Data from: Searching for common threads in threadfins: phylogeography of Australian Polynemids in space and time

Proper management of marine fisheries requires an understanding of the spatial and temporal dynamics of marine populations, which can be obtained from genetic data. While numerous fisheries species have been surveyed for spatial genetic patterns, temporally sampled genetic data is not available for many species. Here we present a phylogeographic survey of the king threadfin, Polydactylus macrochir, across its species range in northern Australia and at a temporal scale of one and ten years. Spatially the overall AMOVA fixation index was Φst = 0.306 (F’st = 0.838), p < 0.0001 and isolation by distance was strong and significant (r2 = 0.45, p < 0.001). Temporally, genetic patterns were stable at a time scale of ten years. However, this did not hold true for samples from the eastern Gulf of Carpentaria, where populations showed a greater degree of temporal instability and lacked spatial genetic structure. Temporal but not spatial genetic structure in the Gulf indicates demographic interdependence but also indicates that fishing pressure may be high in this area. Generally, genetic patterns were similar to another co-distributed threadfin species Eleutheronema tetradactylum, which is ecologically similar. However, the historical demography of both species, evaluated herein, differed, with populations of P. macrochir being much younger. The data are consistent with an acute population bottleneck at the last glacio-eustatic low in sea level and indicate that the king threadfin may be sensitive to habitat disturbances.

海洋渔业的科学管理，需依托对海洋种群时空动态的精准认知，而此类信息可通过遗传数据获取。尽管诸多渔业物种的空间遗传模式已被广泛调查，但多数物种仍缺乏时序采样的遗传数据。本研究针对澳大利亚北部海域全分布范围内的皇丝鳍鲳（king threadfin，*Polydactylus macrochir*）开展了谱系地理学调查，采样时序涵盖1年与10年两个时间尺度。空间层面，整体分子变异方差分析（Analysis of Molecular Variance, AMOVA）固定指数为Φ_ST=0.306（F’_ST=0.838），p<0.0001；距离隔离效应显著且强烈（r²=0.45，p<0.001）。时序层面，10年尺度下的种群遗传模式整体保持稳定。但卡奔塔利湾东部的采样种群并不符合这一规律：该区域种群表现出更强的时序不稳定性，且缺乏空间遗传结构。卡奔塔利湾仅存在时序遗传结构而非空间遗传结构，这表明种群间存在动态依存关系，同时也暗示该区域的捕捞压力可能较高。总体而言，该物种的遗传模式与另一种生态习性相似的同分布丝鳍鲳物种——四指马鲅（*Eleutheronema tetradactylum*）较为相近。但本研究分析表明，二者的历史种群动态存在显著差异：皇丝鳍鲳的种群历史远较四指马鲅年轻。本研究数据与末次冰期全球海平面低位时期发生的剧烈种群瓶颈效应相符，同时表明皇丝鳍鲳可能对生境扰动较为敏感。