27 results

Voluntary behaviour change in recreational fisheries to support sustainability and amenity

Project number: 2023-141
Project Status:
Current
Budget expenditure: $193,128.00
Principal Investigator: Matthew Navarro
Organisation: University of Western Australia (UWA)
Project start/end date: 22 Sep 2024 - 29 Sep 2026
Contact:
FRDC
TAGS
Behaviour

Need

This project responds to an FRDC identified opportunity to review and build on previous experiences aimed towards encouraging recreational fishers to voluntarily diversify their target species.

This project targets three outcomes in the FRDC R&D Plan 2020-25:
-Outcome 1. Growth for enduring prosperity
-Outcome 2. Best practices and production systems
-Outcome 4. Fair and secure access to aquatic resources

Our project consists of two phases, each addressing a discrete need identified through conversations with stakeholders.

Phase 1 – Developing a knowledge base and roadmap:
A robust knowledge base, including data on the the magnitude of behaviour changes achieved by previous initiatives, is required to support the use of voluntary behaviour change interventions for diversifying target species as alternatives to direct regulations. Phase 1 will consist of a backwards looking scan of past-experience to construct this knowledge base from case studies that have implemented an initiative to promote voluntary diversification of recreational target species. This will include a global literature scan, and interviews with stakeholders and managers in Australia to document case studies, identify their successes or failures and compile data on the magnitude of behaviour change achieved. The knowledge base will then be used to identify key knowledge gaps and develop a roadmap of research and information needed to support voluntary behaviour change strategies aimed at diversifying target species as genuine alternatives to direct regulations.

Phase 2 – Improving effectiveness:
Effective behavioural change interventions require careful targeting to ensure they are appropriate and acceptable within a specific context. Phase 2 will look forward with a focus on the future implementation of voluntary approaches that can confidently be applied to promote the voluntary diversification of target species for recreational fishers. This will include a forward-looking test of approaches identified through Phase 1 through interviews, focus groups and a survey of recreational fishers to delve deeply into which approaches are acceptable, where they are acceptable and which approaches are most likely to influence change. The outputs of Phase 2 will include clear advice on which strategies are likely to work in different situations relevant to Australian recreational fisheries.

A project evaluation will take place at the end of phase 1 to evaluate the feasibility of the remaining components, and guide case study selection and strategy for phase 2. This will be based on the interim short report based on phase 1 submitted to the FRDC in the milestone schedule below, as well as progress report 1.

To facilitate co-design and research impact, the research team have engaged with the Australian Fisheries Management Forum (AFMF), the AFSB Fisheries Management Committee (on advice from the AFMF), and the Australian Recreational Fishing Foundation (ARFF). Input from recreational fishing stakeholders into the project will be facilitated through an ARFF advisory panel, with representatives from different jurisdictions across Australia. The advisory panel plan to meet with the research team on 5 occasions across the project (front loaded to facilitate co-design). The model for input from fisheries managers is an on-going discussion but will likely take a similar advisory panel across jurisdictions.

Project risks:
The project relies heavily on the inputs of recreational fishing stakeholders and managers, with potential risks around a lack of availability to participate as well as lack of interest. To manage this risk the project team will work closely with the ARFF advisory group to identify and manage relationships with participants. A secondary project risk is the potential for sharing and disclosure of sensitive information from interviews and focus groups. To manage this risk, the research protocol will be subject to a human ethics review against the National Statement on Ethical Conduct in Human Research. Through this process, issues of anonymity, data management and retention and data sharing will be addressed in-line with national standards and carried throughout the project.

Objectives

1. To develop a global knowledge base of behaviour change strategies that have been used to promote diversification of recreational target species.
2. To identify the magnitude of behaviour change achieved by different strategies.
3. To identify key knowledge gaps forming a road map for supporting voluntary behaviour change strategies aimed at diversifying target species as genuine alternatives to direct regulations.
4. To identify success factors that may have driven success or failure of past behavioural change strategies.
5. To develop a shortlist of strategies that experiences suggest will be effective in an Australian context.
6. To test the shortlist of potential behaviour change strategies from Phase 1 in terms of their acceptability, likelihood to influence change to deepen understanding of success factors (e.g., motivators, species, and/or incentives) within the Australian context.
7. To package key insights, lessons and recommendations for behaviour change initiatives to diversify fish species for recreational fishers.
8. To ensure this knowledge is easily accessed and practical, and framed so as to speak to the values and drivers of recreational fishers.
9. To maximise the reach and amplification of this knowledge through building the capability of fisheries managers.

Genetic stock structure of commercially important deep sea crab species

Project number: 2020-014
Project Status:
Current
Budget expenditure: $20,000.00
Principal Investigator: Jason Kennington
Organisation: University of Western Australia (UWA)
Project start/end date: 30 Jun 2021 - 29 Jun 2022
Contact:
FRDC
TAGS
Sustainability
Stock Assessment
Reproduction
Rac Vic
Rac Tas
SPECIES
Champagne Crabs

Need

Two deep sea crab species crystal crab (Chaceon albus) and champagne crab (Hypothalassia acerba) are captured by both the West Coast Deep Sea Crustacean Managed Fishery (WCDSCMF) and South Coast Crustacean Managed Fishery (SCCMF). The greatest catches of these two species are landed by the WCDSCMF. As part of the MSC certification process for the WCDSCMF, information is required on the stock structure of (PI 1.2.3) and recent surveillance of this fishery identified; "…there is little information on the stock structure of crabs.... and this may weaken a stock assessment". Therefore information on the genetic stock structure will assist in the stock assessment of crystal crab and future MSC re-certification of the WCDSCMF. The information will also aid in the stock assessment and management of the SCCMF crab fisheries. The recent stock assessment of crystal crab in the SCCMF indicated an unacceptable level of stock depletion. Catches in this area have been highly cyclical unlike those on the west coast. This pattern is very similar to that of rock lobster and blue swimmer crab, whereby the main spawning stock resides on the west coast with large and consistent catches, while those on the south coast are sporadic with recruitment e.g. possibly only flowing down in strong Leeuwin Current years. These south coast areas are considered a resource ‘sink’. Irrespective of the similarities, the south coast deep-sea crab fisheries are still managed conservatively under the assumption of self-recruiting (they are not treated as sink populations). Determination of the recruitment linkages between the west and south coast fisheries will have marked implications on the management arrangement required for both fisheries.

Objectives

1. Determine the stock structure of the crystal crab Chaceon albus
2. Determine the stock structure of the champagne crab Hypothalassia acerba
3. Assess the implication of stock structures on the management arrangements required for both fisheries

Investigation of the direct and indirect role of submarine groundwater discharge (SGD) on Western Rock Lobster settlement processes: with consideration of the potential role of contaminants

Project number: 2019-101
Project Status:
Completed
Budget expenditure: $44,000.00
Principal Investigator: Tim J. Langlois
Organisation: University of Western Australia (UWA)
Project start/end date: 1 Jul 2020 - 1 Nov 2022
Contact:
FRDC
TAGS
Wild Catch
Threatened Endangered Protected Species
Stock Assessment
Stakeholder
Resource Access And Allocation
SPECIES
Western Rock Lobster

Need

In Western Australia, the positive and negative effects of SGD in marine benthic communities remains unknown. In Marmion Lagoon, SGD is known to supply up to 50% of the nutrients required for the macrophyte growth rates observed (Johannes and Hearn 1985). Freshwater input has been observed to positively impact seagrass germination (Xu et al., 2016), and although no similar studies exist for temperate seagrass species in the southern hemisphere, SGD may have a role in the creation, maintenance and augmentation of seagrass beds.
The direct influence of SGD on puerulus settlement rates is unknown but freshwater discharge has been shown to be positively correlated with crab larval abundance (Boylan and Wenner, 1993). An ongoing FRDC project (2016-260: Assess causes and implications of anomalous low lobster catch rates) has demonstrated post-puerulus western rock lobster exhibit a strong choice for the chemical signature of seagrass (Brooker et al. in prep). These findings suggest that SGD may affect puerulus settlement rates either directly through chemotaxis or indirectly by impacting the density of seagrass meadows. Hence, there is a need to investigate both the role of SGD and the presence of seagrass on puerulus settlement rates.
Land derived contaminants potentially impacting puerulus settlement and survival could include heavy metals and endocrine disrupting chemicals, such as flame-retardants or pesticides targeting insects (McKenney, 1999). Adult lobster have been shown to be repelled by the presence of copper (McLeese, 1975) and both flame-retardants (polybrominated diphenyl ethers - PBDEs) (Davies and Zou, 2012) and various insecticides (Ghekiere et al., 2005) have been shown to disrupt moulting in marine crustacea. Alkylphenol pollution was implicated in a major die-off of the American lobster (Homarus americanus) population that occurred in Long Island Sound in 1999, with acute impact on post-puerulus mortality during moulting (Laufer et al., 2013). There is a need to investigate both the occurrence and concentration of likely contaminants at potential source locations within the Western Rock Lobster fishery and assess their impact on post-puerulus survival.

Objectives

1. Identify areas of significant submarine groundwater discharge (SGD) nearby established western rock lobster settlement monitoring sites.
2. Investigate the direct role of SGD on western rock lobster settlement rates.
3. Investigate the link between SGD and the extent and condition of important lobster habitat (e.g. seagrass).
4. Identify and map input of contaminants by SGD in key fishery areas.
5. Investigate impact of contaminants on the survival of puerulus and post-puerulus lobster.

Final report

Authors: Tim Langlois John Fitzhardinge Simon de Lestang Claude Spencer Stanley Mastrantonis and Anita Giraldo
Final Report • 2025-02-21 • 3.83 MB
2019-101-DLD.pdf

Summary

The influence of Submarine Groundwater Discharge (SGD) on coastal ecosystems of the West Coast Bioregion of Western Australia, and particularly its impact on the Western Rock Lobster (WRL) and the West Coast Rock Lobster Managed Fishery (WCRLMF), is poorly understood. This is despite that the region's unique oceanography and geological history, where the prevailing oceanography suppresses upwelling and there is limited nutrient input from the land, would predict that SGD could have a significant role in the productivity of coastal ecosystems. In addition, this region is reported to be drying and warming under the influence of climate change, and localised decreases in SGD have already been reported. Three linked objectives were originally proposed within this project:

 

1. Identify areas of significant submarine groundwater discharge (SGD) nearby established western rock lobster settlement monitoring sites.

2. Investigate the direct role of SGD on western rock lobster settlement rates.

3. Investigate the link between SGD and the extent and condition of important lobster habitat (e.g. seagrass).

 

To address the knowledge gaps surrounding SGD and inform further research, a workshop was convened in December 2020, bringing together experts from various disciplines. The workshop aimed to identify key research priorities and effective methodologies for studying SGD and its potential role in the productivity of coastal ecosystems.

 

The influence of SGD on coastal ecosystems of the West Coast Bioregion are poorly understood. After the expert workshop, the project identified that the initial objectives proposed were not achievable and used the outputs of that workshop and pilot studies, to evaluate potential field methods, and recommend that future studies should instead focus on detailed characterisation of SGD within locations of interest. The proposed multi-sensor sampling approach and survey design provided here, would provide a robust basis for any future investigation of the role of SGD on WRL ecology and any implications for the WCRLMF.

 

Climate driven shifts in benthic habitat composition as a potential demographic bottleneck for Western Rocklobster: understanding the role of recruitment habitats to better predict the under-size lobster population for fishery sustainability

Project number: 2019-099
Project Status:
Current
Budget expenditure: $433,791.00
Principal Investigator: Tim J. Langlois
Organisation: University of Western Australia (UWA)
Project start/end date: 31 Aug 2020 - 29 Feb 2024
Contact:
FRDC
TAGS
Sustainability
Stock Assessment
Reproduction
Modelling
Life History
SPECIES
Western Rock Lobster

Need

The marine heat waves (MHW) of 2010/11, 2011/12 and 2012/13 provide a benchmark with which to investigate changes in habitat composition and potential flow on effects to the fishery.

A 2018 independent review of the science used for stock assessment of the fishery recommended that studies should be undertaken to

a) investigate the impacts of the previous MHW on juvenile recruitment to the fishery and,

b) to better understand the role of habitat composition in recruitment

To understand the impact of habitat change on the fishery, either through warming events or changes in coastal processes, we need an increased understanding of the role of habitat on the survivorship and growth of puerulus, post-puerulus, juvenile and adult life stages of lobster.

In the 40 year time-series of puerulus settlement index a very strong relationship has persisted between puerulus abundance and commercial lobster catches 3 - 4 years larter (de lestang et al., 2010). An undersize catch rate index, based on historical (1985 - present) catch-rate records, evidenced the existence of a strong correlation between puerulus and undersize catch rate (de Lestang pers. com.). However, two-four years after the MHW of 2010/11, this relationship degraded, with the observed catch rate of lobsters being far less than expected at northern locations of the fishery. Although the relationship has now started to return to its historical form, the severity and longevity of its departure are cause for concern and highlight the marked impact future MHW or changes in coastal processes could have on the fishery.

Change in the extent and configurations of coastal habitats is already occurring in response to natural physical forcing (coastal processes) and accelerated by climate change related stressors. It is crucial to have a detailed knowledge of how habitat change affects survival and recruitment key life-stages of the western rock lobster, so these can be taken into consideration for management practices that ensure the sustainability of the fishery. Such information is currently lacking.

Objectives

1. The overall objective is to evaluate the implications of habitat change for the western rock lobster fishery, by determining the relative importance of habitat for the survivorship and growth of critical western rock lobster life stages, to inform the interpretation of existing settlement and recruitment metrics where and when habitat change also occurs. This will be examined via four linked objectives:
2. Synthesise evidence of habitat change: use novel and historical habitat imagery and other remote sensing datasets to determine the spatial extent of habitat loss and recovery, either attributed to 2011/2012 marine heat wave or changes in coastal processes.
3. Investigate fine-scale correlations in anomalies between predicted and observed undersize catch rate index and areas of habitat loss and recovery, either attributed to 2011/2012 marine heat waves or changes in coastal processes.
4. Evaluate evidence of essential benthic habitat for juvenile lobster, by measuring how habitat quality (cover and composition) influences lobster survival.
5. Create a spatial index of essential habitats to inform the interpretation of existing settlement and recruitment metrics.

Final report

Authors: Stanley Mastrantonis Tim Langlois Sharyn Hickey Ben Radford Claude Spencer and Simon de Lestang
Final Report • 2025-05-29 • 8.41 MB
2019-099-DLD.pdf

Summary

The West Coast Rock Lobster Managed Fishery (WCRLMF) is one of the most valuable and sustainable single-species fisheries in Australia. WCRLMF is managed, in part, using larval (puerulus) settlement indices obtained from artificial seagrass stations that are continuously monitored at eight locations throughout the shallow coastal habitats of the Western Bioregion of Western Australia. The settlement indices correlate to subsequent catch rates of the Western Rock Lobster (WRL) and are used to predict catch into the WCRLMF in typically 3-4 years times. Recently, the relationship of the settlement indices to catch have become less evident in some parts of the fishery, particularly after the marine heatwave that occurred in Western Australia in 2011.  Since the heatwave reportedly impacted habitats, these ocean climate mitigated changes WRL recruitment habitats, such as seagrasses and macroalgae, are hypothesised to be the source of increased unexplained variation in the WRL population, but causal links remain unclear.

 

Modelling and tracking the changes in coastal habitat in space and time has become an important aspect of managing our environments more generally. This project set out to investigate if including measures of recruitment habitat into the WCRLMF stock assessment will improve management of the fishery.

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PROJECT NUMBER • 2019-011
PROJECT STATUS:
COMPLETED

Optimising Compliance Outcomes in Recreational Fisheries

This study investigated strategies to enhance compliant participation among recreational fishers, using the Peel-Harvey Blue Swimmer Crab fishery in Western Australia (WA) and the Blue Swimmer Crab fishery in South Australia (SA) as case studies. 
ORGANISATION:
University of Western Australia (UWA)
TAGS
Sustainability
Recreational Fishing
Rac Wa
Rac Sa
Human Dimensions Research
SPECIES
Blue Swimmer Crab

Develop a strong current warning system and inform knowledge of the nearshore current regime influencing the Western Rock Lobster fishery

Project number: 2017-147
Project Status:
Completed
Budget expenditure: $182,000.00
Principal Investigator: Chari Pattiaratchi
Organisation: University of Western Australia (UWA)
Project start/end date: 31 Dec 2017 - 29 Dec 2021
Contact:
FRDC
TAGS
Wild Catch
Stock Assessment
Oceanography
Modelling
Fishing Gear
SPECIES
Western Rock Lobster

Need

By combining this greater coverage with information derived from commercial fishers (e.g. days when gear is drowned or lost to determine key current velocities) a purpose built webapp can be developed, hosted on an existing service, which allows fishers to asses the risks posed by ocean currents to their fishing operation before they set their gear. This would also allow for fishers to predict days when drowned gear may resurface and therefore the fishing operation may continue.

In addition to this helping the fishing operation, greater current modelling coverage over this part of the fishery will allow for the fine-scale assessment of the links between water movement and puerulus settlement. As part of FRDC project “2016-260 WRL IPA: assess causes and implications of anomalous low lobster catch rates in the shallow water areas near the centre of the Western Rock Lobster fishery” 40 additional puerulus collectors will be added to the current DOF monitoring program which will provide extensive coverage of settlement rates between Seven Mile, Dongara and Jurien Bay.

Objectives

1. Establish additional coastal radar station
2. Establish a predictive warning system for ocean conditions that can be used by the WRL fishery to improve efficiency
3. Assess the relationship between water circulation and puerulus settlement rates

Assess causes and implications of anomalous low lobster catch rates in the shallow water areas near the centre of the Western Rock Lobster fishery

Project number: 2016-260
Project Status:
Completed
Budget expenditure: $384,180.50
Principal Investigator: Tim J. Langlois
Organisation: University of Western Australia (UWA)
Project start/end date: 8 Jan 2017 - 19 Dec 2019
Contact:
FRDC
TAGS
Wild Catch
Stock Assessment
Distribution
SPECIES
Western Rock Lobster

Need

A reduction in fishing effort in 2008 and change to quota management in 2010 resulted in record low harvest rates and high biomass levels across the Western Rock lobster fishery.

Counter to this trend however has been the increasingly low catch rates that have been observed in the shallow water areas (20 m) near the centre (and possibly other areas) of the fishery over a much longer time period. The adjacent deep water areas show good catch rates comparable with the rest of the fishery.

The low catch rates in the shallow water (20 m) of the fishery are particularly surprising given the relatively high levels of puerulus recruitment immediately to the north and south of this region, which would suggest there should be high levels of sub-legal and legal biomass, and thus good catch rates in the shallows.

Unlike areas that have recently been impacted by the 2011 marine heat wave (e.g. Kalbarri), the processes behind the atypical catch rates in this central shallow water region are unknown and appear to form a worsening long term trend.

In the short term, this trend could impact stock assessments. In the longer term, an expansion of a low catch rate region could result in significant reduction in the overall productivity of the fishery.

Understanding the processes behind the unexpected low catch rates will allow prediction of future trends, management adaptation and the potential for mitigation.

Objectives

1. Determine the spatial extent and temporal trends in regions exhibiting abnormally low legal catch rates throughout the lobster fishery.
2. Identify the lobster life stage(s) resulting in abnormally low legal catch rates in the main area of low catch rates.
3. Examine factors that may be causative of the abnormally low legal catch rates.
4. Identify the implications of the low-catch regions to the stock assessment and management of the fishery.

Final report

Authors: Tim Langlois Michael Brooker Ashlyn Miller Jessica Kolbusz John Fitzhardinge Simon de Lestang Jason How Oscar Doncel Canon Anita Giraldo Brooke Gibbons Matt Taylor
Final Report • 14.30 MB
2016-260-DLD.pdf

Summary

Current and former West Coast Rock Lobster Managed Fishery (WCRLMF) fishers have anecdotally observed a trend of low catch rates since the 1990’s in the near-shore shallow water areas (<8 m) near the centre of the fishery (Dongara-Leeman). Since the atypically low puerulus counts of 2007-2010, this trend of decreasing catch rates in this area have been reported by fishers to extend out to deeper waters (e.g. to the edge of the shallows, < 20 m). Fishers were concerned that this trend of reduced productivity could be impacting the current stock assessment and has the potential to expand throughout the fishery.

These objectives of the research were achieved, in particular standardised meshed pot catch and release surveys were highly useful to establish the extent of the low catch zone and that sub-legal to early juvenile lobster were found to be indicative of the low catch zone. The iterative assessment process, presented to fishers over multiple workshops, indicated that loss of essential habitat, relating to early juvenile lobster survival or recruitment success, was the most likely causative factor of the low catch zone.
To inform the stock assessment and management of the fishery, the project has highlighted the importance of data on 1) the abundance of sub-legal lobster in near shore habitats and 2) monitoring change in/condition of near shore habitats as a potential indicator of early juvenile lobster survival or recruitment success for the stock assessment and management of the WRL fishery. The project has highlighted that limited historical data is available on these potential indicators, but new FRDC WRL IPA funded projects have subsequently been created to further synthesise available information and collect new data for both early juvenile / pre-recruit lobster abundance (FRDC 2019-159 Independent Shallow Survey) and condition and change in near shore habitats (FRDC 2019-099 Habitat as a limit to Western Rock Lobster recruitment) to further inform the stock assessment and management of the fishery.
This project has demonstrated that the active input of current and former fishers can inform scientific studies and an iterative assessment process, of the potential processes limiting lobster catch rates, presented to fishers over multiple workshops can provide information to further improve the stock assessment and management of the fishery.

Governance, social and economic sustainability of WA's Western Rocklobster and finfish industries

Project number: 2011-203
Project Status:
Completed
Budget expenditure: $292,886.72
Principal Investigator: Paul McLeod
Organisation: University of Western Australia (UWA)
Project start/end date: 11 Sep 2011 - 11 May 2014
Contact:
FRDC
TAGS
Sustainability
Supply Chain
Stakeholder
Food Safety
Fisheries Management
SPECIES
Western Rock Lobster

Need

The WA rock lobster and finfish industries are in transition. Contraction of catches and consequent management changes have made long term economic sustainability an issue that now needs to be addressed within Integrated Fisheries Management (IFM).

Achieving this requires:

(1) An assessment of economic sustainability across all sectors in the supply chain. Decreasing volumes mean unit costs will likely rise. Rationalization will be required that reflects the optimal economic scale in catching, processing and marketing. Optimizing the supply chain processes requires a better understanding of demand and pricing in domestic and international markets, including estimates of future prices and mechanisms to encourage greater efficiencies and better pricing outcomes. An essential component of long term economic sustainability is the assessment of potential opportunities to "value add" and to increase prices received by producers through coordinated value adding and marketing activities.

(2) Industry governance, funding and management arrangements that encourage long term sustainability based on optimizing the whole of the fishery. There is a need to "audit" governance structures to determine consistency with achieving long term economic sustainability and identify opportunities to make improvements.

(3) Assembling the best available information for managers to make the application of IFM consistent with long term sustainability of all parts of the industry. The governance process (management regimes, data collection, funding, allocation) needs to be part of a long term pathway to economic sustainability.

These broad needs were indentified in discussions with Heather Brayford and Lindsay Joll at DoF. Auditing governance structures to determine an optimal structure for long term economic sustainability was recognized as the area where this project would interact positively with DoF work going on to design integrated governance and management practices across fisheries generally and these fisheries in particular. They have agreed that Dr Lindsay Joll could be nominated as a co-investigator.

Objectives

1. Determine the optimal feasible strategies for sustaining industry profitability.
2. Determine the optimal Governance structure to secure regulatory objectives at least cost
3. Identify the relevant management information necessary to deliver sustainable commercial outcomes over time.

Final report

ISBN: 978-0-9756020-4-1
Author: Paul McLeod
Final Report • 2015-03-26 • 9.55 MB
2011-203-DLD.pdf

The biological oceanography of Western Rock Lobster larvae

Project number: 2010-047
Project Status:
Completed
Budget expenditure: $614,243.87
Principal Investigator: Anya Waite
Organisation: University of Western Australia (UWA)
Project start/end date: 14 May 2010 - 29 Jun 2012
Contact:
FRDC
TAGS
Sustainability
Population Dynamics
Oceanography
Food Web
SPECIES
Western Rock Lobster

Need

Lack of knowledge of Western Australia’s fisheries oceanography fundamentally limits understanding of the recruitment of Western Rock Lobster, Panulirus cygnus, in a fishery worth $200-300 million/year to Australia. The life cycle of P. cygnus includes a planktonic “phyllosoma” larval stage that can be transported ~1500 km offshore, via ocean currents. Development then continues at sea for up to 11 months, before juveniles (“puerulus”) cross the shelf to recruit to coastal reef areas. Critical to improving management of this fishery is an understanding of oceanographic mechanisms driving coastal recruitment. The last three years of puerulus settlement have been low, with the latest (2008/09) the lowest in 40 years. This recent low settlement remains unexplained by environmental drivers previously identified as important, so its cause represents a key unknown for managers assessing the fishery’s sustainability. We will test the hypothesis that variation in settlement is driven by variation in food availability during the open-ocean stage of the phyllosoma larvae. We suggest that ocean productivity, particularly the nitrate-driven classic food chain supporting diatoms, and copepods, (as the ultimate prey of phyllosoma), limits phyllosoma growth and survival in their oceanic phase. Our work targets the peak autumn/winter plankton bloom in the Leeuwin Current, quantifying oceanographic parameters crucial to modelling rock lobster larval dynamics and attempting to link these directly to the food chain on which the phyllosoma as active predators, rely very heavily upon for survival.

Objectives

1. Analyze phyllosoma densities, sizes, genetics at four latitudes (Rottnest-Shark Bay, WA)
2. Analyze offshore food web structures supporting phyllosoma growth at sea
3. Assess potential for Leeuwin Current autumn/winter bloom to support phyllosoma growth
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