2 results

Strategic Planning Workshop for Yellowtail Kingfish Stock Assessment in South-Eastern Australia

Project number: 2019-103
Project Status:
Completed
Budget expenditure: $11,328.74
Principal Investigator: John Stewart
Organisation: Department of Primary Industries and Regional Development (NSW)
Project start/end date: 14 Jan 2020 - 31 Jul 2020
Contact:
FRDC

Need

Yellowtail Kingfish is a high priority species for recreational fishers and the basis of an important commercial fishery in NSW. The biological stock structure is reasonably well understood, with genetic analyses showing that the population in Western Australia is genetically distinct from the population along the eastern and southern Australian coasts (Commonwealth, Queensland, New South Wales, Victorian, Tasmanian and South Australian waters) and New Zealand. Tagging studies have confirmed movements between Australia and New Zealand and South Australia to NSW. Therefore Yellowtail Kingfish are assessed through the Status of Australian Fish Stocks (SAFS) initiative at the biological stock level, being two stocks - Eastern Australia and Western Australia.

The most recent (2018) SAFS assessment for the Eastern Australian biological stock of Yellowtail Kingfish was ‘Undefined’, due mainly to knowledge gaps around the degree of mixing throughout this stock which spans more than 3,000 km of coastline. Reasonable data for assessment exists only within NSW, and uncertainty around whether an assessment of that component of the stock reflected the entire stock resulted in an ‘Undefined’ status, with a recommendation that this uncertainty be resolved.

Yellowtail Kingfish within NSW has been assessed as ‘Growth Overfished’ (2003/04 to 2013/14), and current evidence indicates a Depleted stock. There are ongoing discussions within NSW about appropriate management changes that may assist recovery; however these are hampered by the ‘Undefined’ status in SAFS.

The FRDC National Priority 1 aims to reduce the percentage of ‘Undefined’ stocks within SAFS, which also has an objective of providing a roadmap to recovery for ‘Depleted’ stocks. To address both of these and to promote better and more collaborative monitoring, assessment and management across all relevant jurisdictions, there is a clear need to review existing knowledge across the entire stock and to identify areas of uncertainty that require addressing.

Objectives

1. Review the available data and management regimes for the south-eastern Australian stock of Yellowtail Kingfish from each relevant jurisdiction
2. Review the reasons for the ‘Undefined’ status in SAFS
3. Discuss appropriate spatial scales for assessment and management across the south-eastern Australian biological stock
4. Identify knowledge gaps required to be filled in order to produce a defined stock status for SAFS
5. Discuss cross-jurisdictional assessment and management options for Yellowtail Kingfish

Final report

ISBN: 978-1-76058-450-4
Authors: John Stewart Julian Hughes Holly Gunton
Final Report • 2021-06-30 • 895.32 KB
2019-103-DLD.pdf

Summary

The project facilitated cross-jurisdictional and cross-sectoral discussions on aspects of the Eastern Australia biological stock of Yellowtail Kingfish.  Several knowledge gaps relating to biological and life-history parameters, as well as reliable data on the recreational fishery across all jurisdictions, were found to be inhibiting assessment, and therefore management, of this stock.  Knowledge gaps common across jurisdictions included understanding patterns of movement and connectivity throughout the stock, and reproductive patterns such as main spawning areas and times.  It was noted that this lack of information was one reason for differing management arrangements (minimum legal lengths and bag limits) between jurisdictions.  A survey of long-term, highly experienced commercial, recreational and charter fishers in NSW was done to provide feedback on data to be used in assessing stock status.  Comments from these knowledgeable fishers resulted in several reconstructed catch history scenarios being used in the assessment, in addition to gathering observations on long-term changes to the fishery.  As a result significant progress was made on the Status of Australian Fish Stocks (SAFS) assessment for 2020.  The Eastern Australian stock of Yellowtail Kingfish for 2020 was classified as a ‘Sustainable’ stock, noting that until knowledge around population dynamics, in particular the distribution and movements of the spawning stock and the source of juveniles, is improved that the assessment will remain highly uncertain.

Informing adaptive management of portunid fisheries in New South Wales

Project number: 2017-006
Project Status:
Completed
Budget expenditure: $699,999.69
Principal Investigator: Matt D. Taylor
Organisation: Department of Primary Industries and Regional Development (NSW)
Project start/end date: 16 May 2018 - 15 Jun 2022
Contact:
FRDC

Need

The spawning dynamics and early life history are largely unknown for BSC and GMC in NSW, as are spawning areas, sources and sinks, important juvenile nurseries, and the effect of environmental variability on both spawning and recruitment. While this has led to some limitations to management and uncertainty in the past, NSW have recently launched two major management initiatives for the species for which this information is essential: 1) management of commercial BSC and GMC harvest through share-linked catch quota; and 2) fisheries enhancement for BSC and GMC.

In 2017, the Commercial Fisheries Adjustment Program has seen the NSW Government subsidise the investments of many fishing businesses to access catch quota for BSC and GMC. Quota allocation depends on scientifically-based assessment of Total Allowable Catch (TAC). At present the only source of information on which to base TAC is historic catch and effort, but these are highly variable and the mechanistic factors underlying this variation are unclear. The recent NSW Marine Stocking Fishery Management Strategy outlines the development of release programs for both BSC and GMC. Effective implementation of this strategy relies on a thorough knowledge of the requirements of young crabs and the factors affecting their recruitment such that recruitment limitation can be identified and releases targeted to address it (see Taylor, 2017). Through a review of existing work on these species in other states, and consultation with managers and industry, we have identified targeted research questions that will directly enhance the capacity of NSW DPI-Fisheries to design and implement effective harvest management, fishery enhancement and restoration programs for BSC and GMC. The need for this information is especially evident in the attached letters of support from commercial and recreational stakeholders, and the contribution of $250K cash from the NSW Recreational Fishing Saltwater Trust.

Objectives

1. Describe temporal and spatial patterns in settlement and juvenile habitat use, to determine if spawning, nursery habitat availability, or connectivity creates localised recruitment bottlenecks in NSW estuaries
2. Define and model links between environmental (physicochemical and oceanographic) variables and these patterns, and potential effects on catch rates
3. Use this information to develop an independent measure of recruitment, which links the effects of environmental variability on recruitment to future catch quotas
4. Interpret patterns in recruitment limitation to target a large-scale release of BSC, and analyse post-release abundance patterns to better understand recruitment bottlenecks and improve modelled relationships
Final Report • 23.63 MB
2017-006-DLD.pdf

Summary

This report describes new research by the NSW Department of Primary Industries and the University of NSW into Blue Swimmer Crab and Giant Mud Crab in south-eastern Australia. Over 3 years, data was collected through extensive field sampling and modelled alongside environmental and oceanographic variables to examine how crab populations respond to environmental variability, with a focus on their abundance, distribution and reproduction. Findings were then compiled to test whether the new knowledge could aid in predicting some of the variability observed in fisheries harvest for portunid species. The patterns resolved will aid future stock assessments, and inform management (including regulation, quota setting, and fisheries enhancement) of portunid fisheries in south-eastern Australia into the future.
View Filter

Organisation