Laboratorio de Ecotoxicología Acuática, Instituto de Biodiversidad y Biología Experimental y Aplicada, (IBBEA, CONICET-UBA), Buenos Aires, Argentina.
Facultad de Ciencias Veterinarias, Universidad de Buenos Aires, Buenos Aires, Argentina.
J Fish Biol. 2023 Apr;102(4):977-991. doi: 10.1111/jfb.15338. Epub 2023 Feb 28.
We studied the reproductive strategy, sexual system and growth of dientudo paraguayo Acestrorhynchus pantaneiro. After 2 years of monitoring in shallow areas of a floodplain lake from the lower Paraná basin (Argentina), it was evidenced that water temperature modulated gonadal maturation, but it was the river water level the synchronising stimulus that triggered spawning. This species exhibited a single annual breeding period from October to January, with most spawning activity in November. According to the von Bertalanffy growth curve, fish would reach autumn to winter months with L of ~120 mm, already mature males. The first mature females were found at L of 210 mm, becoming sexually mature between the second and third breeding seasons. This is the first integrative study that includes the body-length frequency distribution and sex differential size at first maturity and growth, and reports the presence of intersex gonads questioning its sexual pattern from gonochoristic to sequential hermaphrodite species. The sexual pattern, the multiple spawning behaviour and a medium to high absolute fecundity support the opportunistic and invasive behavior observed in previous contributions for this characiform species.
我们研究了巴拉圭扁咽齿脂鲤的繁殖策略、性系统和生长情况。在对巴拉那河下游泛滥平原湖的浅水区进行了 2 年的监测后，发现水温调节了性腺的成熟，但调节产卵的是河水水位的同步刺激。该物种每年只繁殖一次，时间从 10 月到 1 月，大多数产卵活动发生在 11 月。根据 von Bertalanffy 生长曲线，鱼将在秋季到冬季达到 L 约 120mm，此时雄性已经成熟。第一次发现成熟的雌性鱼的长度为 L 210mm，在第二和第三繁殖季节之间达到性成熟。这是首次对体长频率分布和初次成熟和生长时的雌雄大小差异进行综合研究，并报告存在雌雄同体性腺，质疑其从雌雄同体到连续雌雄同体物种的性模式。性模式、多次产卵行为和中等至高的绝对繁殖力支持了之前对这种鲇形目鱼类的观察到的机会主义和入侵行为。
