Seascapes Shaped the Local Adaptation and Population Structure of South China Coast Yellowfin Seabream (Acanthopagrus latus).

Understanding the genetic composition and regional adaptation of marine species under environmental heterogeneity and fishing pressure is crucial for responsible management. In order to understand the genetic diversity and adaptability of yellowfin seabream (Acanthopagrus latus) along southern China coast, this study was conducted a seascape genome analysis on yellowfin seabream from the ecologically diverse coast, spanning over 1600 km. A total of 92 yellowfin seabream individuals from 15 sites were performed whole-genome resequencing, and 4,383,564 high-quality single nucleotide polymorphisms (SNPs) were called. By conducting a genotype-environment association analysis, 29,951 adaptive and 4,328,299 neutral SNPs were identified. The yellowfin seabream exhibited two distinct population structures, despite high gene flow between sites. The seascape genome analysis revealed that genetic structure was influenced by a variety of factors including salinity gradients, habitat distance, and ocean currents. The frequency of allelic variation at the candidate loci changed with the salinity gradient. Annotation of these loci revealed that most of the genes are associated with osmoregulation, such as kcnab2a, kcnk5a, and slc47a1. These genes are significantly enriched in pathways associated with ion transport including G protein-coupled receptor activity, transmembrane signaling receptor activity, and transporter activity. Overall, our findings provide insights into how seascape heterogeneity affects adaptive evolution, while providing important information for regional management in yellowfin seabream populations.