Invasive species have become widespread in aquatic environments throughout the world, yet there are few studies that have examined genomic variation of multiple introduced species in newly colonized environments. In this study, we contrast genomic variation in two salmonid species (anadromous Chinook Salmon, Oncorhynchus tshawytscha, 11,579 SNPs and resident Brook Charr Salvelinus fontinalis, 13,522 SNPs) with differing invasion success after introduction to new environments in South America relative to populations from their native range in North America. Estimates of genetic diversity were not significantly different between introduced and source populations for either species, indicative of propagule pressure that has been shown to maintain diversity in founding populations relative to their native range. Introduced populations also demonstrated higher connectivity and gene flow than those in their native range. Evidence for candidate loci under divergent selection was observed, but was limited to specific introduced populations and was not widely evident. Patterns of genomic variation were consistent with general dispersal potential of each species and therefore also the notion that life history variation may contribute to both invasion success and subsequent genetic structure of these two salmonids in Patagonia.

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Abstract.-The Patagonian toothfish Dissostichus eleginoides is one of the most important fisheries from the Southern Ocean. The biology of this species is relatively well studied and some nutritionals issues have also been reported; however there is no information about the composition of the bacterial community of the gastrointestinal tract, which is essential to characterize the microbiota of this fish. The bacterial flora of D. eleginoides is here described for the first time using culturable methods. By applying traditional culture-based techniques and 16S rDNA sequencing methods it was possible to characterize the families Vibronaceae and Moraxellaceae, which were mainly represented by Vibrio and Psychrobacter, respectively. This Patagonian fish shows a microbiota very similar to other cold waters fishes.

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ABSTRACT. The Patagonian toothfish or Chilean sea bass (Dissostichus eleginoides), found in the Southern Ocean surrounding Antarctica, is an important fishery species for Chile. This high-value species is regarded as overfished, making it an attractive target for aquaculture. When developing a reproduction program for any aquaculture species, it is important to implement genetic tools to evaluate diversity, inbreeding, and parentage. We calculated genetic diversity and paternity/maternity exclusion probabilities based on five commonly-used microsatellite loci in a natural population of Patagonian toothfish from southern Chile (n = 34) in order to evaluate the potential utility of these five markers in stock management. The observed number of alleles per locus (Na) and observed heterozygosities (HO) are within range as described by studies performed in other subAntarctic regions. All five loci were strongly polymorphic, with HO > 0.6 and Na > 7, and paternity exclusion probabilities were high (PE > 0.99), indicating the potential utility of these loci in paternity/maternity exclusion analyses of Patagonian toothfish.