Department of Agriculture and Food Western Australia
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A multidecadal analysis of groundwater level and streamflow decline in Southern Forest catchments, Western Australia
No full textPrevious analysis of hydrological data in the eucalypt dominated forests of Western Australia’s Darling Ranges show that reduced winter rainfall over the last 50 years has lowered groundwater levels and diminished streamflow by up to 70%. Consequently, climate-independent reverse osmosis seawater desalination and groundwater resources now supply Perth and nearby regional areas, as runoff from forested catchments is no longer sufficient or reliable. In the high rainfall (~1200 mm/yr) mixed forest areas dominated by Eucalyptus diversicolor (karri) and Eucalyptus marginata (jarrah) 200 km to the south of Perth (the ‘Southern Forest’), similar analysis of climate impacts on watertables has not been conducted. In this paper we collate over 48 years of groundwater data (1975/76–2024) along with climate and streamflow records to understand changes in the Southern Forest catchments. We assemble data from eleven research catchments that were intensively studied from 1975/1976 until mid-1990s, then abandoned. Some of these small watersheds were logged (1976–78 or 1982–83) and others left as unlogged controls. Both were monitored to study impacts on streamflow and water quality. We returned to these catchments after two decades of lapsed monitoring, comprising a period of reduced rainfall and forest regrowth, to determine how watertables contained in the deeply weathered regolith had responded. Analysis of climate data indicates that, like the Darling Ranges, annual rainfall reduced during the latter part of the 20th century. There have also been changes to seasonal rainfall and temperature patterns. Relative responses vary depending on location. Results from over 48 years of groundwater monitoring, comparing levels taken at the end of each dry season, show watertables in the deeply weathered regolith have fallen on average by 5.1 to 6.7 m ( \u3c 0.16 m/yr) beneath the stream zone and hillslopes in the paired and comparison catchments. In all cases, watertables are now \u3e 5 m below the stream zone (range: 5 to 13 m bgl), indicating little or no connection. Average falls were greater in the intermediate and higher rainfall catchments (paired catchments – 6.3 m (treated), 5.9 m (control); comparison catchments, 8.9 m (treated), 4.6 m (control)), with maximum falls of 10-12 m in some individual bores. In the low rainfall Yerraminnup catchments, falls were less (~2 m), however most bores are now dry. The timing and magnitude of reductions in watertables was variable between catchments, but in all cases had accelerated since 2000 and especially after 2010, when the driest years in the region were recorded. Reduced watertables at the end of the dry season equate to losses of 42% of the saturated zone storage under the stream zone and up to 64% storage under hillslopes. If rates of fall are sustained into the future, extensive areas of saturated regolith under hillslopes and stream zones would be depleted. Regionally, reduced rainfall and watertable decline has contributed to a 66% reduction in streamflow of the Donnelly River since monitoring commenced in 1952. From 2000, the Donnelly River has become intermittent, with dry periods in summer regularly exceeding 100 days. Ecologically important forests and riverine systems may become vulnerable to receded streamflow if these trends remain. In dry years, seasonal flows are dominated by water generated from upland cleared catchments, with first and last flows resulting from overflowing farm dams. CSIRO modelling, that accounts for the effects of non-stationarity, and uses current Global Climate Models, indicates a potential for additional reductions of streamflow of 32–45% by 2059, if forecasts of reduced rainfall remain classified as ‘almost certain’. This paper presents several metrics to help explain recent drying recorded in the Southern Forest. It suggests some drivers that explain the change in streamflow regime and outlines actions to improve data available to inform future decision making
Skeleton weed in Western Australia: 2025 Management guide
No full textSkeleton weed can reduce crop yields by competing for moisture and nutrients (mainly nitrogen).
This guide helps you manage and eradicate skeleton weed infestations on your property, and helps to stop the spread across WA.
Without the coordinated program aimed at controlling the spread, skeleton weed would now be much more abundant and widely established throughout cereal growing areas.
If you find skeleton weed on your property, we can help you get rid of it.
Skeleton weed is unpredictable and can spread over long distances due to wind dispersal, but once identified it can be managed effectively and eradicatedhttps://library.dpird.wa.gov.au/bs_bulletins/1002/thumbnail.jp
Western Australia’s marine heatwave update - 9th May 2025
No full textCategory 1 – Moderate marine heatwave (MHW) conditions continue for the Gascoyne and South Coast Bioregions. Marine heatwave conditions in the North Coast Bioregion have abated and the West Coast Bioregion remains warm but neither are categorised as experiencing MHW conditions
WA Insecticide Guide 2025 - Winter Spring
No full textPlease note: this second version published in September 2025 replaces the first version published in June 2025.
The insecticides listed in the tables within this guide can be used on any crop appearing on the chemical label, if the rate used does not exceed the highest rate that is registered for use on that crop.
There are many products with different trade names that contain the same active ingredient. This list is not exhaustive and does not imply any specific recommendations of brand names.
Unless otherwise specified, all insecticides listed are emulsifiable concentrates (EC). Other insecticide formulations are suspension concentrate (SC), wettable powder (WP), capsule suspension (CS), wettable granules (WG), emulsion (EW) dry flowable (DF) and water dispersible granules (WDG). Ultra-low volume (ULV) insecticides are not listed.
Read the chemical label before use and check label withholding periods for grazing or hay/silage/fodder production before application.
Please turn on punctuation if using a screen reader.
The information tabled is a guide only. Whilst every care has been taken in preparation of the information, some errors or omissions may have occurred.https://library.dpird.wa.gov.au/fc_pestfactswa/1035/thumbnail.jp
West Coast Demersal Scalefish Resource recovery support package: 2024-25 report
No full textThe West Coast Demersal Scalefish Resource (WCDSR) includes over 100 species in inshore (20–250 m deep) and offshore ( \u3e 250 m) demersal habitats of the West Coast Bioregion. These species are caught by charter, commercial and recreational fishers. The WCDSR is in recovery and managed under a 20-year recovery plan (2010–2030). DPIRD tracks recovery progress through scientific stock assessments of indicator species (snapper, WA dhufish, and baldchin groper) every 3 years. The 2021 WCDSR stock assessment showed limited recovery and additional management action was required. In December 2022, the Minister for Fisheries announced commercial and recreational (including charter) sector management packages and a $10 million package to support recovery
Review of a regional scale grassland condition monitoring method
No full textThis paper outlines the review and development of site selection and field data collection protocols for enabling the continuation of the state government\u27s Western Australian Rangeland Monitoring System (WARMS) beyond 2024. The primary purpose of WARMS remains to detect change in the condition and trend of the extensive rangelands across Western Australia. The Department of Primary Industries and Regional Development (DPIRD) aims to align WARMS with the move to risk-based monitoring and assessment outlined in DPIRD\u27s Framework for Sustainable Pastoral Land Management. Regular reviews of monitoring methods, collaboration with industry stakeholders and governing bodies are required to ensure the system\u27s robustness and relevance for management of public lands. A revision of DPIRD\u27s grassland field site-selection and data collection protocols is presented with two main goals: (1) to improve monitoring effectiveness by aligning sites with key pastures and broad ecosystem types identified in ecological State and Transition models (Richards et al. 2023), and reducing the total number of sites monitored; and (2) to modify site spatial configuration and align data collection with national standards for fractional cover data collection, while maintaining longitudinal continuity with the WARMS program. The co-location of nationally comparable sites with suitable WARMS sites would be an efficient way to provide the ground measured data needed for calibration of remotely sensed fractional cover estimates, if the changes in data collection protocols prove compatible with previous WARMS condition trend detection. Methods for using remote sensing data to directly monitor rangeland condition and degradation risk will be explored. In 2024 we began a field program of monitoring pasture condition using the existing WARMS site layout in tandem with the star transect layout for cover measurement in the Kimberley region of Western Australia. Data from the two transect configurations will be analysed to assess the practicality of substituting the existing WARMS measurement layout for the star layout without compromising the long-term trend detection
Fisheries Research Report No. 361: 2024 assessment of the status of the Elasmobranch Resource of Western Australia
No full textThis document provides the 2024 risk-based weight of evidence stock assessment for the elasmobranch (sharks and rays) resource of Western Australia (WA). Gummy (Mustelus antarcticus), dusky (Carcharhinus obscurus), whiskery (Furgaleus macki), and sandbar (C. plumbeus) sharks are the most commonly captured species (~80% of the elasmobranch catch) and have been selected as indicator species for the status of the temperate elasmobranch ‘suite’. However, over 100 elasmobranch species have been caught in commercial and/or recreational fisheries in WA and, with the increasing number of elasmobranch species being listed in national and international protection lists, species-specific scientific advice on stock status at the local level is needed for these species
Role of recreational fisher information in fisheries management
No full textFisheries managers work with the three components of fisheries—biota, environment, and people - to achieve recreational, stewardship, and socioeconomic goals. Although manipulation of biota and the aquatic environment remains popular (e.g. harvest regulation, protecting or enhancing habitats, and guarding water quality), the human dimension of fisheries must also be considered throughout the fisheries management process. Managers can and should engage fishers in a myriad of ways, from identification of problems to guidance on alternatives, and from measurement of change to evaluation of success. In this chapter, we review common fisheries management goals and objectives; detail information needs stemming from those objectives that can be answered by recreational fishers; suggest areas where increased use or application would more proactively address management objectives; and provide examples of integration of recreational fisher information into the decision-making process. Relevant examples of fisheries management frameworks that require recreational fisher information include the multinational Gulf of Mexico and Caribbean flats fishery; collaborative data collection in United Kingdom sea angling fisheries and Florida Everglades largemouth bass fisheries; co-management of mixed commercial-recreational fisheries in Western Australia; co-operative management of marine fisheries in New Zealand; and co-design of fisheries management plans for UK fisheries.https://library.dpird.wa.gov.au/books/1062/thumbnail.jp
Resource Assessment Report No.6: Western Rock Lobster Resource - 2025 update assessment
No full textExecutive Summary
The western rock lobster (WRL) fishery is considered sustainable with catches being slightly below those associated with the maximum economic yield (MEY) proxy (39% harvest rate), which ensures the large lobster biomass and economical catch rates are maintained. The marine environment continues to be the biggest driver in stock dynamics with post larval recruitment (puerulus) and adult behaviour, including catchability, strongly influenced by oceanic conditions. Recent seasons have seen strong Leeuwin Currents and warm ocean conditions. Over the past few seasons, puerulus settlement levels have been below average at numerous locations and it has been almost 10 years since there was a coast wide above average “spike” in puerulus settlement (2016). The spatial distribution of fishing suggests a possible southward concentration of the lobster stock with the northern end of Zone B potentially showing some signs of reduced productivity. This may be a short-term anomaly or part of a longer-term climate driven progression.
For the 2024/25 fishing season multiple lines of evidence indicate that the WRL resource is at an acceptable level of depletion (LOW risk of unacceptable stock depletion).
This assessment is based on empirical data from the commercial and recreational fisheries, fishery independent surveys and stock assessment models. In summary: Catch and effort data do not indicate a high level of lobster depletion in any region of the fishery. Catch rates remain well above historical levels throughout the fishery. The size composition of lobster measured through multiple surveys does not indicate a high level of lobster depletion in any region. Fishery independent recruitment surveys do indicate a recent period of below average recruitment, but this is most likely associated with unfavourable environmental conditions. Fishery independent surveys indicate that breeding biomass is well above historic levels throughout the fishery. A data moderate (Level 4) fishery wide model estimates that the resource is not over-fished and over-fishing is not occurring. The fine spatial and temporal scale (Level 5) integrated model estimates legal biomass and egg production are well above historic levels and harvest rates are below that used as a proxy for MEY (39%). A continuation of the current TACC (6800 t) will maintain high biomass levels throughout the fishery over the following five fishing seasons
The efficacy of rosemary oil and microencapsulated essential oils on Zeuxapta seriolae mitigation in yellowtail kingfish, Seriola lalandi
No full textTwo additives, rosemary oil and a commercial herbal product (HP; AROTEC-G) containing garlic essential oil, carvacrol and thymol were investigated for their potential to reduce the parasitic burden in yellowtail kingfish (YTK; Seriola lalandi) infected with Zeuxapta seriolae. Naturally infected fish were fed diets supplemented with either 2.5 mL.kg−1 rosemary oil or two concentrations of HP (5 and 10 g.kg−1) for 20 days. At 10 and 20 days, the effect of the diets on parasite abundance was evaluated. Feed intake and growth were similar across treatments (p \u3e 0.05). By day 10, both rosemary oil and HP significantly reduced parasite burden compared to the control (p = 0.03). Praziquantel (PZQ) baths on days 10 and 20 found that the supplements were more effective in reducing new parasite recruitment rather than eliminating adult parasites. The HP product, at both doses, significantly reduced reinfection by day 20. Rosemary oil reduced parasite load by 43% compared to the control by day 20. Liver and kidney function remained unaffected. This study concluded that rosemary oil and blended essential oils can assist in the management of Z. seriolae infection in YTK culture