Data from: Genetic diversity and population structure of the threatened freshwater catfish, Tandanus tandanus, in Victoria, Australia

In Australia, many species of freshwater fish have rapidly declined following European settlement in the late eighteenth century. The freshwater catfish (Tandanus tandanus) is listed as threatened in Victoria and accordingly, broodstock management and a captive breeding program to facilitate the reintroduction of hatchery bred fish into depleted populations have been suggested. Little work has been conducted on Victorian populations of T. tandanus, despite its threatened status. This study assessed the genetic diversity and genetic structure of T. tandanus in Victoria, using mitochondrial and microsatellite markers. Genetic diversity of T. tandanus in Victoria varied greatly between sites, with the Mallee containing the highest diversity at both markers. Sites where T. tandanus had been introduced in the past typically contained lower measures of genetic diversity, with the exception of the Wimmera site for microsatellite markers. Populations could be assigned to one of four broodfish zones in Victoria, based on levels of genetic differentiation; (1) Mallee, Little Murray, Wimmera, Gum Lagoon and Safe Lagoon; (2) Loddon and Avoca; (3) Turners Lagoon and Phyland Lagoon; and (4) Goulburn. These results will assist managers with implementing broodstock management and a captive breeding program by identifying which sites should be sourced for broodstock and where to reintroduce their progeny, without compromising genetic variation or structure in T. tandanus populations in Victoria.

18世纪晚期欧洲殖民者定居澳大利亚以来，该国诸多淡水鱼类物种数量快速衰减。淡水鲶鱼（Tandanus tandanus）在维多利亚州被列为受威胁物种，据此有研究建议开展亲鱼（broodstock）管理与人工繁育计划，以将孵化场繁育的鱼苗重新引入至种群衰减的栖息种群中。尽管该物种在维多利亚州已处于受威胁状态，但针对当地T. tandanus种群的相关研究仍十分匮乏。本研究采用线粒体标记（mitochondrial markers）与微卫星标记（microsatellite markers），对维多利亚州境内T. tandanus的遗传多样性及遗传结构展开了评估。维多利亚州T. tandanus的遗传多样性在不同采样点间差异显著，其中马利（Mallee）区域在两类标记下的遗传多样性均为最高。既往被人为引入T. tandanus的采样点，其遗传多样性水平通常较低，但微卫星标记分析显示威默拉（Wimmera）区域为例外情况。基于遗传分化水平，维多利亚州的T. tandanus种群可划分为4个亲鱼繁育分区：(1) 马利、小默里（Little Murray）、威默拉、格姆泻湖（Gum Lagoon）与塞夫泻湖（Safe Lagoon）；(2) 洛登（Loddon）与阿沃卡（Avoca）；(3) 特纳泻湖（Turners Lagoon）与法兰德泻湖（Phyland Lagoon）；(4) 古尔伯恩（Goulburn）。本研究结果可为管理者实施亲鱼管理与人工繁育计划提供科学依据，通过明确应选取哪些采样点作为亲鱼来源，以及应将鱼苗后代放归至何处，在不破坏维多利亚州T. tandanus种群遗传多样性与遗传结构的前提下，助力其种群恢复。