Giant Crabs are a long, lived, slow reproducing xanthoid crab distributed from southern Western Australia to central New South Wales that are considered to be a single stock across southern Australia.

The giant crab fishery (GCF) across southern Australia has a small tonnage of large, individually valuable animals. Despite the implementation of harvest strategies and management plans guiding the setting of conservative TACC’s, declining trends are evident across the shared Southern Australian resource.

The fishery has had ongoing problems collecting quality stock assessment data, leading to uncertainty in the assessment and management. Owing to the size of the fishery, and the remote nature of the fishing operations, assessments now rely on fisher dependant catch rate data with an inherent high level of volatility due to the small number of operators.

Attempts to improve the collection of fishery data over the years have been challenging, in particular for fisher-based collection of length-frequency data from volunteer measuring programs.

Innovative data collection methods for small scale fisheries such as the GCF are required to improve the monitoring of stock status of this important commercial fishery and enhance long-term sustainability of the Giant Crab resource.

A length based model has previously been developed and was designed to integrate assessments across the jurisdictions. The model for giant crab and was being used for South Australia and Tasmania but was not applied to Victoria due to data limitations. In recent years the modelling has discontinued in SA and Tas because of insufficient length frequency data, which compounded uncertainty present due to weak growth data. The lack of length data in previous years was the critical change that has forced the model to be discontinued.
So our ability to understand changes in the stock has become weakest at precisely the period in the history of the fishery when information is most needed. This project is designed specifically in response to this need to address the lack of data through development of an efficient method to collect LF information, with minimal burden on fishers to improve accuracy of stock assessments.

In finfish aquaculture, the most broadly useful antimicrobial is oxytetracycline (OTC). The aquaculture industry and the Subcommittee for Aquatic Animal Health have outlined that access to this product for non-salmonid finfish is a priority. Bacterial diseases are increasingly managed by eradication, maintenance of animals of specified health status, vaccination, and good hygiene, but antimicrobial therapy remains vital for treating bacterial diseases in finfish aquaculture. Appropriate use of antimicrobials cures sick animals and speeds recovery, improving welfare and reducing the spread of infection. Use of OTC is not intended for prophylactic treatment, but to manage disease outbreaks. Use in South Australia, for example, is sporadic (~1 to 2 times per year for a sector). The Aquaculture industry is committed to Australia’s antimicrobial strategy, and as required by APVMA this proposal includes an antimicrobial resistance risk assessment. Available data for OTC can satisfy the APVMA module requirements for efficacy, chemistry and manufacture, toxicology, trade and occupational health and safety. These are available in published literature, a range of industry studies of animals treated off-label and laboratory studies. There is a lack of data to satisfy the requirements mainly in the environment modules and the antimicrobial resistance risk assessment.

Yellowtail Kingfish is a high priority species for recreational fishers and the basis of an important commercial fishery in NSW. The biological stock structure is reasonably well understood, with genetic analyses showing that the population in Western Australia is genetically distinct from the population along the eastern and southern Australian coasts (Commonwealth, Queensland, New South Wales, Victorian, Tasmanian and South Australian waters) and New Zealand. Tagging studies have confirmed movements between Australia and New Zealand and South Australia to NSW. Therefore Yellowtail Kingfish are assessed through the Status of Australian Fish Stocks (SAFS) initiative at the biological stock level, being two stocks - Eastern Australia and Western Australia.

The most recent (2018) SAFS assessment for the Eastern Australian biological stock of Yellowtail Kingfish was ‘Undefined’, due mainly to knowledge gaps around the degree of mixing throughout this stock which spans more than 3,000 km of coastline. Reasonable data for assessment exists only within NSW, and uncertainty around whether an assessment of that component of the stock reflected the entire stock resulted in an ‘Undefined’ status, with a recommendation that this uncertainty be resolved.

Yellowtail Kingfish within NSW has been assessed as ‘Growth Overfished’ (2003/04 to 2013/14), and current evidence indicates a Depleted stock. There are ongoing discussions within NSW about appropriate management changes that may assist recovery; however these are hampered by the ‘Undefined’ status in SAFS.

The FRDC National Priority 1 aims to reduce the percentage of ‘Undefined’ stocks within SAFS, which also has an objective of providing a roadmap to recovery for ‘Depleted’ stocks. To address both of these and to promote better and more collaborative monitoring, assessment and management across all relevant jurisdictions, there is a clear need to review existing knowledge across the entire stock and to identify areas of uncertainty that require addressing.