Along-shelf connectivity and circumpolar gene flow in Antarctic silverfish (Pleuragramma antarctica)

• Main Authors: Caccavo, Jilda Alicia, Papetti, Chiara, Wetjen, Maj, Knust, Rainer, Ashford, Julian R., Zane, Lorenzo
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2020
• Subjects: molecular ecology; EST-linked microsatellites; Antarctic fish; Pleuragramma antarctica; population genetic structure; Antarc*; Antarctic; Antarctic Peninsula; Antarctic silverfish; Antarctica; South Orkney Islands
• Online Access: https://doi.org/10.5061/dryad.m0cfxpp0z

The Antarctic silverfish ( Pleuragramma antarctica ) is a critically important forage species with a circumpolar distribution and is unique among other notothenioid species for its wholly pelagic life cycle. Previous studies have provided mixed evidence of population structure over regional and circumpolar scales. The aim of the present study was to test the recent population hypothesis for Antarctic silverfish, which emphasizes the interplay between life history and hydrography in shaping connectivity. A total of 1067 individuals were collected over 25 years from different locations on a circumpolar scale. Samples were genotyped at fifteen microsatellites to assess population differentiation and genetic structuring using clustering methods, F -statistics, and hierarchical analysis of variance. A lack of differentiation was found between locations connected by the Antarctic Slope Front Current (ASF), indicative of high levels of gene flow. However, gene flow was significantly reduced at the South Orkney Islands and the western Antarctic Peninsula where the ASF is absent. This pattern of gene flow emphasized the relevance of large-scale circulation as a mechanism for circumpolar connectivity. Chaotic genetic patchiness characterized population structure over time, with varying patterns of differentiation observed between years, accompanied by heterogeneous standard length distributions. The present study supports a more nuanced version of the genetic panmixia hypothesis that reflects physical-biological interactions over the life history. Pleuragramma2018_Genotypes_15loci_GENEPOP.txt Text file containing the genotypes of all analyzed individuals at the 15 microsatellite loci considered in the final analysis. Data are divided by the 19 population divisions based on the 19 sampling provenances of samples. File prepared using CREATE ver 1.37 (Coombs et al. 2008) for compatibility with GENEPOP online (Rousset 2008), a common format for downstream bioinformatics analyses. Coombs JA, Letcher BH, Nislow KH (2008) ...