Project number: 2019-010
Project Status:
Completed
Budget expenditure: $189,065.00
Principal Investigator: Karen Evans
Organisation: CSIRO Oceans and Atmosphere Hobart
Project start/end date: 16 Feb 2020 - 16 Aug 2021
Contact:
FRDC

Need

Much effort has been placed over the last couple of decades on the development of harvest strategies, stock assessments, risk assessments and the strategic use of ecosystem models to facilitate meeting the needs of the Commonwealth’s Harvest Strategy Policy. A focus on modelling to improve fisheries management has required effort towards method development. However, little effort has been made towards revisiting and updating the biological parameters that fundamentally underpin such modelling (e.g. growth rates, age and size at maturity, natural mortality rates, dietary information, mixing rates and stock structure) and the tools or methods used to derive them. As a result, most models now rely on parameters and community dietary data derived from information collected during the 1970s-1990s, (e.g. available maturity ogives for blue-eye trevalla are over 20 years old), or information that is borrowed from other regions or species. Whether such old or borrowed values are now representative for commercial Australian fish species is unknown but many factors point to major changes occurring in our marine environment. Australian waters in the south east and south west are climate hotspots and, overall, Australian waters have warmed faster than the global average. Key components of the productivity of marine fish (growth, maturity, and recruitment) are expected to be undergoing directional changes under a changing climate and it is entirely possible that there have been changes in fundamental productivity parameters for some Australian stocks. The reliance of current assessments on what is likely to be out-of-date information leads to increased uncertainty, which propagates into management decisions. Without an understanding of any changes in biological parameters and how any change might impact assessment frameworks, determining whether current management measures are ensuring sustainability becomes highly uncertain.

Objectives

1. Identify the origin of current biological information used in assessments of species (including empirical stock assessments and ecosystem modelling efforts) carried out under the Commonwealth Harvest Strategy Policy, including the pedigree of the information (provenance, age, appropriateness of methods used).
2. Assess the implications and risks associated with using dated and borrowed information in assessments currently used for informing fisheries management, including the scale of any risks and the species for which a change in biological parameters used in assessments has the greatest impact.
3. Identify the methods that might be applied to update priority biological parameters, including a review of the efficacy and applicability of novel methods and approaches developed in recent years.
4. Articulate a work plan including appropriate sampling regimes required for updating priority biological parameters used in assessments for those species identified as being at most at risk.

Final report

Authors: Karen Evans Elizabeth A. Fulton Cathy Bulman Jemery Day Sharon Appleyard Jessica Farley Ashley Williams Shijie Zhou
Final Report • 2023-01-12 • 4.62 MB
2019-010-DLD.pdf

Summary

The project re-assesses key biological parameters for south-eastern Australian fish stock.

Project products

Fact Sheet • 2023-01-12 • 163.65 KB
2019-010 biological parameters table.xlsx

Summary

Table of biological parameters accompanying the final report for project 2019-010