Tactical Research Fund: Evaluating Source-sink Relationships Of The Western Rock Lobster Fishery Using Oceanographic Modelling
Funder
Fisheries Research and Development Corporation
Funding Amount
$75,000.00
Summary
The puerulus settlement in 2007/08 was the second lowest in 40 years and follows several years of below-average settlements. Previous studies have shown that environment factors such as the Leeuwin Current and storms affect the abundance and spatial distribution of puerulus settlement. However it is important to identify if there are some changes to these environmental factors contributing to the low recruitment. Initial monitoring indicates very low 2008/09 settlement despite the Leeuwin Curr ....The puerulus settlement in 2007/08 was the second lowest in 40 years and follows several years of below-average settlements. Previous studies have shown that environment factors such as the Leeuwin Current and storms affect the abundance and spatial distribution of puerulus settlement. However it is important to identify if there are some changes to these environmental factors contributing to the low recruitment. Initial monitoring indicates very low 2008/09 settlement despite the Leeuwin Current being above average this year. This event is unexpected based on previous settlements during years of strong Leeuwin Current and has serious implications for the management of the fishery. The breeding stock overall is believed to be within historic ranges and so is not expected to have contributed to the recent decline in settlement. However it is possible that the breeding stock in certain parts of the fishery may be more critical than others and this could have changed over the years due to climate change effects. Advances in quality of satellite data in the 1990s measuring sea surface topography (altimeter satellites) have enabled significant improvements in our understanding of the environmental factors, with the assistance of oceanographic modelling. Previous oceanographic models were focussed on the open ocean circulation off the continental shelf. Recent advances enable the development of high-resolution models at 10 km spatial scale which resolve the dominant processes on the shelf. Understanding the causes of recruitment variability and their long-term trends has important implications in the stock assessment and management of the fishery. The management response would be significantly different if the cause of the series of low recruitment was due to egg production or environmental factors. An adjustment to the sustainable harvest rate may be required if there are long-term environmental trends that affect the average recruitment of the western rock lobster. Objectives: 1. To determine the relative contribution of larval production from different areas to the abundance and spatial distribution of puerulus settlement over 15 years using a larval advection model Read moreRead less
Larval Transport And Recruitment Processes Of Southern Rock Lobster
Funder
Fisheries Research and Development Corporation
Funding Amount
$333,640.00
Summary
This project arises from the need within the SRL fishery to address a series of regional and fishery-wide questions including:
What areas contribute to successful recruitment within regions of the fishery?
Will increasing the spawning biomass in regions, where it is currently very low, be likely to increase recruitment to the fishery globally, only in certain restricted areas or not at all?
To what extent are management zones linked via larval transport from both west ....This project arises from the need within the SRL fishery to address a series of regional and fishery-wide questions including:
What areas contribute to successful recruitment within regions of the fishery?
Will increasing the spawning biomass in regions, where it is currently very low, be likely to increase recruitment to the fishery globally, only in certain restricted areas or not at all?
To what extent are management zones linked via larval transport from both west to east and east to west?
What drives puerulus settlement across the range of the fishery and how can regional and interannual differences in settlement be utilised to assess the health of the stock, and assist in the future with the prediction of catch rates?
These needs have been identified by managers, industry and research providers in South Australia, Victoria and Tasmania. In Tasmania, the Crustacean Research Advisory Group gave this issue their highest priority ranking due to its importance in targeting the current management objective aimed at rebuilding egg production.
Addressing these questions will help to ensure the sustainability of the fishery, assess the merits of alternative management strategies for improving recruitment (and hence yield) and provide the basis for possible future predictions of catch rates based on puerulus and or ocean monitoring.
Objectives: 1. To examine the relationship between spawning region and settlement success across the range of the SRL fishery - identify where successfully settling puerulus come from 2. To model the effects on settlement, throughout the range of the fishery, of changing spawning output in various areas of the fishery – provide information on whether increasing spawning stock biomass in some areas will help to increase recruitment and, hence, yield 3. To identify major physical processes contributing to differences in settlement between years and between regions – help understand whether variations in puerulus settlement result from management changes or environmental effects 4. To identify mechanisms for incorporating findings of the project into on-going assessments of recruitment indices and stock status – how best to develop the model outputs into a form that managers, researchers and industry can use on an on-going basis Read moreRead less
Ascorbate and glutathione integrate the control of grapevine development. This project aims to make a step-change in understanding how the growth of woody perennial crops is regulated. The study of herbaceous annual plants has established that the antioxidants, ascorbate and glutathione, are important in regulating every step of plant development. However, this cannot readily translate to perennial life cycles. This project will develop novel genetic tools in grapevine that enable functional stu ....Ascorbate and glutathione integrate the control of grapevine development. This project aims to make a step-change in understanding how the growth of woody perennial crops is regulated. The study of herbaceous annual plants has established that the antioxidants, ascorbate and glutathione, are important in regulating every step of plant development. However, this cannot readily translate to perennial life cycles. This project will develop novel genetic tools in grapevine that enable functional studies of these antioxidants in a perennial plant for the first time. It will investigate how ascorbate and glutathione regulate the development of grapevine, and how these functions integrate with hormone and energy metabolism. The outcomes will advance our ability to manage perennial crops in current and future climates.Read moreRead less
An Investigation Of The Habitat Requirements Of Post-puerulus Stocks Of Western Rock Lobster (Panulirus Cygnus)
Funder
Fisheries Research and Development Corporation
Summary
Objectives: 1. Investigate natural habitat of post-puerulus western rock lobster; compare densities of p. settlement on artificial collectors & in natural habitats; 2. Predict catches more accurately; enhance abundance & survival of post-p hence adult through knowledge of habitat requirements.
A Preliminary Study Of The Dynamics Of Recreational Fishing In The Western Rock Lobster Fishery For Use In Integrated Fisheries Management
Funder
Fisheries Research and Development Corporation
Funding Amount
$33,149.00
Summary
The western rock lobster fishery is to be one of the first of Western Australia’s fisheries to move to an integrated fisheries management (IFM) approach. Fundamental to this approach is the allocation of catch shares to the commercial and recreational fishing sectors and the implementation of appropriate controls to ensure that these catch shares are not exceeded. Although the commercial fishery has been the subject of much study, no dynamic models of the impact on the rock lobster fishery of r ....The western rock lobster fishery is to be one of the first of Western Australia’s fisheries to move to an integrated fisheries management (IFM) approach. Fundamental to this approach is the allocation of catch shares to the commercial and recreational fishing sectors and the implementation of appropriate controls to ensure that these catch shares are not exceeded. Although the commercial fishery has been the subject of much study, no dynamic models of the impact on the rock lobster fishery of recreational fishing effort have been developed. The only models that exist are empirical, statistical models that describe the catch and effort that are likely to be experienced following the specific levels of puerulus settlement that were recorded. To ensure that integrated fisheries management of the western rock lobster fishery is successful, there is an urgent need to develop a conventional fisheries model to describe the relationships between recreational and commercial catches and recreational fishing effort, particularly in the nearshore region where recreational fishing effort is concentrated. Knowledge of such relationships is essential if the response of catch shares to controls on recreational effort is to be predicted. The proposed study is intended as a pilot study to develop a basic model of the nearshore commercial and recreational fishery in several specific locations for use in the development of an IFM approach for the western rock lobster fishery and to identify more clearly the framework of a more detailed model of the fishery that will be required in the future to support IFM. Objectives: 1. To model commercial and recreational fishing of the nearshore rock lobster fishery. Read moreRead less
Modelling To Explore Management Strategies To Optimise The Value Of The Rock Lobster Fishery Of Western Australia
Funder
Fisheries Research and Development Corporation
Funding Amount
$140,183.00
Summary
It is recognised by industry that the yield currently obtained from the western rock lobster fishery cannot be enhanced by increasing exploitation without also reducing the breeding stock to an unacceptable level. The value of the fishery can only be increased by reducing costs or by increasing the value of the catch. Modelling of the fishery is required to investigate the potential improvement in value that might be obtained from an optimal set of management controls designed to improve marke ....It is recognised by industry that the yield currently obtained from the western rock lobster fishery cannot be enhanced by increasing exploitation without also reducing the breeding stock to an unacceptable level. The value of the fishery can only be increased by reducing costs or by increasing the value of the catch. Modelling of the fishery is required to investigate the potential improvement in value that might be obtained from an optimal set of management controls designed to improve market prices through controlling the supply of lobsters to the market both within and among fishing seasons. The ability to predict future catches based on puerulus settlement indices offers the rock lobster industry in Western Australia a unique opportunity to improve prices by varying the exploitation rate between seasons in order to more closely match market demand.
A modelling project to address this need will require the development of a more statistically sound model of the lobster fishery than was provided by the descriptive model developed by Walters et al. (1993). This will benefit the participants in the fishery by providing an understanding of the uncertainties associated with model predictions, and the validity of the new model when applied to different sectors of the fishery. The earlier model used information from only a small subset of the data available from the fishery, and the new model will utilise far more of the available data, thus providing a more robust description of the rock lobster fishery.
Development of the proposed model is seen as an essential and strategic element of the research programme for this fishery. Objectives: 1. To develop a statistically sound biological model to represent the fish stock and its interaction with fishers within the constraints of management strategies; 2. To incorporate marketing data into the model to allow the prediction of changes in product value with different management scenarios; 3. To determine the time-dependent set of management controls (size, catch, and effort) that would optimise the value of the landed product, and to identify alternative locally optimum sets of controls producing similar (but reduced) value. Read moreRead less
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
Funder
Fisheries Research and Development Corporation
Funding Amount
$433,791.00
Summary
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 recruitme ....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. Read moreRead less
Identifying Factors Affecting The Low Western Rock Lobster Puerulus Settlement In Recent Years
Funder
Fisheries Research and Development Corporation
Funding Amount
$408,405.00
Summary
The puerulus settlement in 2007/08 was the second lowest in 40 years and follows a number of years of below-average puerulus settlements. The settlement for the August and September 2008 indicate that the 2008/09 settlement may be even lower. Previous studies have shown that environment factors such as the Leeuwin Current and storms in late winter/spring affect the abundance and spatial distribution of puerulus settlement. However with the series of low recruitments currently being experience ....The puerulus settlement in 2007/08 was the second lowest in 40 years and follows a number of years of below-average puerulus settlements. The settlement for the August and September 2008 indicate that the 2008/09 settlement may be even lower. Previous studies have shown that environment factors such as the Leeuwin Current and storms in late winter/spring affect the abundance and spatial distribution of puerulus settlement. However with the series of low recruitments currently being experienced, it is important to identify if (a) there are other environmental factors, which may be contributing to the low recruitment, (b) if the breeding stock in certain parts of the fishery are particularly critical, and (c) if there are any long-term trends apparent in these environmental factors. Advances in quality of satellite data in the 1990s measuring sea surface topography (altimeter satellites) and chlorophyll/productivity (ocean colour satellite) have enabled significant improvements in our understanding of the environmental factors, with the assistance of oceanographic modelling. Previous oceanographic models were focussed on the open ocean circulation off the continental shelf. Recent advances in modelling enable the development of high-resolution models at 10 km spatial scale which resolve the dominant processes on the shelf. Future climate projection using the same modelling framework have been proposed in WAMSI research. Understanding the causes of recruitment variability and their long-term trends has important implications in the stock assessment and management of the fishery. The management response would be significantly different if the cause of the series of low recruitment was due to egg production (overall or particular parts of the fishery) or environmental factors. Similarly an adjustment to the sustainable harvest rate may be required if there are long-term environmental trends that affect the average recruitment of the western rock lobster. Objectives: 1. To use a larval advection model and the rock lobster population dynamics model to assess the effect of the spatial distribution of the breeding stock on the puerulus settlement 2. To assess environmental factors (water temperature, current, wind, productivity, eddies) and breeding stock affecting puerulus settlement 3. To examine climate change trends of key environmental parameters and their effect on the western rock lobster fishery Read moreRead less
Condition And Its Assessment In The Southern Rock Lobster. Field Application Of The Techniques For Condition Assessment Developed In The Laboratory
Funder
Fisheries Research and Development Corporation
Funding Amount
$249,591.00
Summary
Objectives: 1. Obtain an understanding of variations in growth and recruitment through the establishment of the potential of selected indices to characterise temporal and spatial changes in condition of lobsters within the fishery.
Pilot Study Of Larval Recruitment And Genetic Variation Of Southern Rock Lobster Populations
Funder
Fisheries Research and Development Corporation
Funding Amount
$56,600.00
Summary
Objectives: 1. Compare effectiveness of existing Jasus spp puerulus collectors & determine the most suitable. 2. Estimate spatial variability & timing of puerulus settlement; can puerulus be obtained in sufficient quantities? 3. Develop mt DNA analysis techniques to identify p. Genetic variability information.