Throughflow troughs for the measurement of shallow seepage on hillslopes

Throughflow troughs were installed to assess their effectiveness in quantifying shallow sub-surface flows on hillslopes. The majority of flow was found to occur from decayed root channels in clay sub-soils below the lowest gutter. The conclusion at this site is that shallow throughflow troughs installed on a small scale are not capable of quantifying all of the seepage occurring on hillslopes

An assessment of Wisalts banks at Dangin

This report compares two alternative approaches for the treatment and management of salt affected land at Dangin, Western Australia by determining whether there are benefits from a WISALTS bank system which would not accrue from standard soil conservation recommendations; comparing the costs and benefits of the two systems; and determining the nature of the effects of the two systems, particularly with respect to soil salinity

Horticultural capability study of soils adjacent to plantations at Carnarvon, Western Australia

A detailed soil survey and horticultural capability assessment was undertaken over 1,804 ha of land adjacent to existing plantations on levees of the Gascoyne River near Carnarvon. The study provides mapped land resource data and advice in relation to land management and the possibility of further land release for horticulture. In the assessment of horticultural capability primary consideration has been given to the risk of erosion during flood events, to salinity, and to soil drainage conditions

Pre-recruitment abundance indices for eastern king prawn, blue swimmer crab and snapper in south-eastern Queensland

Fisheries Queensland scientists conduct an annual beam trawl survey in south-eastern Queensland to collect information on pre-recruit eastern king prawns, blue swimmer crabs and snapper. After a successful pilot study was completed in 2006, the survey commenced in 2007 and has been conducted every year since, except in 2016. The survey provides an independent estimate of pre-recruit abundance for this time series. This report assessed the analysis methods and mathematical models used to estimate abundance indices for each species, to ensure the results are useful as empirical evidence in species sustainability assessments, periodic stock assessments and for fishery management purposes. The report identifies the most appropriate mathematical models for estimating abundance indices, where and how the indices are currently used and opportunities to value add to the existing survey into the future

Stock assessment of the Queensland Gulf of Carpentaria Spanish mackerel (Scomberomorus commerson) fishery

Spanish mackerel (Scomberomorus commerson) is a pelagic species that forms genetic populations (stocks) around northern Australia. For this stock assessment, we have investigated fish harvested from eastern waters of the Gulf of Carpentaria, Queensland. This stock assessment was set up as an age-structured model with a yearly time step and length-based selectivity. The annual data inputs included total fish harvest, standardised catch rates, length structures and conditional age at length data. The model used data from 1940 to 2018. The assessment suggested the stock in 2018 was between 30 and 40 per cent unfished spawning biomass. The recommended biological catch was estimated at 21 t, which is below the 2018 harvest of 181 t. This initial catch estimate aims to allow the stock to rebuild to the target 60 per cent spawning biomass. Smaller harvests are estimated at first to be taken in early years, which increase through time as the fish population builds higher

Land resources study of the Carnarvon Land Conservation District and part of Boolathana Station, Western Australia

A survey of the land resources of 36,343 ha covering the Carnarvon Land Conservation District and an adjoining portion of Boolathana station was conducted to assist future land use planning and management. This report describes the soil, landform and vegetation conditions of land units shown on an accompanying 1:50,000 scale map. These land units are components of land systems previously mapped at 1:250,000 scale for the Carnarvon Basin by Payne et al. (1987). As part of the study, further, more detailed land resource mapping and land capability assessments were conducted at specific locations. Land use planning and management considerations arising from that work have been extrapolated to the broader scale mapping herein covering the entire study area. The three major land use issues of concern are: • grazing or stockholding on special leases: • land release for horticulture; and • future urban development. The report provides a framework against which current and future land uses can be examined in relation to their compatibility with the condition and capability of the land resources. It is primarily intended as a reference document for people concerned with land use and land management decisions within the area. These include the Carnarvon Land Conservation District Committee; the Department of Agriculture, Western Australia, rangeland advisers; land use planners and land administrators

Stock assessment of the Australian east coast spotted mackerel (Scomberomorus munroi) fishery 2018

Australian east coast spotted mackerel, Scomberomorus munroi, is a pelagic fish species harvested by commercial, charter and recreational fishers. It forms a single genetic stock in Queensland and New South Wales. The stock is shared with NSW although over 80 per cent of the harvest is from Queensland waters. Spotted mackerel exhibit schooling behaviours that make them susceptible to overfishing. The Queensland commercial line and net fishery operates under a quota system for spotted mackerel (140 tonnes total allowable commercial catch). Recent commercial harvest (2013–2018) was around 64 tonnes per year. Catch shares (in 2013–14) in Queensland were around 55 per cent commercial and 45 per cent recreational. The formal stock assessment was requested to update the status of the stock and inform fishery management agencies and stakeholders on estimates of sustainable harvest that will build and maintain the fishery in the long term. The 2018 stock assessment combined data in an annual age-structured population model tailored for the biology, management and fishing history of spotted mackerel. The age-structured population model analysed 252 scenarios based on different combinations of input data, including harvest histories, age structures, standardised catch rates and considered both high and low estimates of natural mortality. The assessment suggests that the spotted mackerel biomass in 2016–17 is between 40 and 60 per cent of unfished biomass (all sectors and jurisdictions). The assessment provides estimates of the maximum sustainable yield (MSY) and recommends a total allowable catch to rebuild the stock to the Sustainable Fisheries Strategy (SFS) longer term target of 60% unfished biomass (as a proxy for MEY) by 2027

Stock assessment of the Queensland east coast common coral trout (Plectropomus leopardus) fishery. April 2019

Queensland’s common coral trout (Plectropomus leopardus), a species of grouper, is a line caught fish forming a single population (stock) across the Great Barrier Reef (GBR). Common coral trout are protogynous hermaphrodites (born female, many later changing sex to male) and aggregate to spawn during spring and summer. They can grow to 5 kg and 18 years of age. The stock extends north from the GBR into the eastern Torres Strait where it is under Commonwealth jurisdiction. In financial year 2017-18, the Queensland jurisdiction accounted for around 90% of the total harvest. From 2013-14 to 2017-18, the Queensland total harvest averaged 983 tonnes (t) per year. The catch breakdown is 82% commercial (806 t) and 18% recreational (177 t). The previous stock assessment estimated that in July 2012 the stock was at 60% of unfished biomass (i.e. before fishing began) over the areas commonly fished by commercial fishers. This stock assessment updates the existing model to cover the full extent of the GBR in Queensland waters and includes harvest information from the recreational sector. This stock assessment used a spatial age-structured model with a yearly time step based on financial years. The model considered twelve spatial sub-populations (“strata”) of fish based primarily on differences in coral reef habitat. The model incorporated data spanning the period from 1961-62 to 2017-18 (including commercial harvest (1988-89 to 2017-18); historical commercial (1961-62 to 1981-82); recreational harvest (1996-1997 to 2013-14); age monitoring (1994-95 to 2004-05); and underwater visual surveys (1982-83 to 2017-18)). The purpose of this report is to estimate biological reference points. The model provides estimates of the level of biomass of common coral trout relative to unfished levels, maximum sustainable yield (MSY) and the yield consistent with a biomass ratio of 68% (a proxy for maximum economic yield in this fishery)