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The Patagonian toothfish, Dissostichus eleginoides, is a valuable fishery species and has a discontinuous distribution across the Southern Ocean. Identification of the genetic stock structure of toothfish would allow evaluation of the suitability of the spatial scale at which fisheries management operates. Genetic subdivision seems likely given the species distribution. Population genetics studies of this species have been performed; however, they have been limited by sample size, spatial coverage and/or the type of markers investigated. As a potential solution, we developed methods for extracting toothfish DNA from otoliths that are available in large numbers from collections held at several research institutes. Genetic differentiation between the three oceanic sectors was investigated. Four mitochondrial and four nuclear markers with multiple single nucleotide polymorphisms were sequenced by high throughput sequencing for samples from six locations. Genetic differentiation was found between three sectors with nuclear markers. However, only the Pacific sector was differentiated from other sectors with mitochondrial markers. This study demonstrates the usefulness of otolith DNA as a means of increasing sample sizes for population genetics research of fish. Additionally, the combination of nuclear and mitochondrial markers may allow insight into how the observed differences in movements between male and female toothfish impact population structure.

Antarctic krill (Euphausia superba; hereafter krill) are an incredibly abundant pelagic crustacean which has a wide, but patchy, distribution in the Southern Ocean. Several studies have examined the potential for population genetic structuring in krill, but DNA-based analyses have focused on a limited number of markers and have covered only part of their circum-Antarctic range. We used mitochondrial DNA and restriction site-associated DNA sequencing (RAD-seq) to investigate genetic differences between krill from five sites, including two from East Antarctica. Our mtDNA results show no discernible genetic structuring between sites separated by thousands of kilometres, which is consistent with previous studies. Using standard RAD-seq methodology, we obtained over a billion sequences from >140 krill, and thousands of variable nucleotides were identified at hundreds of loci. However, downstream analysis found that markers with sufficient coverage were primarily from multicopy genomic regions. Careful examination of these data highlights the complexity of the RAD-seq approach in organisms with very large genomes. To characterize the multicopy markers, we recorded sequence counts from variable nucleotide sites rather than the derived genotypes; we also examined a small number of manually curated genotypes. Although these analyses effectively fingerprinted individuals, and uncovered a minor laboratory batch effect, no population structuring was observed. Overall, our results are consistent with panmixia of krill throughout their distribution. This result may indicate ongoing gene flow. However, krill’s enormous population size creates substantial panmictic inertia, so genetic differentiation may not occur on an ecologically relevant timescale even if demographically separate populations exist.

Objective: To assess the impact of introducing a publicly funded infant rotavirus vaccination program on disease notifications and on laboratory testing and results. Design and setting: Retrospective analysis of routinely collected data (rotavirus notifications [2006–2008] and laboratory rotavirus testing data from Queensland Health laboratories [2000–2008]) to monitor rotavirus trends before and after the introduction of a publicly funded infant rotavirus vaccination program in Queensland in July 2007. Main outcome measures: Age group-specific rotavirus notification trends; number of rotavirus tests performed and the proportion positive. Results: In the less than 2 years age group, rotavirus notifications declined by 53% (2007) and 65% (2008); the number of laboratory tests performed declined by 3% (2007) and 15% (2008); and the proportion of tests positive declined by 45% (2007) and 43% (2008) compared with data collected before introduction of the vaccination program. An indirect effect of infant vaccination was seen: notifications and the proportion of tests positive for rotavirus declined in older age groups as well. Conclusions: The publicly funded rotavirus vaccination program in Queensland is having an early impact, direct and indirect, on rotavirus disease as assessed using routinely collected data. Further observational studies are required to assess vaccine effectiveness. Parents and immunisation providers should ensure that all Australian children receive the recommended rotavirus vaccine doses in the required timeframe.