人工驯养鼋繁殖习性研究

鼋(Pelochelys cantorii, 1864)属于中国国家一级重点保护野生动物, 生物学资料相对匮乏, 2015和2016年连续2年对人工驯养的4只亲鼋(2雌2雄)进行了繁殖生物学研究。人工驯养鼋的产卵期集中在5—8月, 夜间产卵, 无护卵行为。通过视频观察分析, 鼋产卵过程可分为Ⅳ个阶段。2只雌鼋2015年共产卵10窝, 每窝32—50枚, 共406枚, 受精273枚, 受精率为67.24%, 孵出稚鼋140只, 孵化率为51.28%; 2016年共产卵11窝, 每窝40—55枚, 共489枚, 受精353枚, 受精率为72.19%, 孵出稚鼋212只, 孵化率为60.06%。鼋卵圆形, 刚性, 均重(16.82±1.99) g, 卵直径(3.10±0.18) cm, 刚孵出稚鼋均重(13.60±0.85) g, 在人工控温下平均孵化期为(64.94±3.47)d。繁殖数据表明这2对鼋处于生育盛年期。针对2016年的繁殖数据分析, 2只雌鼋每窝产卵量无明显差异, 卵均重和卵直径间有显著相关性, 雌鼋1个体体重大于雌鼋2, 前者产的卵均重显著大于后者, 孵出稚鼋的初重差异也显著, 卵大, 稚鼋也大。孵出的稚鼋以活鱼苗为饵料, 在温室内人工养殖周年, 均重可以达(510.30±82.77) g。研究旨在为鼋繁育生物学提供基础性数据, 为其资源保护做贡献。

REPRODUCTION TRAITS OF CAPTIVE ASIAN GIANT SOFTSHELL TURTLES, PELOCHELYS CANTORII

The Asian giant softshell turtle Pelochelys cantorii (Trionychidae) is seriously endangered and has designated as the first grade of protected animal in China in 1989. In 2000, it has been listed as endangered species by the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, and put on par along with the Giant panda Ailuropoda melanoleuca and the white-flag dolphin Lipotes vexillifer. This animal typically suffers from gradual reduction in its total population because of inadequate safety, food, and health protections. Sparse data, extensively referred in the literature, emphasize on the reproductive for this species, in order to enhance individuals’ knowledge about the reproduction of P. cantorii. For this purpose, we attempted to study the nesting behavior, clutch size, egg size, incubation period, as well as other reproductive characteristics of 4 adults (2♂, 2♀) under captive conditions from 2015 to 2017. Oviposition season is commenced from May to August; the egg-laying behaviors are typically occurred at the night. Clutches are made up of eggs with spherical and rigid shells without parental care behaviors. All adult females laid 5—6 clutches mean egg number=(42.6±5.3); (32—55); n=21] during the breeding season in 2015 and 2016. In 2016, the mean egg’s mass, egg’s diameter, and mass of the newly hatchings were (16.82±1.99) g (n=476), (3.10±0.18) cm (n=476), and (13.60±0.85) g (n=202), respectively. Analysis of reproductive data obtained by 2016 based on the size and mass of the eggs, which were positively correlated (r=0.916, P<0.01), showed that there was no significant difference in average size of clutch between these two females (Using analysis of variance (ANOVA),F_1,9=0.442, P=0.283). The weight of female No. 1 was more than that of female No. 2, the mass of female No. 1’s egg and newly hatchings were both more than that of female No. 2 as well. The juveniles fed by live fish seedlings could be reared to (510.30±82.77) g in the greenhouse for one year. The achieved findings affiliated with reproduction traits in P. cantorii can shield some light, and those results might be used to improve the conservation of the species.