3 results

Development of "guidance" for conducting stock assessments in Australia

Project number: 2021-077
Project Status:
Current
Budget expenditure: $97,000.00
Principal Investigator: Thor Saunders
Organisation: Department of Agriculture and Fisheries (NT)
Project start/end date: 31 Dec 2021 - 29 Jun 2023
Contact:
FRDC

Need

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

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

Where should I farm my oysters? Does natural Cadmium distribution restrict oyster farm site selection in the Northern Territory?

Project number: 2018-005
Project Status:
Current
Budget expenditure: $123,272.00
Principal Investigator: Matthew Osborne
Organisation: Department of Agriculture and Fisheries (NT)
Project start/end date: 10 Feb 2019 - 29 Sep 2022
Contact:
FRDC
SPECIES

Need

RD&E that addresses critical hurdles to Aboriginal capacity and enterprise development (e.g. quality assurance strategies) have been identified as priority areas of the NT RAC and the Indigenous Reference Group (IRG). NT Fisheries has been conducting research to support Aboriginal aspirations to establish tropical oyster farms in the Northern Territory (NT).

Heavy metals have been a longstanding concern as an impediment to the development of a tropical oyster industry. Cadmium (Cd) bioaccumulates in the tissue of oysters, and unlike E. coli or toxic algae, has a long depuration period. As a result Cd levels are a major determining factor on the saleability of farmed tropical oysters. McConchie, D.M & Lawrance, L.M (1991) and FRDC Project 2012-223 identified high Cd concentrations, which varied considerably across locations and water depth, in blacklip oysters (Saccostrea echinata) at location in Shark Bay, WA and South Goulburn Island, NT respectively. Following these projects naturally occurring heavy metals have been a presumed barrier to the establishment of an oyster industry in the NT, due predominantly to the exceedance of Cd trigger levels in the Food Standards Australia and New Zealand (FSANZ).

However, recent testing on market sized oysters farmed on long line trials at Pirlangimpi on Tiwi Islands have not shown high heavy metal concentrations and complied with the FSANZ. This suggests that Cd exceedance may not be an issue in all locations. We propose a multi-location survey of blacklip oyster (Saccostrea echinata) heavy metal concentrations across the NT to identify the best locations for commercialisation of this emerging aquaculture species. With the aim of identifying locations, like Pirlangimpi, that could produce oysters that comply with the Food Standards Australia and New Zealand (FSANZ). The results are needed to inform the development of a NT tropical oyster industry and the establishment of a NT shellfish quality assurance program.

Objectives

1. Map the distribution and concentration of Cadmium in wild blacklip oysters across the Northern Territory.
2. Aboriginal communities better understand the role of shellfish quality assurance programs and the implications of Cadmium on oyster farming.
3. Risks associated with Cadmium are better understood and inform the development of a NT Shellfish Quality Assurance Program.
4. Knowledge is shared and retained through Aboriginal participation in the research project.
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