Investigation of genetic structure between deep and shallow populations of the southern rock lobster, Jasus edwardsii in Tasmania, Australia

The southern rock lobster, Jasus edwardsii, shows clear phenotypic differences between shallow water (red coloured) and deeper water (pale coloured) individuals. Translocations of individuals from deeper water to shallower waters are currently being trialled as a management strategy to facilitate a phenotypic change from lower value pale colouration, common in deeper waters, to the higher value red colouration found in shallow waters. Although panmixia across the J. edwardsii range has been long assumed, it is critical to assess the genetic variability of the species to ensure that the level of population connectivity is appropriately understood and translocations do not have unintended consequences. Eight microsatellite loci were used to investigate genetic differentiation between six sites (three shallow, three deep) across southern Tasmania, Australia, and one from New Zealand. Based on analyses the assumption of panmixia was rejected, revealing small levels of genetic differentiation across southern Tasmania, significant levels of differentiation between Tasmania and New Zealand, and high levels of asymmetric gene flow in an easterly direction from Tasmania into New Zealand. These results suggest that translocation among Tasmanian populations are not likely to be problematic, however, a re-consideration of panmictic stock structure for this species is necessary.

南方岩龙虾（Jasus edwardsii）的浅水区个体与深水区个体间存在显著表型差异：前者体色呈红色，后者则为浅白色。目前，将深水区个体移植至浅水区的操作正作为一项管理策略进行试验，旨在推动种群表型从深水区常见的低经济价值浅体色，转变为浅水区特有的高经济价值红色体色。尽管长期以来学界普遍认为J. edwardsii的分布范围内存在随机交配（panmixia）现象，但评估该物种的遗传变异仍至关重要，以确保准确把握种群连通性水平，同时避免移植操作引发意外后果。本研究采用8个微卫星位点（microsatellite loci），对澳大利亚塔斯马尼亚南部的6个采样点（3个浅水区、3个深水区）以及新西兰的1个采样点开展了遗传分化分析。分析结果推翻了随机交配的假设，结果显示塔斯马尼亚南部区域仅存在微弱的遗传分化，塔斯马尼亚与新西兰之间则存在显著遗传分化，且存在从塔斯马尼亚向东流向新西兰的高强度不对称基因流。本研究结果表明，塔斯马尼亚境内的种群移植操作大概率不会引发问题，但仍需重新审视该物种的随机交配种群群体结构。