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Estimation of effective number of breeders and effective population size in an abundant and heavily exploited marine teleost
No full textObtaining reliable estimates of the effective number of breeders (Nb) and generational effective population size (Ne) for fishery-important species is challenging because they are often iteroparous and highly abundant, which can lead to bias and imprecision. However, recent advances in understanding of these parameters, as well as the development of bias correction methods, have improved the capacity to generate reliable estimates. We utilized samples of both single-cohort young of the year and mixed-age adults from two geographically and genetically isolated stocks of the Australasian snapper (Chrysophrys auratus) to investigate the feasibility of generating reliable Nb and Ne estimates for a fishery species. Snapper is an abundant, iteroparous broadcast spawning teleost that is heavily exploited by recreational and commercial fisheries. Employing neutral genome-wide SNPs and the linkage-disequilibrium method, we determined that the most reliable Nb and Ne estimates could be derived by genotyping at least 200 individuals from a single cohort. Although our estimates made from the mixed-age adult samples were generally lower and less precise than those based on a single cohort, they still proved useful for understanding relative differences in genetic effective size between stocks. The correction formulas applied to adjust for biases due to physical linkage of loci and age structure resulted in substantial upward modifications of our estimates, demonstrating the importance of applying these bias corrections. Our findings provide important guidelines for estimating Nb and Ne for iteroparous species with large populations. This work also highlights the utility of samples originally collected for stock structure and stock assessment work for investigating genetic effective size in fishery-important species
An assessment of dingo ancestry in camp dogs in Western Australia
No full textHybridisation between Australian dingoes and domestic dogs is a controversial area of interest and research. An ongoing canine sterilisation programme in rural and remote Western Australia provided an opportunity to assess the dingo ancestry of camp dogs and opportunities for hybridisation. Blood samples were collected from 345 individual community dogs at 21 locations. Dogs were screened using 23 microsatellite loci and ancestry percentage assigned using an iterative Bayesian assignment algorithm. A single individual was a dingo, 96% were domestic dogs and 3.5% were hybrids. Camp dog and dingo hybridisation in these areas is of little concern in terms of conserving dingo purity
State Barrier Fence - Esperance extension project overview 2024
No full textWestern Australia’s State Barrier Fence plays an important role in protecting landholders inside the fence by preventing the movement of animal pests, including wild dogs and emus, from pastoral areas into the agricultural regions. It is a state asset which is managed by the Department of Primary Industries and Regional Development.
The original fences (numbers 1, 2 and 3) were constructed between 1902 and 1907. Originally known as the Rabbit Proof Fences, it has also been known as the State Vermin Fence, the Emu Fence and now the State Barrier Fence. Since 2010, the fence has been upgraded to wild dog standard.
The current fence is approximately 1209 km long, extending from the Zuytdorp cliffs north of Kalbarri (in the State’s north) through to Jerdacuttup east of Ravensthorpe (in the State’s south). A significant gap in the State Barrier Fence remains to be constructed near Esperance.
The 660 km extension to the State Barrier Fence will protect south-eastern agricultural enterprises from the impact of emus, wild dogs and kangaroos coming from the rangelands and adjacent woodlands. Once completed, the Esperance Extension will provide confidence to livestock industries for new investment and increased production in the region.
The proposed Esperance extension will provide significant benefits to agriculture and have other associated positive impacts for the region. These benefits were endorsed by the agricultural industry in the Esperance community. The Esperance Extension has been supported by successive State governments, with initial scoping for the project undertaken as far back as 2011
Innovation - food waste
No full textJoin us for an enlightening session with Nick Stamatiou from Whole, where we\u27ll delve into the realm of food waste innovation. Nick will share insights into Whole\u27s transformative mission to combat food waste and revolutionise the way we approach food production and consumption
Calculating canola seeding rate and recording sheet
No full textCanola seeding rate needs to be high enough to get a good establishment to set up the crop for its potential yield and provide insurance against slugs, mites, disease, and other seeding issues. However, there is no point spending more on seed than needed.
This is the companion page for the online Canola seeding rate calculator, which enables you to calculate the seed rate you require for your target plant density
Condition scoring of sheep
No full textCondition scoring sheep is an easy and accurate method of estimating the condition or \u27nutritional wellbeing\u27 of your sheep flock. It requires an assessment of the amount of muscle and fat covering the backbone and the short ribs of each sheep. This gives a picture of the sheep’s store of energy. It is the best method for monitoring pregnant and lactating ewes but is also useful for monitoring the growth of weaners
Field pea – essentials for growing a successful crop
No full textThis factsheet provides essential management practices for growing a successful field pea crop
Water quality for livestock
No full textMeasure water quality and quantity to effectively plan and monitor water supplies for livestock. If water quality is poor, livestock may drink less than they need, or rarely, may stop drinking altogether. When animals drink less, they will eat less and lose condition, and if they are lactating, their milk production will reduce or cease.
Water quality for livestock in Western Australia is most affected by water salinity, and the presence of water contaminants such as blue-green algae, organic material, heavy metals and chemicals