Impacts of water development in the Gulf of Carpentaria 2018-079
Using an ecosystem modelling approach, this study quantified the impacts and risks of water resource developments (anthropogenic alteration of freshwater discharge) to the Gulf of Carpentaria ecosystem. Key model targets included Banana Prawns (Penaeus merguiensis), Barramundi (Lates calcarifer), mud crabs (Scylla spp.) and Largetooth Sawfish (Pristis pristis), as well as mangrove and seagrass habitats.
The research provided some considerations and recommendations with respect to water resource development implementation. In particular, it provided helpful guidelines on the time of flow, the quantity of water allocated for extraction or impoundment, the number of water resource developments and their types and settings. The work also identified existing knowledge gaps and discussed how differences in catchments and the effect of climate change need to be taken into account. One important knowledge gap that this study did not consider was wider ecosystem components and secondary impacts from water resource developments, such as increased sediment load.
More information: Eva Plaganyi-Lloyd eva.plaganyi-lloyd@csiro.au
Accurate toxin testing for WA molluscs 2018-107
The lack of accurate toxin tests for bivalve molluscs in Western Australia has caused significant economic losses to the sector due to precautionary closures that could have been avoided by using more sensitive tests. This project identified a reliable toxin test that can be safely used to analyse mollusc flesh and provide accurate information to inform management decisions.
Bivalve molluscs for human consumption in WA are regularly tested for the presence of phytoplankton species that potentially produce marine biotoxins and for the marine biotoxins themselves.
Some Pseudo-nitzschia species are producers of the toxic domoic acid (DA), but not all strains of Pseudo-nitzschia produce toxins. Previously, the detection of this phytoplankton has triggered sector closures regardless of the presence or absence of DA in the molluscs.
These extensive closures were the catalyst for this study, which found a test that can detect DA in shellfish flesh and therefore ensure that closures only occur when a health risk is present.
More information: Stuart Helleren stuart.helleren@dalconenviromental.com.au
Reporting on bycatch 2018-114
Bycatch (non-target species or sizes caught while fishing) remains an important issue concerning the world’s fisheries. There is growing acceptance and international, national and regional agreements and instruments that encourage and/or require governments
to report on the status of bycatch.
This project, and its precursor ‘Developing a National Bycatch Reporting System’ (FRDC Project 2015-208), constitutes Australia’s first national attempt to report
on bycatch from its commercial fisheries.
It is the result of the application of a five-step method developed in the first project.
The latest project has yielded: (i) a baseline to be used by Australia to track performance in managing discards, endangered, threatened and protected species (ETPs) interactions and the quality of its bycatch information; (ii) the identification of key information gaps where future work to monitor and reduce discards should focus; (iii) a method that may be used by other countries and jurisdictions to estimate and report on bycatch to various entities and processes, including the general public.
More information: Steve Kennelly steve.kennelly@icic.net.au
Impact of stocking on Queensland’s east coast Barramundi catch 2018-047
Researchers from Queensland’s Department of Agriculture and Fisheries, James Cook University and the University of Western Australia tested a range of otolith-based and genetic methods to differentiate between hatchery-born and wild-born Barramundi (Lates calcarifer). The project took place in the Dry Tropics region, where extensive historical and ongoing impoundment stocking (release of hatchery-born Barramundi into freshwater bodies) may be contributing to the downstream wildcatch marine and estuarine fishery.
Fish samples were collected from the commercial and recreational wildcatch marine and estuarine fishery in 2019 and 2020, following the major Townsville floods in February 2019. The team identified a cost-effective means of using trace elements in fish otoliths to reliably differentiate between hatchery-origin and wild-origin fish, measure the contribution of stocked fish to the wild population, and assess the sustainability of the wildcatch fishery. The report found that Barramundi that spend time in freshwater as juveniles grow faster and larger than those that spend their entire lives in salt water. It found that 33 per cent of the Barramundi caught in the Townsville and Burdekin marine fishery had spent at least one year in fresh water as juveniles.
More information: Susannah Leahy susannah.leahy@daf.qld.gov.au
See also: frdc.com.au/barramundi-benefit-gap-year-fresh-water
Monitoring recreational catch of Southern Rock Lobsters 2019-183
Southern Rock Lobster (Jasus edwardsii) is an important fishery species in Tasmania. The commercial sector harvests approximately 1000 tonnes per year to a landed value of approximately $90 million, while more than 18,000 recreational licensees harvested more than 80 tonnes in the 2020–21 season. Lobsters are also taken as part of Indigenous cultural activities and by Indigenous individuals, thought to be more than 1000 participants.
The East Coast Stock Rebuilding Strategy was introduced in 2013 to limit the recreational and commercial catch in this zone. Based on historical usage, 79 per cent of the total zone catch was allocated to the commercial sector and 21 per cent was allocated to the recreational sector.
The catch share arrangement does not apply to the Indigenous sector. Since then, the recreational sector has exceeded its notional limit four times, including an over-catch of 46 per cent in the 2020–21 season.
This project investigated alternative options to monitor and manage recreational catch. It found that effective catch constraints could be achieved by shortening the season, decreasing the bag limit or introducing an individual season limit. A smartphone app for real-time monitoring of individual season limits without the need for other measures, such as catch tags, was developed. The app was trialled in April 2021 by recreational fishers who had previously taken part in a survey, with most finding it easy to use. The app was rolled out on a voluntary basis by Tasmania’s Department of Primary Industries, Parks, Water and Environment (DPIPWE) (now the Department of Natural Resources and Environment Tasmania) for the 2021–22 recreational rock lobster season. This voluntary trial period will help ensure the app meets the objectives of catch monitoring and is practically acceptable to fishers. Findings from this trial, and a literature review of alternative management and monitoring options included in the project, will be used by the department to determine changes to current management arrangements over coming fishing seasons.
More information: Nils Krueck nils.krueck@utas.edu.au
Modelling environmental changes and effects on wild-caught species in Queensland 2019-013
This project studied environmental factors that may be influencing the recruitment, catchability or productivity of Snapper (Chrysophrys auratus), Pearl Perch (Glaucosoma scapulare) and Spanner Crab (Ranina ranina) stocks in Queensland. Two environmental variables (gridded sea level anomaly [GSLA] and chlorophyll a concentration [Chl-a]) were found to have strong associations with either abundance or catchability across the three target species. A third variable, sea surface temperature (SST), also had strong associations with Snapper numbers.
All three environment variables were found to have consistent long-term trends, with rates of change depending on the region under consideration. Using stock assessment modelling, this project demonstrated that these environmental variables significantly influence stock recovery.
More information: Jerzy Filar j.filar@uq.edu.au
The benefits of restoring tidal connectivity 2019-079
This project focused on how restoring tidal connectivity to a portion of the Clarence River estuary (Lake Wooloweyah) can benefit fishery productivity.
Recent legislation has highlighted the importance of ecological restoration via key initiatives, such as the NSW Marine Estate Management Act 2014, Coastal Management Act 2016 and Biodiversity Offsets Scheme, and has resulted in funds for works becoming more readily available (for example, recreational fishing grants and natural infrastructure grants).
Previous research in the Clarence River estuary has demonstrated the substantial economic returns in prawn catches from repairing intertidal habitats. This foundational research demonstrated that the benefits to prawns can serve as an indicator of all ecological benefits, including other target species.
The findings from this work suggest that there is potential for adding significant value to the fisheries by modifying the hydrology of the estuary system. The approach is replicable in most other estuaries where commercial fisheries occur and can be used to inform management of estuarine habitats and therefore fishery productivity.
More information: Troy Gaston troy.gaston@newcastle.edu.au
Trialling automated longlines 2019-129
This project explored the use of automated longlines as an alternative to traditional gillnet fishing for Gummy Shark (Mustelus antarcticus) in the Bass Strait with a view to assessing the economic and ecological ramifications of a fundamental gear change. The investigation also included monitoring of bycatch of species of interest to other commercial fishing sectors and conservation.
Previous research in waters off South Australia has demonstrated the effectiveness of automated longlines in targeting Gummy Shark and reducing interactions with endangered, threatened and protected species (ETPs). However, the ecological and economic implications of changing from gillnets to automated longlines in Bass Strait were unknown.
During the trials, interactions with ETPs were low, with animals incidentally caught or entangled released unharmed. Similarly, despite numerous observations, there were no recorded interactions with seabirds, reflecting the development and application of effective mitigation measures.
An economic analysis based on discounted cash-flow analysis, which forecast revenue and operating cost over a 10-year term, showed that this investment in gear change may be worthwhile for an average operation (fishing more than 50 days per year). However, when analysed for a full-time operation (more than 150 days per year), converting to automated longline is unattractive at catch rates achieved in the trials.
When considering these results, however, it is important to keep in mind that the trials of automated longlines were limited spatially and temporally, and the results should be treated cautiously when extending the findings to broader areas of Bass Strait and to other times of the year. In particular, catches and catch rates of commercial and bycatch species and interactions with ETPs may vary from those observed in the trials.
More information: Ian Knuckey first@fishwell.com.au
Fishing apps in COVID-19 times 2019-213
This project set out to use the Australian Recreational Fishing Foundation (ARFF) Tackle Box mobile application to assess the impact of COVID-19 restrictions on recreational fishing (effort and behaviour) in Queensland.
The data revealed that fishers travelled shorter distances to go fishing in 2020 than in 2019, and there was a drop in interstate fishers followed by a spike when the Queensland border reopened after a lengthy closure.
During 2020, the inability to compete in traditional fishing competitions around Australia accelerated a shift to photo-based online competitions and the development of alternative formats such as Tackle Box, Track My Fish and other apps. App-based fishing competitions have created several new ways to engage recreational fishers in citizen science. They also provide the opportunity to examine demographics in ways not previously possible.
More information: Adam Martin adam@fishies.com.au
Understanding seafood traceability and labelling 2020-093
This project consists of two discussion papers, one on seafood traceability and one on labelling.
The first paper defines traceability; explains why it is important; identifies barriers to adoption; documents laws, standards and guidelines; describes traceability elements, systems and technologies; and suggests recommended actions and associated risks going forward.
The second paper provides an update on the issues, challenges and relevant laws in labelling, as well as suggesting options and risks going forward.
Both papers are living documents and will be reviewed every 12 to 18 months.
More information: Meaghan Dodd meaghan@intuitivefoodsolutions.com.au
Demonstrating Australian Southern Bluefin Tuna sustainability credentials 2021-037
The project established that Southern Bluefin Tuna (Thunnus maccoyii) significantly exceeds the Marine Stewardship Council sustainability criteria required to meet Marine Stewardship Council Principle 1: Sustainable fish stocks. The method used by CSIRO was confirmed by the Commission for the Conservation of Southern Bluefin Tuna Extended Scientific Committee in August 2021 and may be seen as a model to be used by other fisheries facing similar challenges with certification bodies.
This research project is an important step for the Australian Southern Bluefin Tuna fishery being allowed to catch fish for farms. The project directly addressed the point that is seen as the remaining barrier to the fishery achieving Marine Stewardship Council certification.
More information: Brian Jeffriess first@asbtia.com.au
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