Determining the spatial distribution and abundance indices for Moreton Bay Bugs, Thenus parindicus and Thenus australiensis in Queensland to improve stock assessment and management
Moreton Bay bugs (Scyllarid lobsters) are a commercially important fished resource in northern Australian coastal waters. About 600 tonnes of bugs is reported in logbooks annually, valued at about $15 million (~$25/kg) nationally. About 90% of the catch is taken in the Queensland east coast otter trawl fishery (QECOTF) (https://www.fish.gov.au/report/154-MORETON-BAY-BUGS-2018).
Historically, Moreton Bay bugs were retained as byproduct of prawn and scallop trawling, but over time their popularity and price have increased and they have become increasingly targeted by fishers. In recent years in the Queensland scallop fishery, the scallop catch has declined and fishers have targeted bugs to such an extent that their catch value now exceeds that of the scallops.
Quantifying the fishing effort targeted at bugs and differentiating it from the prawn and scallop effort is challenging. This complicates the estimation of reliable catch rate time series that can be used as an index of abundance for each group (i.e. bugs, prawns, scallops).
Despite their high value, Queensland has not previously undertaken a stock assessment of Moreton Bay Bugs, beyond yield-per-recruit analyses. This is largely because the Bug catch is composed of two species, reef bugs (Thenus australiensis) and mud bugs (Thenus parindicus) which are not differentiated by fishers in the logbook data. Mud bugs are the smaller of the two species and generally occur in depths of 10–30 m, while the larger reef bug generally occurs in depths of 30–60 m. Although there is some spatial separation of the species it is not possible to breakdown the catch of each from the logbook data alone.
This project aims to examine and define the spatial distribution of the two bug species. By surveying and sampling bugs, and examining seafloor properties, we hope to predict and map the distribution of each species. Once clear distinctions are made, we plan to use all available data on catch rates and gear technology used by the fleet, to derive standardised catch rate time series for each species, which can be used as indices of abundance for improved management and assessment.
Final report
We report on the first comprehensive investigation into the spatial distribution of Moreton Bay Bugs within the Queensland East Coast Otter Trawl Fishery. This research was a collaboration between the Queensland Department of Agriculture and Fisheries and James Cook University, applying interdisciplinary approaches to successfully model habitat preferences of the two Moreton Bay Bug species and map their distributions along Queensland’s east coast. Historic catch records were then split according to each species’ spatial distribution. From these records, standardised catch rates were produced as indices of abundance for each species for use in future stock assessments of the Moreton Bay Bug fishery.
Survey for WSSV vectors in the Moreton Bay White Spot Biosecurity Area
Compilation of information for the US Marine Mammal Protection Act Comparability Finding process
2020-2025 Strategic Plan for the Australian Oyster Industry
Developing a value proposition and future track for the National Aquaculture Council (NAC)
R&D includes the activities companies and groups undertake to innovate and introduce new products and services or to improve their existing offerings. The FRDC invests in RD&E to generate knowledge that can be used to create change which will benefit the fishing and aquaculture sectors and this, in turn, benefits Australia more broadly. This research is needed now to provide knowledge to clarify directions and roles in the context of national seafood leadership. Importantly, there is a need for Seafood Industry Australia and NAC to confirm their respective focus to the satisfaction of members, noting that SIA also has an aquaculture remit.
NAC has been representing the sector with severely limiting resources and at the end of last year, the Tasmanian Salmon Growers Association (TSGA), the largest aquaculture sector determined not to renew its membership on a wait and see basis. It is critical and timely for NAC to consult with its current and past members, and sectors not previously represented - including smaller and emerging sectors - and with other key stakeholders, to understand what their needs are for national representation. This includes understanding the RD&E for the sectors, and where these intersect with the objective to confirm what direction should be taken.
In addition, the research and priority setting would provide guidance to FRDC's RD&E planning to align with industry priorities and building on the work completed to date to inform the 2020-2025 vision.
Should it be determined that the NAC is needed and supported, a second phase of work (outside the scope of this application) would be identified to identify the structural, human, and financial resources needed to deliver the value for members. (The implementation of any operating models discerned, will be beyond the scope of FRDC-funded research).