Development and characterisation of novel microsatellite loci for the baldchin groper (Choerodon rubescens) and cross-amplification in seven other labrid species

We describe the development and characterisation of novel microsatellite loci for the baldchin groper, Choerodon rubescens. The purpose was to identify loci that can be used to resolve uncertainties about the population (stock) structure of this fish species, which is endemic to a narrow region of the west coast of Australia and showing evidence of overfishing in some locations. Of 22 loci characterised, 12 appear to be ideally suited for population-level analyses. Utilising data obtained from four sampling locations across the distribution of C. rubescens, the total number of alleles observed at each of the 12 loci ranged from 2 to 24, while the overall values of expected heterozygosity ranged from 0.19 to 0.89. Cross-amplification of the 12 loci in seven other labrid species was often successful, especially in congeners

Pelagic early life stages promote connectivity in the demersal labrid Choerodon rubescens

Population connectivity has profound ecological and evolutionary implications. In marine species with complex life cycles, the nature of these implications depends on both the amount of dispersal and the life-cycle stage(s) through which dispersal occurs. For demersal fishes with such life cycles, the pelagic early life stages (ELS) are generally considered the main dispersive phase, though this assumption has rarely been tested. This research investigates genetic connectivity in the reef-dwelling labrid Choerodon rubescens, which is a prized eating fish endemic to ca 1200km of the west coast of Australia. This species has demersal juveniles and adults, and pelagic ELS that are predicted to last about 25-30days. The aim of the study was to use patterns of variation at 12 microsatellite loci to test the hypothesis that C. rubescens is genetically homogeneous across its main distribution. The genetic analyses were based on samples of 26-40 individuals from six locations, which collectively span all of the areas where C. rubescens is common. The values of global FST (0.0019) and DEST (0.0010) were not significantly different from zero and Bayesian clustering indicated that all individuals belonged to a single genetic group. In addition, Mantel tests showed no evidence of isolation by distance. These results support the view that C. rubescens is genetically homogeneous over all or most of its geographic range. Since published otolith microchemistry evidence indicates that the juveniles and adults of C. rubescens are relatively sedentary, these results also imply that the pelagic ELS are the main avenue of dispersal in this species. This study highlights the value of combining the results of complementary methods for assessing the relative importance of the different life-cycle stages in dispersing a fish species. The results also have implications for the management of C. rubescens, which has shown signs of localised overfishing. Specifically, the dispersal of the ELS provides a mechanism for the recruitment of C. rubescens to non-natal reefs. Such connectivity could help this species to recover from localised depletions in abundance and ameliorate the potential evolutionary consequences of any localised overfishing, such as reductions in genetic diversity or selective responses to harvesting

Influence of physico-chemical and biotic factors on the distribution of a penaeid in a temperate estuary

The distribution, abundance and size structure of a penaeid with tropical affinities (Metapenaeus dalli) was investigated in a temperate, microtidal estuary in south-western Australia. Sampling was conducted every lunar month for two years at 20 sites across five regions (nine subregions) in nearshore waters by hand trawl, and at 16 sites across four regions (eight subregions) in offshore waters by otter trawl. Densities of M. dalli changed markedly seasonally, with greatest values recorded in nearshore waters from October to February, and in offshore waters from March to July. These densities also varied spatially, with the highest recorded in the Lower Canning, Middle Swan, and Upper Melville Water regions. Spearman's rank correlation showed a positive relationship between the density of M. dalli in nearshore waters and surface water temperature in all nine subregions, whilst densities of M. dalli in offshore waters were negatively correlated with bottom water temperature in most of the estuary; these correlations reflect the movement of adult prawns into shallow waters for breeding in summer, as well as the subsequent recruitment and movement back into deeper waters over the winter months. Mean carapace lengths remained relatively unchanged over the late autumn and winter months (May to August), before rapidly increasing with temperature in late spring. The spatial and temporal distribution of M. dalli differed significantly from those of other crustaceans in the estuary, particularly the penaeid Penaeus latisulcatus, which was concentrated mainly in the Lower and Upper Melville Water regions. The distribution of M. dalli was statistically indistinct from that of the apogonid Ostorhinchus rueppellii, which predates heavily on postlarval M. dalli, and very similar to those of two scyphozoans, Aurelia aurita and Phyllorhiza punctata, that likely predate on larval M. dalli. These findings highlight the partitioning of species within the estuary and the significance of site selection for maximising the post-release survival of hatchery-reared M. dalli produced by aquaculture-based enhancement programs

Estimating predation rates of restocked individuals: The influence of timing-of-release on metapenaeid survival

Abstract The success of aquaculture-based enhancement programs is greatly influenced by the survival of released individuals. Immediate post-release mortality through predation is one of the greatest obstacles to the success of releases, and the choice of a release site or time-of-release can be critical in maximising survival. This paper develops a quantitative method of estimating predation rate to inform release programs, and describes its use in determining whether hatchery-reared Western School Prawns Metapenaeus dalli should be released into the Swan-Canning Estuary in temperate south-western Australia during the night or day. Fish faunal composition was determined during the day and night, both before and after the release of ∼130,000 postlarval M. dalli. Far greater numbers of species and individuals were recorded at night. Stomach contents of 16 abundant teleost species were estimated volumetrically (%V) and any postlarval M. dalli counted. Although diet varied among species, diel phase and size class, crustaceans (including M. dalli) were a key dietary component (>10%V) of 12 species. The data on the abundance of these fish species and the number of M. dalli they consumed were combined and bootstrapped to estimate the total relative number of M. dalli consumed at the time-of-release. The results indicated that while six species consumed M. dalli, two species, Ostorhinchus rueppellii (Apogonidae) and Atherinomorus vaigiensis (Atherinidae), were responsible for ∼99% of the predation, and that the total number of postlarval prawns consumed was 288% higher at night than in the day. These findings suggest that releasing M. dalli during the day will greatly reduce predation and consequently allow a greater survival rate at this release site. The simple methodology developed here could be readily employed to inform release strategies for other species

Recreational Fishing Initiatives Fund Final Report: Can recreational fishers provide a cost effective means for monitoring artificial reefs?

Artificial reefs have been constructed and deployed in over 50 countries around the world to enhance the productivity of aquatic habitats and fishing experiences. In April 2013, two purpose-built concrete artificial reefs were deployed in Geographe Bay, Western Australia to provide additional fish habitat and increase upwelling and thus enhance recreational fishing opportunities. Due to the relatively high cost of planning, purchasing and deploying these structures, it is important to understand spatial and temporal usage of the reef by fish assemblages, in order to determine the extent to which fishing opportunities are actually enhanced. One potential method to reduce monitoring costs is to utilise volunteers from the general public to collect data, i.e. citizen science. The overall objective of this project was to determine whether recreational fishers, through a citizen science program, could potentially provide an effective means for monitoring artificial reefs

Pulping characteristics of reafforestation species grown in Solomon Islands (ODNRI Bulletin No. 32)

Samples of Pinus caribaea, Pinus oocarpa, Campnosperma brevipetiolata, Eucalyptus deglupta, Terminalia brassii and Terminalia calamansanai, all of which have shown potential for growing in plantations in Solomon Islands, were examined to determine their potential value for the production of pulpwood chips for export. Details are given of growing conditions, size of trees, wood characteristics, fibre dimensions and pulping by sulphate, soda and soda/anthraquinone processes. P. caribaea, P. oocarpa, C. brevipetiolata and F. deglupta were all considered promising for the production of pulpwood. T. brassii and T. calamansanai, both of which required very severe chemical conditions to pulp, were not considered promising

Restocking of the Western School Prawn (Metapenaeus dalli) in the Swan Canning Riverpark

This report provides the first comprehensive investigation into the biology and ecology of the Western School Prawn (Metapenaeus dalli) in the Swan-Canning Estuary in south-western Australia. It provides knowledge to help manage the fishery and evaluate release strategies for the aquaculture-based enhancement of this species. The study involved Murdoch University, the Department of Biodiversity, Conservation and Attractions (DBCA) (formerly Department of Parks and Wildlife and the Swan River Trust) and the Australian Centre for Applied Aquaculture Research (ACAAR). It was designed to complement a concurrent project to develop aquaculture techniques to produce and release M. dalli and re-engage the local community with prawning and the estuary (led by ACAAR, DBCA’s Parks and Wildlife Service and the West Australian Fish Foundation), funded by the Recreational Fishing Initiatives Fund. The Fisheries Research and Development Corporation provided matching funds for the current study. Biological data on M. dalli were collected from 20 sites in nearshore and 16 in the offshore waters of the Swan-Canning Estuary, ranging from the mouth of the system to ~40 and 30 km upstream in the Swan and Canning rivers, respectively, in every lunar month between October 2013 and March 2016. Laboratory studies were also completed to investigate the survival and growth of larval prawns in different salinity, water temperature and algal food conditions. Results were presented as part of the Prawn Watch program to engage the community in the research and encourage stewardship of the fishery and the estuary

Asteroseismology of Eclipsing Binary Stars in the Kepler Era

Eclipsing binary stars have long served as benchmark systems to measure fundamental stellar properties. In the past few decades, asteroseismology - the study of stellar pulsations - has emerged as a new powerful tool to study the structure and evolution of stars across the HR diagram. Pulsating stars in eclipsing binary systems are particularly valuable since fundamental properties (such as radii and masses) can determined using two independent techniques. Furthermore, independently measured properties from binary orbits can be used to improve asteroseismic modeling for pulsating stars in which mode identifications are not straightforward. This contribution provides a review of asteroseismic detections in eclipsing binary stars, with a focus on space-based missions such as CoRoT and Kepler, and empirical tests of asteroseismic scaling relations for stochastic ("solar-like") oscillations.Comment: 28 pages, 12 figures, 2 tables; Proceedings of the AAS topical conference "Giants of Eclipse" (AASTCS-3), July 28 - August 2 2013, Monterey, C

New Results on Standard Solar Models

We describe the current status of solar modelling and focus on the problems originated with the introduction of solar abundance determinations with low CNO abundance values. We use models computed with solar abundance compilations obtained during the last decade, including the newest published abundances by Asplund and collaborators. Results presented here make focus both on helioseismic properties and the models as well as in the neutrino fluxes predictions. We also discuss changes in radiative opacities to restore agreement between helioseismology, solar models, and solar abundances and show the effect of such modifications on solar neutrino fluxes.Comment: 9 pages. Review talk presented at "Synergies between solar and stellar modelling", Rome, June 2009. To be published by Astrophysics and Space Scienc

Prospects for asteroseismology

The observational basis for asteroseismology is being dramatically strengthened, through more than two years of data from the CoRoT satellite, the flood of data coming from the Kepler mission and, in the slightly longer term, from dedicated ground-based facilities. Our ability to utilize these data depends on further development of techniques for basic data analysis, as well as on an improved understanding of the relation between the observed frequencies and the underlying properties of the stars. Also, stellar modelling must be further developed, to match the increasing diagnostic potential of the data. Here we discuss some aspects of data interpretation and modelling, focussing on the important case of stars with solar-like oscillations.Comment: Proc. HELAS Workshop on 'Synergies between solar and stellar modelling', eds M. Marconi, D. Cardini & M. P. Di Mauro, Astrophys. Space Sci., in the press Revision: correcting abscissa labels on Figs 1 and