Developing stock assessment approaches and management frameworks for enhanced and environmentally driven stocks: an inland fisheries case study

Project number: 2023-040
Project Status:
Current
Budget expenditure: $504,599.00
Principal Investigator: David Crook
Organisation: Department of Primary Industries and Regional Development (NSW)
Project start/end date: 30 Jun 2024 - 13 Dec 2026
Contact:
FRDC

Need

This application addresses NSW, VIC, SA and QLD RAC priority: “Developing stock assessment approaches and management frameworks for enhanced and environmentally driven stocks: an inland fisheries case study”. The activities outlined below have been developed with the aim of improving stock status reporting for inland fish species and achieving tangible progress towards the development of inland fishery stock management strategies (SMSs).

Project activities will be led by members of the core project team (listed below). A technical working group (TWG) consisting of the project team and additional experts from all relevant jurisdictions will be formed to facilitate ongoing input and guidance on project activities. The TWG will meet regularly (e.g., quarterly) throughout the project. Members of the TWG will be invited to participate in workshops and, where appropriate, in the authorship and review of project outputs. The TWG will include experts with strong experience in recreational fishing assessment and Indigenous fishing. In line with the NSW DPI Fisheries First Nations Aboriginal Engagement Strategy, it is envisaged that engagement with the Indigenous sector will move from the “Inform” level of engagement towards “Consultation” and “Collaboration” as the work enters the implementation phase. Engagement with the recreational sector will similarly develop as the outcomes of the project are operationalised.

The term ‘stock management strategy’ is used in this application to describe a transparent and consistent decision-making framework that specifies pre-determined management actions needed to achieve agreed ecological, economic and social/cultural objectives. This terminology (rather than ‘fishery harvest strategy’) has been adopted to align the project objectives with fishery harvest strategy principles (Sloan et al. 2014) whilst recognising that key drivers of inland fishery performance (water management, stock enhancement, climatic conditions, etc.) may not be related to fishing mortality (i.e., harvest).
An important aspect of the project is to identify differences in terminology, improve understanding of inland fisheries management, and to better align the language and principles of stock assessment science within the inland fisheries context, particularly in light of the available high quality fishery independent data. This will require a fundamental consideration of the compatibility of stock assessment approaches with our existing understanding of inland fisheries ecology, as well as progress on incorporating appropriate assessment methods and reference points into fit-for-purpose inland fishery management frameworks.

The project consists of four desktop activities aimed at achieving these goals:
1. Evaluate key drivers of population dynamics in inland fisheries
Information on the importance of fishing mortality relative to other drivers of fish population dynamics (e.g., environmental conditions, stock enhancement) is required to identify management levers that can be used within a framework comprising management and harvest strategies to influence fishery performance. This activity will use a review of the international scientific literature and analyses of existing datasets to identify important drivers of population dynamics for two key species (Murray Cod and Golden Perch) in the MDB, recognising impacts may vary with temporal and spatial scales.

2. Evaluate applicability of alternative stock assessment approaches
A wide range of stock assessment approaches are available to support fisheries management, ranging from simplistic approaches with low data requirements to complex models that require estimation of many input parameters. Fishery stock assessment models have rarely been applied to inland fisheries management in Australia and their utility in this context is currently unresolved. In this activity, we will conduct analyses to test the utility of a variety of stock assessment approaches using the population dynamics drivers identified in Activity 1. Results of the analyses will be used to identify the most promising stock assessment methods and the suitability of these methods will then be comprehensively tested by modelling existing data on Murray Cod and Golden Perch.

3. Contextualise key elements of harvest strategies for inland fisheries
The ‘National Guidelines to Develop Fishery Harvest Strategies’ identifies seven key elements of a fishery harvest strategy. To date, these key elements have been interpreted mainly in the context of harvest strategies for marine and coastal fisheries, where fishing mortality is a major driver of population dynamics. Activity 3 will use the outcomes of a technical workshop to produce a detailed evaluation of the key harvest strategy elements in the context of inland fisheries. Workshop participants will consider a series of questions relating to how each key element might be best operationalised for the development of inland fishery SMSs. This information will be summarised and used as an input to Activity 4.
This activity will be informed by outputs from Activities 1 and 2 allowing the workshop to draw upon relevant insights as appropriate.

4. Guiding principles for SMS development for inland fisheries
Using outputs from Activities 1-3 as a basis, we will produce a stand-alone report that presents guiding principles for SMS development for inland fish species. This report will serve as a companion document to the revised National Guidelines to Develop Fishery Harvest Strategies (FRDC 2021-135), providing a more detailed consideration of the specific issues relating to SMS development for inland species.

Objectives

1. Evaluate key drivers of inland fisheries performance and identify related management levers
2. Identify and test stock assessment methods for application in inland fisheries SMSs
3. Guiding principles for inland fishery SMS development available for use by fisheries managers and other stakeholders.
4. Produce a stand-alone report on guiding principles for inland fishery SMS development

Related research

Environment
Industry
PROJECT NUMBER • 2022-049
PROJECT STATUS:
CURRENT

Optimising the nutrition of farmed Murray Cod

1. Determine a baseline for the most optimal macronutrient levels (principally protein and lipid) for medium and large Murray cod in extruded diets.
ORGANISATION:
Deakin University Geelong Waurn Ponds Campus
Environment

Field based trials and risk assessment of new species to enhance the value of tropical and subtropical impoundment fisheries

Project number: 2022-155
Project Status:
Current
Budget expenditure: $910,505.00
Principal Investigator: Michael Hutchison
Organisation: Department of Agriculture and Fisheries Bribie Island
Project start/end date: 30 Sep 2023 - 29 Jun 2027
Contact:
FRDC

Need

This project offers a significant opportunity to enhance tropical and sub-tropical impoundment fisheries in Queensland and other parts of northern Australia, by using new iconic species to diversify the fisheries and attract new anglers to stocked waterways. Accessibility to large pelagic gamefish is not easy for many anglers. Creating access to trevally in impoundments will make such species more accessible to anglers, potentially reduce the pressure on the wild fishery, and offer a unique freshwater impoundment fishing experience in a protected setting. Since trevally will not breed in impoundments, their abundance can be readily managed through stocking rates.

Access to trevally in impoundments is something that anglers want. In 2006, Queensland stocking groups voted trevally as one of the top three ranked new species for development of impoundment fisheries. Published papers indicate trevally are relatively easy to produce, with production methods like those for Barramundi. The other two highly ranked species, Jungle Perch and Mangrove Jack have proved more difficult to produce in large numbers compared to trevallies, and more than 20 years of trying to develop impoundment Mangrove Jack fisheries has achieved only limited success.

Giant and Bigeye Trevally are iconic sportfish, which if stocked, have potential to increase regional tourism. Local governments have already recognised the value of angling tourism in their regions. For example, Rockhampton, Mackay and Cairns Regional Councils have all developed recreational fishing strategies to boost tourist visitation. Townsville City Council is also in the process of opening the Ross River Dam to stocking to develop angling opportunities and attract additional tourists. Trevally will offer an opportunity to create sustained angling tourism to value-add to existing fisheries in the post-pandemic period.

The only way to determine if one or both trevally species can translate into successful impoundment fisheries compatible with existing Barramundi fisheries, is to conduct comprehensive stocking trials using fingerlings and sub-adult fish. The two highest risk factors identified for trevally stocking in large near coastal impoundments are their potential to impact on prey abundance (and therefore carrying capacity) and rare and threatened species. Rare and threatened species are unlikely to be in the impounded waters dominated by Barramundi, but they could exist in impoundment tributary streams. Therefore, knowledge on whether trevally will mostly remain in the impounded waters or will tend to run upstream into tributaries is critical.

This project aims to use stocking trials to evaluate potential stocking risk factors for Bigeye and Giant Trevally, such as relative survival, growth, diet, residency, impacts on prey abundance and rare and threatened species, catchability by anglers at conservative stocking rates, and angler attitudes to and perceptions of the fishery. This project will serve as a useful case study for other diversification options in northern Australia and elsewhere. Without these trials it would be impossible to progress euryhaline trevally species as new fisheries for large, near-coastal impoundments in Australia. This project directly meets the QRAC priority of field-based trials and risk assessment of new species to enhance the value of tropical and sub-tropical impoundment fisheries.

Objectives

1. Formalise a desk top risk assessment for stocking of Bigeye Trevally and Giant Trevally in tropical and sub-tropical impoundments.
2. Produce Bigeye and Giant Trevally fingerlings for stocking trials
3. Assess the capacity for prey species in a Barramundi dominated impoundment to support conservatively stocked numbers of Bigeye Trevally and Giant Trevally
4. Assess the potential for Bigeye Trevally and Giant Trevally to enter impoundment tributary streams where they could impact on rare and threatened species.
5. Assess relative survival, growth and diets of Bigeye Trevally and Giant Trevally in a Barramundi dominated impoundment.
6. Assess angler attitudes to trevally in Barramundi impoundments
7. Assess angler catch of Bigeye and Giant trevally in an impoundment.
8. Extend trevally fingerling production techniques to hatcheries in Queensland and other parts of northern Australia.