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This study aimed to determine salinity tolerances in Coxiella gastropods from Australian salt lakes and whether different species exhibit characteristically different tolerances. Controlled gradual accumulation experiments were conducted to estimate both the maximum and minimum salinity levels at which 50% of individuals (IC50) remained active for 25 populations representing six species. All studied species showed remarkable euryhalinity and were tolerant of very high levels of salinity, some more than others, while minimum salinity tolerance varied little among populations and species. The experimental trends in salinity tolerances were consistent with the salinity distributions of species in the field, although the former were typically broader than latter. The findings suggest that Coxiella comprises some of the most salt tolerant gastropods globally. [ABSTRACT FROM AUTHOR]

With increasing sea water temperatures, higher latitude temperate and sub-tropical coral reefs are becoming increasingly tropicalised. Although these cooler areas might offer refuge to tropical species escaping the heat, the reshaping of ecosystems can have devastating effects on the biodiversity in these areas, especially when habitat structure is affected. Recently, feeding aggregations of corallivorous gastropod Drupella cornus, a tropical species capable of large-scale reef degradation, were found at Rottnest Island in Western Australia (32°S). We provide evidence that D. cornus spawned at Rottnest Island for 2 consecutive years in 2021 and 2022, and Drupella veligers from an egg case collected at the island hatched and grew at temperatures in the laboratory that were predominantly lower than those at Rottnest Island at the same time. The spawning was possibly triggered by higher than usual La Niña-associated SSTs during the survey period, or the long period of high sea water temperature anomalies recorded around Rottnest Island. A spawning population of D. cornus can greatly affect these higher latitude reef areas, especially when accompanied by increased heat stress. Monitoring and management should be implemented to further understand what effects a breeding population of D. cornus has on Rottnest Island. [ABSTRACT FROM AUTHOR]

Giant ostracods in the subfamily Mytilocypridinae are an important component of the biota of Australian salt lakes, which are predominantly temporary, and often located in remote arid areas. Mytilocypridines produce desiccation-resistant eggs to persist in these habitats during unfavourable conditions. In this study, we used mytilocypridine eggs collected from sediments in salt lakes in Western Australia to analyse aspects of the ecology of these ostracods. We conducted two rehydration trials, where sediment was collected from dry lakes or the dry margins of lakes, rehydrated in a laboratory setting, and selected mytilocypridine species hatched and raised in cultures. The first trial found that the eggs of mytilocypridine species were unevenly distributed in a dry lake and could be hatched even after 27 months of dry storage with no discernible loss of viability. The second trial assessed the capacity of selected mytilocypridines to hatch and develop into adults under different salinity treatments. One species, Australocypris insularis, hatched and developed across a very wide salinity range (0–100 g/L). Egg/sediment samples provide a means for testing species’ tolerance to physical and chemical variables throughout their entire life cycle, as well as for surveying the mytilocypridines in remote lakes that rarely hold water. [ABSTRACT FROM AUTHOR]

Northern Australia is considered to be one of the last strongholds for three critically endangered sawfishes, Pristis zijsron, Pristis clavata, and Pristis microdon, making these populations of global significance. Population structure and levels of genetic diversity were assessed for each species across northern Australia using a portion of the mitochondrial control region. Statistically significant genetic structure was detected in all three species, although it was higher in P. microdon ( F = 0.811; N = 149) than in either P. clavata ( F = 0.419; N = 73) or P. zijsron ( F = 0.202; N = 49), possibly due to a much higher and/or localized level of female philopatry in P. microdon. The overall levels of haplotype diversity in P. zijsron ( h = 0.555), P. clavata ( h = 0.489), and P. microdon ( h = 0.650) were moderate, although it appears to be reduced in the assemblages of P. zijsron and P. clavata in the Gulf of Carpentaria ( h = 0.342 and h = 0.083, respectively). Since female migration (replenishment) between regions is unlikely, conservation plans should strive to maintain current levels of diversity and abundances in the regional assemblages of each species. [ABSTRACT FROM AUTHOR]

We describe the isolation and characterisation of microsatellite loci for Pagrus auratus and cross amplification in another sparid, Acanthopagrus butcheri. Of 35 loci tested, 12 appear to be appropriate for population genetic studies of P. auratus, which are essential to inform management responses to evidence of overexploitation of this species. Three were ideal for A. butcheri and, when combined with published loci, can be used to assess the genetic implications of restocking depleted populations of this species. [ABSTRACT FROM AUTHOR]