Genomic Stock Structure of the Marine Teleost Tarakihi (Nemadactylus macropterus) Provides Evidence of Potential Fine-Scale Adaptation and a Temperature-Associated Cline Amid Panmixia

Tarakihi ( Nemadactylus macropterus ) is an important fishery species with widespread distribution around New Zealand and off the southern coasts of Australia. However, little known about whether populations are locally adapted or genetically structured. To address this, we conducted whole-genome resequencing 175 tarakihi from Tasmania (Australia) to obtain a dataset 7.5 million genome-wide high-quality single nucleotide polymorphisms (SNPs). Variant filtering, F ST -outlier analysis, redundancy analysis (RDA) were used evaluate population structure, adaptive locus-environment associations. A weak but significant level neutral genetic differentiation was found between = 0.0054–0.0073, P ? 0.05), supporting existence at least two separate reproductive stocks. No clustering detected among (? < 0.001, 0.77). Outlier-based, presumably variation suggests fine-scale structure locations central east (Wairarapa, Cape Campbell, Hawke’s Bay) west coast (Tasman Bay/Golden Bay Upper West Coast South Island). Allele frequencies 55 loci associated one six environmental variables, which 47 correlated strongly yearly mean water temperature. Although genes these linked various functions, most common functions integral components membrane cilium assembly. Projection RDA indicates latitudinal temperature cline. Our work provides first genomic insights panmixia in evidence cline that appears be driven by gradients, together providing crucial information inform stock assessment this species, widen ecological drivers marine species.