# Genetic Diversity and Population Structure of Farmed Longfin Batfish (Platax teira) in the South China Sea

## TL;DR

This study examines the genetic diversity and structure of farmed longfin batfish in China, finding low diversity and shared origins among some populations.

## Contribution

This is the first analysis of genetic diversity and population structure in farmed longfin batfish (Platax teira) in China.

## Key findings

- Low genetic diversity was observed in all four farming populations of P. teira.
- The NA population showed significant inbreeding based on ROH analysis.
- Three populations (NA, XC, ZP) likely share a common origin of fry stocks.

## Abstract

Background: Longfin batfish (Platax teira) is an important economic species in southern China. In recent years, its wild population has significantly declined due to overfishing. Around 2015, breakthroughs in the artificial large-scale seedling technology for P. teira have promoted the growth of its aquaculture scale in regions such as Hainan and Guangdong. Methods: To study the genetic diversity, inbreeding status, and population structure of the current P. teira farming populations in China, we performed whole-genome resequencing technology and high-density SNP markers to analyze the genetics of four main farming populations. A total of 109 individuals from four populations (NA, ZP, XL, and XC) were sequenced, identifying 5,384,029 high-quality SNPs. Results: The results showed that the nucleotide diversity (π) of each population ranged from 0.00155 to 0.00165 and observed heterozygosity (Ho) ranged from 0.253 to 0.282, which indicated low levels of genetic diversity. The results of the ROH analysis show significant inbreeding in the NA population. Genetic differentiation analysis revealed that the genetic differentiation among NA, XC, and ZP populations was relatively low (FST = 0.021–0.029). Conclusions: NA, XC, and ZP populations likely share a common origin of their fry stocks. Based on a phylogenetic tree, principal component analysis (PCA), and population structure analysis, the four populations were divided into four genetic groups. This study is the first analysis of the genetic diversity and population structure of P. teira farming populations in China, laying the foundation for the establishment of a base breeding population and the implementation of genetic improvement programs.