University of Tasmania
ICES J606 Ward.ppt (6.73 MB)

Use of egg production methods in Australia's Pelagic Fisheries

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conference contribution
posted on 2023-12-15, 00:34 authored by Timothy WardTimothy Ward, Gretchen Grammer, Alex Ivey, Jon Smart

Biomass estimates of small pelagic fishes are highly uncertain; estimates of statistical precision only capture a portion of total uncertainty. Although the Daily Egg Production Method provides imprecise estimates of spawning biomass, it has been used to underpin the successful development of Australia’s largest fishery, the South Australian Sardine Fishery (SASF).  The DEPM has also been adopted as the primary assessment tool in the Commonwealth Small Pelagic Fishery (SPF), and its potential application is being trialled in several other Australian fisheries. The DEPM has been adopted in these fisheries because stock assessments based on fishery-dependent data have not provided reliable estimates of biomass or recruitment (due to data limitations and/or violation of model assumptions). Ecological and logistical factors have also prevented the application of other fishery-independent methods, such as acoustic surveys.  This presentation documents how the inherent imprecision of the DEPM has been addressed in the SASF. Two elements of the adaptive approach that we have used to assess and manage the fishery have been critical to its success.  Firstly, we have used statistical approaches that minimise imprecision and provide conservative estimates of spawning biomass. Secondly, the harvest strategies (control rules) we have established have been conservative and designed to address the imprecision of the DEPM. This presentation discusses potential opportunities for 1) further increasing the precision of estimates of spawning biomass (e.g. through improved sampling methods) and 2) using other (more reliable?) products from DEPM surveys, such as spawning area, as the key performance indicator in future harvest strategies. 


Publication title

ASC Extended Abstracts 2015 - ISBN: 978-87-7482-165-6


Sustainable Marine Research Collaboration



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ICES Annual Science Conference 2018

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ICES Annual Science Conference 2018, Hamburg, Germany

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    Institute for Marine and Antarctic Studies


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