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Australia’s fisheries research agencies all conduct stock assessments of varying complexities to assess the status of key fish stocks. However, the modelling approaches taken, data analyses that underpins the stock assessments and the level of peer review that is undertaken are variable (Dichmont et al. 2018, Haddon et al. 2018). The Status of Australian Fish Stocks (SAFS; Flood et al. 2016) program has aimed to make the reporting of these assessments consistent among jurisdictions. Additionally, in recognition of the data limited nature of many of the species being assessed in SAFS there has also been work undertaken to train jurisdictional stock assessment staff in data limited stock assessment techniques (Haddon et al. 2019). However, while there are a substantial amount of modelling tools available, most jurisdictions have stock assessment scientists that are model users rather than developers. Consequently, there is a need to provide guidance on how to use these appropriately so as to strengthen the quality of the outputs of the models. Developing guidance (defined as help and advice about how to do something or about how to deal with problems) is important and a set of stock assessment guidelines that describes each method currently used in Australia, outlines the method, required biological and fishery data, levels of uncertainty, and pros and cons is an important facet to demonstrating best practice in management of Australia’s fisheries. The guidance will provide transparency in the modelling process and has the potential to remove or moderate controversy regarding modelling outputs and the resulting management implications. This guidance (hereafter guidelines) are not intended to be prescriptive but provide guidance on a suite of methods from full-blown bioeconomic models and integrated assessments (e.g., SS3) through to data-poor approaches such as catchMSY.

Objectives

1. Develop a set of stock assessment guidelines to assist stock assessment processes being undertaken by all jurisdictions.

2. Evaluate the need for a national stock assessment working group to provide updates to the guidelines (for example as new modelling approaches are developed) and to address ongoing jurisdictional stock assessment issues.

Basement Jacks - Where's your stock at? Understanding stock structure and connectivity of Mangrove Jack in northern Australia

Project number: 2021-017

Project Status:

Current

Budget expenditure: $250,000.00

Principal Investigator: Grant J. Johnson

Organisation: Department of Agriculture and Fisheries (NT)

Project start/end date: 15 Jan 2023 - 29 May 2026

Contact:

FRDC

TAGS

SPECIES

Need

Mangrove Jack (Lutjanus argentimaculatus) are a long lived (>50 years), late maturing (~6 to 10 years) species that can grow to a large size (>1 metre). Their typical distribution in Australian waters extends from Perth, around the north of the continent to Sydney. Mangrove Jack spend several years as juveniles in freshwater and estuarine habitats before migrating to deeper, offshore waters as they near sexual maturity.

Mangrove Jack are popular amongst all fishing sectors; their aggressive feeding and tendency to aggregate (as both juveniles and adults) also makes them vulnerable to overfishing. Juvenile Mangrove Jack are primarily (but not exclusively) caught by Indigenous fishers, recreational fishers and charter boat clients around estuaries and inshore reefs, whereas adults are caught (occasionally in significant quantities) by offshore trawl operations to the west of Cape York.

The sustainability of Mangrove Jack is assessed under the national Status of Australian Fish Stocks (SAFS) reporting framework, which relies on an understanding of the stock structure of each focal species. Previous genetic analyses using mitochondrial and microsatellite markers suggest that Mangrove Jack form a single homogeneous stock in Australian waters. However, these analytical tools often lack the resolution necessary to detect fine-scale stock structure in larval dispersing fishes. This in turn compromises current stock assessment approaches for Mangrove Jack (undertaken at the jurisdictional or management unit level) as there may be a spatial mismatch between the area of the assessment unit/s and the true stock structure of this species; a situation confounded by a limited understanding of the dynamics of ontogenetic migration/connectivity in Mangrove Jack.

This being the case, there is a pressing need to examine the population structure and connectivity of Mangrove Jack across its Australian range. This will be achieved through a combination of cutting-edge genetic methods (i.e. single nucleotide polymorphisms), otolith micro-chemistry and parasite analyses, in order to address the national FRDC priority “Resolving stock uncertainty for priority species (including Mangrove Jack)”.

Objectives

1. Determine the stock structure of Mangrove Jack across northern Australia

2. Describe the level of inshore/offshore connectivity of Mangrove Jack between Carnarvon and Cape York (encompassing areas prospected by demersal trawl fisheries)

3. Increase stakeholder participation in fisheries research

4. Improve community awareness of fishery management practices

PROJECT NUMBER • 2018-115

PROJECT STATUS:

COMPLETED

National tropical oyster aquaculture workshop - Darwin 2018

The first national workshop on tropical oyster aquaculture was held in Darwin on 22 to 23 October, 2018 at the Waterfront Campus of Charles Darwin University (CDU). The workshop brought together representatives from Aboriginal communities, industry, government agencies, and Australian and...

ORGANISATION:

Department of Agriculture and Fisheries (NT)

TAGS

SPECIES

PROJECT NUMBER • 2018-005

PROJECT STATUS: