Project number: 2015-018
Project Status:
Completed
Budget expenditure: $498,941.00
Principal Investigator: Anthony J. Fowler
Organisation: SARDI Food Safety and Innovation
Project start/end date: 30 Jun 2015 - 29 Jun 2018
Contact:
FRDC

Need

Managing South Australia’s (SA) regional fisheries for southern garfish remains challenging and topical. For numerous decades the populations in the northern gulfs have sustained the most significant fisheries for this species. Furthermore, these fisheries have sustained extremely high levels of exploitation, which has resulted in the truncation of populations to a few age classes. This over-exploitation has been addressed through a ‘stock-recovery’ harvest strategy implemented in 2012 that is ultimately aimed at reducing the exploitation rate from 69% to 30% by 2020. However, the current assessments of the regional fisheries are based almost entirely on data from the commercial hauling net sector. Yet, the fished populations, i.e. those occupying inshore waters of

Information on the relative abundance, population size and age structures and reproductive potential of southern garfish in unfished areas is needed to assess the status of SA's garfish stocks and to evaluate the suitability of indicators based on commercial fishery data for stock assessment. This information is also needed to understand the remarkable resilience of southern garfish to prolonged high fishing pressure.

Objectives

1. To compare the size and age structures, relative abundances and potential for egg production of southern garfish between fished and unfished areas of Spencer Gulf, South Australia
2. To determine patterns of relative abundance, sizes and ages of larval southern garfish throughout Spencer Gulf, South Australia
3. To evaluate the suitability of commercial fishery data for assessing the status of southern garfish fisheries in South Australia

Final report

ISBN: 978-1-876007-19-5
Author: Anthony J. Fowler
Final Report • 2020-02-26 • 4.18 MB
2015-018-DLD.pdf

Summary

During the early 2000s, stock assessments highlighted considerable issues with the status of South Australia’s stocks of Southern Garfish (Hyporhamphus melanochir).  This led to significant management changes that were implemented in 2005, which included the introduction of new extensive spatial closures for hauling net fishing.  These closures effectively restricted the use of hauling nets to the northern parts of Spencer Gulf (SG) and Gulf St. Vincent (GSV).  These spatially-restricted, hauling net fisheries now account for most of the commercial catch of this species.  Stock assessments for Southern Garfish are currently done at the regional scale.  For Northern SG and Northern GSV these assessments are data rich, but nevertheless the data come from limited areas where hauling net fishing is permitted.  There is considerable uncertainty about the extent to which the stock status that is primarily determined from such limited areas applies generally to the regional fisheries.  Furthermore, there is also concern about the extent to which stock status for the fisheries in the southern gulfs are adequately represented by the limited data from the commercial fisheries they support.  This project that was undertaken by SARDI from 2016 to 2019, provided population information on Southern Garfish for throughout GSV, to assess the extent to which spatially-restricted, fishery-dependent data from the northern gulf and patchy data from the southern gulf were indicative of the status of the northern and southern regional fisheries.  This information will also be used to inform a reassessment of the spatial scale at which stock assessments for Southern Garfish are currently done.

Related research

Environment
Environment
Environment