testicular histology revealed 66 immature (69.5%) and 29 mature (30.5%) males. Males with combined testis weight above 4 g were mature, and 1‐year‐old mature males and a 2‐year‐old pregnant female are reported for the first time for the species. Reproductive seasonality does not seem to occur in the study area. Mean age and length at sexual maturation were estimated to be at 2.7 years and 128.5 cm for females, and 2.7 years and 114.0 cm for males. These estimates are lower than most of the estimates for this species. These results add novel and valuable information on the reproductive patterns of this endangered species, threatened by high levels of mortality in gill net fisheries. The information presented here represents an important effort to obtain more reliable parameter estimates for the studied area, needed for a better assessment of its current conservation status.

中文翻译：

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巴西东南部的方济各会海豚（Pontoporia blainvillei）的生殖参数

168个方济各会的海豚，蓬布罗非鱼（73名雌性和95名雄性）的偶然繁殖（n = 163）或滞留（n =5）介绍了巴西东南部2005年至2016年之间的情况。卵巢宏观分析显示55例未成熟（75.3％）和18例成熟（24.7％）女性。每年的怀孕率估计为0.36，产犊间隔为2.8年。睾丸组织学检查显示66例未成熟（69.5％）和29例成熟（30.5％）男性。男性的睾丸总重量超过4 g已成熟，首次报道该物种的1岁成熟男性和2岁怀孕女性。研究区域似乎没有出现繁殖季节性。据估计，性成熟时的平均年龄和长度为：女性为2.7岁128.5 cm，男性为2​​.7岁114.0 cm。这些估算值低于该物种的大多数估算值。这些结果为g鱼网捕捞中高死亡率所威胁的这一濒危物种的繁殖方式提供了新颖而有价值的信息。这里提供的信息代表了一项重要的工作，即为研究区域获得更可靠的参数估计，这是对其当前保护状况进行更好评估所需要的。