The giant Antarctic toothfish Dissostichus mawsoni is one of the most economically valued fishery resources from the Southern Ocean. However, the distinctive biological characteristics and life history of this species, including large body size, long life span, late sexual maturity, and specialization to freezing polar waters, make it particularly vulnerable to overfishing and global climate change. It is therefore of fundamental importance to administer sound management and conservation actions to avoid depletion of this unique species. The crucial issue of whether this species consists of distinct biological units or stocks, which is needed to inform appropriate management and conservation, is currently unresolved. We report here the first RAD-seq analysis of Antarctic toothfish populations, a powerful approach of genome-wide discovery of SNP loci, to assess genetic differentiation between the geographically distant individuals from CCAMLAR Subarea 48.1 locations (South Shetland Islands and West Antarctic Peninsula coasts) and Subarea 88.1 (Ross Sea and McMurdo Sound). We recovered 19,611 SNPs belonging to 13,251 widely shared loci. Comprehensive population structure analyses unambiguously indicated absence of any significant level of population differentiation, thus the null hypothesis of panmixia cannot be rejected. Together with currently known life history traits of D. mawsoni, we suggest this striking lack of genomic differentiation likely reflects high degrees of contemporary and/or historical gene flow rather than shared spawning grounds. Complementary analyses, particularly otolith microchemistry, would contribute useful inference of natal origins.

巨型南极牙鱼Dissostichus mawsoni是南大洋最具经济价值的渔业资源之一。然而，该物种独特的生物学特征和生活史，包括体型大、寿命长、性成熟晚、擅长极地冰冻水域，使其特别容易受到过度捕捞和全球气候变化的影响。因此，实施健全的管理和保护行动以避免这一独特物种的枯竭至关重要。该物种是否由不同的生物单位或种群组成的关键问题目前尚未解决，这是为适当的管理和保护提供信息所必需的。我们在这里报告了南极牙鱼种群的首次 RAD-seq 分析，这是一种在全基因组发现 SNP 位点的有力方法，评估来自 CCAMLAR 分区 48.1 位置（南设得兰群岛和西南极半岛海岸）和分区 88.1（罗斯海和麦克默多湾）的地理上较远的个体之间的遗传差异。我们恢复了属于 13,251 个广泛共享位点的 19,611 个 SNP。综合种群结构分析明确表明没有任何显着的种群分化水平，因此不能拒绝泛混合的零假设。连同目前已知的生活史特征 综合种群结构分析明确表明没有任何显着的种群分化水平，因此不能拒绝泛混合的零假设。连同目前已知的生活史特征 综合种群结构分析明确表明没有任何显着的种群分化水平，因此不能拒绝泛混合的零假设。连同目前已知的生活史特征D. mawsoni，我们认为这种显着缺乏基因组分化可能反映了当代和/或历史基因流的高度，而不是共享的产卵场。补充分析，特别是耳石微化学，将有助于推断出生起源。