The population dynamics and fishable biomass of Snapper in South Australia are fundamentally driven by high inter-annual variation in recruitment, i.e. the numbers of 0+ juveniles that recruit to populations. Throughout the 2000s, SA’s Snapper stocks experienced different trends in recruitment that led to extraordinarily different trends in fishery catches. For the Spencer Gulf/West Coast Stock successive poor year classes led to the significant decline in fishable biomass, and a ‘depleted’ stock status. In contrast, the Gulf St. Vincent Stock increased to unprecedented levels due to numerous strong recruitment year classes, but since 2015 has also experienced considerable declines in fishery catches. In 2019 it was classified as ‘depleting’. From 2018, concerns about both stocks prompted a comprehensive review of the fishery management approach. This resulted in significant changes to the management strategy including a spatial and long-term fishery closure. Despite this, there remains the need to monitor the stocks and demographic processes. Given the significance of variable recruitment for Snapper, the need for regional, annual estimates of recruitment as an indicator of future trends in fishable biomass has re-emerged. Between 2000 and 2010, recruitment surveys were done in Northern Spencer Gulf, for which the sampling methodology, i.e. otter trawling, was non-selective and destructive of benthic and demersal biota. One need here is to develop a cost-effective, non-destructive sampling strategy for future annual sampling. Also, there is the need to develop a better understanding of larval ecology, connectivity, and the causes of variable recruitment. Combined benefits from addressing both needs would significantly enhance predicting future trends in fishable biomass.
Project number:
2019-046
Project Status:
Current
Budget expenditure:
$541,804.00
Principal Investigator:
Troy Rogers
Organisation:
University of Adelaide
Project start/end date:
19 Jan 2020
-
30 Dec 2022
Contact:
FRDC
SPECIES
1. To develop our understanding of the processes that regulate recruitment based on finalising datasets from previous research projects that relate to the early life history, and larval and juvenile ecology of Snapper, as well as the annual variation in environmental factors
2. To undertake an empirical study to compare the utility and effectiveness of several potential sampling methodologies to provide a relative recruitment index for Snapper and to develop a sampling strategy for future surveys
3. To apply the sampling strategy as developed in Objective 2 in the following two years, to provide relative estimates of the recruitment rates for Snapper in NSG and NGSV
PROJECT NUMBER
•
2023-085
PROJECT STATUS:
CURRENT
Snapper Science Program: Theme 1 - Biology and Ecology
1. Quantify the abundance of age 0+ Snapper in northern Spencer Gulf and Gulf St Vincent to provide relative estimates of recruitment for 2024, 2025, and 2026. Examine the otoliths of these fish to improve the understanding of early life history processes.
ORGANISATION:
Flinders University
PROJECT NUMBER
•
2023-072
PROJECT STATUS:
CURRENT
Educational travel trip for Ocean Trap and Line industry development to explore alternative fishing practices which help prevent TEP species interactions and ghost fishing
1. Enable Australian fishing industry representatives to attend the 2023 Ropeless Consortium conference in Halifax, Nova Scotia (and industry meetings)
ORGANISATION:
OceanWatch Australia Ltd
PROJECT NUMBER
•
2019-129
PROJECT STATUS:
CURRENT
Potential transition of shark gillnet boats to longline fishing in Bass Strait - ecological, cross-sectoral, and economic implications
1. Conduct a trial using automatic longlines to target gummy shark in SESSF waters in Eastern and Western Bass Strait
ORGANISATION:
Fishwell Consulting Pty Ltd