In this study, we report the first case of a male reef manta ray, Mobula alfredi, becoming sexually mature in captivity and present its reproductive characteristics. We investigated changes in external morphology, behavior, and levels of steroid hormones in a male M. alfredi during its sexual maturation process. At 2 years and 6 months of age, the male exceeded 300 cm in disc width. Then, at around 3 years of age, the male started to chase a female in the tank and exhibited androgen levels similar to that of another matured male, indicating that the study specimen had begun sexual maturation endocrinologically. Its first copulation event was observed at 5 years and 4 months and appeared behaviorally similar to field observations. Seven months after copulation, we performed a biopsy to collect its semen, including any motile sperm. Taken together, these results indicate that the captive male M. alfredi individual shows signs of sexual maturation (size of disc width, testosterone levels, reproductive behavior) already with the age of 2.5 to 3 years. As a first copulation was observed with 5 years 4 months of age and the presence of sperm were confirmed at the age of 5 years 11 months of age, the studied animal reached its full sexual maturity at the latest at the age of around 5 years.

中文翻译：

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圈养了7年的雄性蝠man Mobula alfredi从出生到性成熟的高分辨率监测：外部形态，行为和类固醇激素水平的变化

在这项研究中，我们报告了第一例雄性蝠man，Mobula alfredi，在圈养中性成熟并表现出其繁殖特征。我们调查了男性苜蓿性成熟过程中外部形态，行为和类固醇激素水平的变化。在2岁零6个月大时，男性的椎间盘宽度超过300厘米。然后，在3岁左右，雄性开始追赶雌性坦克，其雄激素水平与另一名成熟雄性相似，这表明该研究标本已开始内分泌性成熟。在5年零4个月观察到它的第一次交配事件，其行为与实地观察相似。交配七个月后，我们进行了活组织检查以收集其精液，包括活动精子。在一起 这些结果表明，被圈养的男性阿尔弗雷迪犬已经出现了性成熟的迹象（椎间盘宽度大小，睾丸激素水平，生殖行为），年龄在2.5至3岁之间。由于在5岁4个月大时观察到第一次交配，并在5岁11个月大时证实了精子的存在，因此所研究的动物最晚在5岁时达到了完全的性成熟。