Identifying Population Structure and Dynamics for the Cutlassfish Trichiurus japonicus of Taiwan Coasts Using Advanced Molecular Markers

It is crucial to understand the genetic diversity for exploited fisheries populations to forecast their resilience and resistance to future impacts. Multiple cutlassfish species are co-distributed in the tropical-to-temperate ocean, contributing substantial global fisheries catch; i.e., > 1.2 million tons per year. Among these, a dominant species of cutlassfish, Trichiurus japonicus, are harvested throughout the coast of Taiwan, and there is lack of information about its population structure. To enhance understanding of population structure and ensure effective fisheries management, we are carrying out a study to investigate the population genetics of T. japonicus in Taiwan. We collected T. japonicus samples at 8 fishing ports in 2013-current (total N=800). We aim to utilize the recent advance of molecular techniques, including ISSR (Inter-simple sequence repeat) and SNP (Single Nucleotide Polymorphism) to (1) identify the T. japonicus population structure, (2) estimate genetic connections among populations, (3) reconstruct temporal and spatial dynamics, and (4) test correlation between genetic evolution and potential environmental driving forces.