Data from: Paternity assignment and demographic closure in the New Zealand southern right whale

The identification and characterisation of reproductively isolated subpopulations or ‘stocks’ is essential for effective conservation and management decisions. This can be difficult in vagile marine species like marine mammals. We used paternity assignment and ‘gametic recapture’ to examine the reproductive autonomy of southern right whales (Eubalaena australis) on their New Zealand (NZ) calving grounds. We derived DNA profiles for 34 mother-calf pairs from skin biopsy samples, using sex-specific markers, 13 microsatellite loci and mtDNA haplotypes. We constructed DNA profiles for 314 adult males, representing 30% of the census male abundance of the NZ stock, previously estimated from genotypic mark-recapture modelling to be 1085 (95% CL 855, 1416). Under the hypothesis of demographic closure and the assumption of equal reproductive success among males, we predict: (1) the proportion of paternities assigned will reflect the proportion of the male population sampled and (2) the gametic mark-recapture (GMR) estimate of male abundance will be equivalent to the census male estimate for the NZ stock. Consistent with these predictions, we found that the proportion of assigned paternities equalled the proportion of the census male population size sampled. Using the sample of males as the initial capture, and paternity assignment as the recapture, the GMR estimate of male abundance was 1001 (95% CL 542, 1469), similar to the male census estimate. These findings suggest that right whales returning to the NZ calving ground are reproductively autonomous on a generational timescale, as well as isolated by maternal fidelity on an evolutionary timescale, from others in the Indo-Pacific region.

对生殖隔离亚种群（stocks）的识别与特征描述，是制定高效保护与管理决策的核心前提。对于海洋哺乳动物这类移动性极强的海洋物种而言，开展此类工作往往难度颇高。本研究借助父权鉴定与‘配子重捕（gametic recapture）’技术，对新西兰（NZ）产仔场的南露脊鲸（Eubalaena australis）的生殖自主性展开探究。我们完成了34对母-幼鲸的DNA分型，所用遗传标记包括性特异性标记、13个微卫星位点以及线粒体DNA（mtDNA）单倍型。此外，我们还为314头成年雄性个体构建了DNA分型，这些个体占新西兰类群雄性普查种群数量的30%；此前通过基因型标记重捕模型估算，该类群的雄性种群总数为1085（95%置信区间：855~1416）。在种群动态封闭假说以及雄性生殖成功率均等的假设前提下，我们提出两项预测：其一，被鉴定出的父权比例，将与采样雄性占种群总数的比例相一致；其二，新西兰类群的雄性种群数量的配子重捕（GMR）估算值，将与该类群的雄性普查估算值相符。本研究结果与上述两项预测均相符：被鉴定的父权比例恰好等于采样雄性占普查种群总数的比例。以雄性采样样本作为首次捕获组、以父权鉴定结果作为重捕数据，本次研究得到的雄性种群数量GMR估算值为1001（95%置信区间：542~1469），与雄性普查估算值十分接近。上述研究结果表明，返回新西兰产仔场的南露脊鲸，在代际尺度上具备生殖自主性；同时在进化尺度上，由于母系栖息地保真行为，它们与印度-太平洋区域的其他露脊鲸种群彼此生殖隔离。