High Gene Flow With Patterns of Asymmetric Connectivity and Adaptive Divergence in the New Zealand Southern Rock Lobster, Jasus edwardsii (Hutton, 1875)

ABSTRACT Understanding patterns of connectivity and adaptive divergence is crucial for supporting conservation and sustainable management of harvested species. This study utilised single nucleotide polymorphisms (SNPs) to investigate spatially explicit patterns of genetic structure, gene flow and adaptive divergence in the commercially important southern rock lobster Jasus edwardsii across New Zealand (NZ), a species with a 2‐year pelagic larval duration. Using neutral (1608 SNPs) and outlier (250 SNPs) panels, genetic analyses revealed significant population differentiation between J. edwardsii individuals collected from one site in Tasmania (Australia) and those from 22 sites in NZ, supporting earlier findings indicating substantial genetic variation between the two stocks. Within NZ, neutral markers revealed a high degree of genetic connectivity of J. edwardsii , but also subtle genetic differentiation of one northern site only. In contrast, analysis of outlier markers identified three genetically differentiated regions within NZ: the Northeast (NE), Northwest (NW) and Southern (S) groups. Migration models indicated bidirectional but asymmetrical gene flow amongst these groups (S → NW → NE), consistent with larval dispersal and settlement models. Patterns of genetic structure at the outlier loci were strongly correlated with the environmental variables ‘carbonate concentration’, ‘roughness at the seafloor’ and ‘sea surface temperature’ across NZ, which may contribute to differential settlement and survival of J. edwardsii . These findings demonstrate complex patterns of connectivity and the influence of environment factors on genetic structure and local genetic adaptative divergence of J. edwardsii despite its very high dispersal potential. The population genomic and connectivity findings support the current spatially explicit management regime of the rock lobster fishery in New Zealand, and the seascape genomic findings may be of value to the fishery in responding to new or enhanced patterns of environmental variability driven by climate change or to the development of a new aquaculture industry.