Genetic Diversity and Population Structure of the Antarctic Toothfish, Dissostichus mawsoni, Using Mitochondrial and Microsatellite DNA Markers

The Antarctic toothfish, Dissostichus mawsoni , serves as a valuable fishery resource around the Continent since 1997, managed by Commission for Conservation of Marine Living Resources (CCAMLR). Although delineating genetic or stock structure populations is crucial improving management this species, its number and diversity levels remain ambiguous. In present study, we assessed population phylogeographic toothfish across 20 geographic localities spanning from Subareas 88 (88.1, 88.2, 88.3) to 58 (58.4 58.5) using mitochondrial DNA (mtDNA) cytochrome oxidase I (COI) 16S rRNA (16S) sequences seven nuclear microsatellite loci. MtDNA revealed low level polymorphism ( h = 0.571, ? 0.0006) with 40 haplotypes in 392 individuals, connected only 1–5 mutational steps, which indicative shallow evolutionary history. Microsatellites showed range allelic richness (AR) 6.328 (88.3 RB3) 7.274 RB6) within populations. Overall was generally higher than 88, suggesting that effective size (N E ) larger 58. results analyses microsatellites suggest sampled are likely comprise well-admixed single gene pool (i.e., one stock), perhaps due high contemporary flow occurring during prolonged larval phase fish. However, given weak, but significant differentiation found six population-pairs, possibility existence multiple could not be completely excluded. mtDNA AMOVA suggests break between groups F CT 0.011, P 0.004). Moreover, distances ST were proportionally greater increase. patterns isolation distance (IBD) shown mtDNA, might divergence processes underwent faster microsatellites, N being one-quarter DNA. Temporal stability D. also indicated no juveniles adults. findings study will help design strategies resource. We long-term monitoring needed understand dynamics response ongoing climate changes.