No abstract

Nelusetta ayraudi (the ocean leatherjacket) is an endemic Australian monacanthid species distributed from North West Cape (Western Australia) south to southern Queensland. The commercial and recreational fisheries targeting Nelusetta ayraudi have expanded substantially along the coast of New South Wales (NSW) in recent years but there exists little biological information on which to base effective management of this growing fishery. World-wide, only a few studies have aged monacanthids. Of these, researchers have interpreted periodic increments in bony structures such as vertebrae and anterior dorsal spines in preference to those found in otoliths. In this study we estimated age of N. ayraudi by counting growth increments in sectioned otoliths. The periodicity of increment formation was validated using a vital stain, (oxy-tetracycline), injected into young-of-theyear fish. Growth was rapid especially as juveniles with N. ayraudi attaining approximately 220 mm after 1 year and 340 mm after 2 years. No differences in growth rates were detected between sexes or between fish captured at different latitudes (zones). The largest male (605 mm, Total Length-TL) and female (656 mm, TL) were both recorded from northern NSW, with both sexes attaining the maximum age of 6+ years from northern and southern NSW. The von Bertalanffy parameters describing growth for N. ayraudi were L 1 =591 mm (TL), k=0.377 year −1 and t o =−0.247 years.

No abstract

No abstract

Fisheries are currently under pressure to provide increasing amounts of seafood, causing a growing number of marine stocks to be harvested at unsustainable levels. To ensure marine resources remain sustainable, careful management of biological stocks and their genetic integrity is required. The Eastern Rock Lobster, Sagmariasus verreauxi, is commercially harvested along the New South Wales (NSW) coast of eastern Australia and is managed as a single unit. Due to overfishing, the NSW S. verreauxi stock was severely depleted in the mid-1990s but has since been rebuilding. This study evaluates the population genetic structure, putative local adaptation, and potential of a population bottleneck for NSW S. verreauxi. Using neutral single nucleotide polymorphisms (SNPs), we determined NSW S. verreauxi consist of a single genetic stock, with outlier SNPs detecting weak genetic divergence among offshore locations, and evidence of population bottlenecks at all locations. Our findings (i) confirm a single management unit is appropriate; (ii) can be used as a baseline for future genetic monitoring of NSW S. verreauxi; and (iii) highlights the importance of implementing routine genetic monitoring and collecting temporal samples to understand the full impact of overfishing on a species resilience.