Palmer Emily I, Betty Emma L, Murphy Sinéad, Perrott Matthew R, Smith Adam N H, Stockin Karen A
Cetacean Ecology Research Group, School of Natural Sciences, Massey University, Auckland, 0745 New Zealand.
Department of Natural Resources and the Environment, Marine and Freshwater Research Centre, School of Science and Computing, Atlantic Technological University, ATU Galway City, Old Dublin Road, Galway, H91 T8NW Ireland.
Mar Biol. 2022;169(12):158. doi: 10.1007/s00227-022-04139-3. Epub 2022 Nov 28.
Reproductive biology was assessed in 106 female common dolphins () examined post-mortem from stranding and bycatch events along the New Zealand coastline between 1997 and 2019. The average age (ASM) and length (LSM) at sexual maturity was estimated at 7.5 years and 183.5 cm, respectively. The total number of in mature individuals increased with age and appeared to persist throughout life. Ovarian asymmetry was apparent, with the left ovary displaying higher rates of ovulation, and a maximum of 19 recorded for a 24-year-old female. The estimated ovulation and annual pregnancy rates for mature females were 0.39 year and 30%, respectively. Conception and calving occurred year-round, with a weak seasonal increase observed in late austral spring and early austral summer. As these data did not clearly show whether seasonality was present, the gestation, lactation, and resting periods were calculated as either 12.6 or 12.8 months based on the presence/absence of seasonality, respectively. Similarly, calving interval ranged from 3.15 to 3.2 years, depending upon whether seasonality was considered. The estimated LSM of the New Zealand population aligns with other populations globally, although the estimated ASM is younger by approximately 6 months. Other reproductive parameters align with Northern Hemisphere populations, although demonstrate variation, which may reflect adaptations to local conditions such as water temperature and prey availability. As the species is subject to anthropogenic impacts including pollution and bycatch, we suggest our findings be used as a baseline with which to monitor trends in population parameters.
The online version contains supplementary material available at 10.1007/s00227-022-04139-3.
对106头雌性普通海豚进行了生殖生物学评估，这些海豚于1997年至2019年间在新西兰海岸因搁浅和误捕事件进行了尸检。性成熟时的平均年龄（ASM）和体长（LSM）估计分别为7.5岁和183.5厘米。成熟个体的卵泡总数随年龄增加，且似乎终生持续存在。卵巢不对称明显，左卵巢排卵率更高，一头24岁雌性记录到最多19个卵泡。成熟雌性的估计排卵率和年怀孕率分别为0.39次/年和30%。受孕和产犊全年发生，在南半球晚春和初夏观察到微弱的季节性增加。由于这些数据未明确显示是否存在季节性，妊娠、哺乳期和休息期分别根据是否存在季节性计算为12.6个月或12.8个月。同样，产犊间隔根据是否考虑季节性在3.15至3.2年之间。新西兰种群的估计LSM与全球其他种群一致，尽管估计的ASM约年轻6个月。其他生殖参数与北半球种群一致，但存在差异，这可能反映了对当地条件如水温及猎物可获得性的适应。由于该物种受到包括污染和误捕在内的人为影响，我们建议将我们的研究结果用作监测种群参数趋势的基线。
在线版本包含可在10.1007/s00227-022-04139-3获取的补充材料。
