ORCID Profile
0000-0002-4740-4200
Current Organisation
CSIRO
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Publisher: CSIRO Publishing
Date: 2011
DOI: 10.1071/MF10279
Abstract: Climate change presents significant challenges to modelling and managing aquatic resources. Equilibrium assumptions common in many modelling approaches need to be replaced by formulations that allow for changing baselines and integration of ongoing changes and adaptations by species, ecosystems and humans. As ecosystems change, so will the ways humans use, monitor and manage them. Consequently, adaptive management loops and supporting tools deserve more prominence in the management toolbox. Models are critical tools for providing an early understanding of the challenges to be faced by integrating observations and examining possible solutions. We review modelling tools currently available to incorporate the effect of climate change on marine and freshwater ecosystems, and the implications for management of natural resources. System non-linearity can confound interpretations and hence adaptive management responses are needed that are robust to unexpected outcomes. An improvement in the ability to model the effects of climate change from a social and economic perspective is necessary. The outputs from ‘end-to-end’ and socio-ecological models can potentially inform planning, in both Australia and the Pacific region, about how best to build resilience to climate change. In this context, the importance of well directed data-collection programs is also emphasised. Lessons from this region, which is advanced with regard to modelling approaches, can guide increased use of models to test options for managing aquatic resources worldwide.
Publisher: Elsevier BV
Date: 04-2011
Publisher: Wiley
Date: 26-04-2011
Publisher: Oxford University Press (OUP)
Date: 05-2007
Abstract: Plagányi, É. E., Rademeyer, R. A., Butterworth, D. S., Cunningham, C. L., and Johnston, S. J. 2007. Making management procedures operational — innovations implemented in South Africa. – ICES Journal of Marine Science, 64: 626–632. Operational management procedures (OMPs) have become an indispensable fisheries management tool in South Africa in light of their ability to consider the consequences of the main sources of assessment uncertainty. An overview is provided of the MP approaches applied to the major South African fisheries for hake, sardine and anchovy, and west coast rock lobster. As these are among the first OMPs to be implemented worldwide, some for periods longer than 10 y, they provide useful ex les of some of the successes and problems encountered with the approach. Particular emphasis is given to some recent innovations and adaptations. These include moves to (i) joint two-species OMPs for the hake and sardine/anchovy resources (ii) a reference set of weighted operating models for primary testing and tuning in preference to a single model (iii) consideration of a “research-conditional” approach for hake to allow greater catches in the short term, conditional on research being implemented to resolve a key uncertainty and (iv) incorporation of some ecosystem considerations by developing appropriate robustness tests (which link with moves towards an ecosystem approach to fisheries). Key lessons gained from experience over the past decade of OMP implementation in South Africa are summarized.
Publisher: Wiley
Date: 07-07-2018
DOI: 10.1111/FAF.12232
Publisher: Frontiers Media SA
Date: 14-10-2021
Abstract: Graphical summary of multiple aspects of Southern Ocean food web structure and function including alternative energy pathways through pelagic food webs, climate change and fisheries impacts and the importance of microbial networks and benthic systems.
Publisher: Elsevier BV
Date: 2016
Publisher: Frontiers Media SA
Date: 08-11-2019
Publisher: Springer Science and Business Media LLC
Date: 03-2013
DOI: 10.1038/495314B
Publisher: Proceedings of the National Academy of Sciences
Date: 08-02-2017
Publisher: Proceedings of the National Academy of Sciences
Date: 11-05-2015
Abstract: Rotating the harvest of natural resources is a management strategy that humans have used on land for centuries, but it is less commonly applied to marine resources. Marine animals, such as sea cucumbers, scallops, and abalone, may be particularly suited for this form of management. Although highly important to many communities worldwide, they are often severely overexploited, underlining the need for effective and easy to manage harvest strategies. We modeled the rotational zone strategy applied to the multispecies sea cucumber fishery in Australia’s Great Barrier Reef Marine Park and show a substantial reduction in the risk of localized depletion, higher long-term yields, and improved economic performance. Hence, our results support the use of rotational harvests to better manage these marine resources.
Publisher: JSTOR
Date: 06-1999
DOI: 10.2307/3546693
Publisher: Elsevier
Date: 2016
DOI: 10.1016/BS.AMB.2016.04.002
Abstract: Climate influences marine ecosystems on a range of time scales, from weather-scale (days) through to climate-scale (hundreds of years). Understanding of interannual to decadal climate variability and impacts on marine industries has received less attention. Predictability up to 10 years ahead may come from large-scale climate modes in the ocean that can persist over these time scales. In Australia the key drivers of climate variability affecting the marine environment are the Southern Annular Mode, the Indian Ocean Dipole, the El Niño/Southern Oscillation, and the Interdecadal Pacific Oscillation, each has phases that are associated with different ocean circulation patterns and regional environmental variables. The roles of these drivers are illustrated with three case studies of extreme events-a marine heatwave in Western Australia, a coral bleaching of the Great Barrier Reef, and flooding in Queensland. Statistical and dynamical approaches are described to generate forecasts of climate drivers that can subsequently be translated to useful information for marine end users making decisions at these time scales. Considerable investment is still needed to support decadal forecasting including improvement of ocean-atmosphere models, enhancement of observing systems on all scales to support initiation of forecasting models, collection of important biological data, and integration of forecasts into decision support tools. Collaboration between forecast developers and marine resource sectors-fisheries, aquaculture, tourism, bio ersity management, infrastructure-is needed to support forecast-based tactical and strategic decisions that reduce environmental risk over annual to decadal time scales.
Publisher: Bulletin of Marine Science
Date: 07-2018
Publisher: CSIRO
Date: 2015
Publisher: Wiley
Date: 20-12-2022
DOI: 10.1111/COBI.13864
Abstract: Short‐lived, fast‐growing species that contribute greatly to global capture fisheries are sensitive to fluctuations in the environment. Uncertainties in exact stock–environment relationships have meant that environmental variability and extremes have been difficult to integrate directly into fisheries management. We applied a management strategy evaluation approach for one of Australia's large prawn stocks to test the robustness of harvest control rules to environmental variability. The model ensemble included coupled environmental‐population models and an alternative catchability scenario fitted to historical catch per unit effort data. We compared the efficacy of alternative management actions to conserve marine resources under a variable environment while accounting for fisher livelihoods. Model fits to catch per unit effort were reasonably good and similar across operating models (OMs). For models that were coupled to the environment, environmental parameters for El Niño years were estimated with good associated precision, and OM3 had a lower AIC score (77.61) than the base model (OM1, 80.39), whereas OM2 (AIC 82.41) had a similar AIC score, suggesting the OMs were all plausible model alternatives. Our model testing resulted in a plausible subset of management options, and stakeholders selected a permanent closure of the first fishing season based on overall performance of this option ability to reduce the risk of fishery closure and stock collapse robustness to uncertainties and ease of implementation. Our simulation approach enabled the selection of an optimal yet pragmatic solution for addressing economic and conservation objectives under a variable environment with extreme events.
Publisher: Oxford University Press (OUP)
Date: 19-10-2023
Publisher: Routledge
Date: 26-02-2016
Publisher: Oxford University Press (OUP)
Date: 05-2007
Abstract: Rademeyer, R. A., Plagányi, É. E., and Butterworth, D. S. 2007. Tips and tricks in designing management procedures. – ICES Journal of Marine Science, 64: 618–625. Management procedures (MPs) are becoming widely used in fisheries management, but guidelines to assist in their construction, evaluation, and implementation are few. We provide simple guidelines by drawing on experience from developing and applying MPs in southern Africa and internationally. Suggestions are provided on how to choose between candidate MPs and on key trade-offs in selecting between data-based (empirical) and model-based formulations. Assistance is also provided in dealing with different sources of uncertainty, such as deciding which operating models should be included in a reference set used for primary simulation testing and tuning (in contrast to robustness or sensitivity tests), and on how weights for the associated alternative hypotheses are most practically assigned. Finally, some guidelines are given for presenting the results effectively, which is one of the key challenges of a successful implementation process.
Publisher: Frontiers Media SA
Date: 16-06-2021
DOI: 10.3389/FMARS.2021.686065
Abstract: The Torres Strait tropical rock lobster Panulirus ornatus (TRL) fishery is of immense social, cultural and economic importance to the region’s Indigenous fishers from both Australia and Papua New Guinea (PNG). During 2020, the COVID-19 pandemic indirectly impacted this fishery as well as a number of other fisheries reliant on international export markets. The TRL fishery is managed using an empirical (data-based) Harvest Control Rule (eHCR) to rapidly provide a recommended biological catch (RBC), based on catch, fishery-independent survey indices and catch-per-unit-effort (CPUE). Here, we summarize the impacts of COVID-19 on each of these critical data inputs and discuss whether the eHCR was considered adequately resilient to this unprecedented disruption to the system. Next, we use a quantitative supply chain index to analyze the impact of disruptions to the supply chain, and inform on potential adaptation strategies. The catch and CPUE data were impacted to varying degrees by external constraints influencing fishing effort, but the fishery-independent survey wasn’t affected and hence there remains an unbroken survey time-series for the fishery extending back to 1989. The eHCR was shown to be reasonably robust because it incorporates longer-term trends over a 5-year period, and accords substantially more weighting (80%) to the fishery-independent survey rather than CPUE data which can be affected by trade and other disruptions. Despite the eHCR not having been tested for scenarios such as a global pandemic, this robustness is a positive given the types of disruptions we will likely face in future climate. The weak links identified in the supply chain were the same as those previously highlighted as sensitive to climate change disruptions. Our supply chain analysis quantifies the impact on system resilience of alternative paths connecting producers to consumers and reinforces that supply chains may be particularly vulnerable to external disruptions if they are not sufficiently erse.
Publisher: National Inquiry Services Center (NISC)
Date: 06-2004
Publisher: Frontiers Media SA
Date: 09-01-2019
Publisher: Frontiers Media SA
Date: 30-10-2020
Publisher: No publisher found
Date: 2010
Publisher: Canadian Science Publishing
Date: 10-2000
DOI: 10.1139/F00-158
Abstract: Prey abundance is only a useful correlate of fish growth rate if it is considered within a match/mismatch hypothesis framework. We developed a model to explore the extent to which the growth rates of juvenile anchovies (Engraulis capensis) are influenced by temporal and spatial match/mismatches with the copepod Calanoides carinatus, a major component of their diet. The distributions of copepods and anchovies are dynamic, so that predation by anchovy may dramatically impact on its prey's spatial distribution. Predation rates by resident fish were commensurate with the average and maximum specific copepod production rates at fish densities of approximately 1 and 3.5 t·km -2 , respectively. The spatial arrangement of fish biomass and the temporal overlap between fish and copepod abundances substantially modified both anchovy and copepod growth estimates. Predicted optimal shoal sizes suggest that additional factors such as predator avoidance or the energetics of maintaining school structure may be important. The model emulated observed variability in anchovy growth rates and confirmed the prediction that the availability of high-sustained abundances of food along the West Coast may be a critical "bottleneck" contributing to the strength of recruitment to the South African pelagic purse-seine fishery.
Publisher: Elsevier BV
Date: 11-2013
Publisher: Informa UK Limited
Date: 09-2008
Publisher: Elsevier BV
Date: 07-2020
Publisher: CSIRO
Date: 2022
DOI: 10.25919/1PYY-SP16
Publisher: Resilience Alliance, Inc.
Date: 2018
Publisher: American Geophysical Union (AGU)
Date: 02-2019
DOI: 10.1029/2018EF000990
Publisher: Wiley
Date: 30-08-2014
DOI: 10.1111/FAF.12093
Publisher: Elsevier
Date: 2009
Publisher: CSIRO
Date: 2022
DOI: 10.25919/QBEQ-7955
Publisher: Elsevier BV
Date: 11-2013
Publisher: Wiley
Date: 28-06-2012
Publisher: Inter-Research Science Center
Date: 2000
DOI: 10.3354/MEPS194113
Publisher: Oxford University Press (OUP)
Date: 23-04-2017
Abstract: Incorporating social and economic relationships, together with ecological sustainability objectives into models to provide management advice creates a number of challenges, particularly when this advice requires complex trade-offs between objectives. This is further complicated by differences in quality and quantity of data across fisheries, and difficulties in quantifying some measures, particularly around social objectives and outcomes. Internationally, a wide variety of approaches have been used, some as part of the formal management strategy evaluation process, and others more exploratory. In this paper, we outline the general challenges around incorporating multiple objectives into models for management advice under different levels of data availability. We present three case Australian study fisheries where different approaches have been used to include social, economic and ecological considerations, reflecting the differences in data types and availability. We focus on Australian fisheries as these were among the first in the world to embrace a management objective of maximizing net economic returns as the primary objective of fisheries management, and, more recently, social objectives have increasingly been promoted in fisheries management. Quantifying the latter has created challenges for the development of fisheries models, requiring innovate ways to link the different components.
Publisher: Springer Science and Business Media LLC
Date: 16-10-2012
Publisher: JSTOR
Date: 03-1999
DOI: 10.2307/3677241
Publisher: Bulletin of Marine Science
Date: 2013
Publisher: Elsevier BV
Date: 03-2023
Publisher: Wiley
Date: 05-09-2014
DOI: 10.1111/FAF.12004
Publisher: Bulletin of Marine Science
Date: 2013
Publisher: CSIRO/AFMA Final Report
Date: 2016
Publisher: Springer Science and Business Media LLC
Date: 15-09-2022
Publisher: Elsevier BV
Date: 06-2011
Publisher: Oxford University Press (OUP)
Date: 12-05-2011
Abstract: Plagányi, É. E., Weeks, J. S., Skewes, T. D., Gibbs, M. T., Poloczanska, E. S., Norman-López, A., Blamey, L. K., Soares, M., and Robinson, W. M. L. 2011. Assessing the adequacy of current fisheries management under changing climate: a southern synopsis. – ICES Journal of Marine Science, 68: 1305–1317. Climate change is likely to have a significant impact on both target and non-target marine stocks worldwide, with the concomitant need for management strategies capable of sustaining fishing in future. We use several southern hemisphere fisheries to highlight the likely impacts of climate change at a range of levels, from in idual to population responses, as well as ecosystem ramifications. Ex les span polar (Antarctic krill fishery), temperate (west coast pelagic fishery, abalone and rock lobster), and tropical (Torres Strait rock lobster) commercially important fisheries. Responses of these fisheries to either past observed environmental changes or projected future changes are used to deduce some anticipated implications of climate change for fisheries management, including economic impacts and governance considerations. We evaluate the effectiveness of current single-species assessment models, management strategy evaluation approaches and multispecies assessment models as future management tools to cope with likely climate-related changes. Non-spatial stock assessment models will have limited ability to separate fishery effects from the impacts of climate change. Anthropogenic climate change is occurring at a time-scale relevant to current fisheries management strategic planning and testing. Adaptive management frameworks (with their feedback loops) are ideal for detecting and adapting to changes in target stocks.
Publisher: Wiley
Date: 04-2012
DOI: 10.1890/11-0441.1
Abstract: The nature and impact of fishing on predators that share a fished resource is an important consideration in ecosystem-based fisheries management. Krill (Euphausia superba) is a keystone species in the Antarctic, serving as a fundamental forage source for predators and simultaneously being subject to fishing. We developed a spatial multispecies operating model (SMOM) of krill-predator fishery dynamics to help advise on allocation of the total krill catch among 15 small-scale management units (SSMUs) in the Scotia Sea, with a goal to reduce the potential impact of fishing on krill predators. The operating model describes the underlying population dynamics and is used in simulations to compare different management options for adjusting fishing activities (e.g., a different spatial distribution of catches). The numerous uncertainties regarding the choice of parameter values pose a major impediment to constructing reliable ecosystem models. The pragmatic solution proposed here involves the use of operating models that are composed of alternative combinations of parameters that essentially try to bound the uncertainty in, for ex le, the choice of survival rate estimates as well as the functional relationships between predators and prey. Despite the large uncertainties, it is possible to discriminate the ecosystem impacts of different spatial fishing allocations. The spatial structure of the model is fundamental to addressing concerns of localized depletion of prey in the vicinity of land-based predator breeding colonies. Results of the model have been considered in recent management deliberations for spatial allocations of krill catches in the Scotia Sea and their associated impacts on dependent predator species.
Publisher: Wiley
Date: 07-09-2018
DOI: 10.1111/COBI.13161
Abstract: The decline of coral cover on Australia's Great Barrier Reef (GBR) has largely been attributed to the cumulative pressures of tropical cyclones, temperature-induced coral bleaching, and predation by crown-of-thorns starfish (CoTS). In such a complex system, the effectiveness of any management intervention will become apparent only over decadal time scales. Systems modeling approaches are therefore essential to formulating and testing alternative management strategies. For a network of reefs, we developed a metacommunity model that incorporated the cumulative pressures of tropical cyclones, coral bleaching, predation, and competition between corals. We then tested the response of coral cover to management interventions including catchment restoration to reduce discharge onto the reef during cyclone-induced flood events and enhanced protection of trophic networks supporting predation of CoTS. Model results showed good agreement with long-term monitoring of the GBR, including cyclical outbreaks of CoTS driven by predator-prey dynamics on the network of reefs. Testing of intervention strategies showed that catchment restoration would likely improve coral cover. However, strategies that combined catchment restoration with enhanced CoTS predation were far more effective than catchment restoration alone.
Publisher: Springer Science and Business Media LLC
Date: 23-07-2020
Publisher: Wiley
Date: 28-01-2013
DOI: 10.1111/FME.12015
Publisher: Wiley
Date: 22-08-2017
DOI: 10.1111/FAF.12241
Publisher: Inter-Research Science Center
Date: 31-08-2017
DOI: 10.3354/MEPS12252
Publisher: Elsevier BV
Date: 07-2019
Publisher: Oxford University Press (OUP)
Date: 26-05-2017
Abstract: Policy- and decision-makers require assessments of status and trends for marine species, habitats, and ecosystems to understand if human activities in the marine environment are sustainable, particularly in the face of global change. Central to many assessments are statistical and dynamical models of populations, communities, ecosystems, and their socioeconomic systems and management frameworks. The establishment of a national system that could facilitate the development of such model-based assessments has been identified as a priority for addressing management challenges for Australia’s marine environment. Given that most assessments require cross-scale information, in idual models cannot capture all of the spatial, temporal, biological, and socioeconomic scales that are typically needed. Coupling or integrating models across scales and domains can expand the scope for developing comprehensive and internally consistent, system-level assessments, including higher-level feedbacks in social–ecological systems. In this article, we summarize: (i) integrated modelling for marine systems currently being undertaken in Australia, (ii) methods used for integration and comparison of models, and (iii) improvements to facilitate further integration, particularly with respect to standards and specifications. We consider future needs for integrated modelling of marine social–ecological systems in Australia and provide a set of recommendations for priority focus areas in the development of a national approach to integrated modelling. These recommendations draw on—and have broader relevance for—international efforts around integrated modelling to inform decision-making for marine systems.
Publisher: Wiley
Date: 31-10-2014
Publisher: Elsevier BV
Date: 2011
Publisher: Elsevier BV
Date: 08-2019
Publisher: Springer Science and Business Media LLC
Date: 17-08-2017
Publisher: Elsevier BV
Date: 02-2018
Publisher: The Royal Society
Date: 04-2021
DOI: 10.1098/RSOS.201296
Abstract: On the iconic Great Barrier Reef (GBR), the cumulative impacts of tropical cyclones, marine heatwaves and regular outbreaks of coral-eating crown-of-thorns starfish (CoTS) have severely depleted coral cover. Climate change will further exacerbate this situation over the coming decades unless effective interventions are implemented. Evaluating the efficacy of alternative interventions in a complex system experiencing major cumulative impacts can only be achieved through a systems modelling approach. We have evaluated combinations of interventions using a coral reef meta-community model. The model consisted of a dynamic network of 3753 reefs supporting communities of corals and CoTS connected through ocean larval dispersal, and exposed to changing regimes of tropical cyclones, flood plumes, marine heatwaves and ocean acidification. Interventions included reducing flood plume impacts, expanding control of CoTS populations, stabilizing coral rubble, managing solar radiation and introducing heat-tolerant coral strains. Without intervention, all climate scenarios resulted in precipitous declines in GBR coral cover over the next 50 years. The most effective strategies in delaying decline were combinations that protected coral from both predation (CoTS control) and thermal stress (solar radiation management) deployed at large scale. Successful implementation could expand opportunities for climate action, natural adaptation and socioeconomic adjustment by at least one to two decades.
Publisher: Elsevier BV
Date: 11-2014
Publisher: Elsevier BV
Date: 08-2015
Publisher: Proceedings of the National Academy of Sciences
Date: 11-02-2013
Abstract: Evaluating the success of natural resource management approaches requires methods to measure performance against biological, economic, social, and governance objectives. In fisheries, most research has focused on industrial sectors, with the contributions to global resource use by small-scale and indigenous hunters and fishers undervalued. Globally, the small-scale fisheries sector alone employs some 38 million people who share common challenges in balancing livelihood and lifestyle choices. We used as a case study a fishery with both traditional indigenous and commercial sectors to develop a framework to bridge the gap between quantitative bio-economic models and more qualitative social analyses. For many indigenous communities, communalism rather than capitalism underlies fishers’ perspectives and aspirations, and we find there are complicated and often unanticipated trade-offs between economic and social objectives. Our results highlight that market-based management options might score highly in a capitalistic society, but have negative repercussions on community coherence and equity in societies with a strong communal ethic. There are complex trade-offs between economic indicators, such as profit, and social indicators, such as lifestyle preferences. Our approach makes explicit the “triple bottom line” sustainability objectives involving trade-offs between economic, social, and biological performance, and is thus directly applicable to most natural resource management decision-making situations.
Publisher: Proceedings of the National Academy of Sciences
Date: 29-10-2015
Publisher: Springer Science and Business Media LLC
Date: 09-05-2022
DOI: 10.1038/S41467-022-30213-X
Abstract: Management of coral predators, corallivores, is recommended to improve coral cover on tropical coral reefs under projected increasing levels of accumulated thermal stress, but whether corallivore management can improve coral cover, which is necessary for large-scale operationalisation, remains equivocal. Here, using a multispecies ecosystem model, we investigate intensive management of an invertebrate corallivore, the Crown-of-Thorns Starfish ( Acanthaster cf. solaris ), and show that culling could improve coral cover at sub-reef spatial scales, but efficacy varied substantially within and among reefs. Simulated thermal stress events attenuated management-derived coral cover improvements and was dependent on the level of accumulated thermal stress, the thermal sensitivity of coral communities and the rate of corallivore recruitment at fine spatial scales. Corallivore management was most effective when accumulated thermal stress was low, coral communities were less sensitive to heat stress and in areas of high corallivore recruitment success. Our analysis informs how to manage a pest species to promote coral cover under future thermal stress events.
Publisher: Elsevier BV
Date: 05-2022
Publisher: No publisher found
Date: 2010
Publisher: Wiley
Date: 03-05-2013
DOI: 10.1111/CJAG.12004
Publisher: The Royal Society
Date: 05-11-2015
Abstract: Models provide useful insights into conservation and resource management issues and solutions. Their use to date has highlighted conditions under which no-take marine protected areas (MPAs) may help us to achieve the goals of ecosystem-based management by reducing pressures, and where they might fail to achieve desired goals. For ex le, static reserve designs are unlikely to achieve desired objectives when applied to mobile species or when compromised by climate-related ecosystem restructuring and range shifts. Modelling tools allow planners to explore a range of options, such as basing MPAs on the presence of dynamic oceanic features, and to evaluate the potential future impacts of alternative interventions compared with ‘no-action’ counterfactuals, under a range of environmental and development scenarios. The modelling environment allows the analyst to test if indicators and management strategies are robust to uncertainties in how the ecosystem (and the broader human–ecosystem combination) operates, including the direct and indirect ecological effects of protection. Moreover, modelling results can be presented at multiple spatial and temporal scales, and relative to ecological, economic and social objectives. This helps to reveal potential ‘surprises', such as regime shifts, trophic cascades and bottlenecks in human responses. Using illustrative ex les, this paper briefly covers the history of the use of simulation models for evaluating MPA options, and discusses their utility and limitations for informing protected area management in the marine realm.
Publisher: Elsevier BV
Date: 09-2019
Publisher: Inter-Research Science Center
Date: 09-10-2014
DOI: 10.3354/MEPS10858
Publisher: Oxford University Press (OUP)
Date: 04-12-2008
Abstract: Edwards, C. T. T., Rademeyer, R. A., Butterworth, D. S., and Plagányi, É. E. 2009. Investigating the consequences of Marine Protected Areas for the South African deep-water hake (Merluccius paradoxus) resource. – ICES Journal of Marine Science, 66: 72–81. Protected areas are often touted as important management tools to mitigate the uncertainty inherent in marine ecosystems, and thereby improve the long-term prospects for sustainable resource use. However, although they certainly play an important role in conservation, their usefulness in improving fishery yields is contentious. We present a simulation model that explores spatial closure options, and apply it to the demersal hake trawl fishery off South Africa. The model is based on the age-structured approach used for current assessments, representing the dynamics of the deep-water hake Merluccius paradoxus within a zonally disaggregated spatial system. Fitting the model to two zones, which demarcate a potential closed area from the remaining fished area, we investigate the consequences that such a protected area could have for the fishery. Our model suggests that area closures would have a negligible benefit for the fishery, regardless of the level of hake movement between areas. This is likely the result of the model's simplicity, and we suggest additional factors that should be considered to quantify the impact of Marine Protected Areas on the fishery more reliably.
Publisher: Informa UK Limited
Date: 09-2008
Publisher: Springer Science and Business Media LLC
Date: 12-08-2014
Publisher: Oxford University Press (OUP)
Date: 16-05-2013
Abstract: Essington, T. E., and Plagányi, É. E. Pitfalls and guidelines for “recycling” models for ecosystem-based fisheries management. – ICES Journal of Marine Science, 71: . Ecosystem models have been developed for many marine systems to provide guidance on fisheries management strategies that protect key ecological functions. These models are commonly “recycled”, i.e. applied to new questions or policy concerns after the initial phase of model development, testing, and application. Because decisions about the model structure are typically based on the intended model use, it is important to recognize limits in the capacity of models to address questions for which they were not specifically designed. Here, we evaluate existing foodweb models in the context of their ability to identify key forage species in foodwebs and to test management strategies for fisheries that target them. We find that the depth and breadth with which predator species are represented are commonly insufficient for evaluating sensitivities of predator populations to forage fish depletion. We demonstrate that aggregating predator species into functional groups creates bias in foodweb metrics such as connectance. Models also varied considerably with respect to the extent that they have been tuned or fitted to retrospective patterns and the degree to which key sensitivities are identified. We use this case study to provide several general recommendations when “recycling” ecosystem and foodweb models. Briefly, we suggest as routine procedure careful scrutiny of structural model attributes, of scales at which ecological processes are included, and quality of fits for key functional groups.
Publisher: CSIRO
Date: 2014
Publisher: Wiley
Date: 17-10-2007
DOI: 10.1111/J.1558-5646.2007.00276.X
Abstract: Poor public perceptions and understanding of evolution are not unique to the developed and more industrialized nations of the world. International resistance to the science of evolutionary biology appears to be driven by both proponents of intelligent design and perceived incompatibilities between evolution and a ersity of religious faiths. We assessed the success of a first-year evolution course at the University of Cape Town and discovered no statistically significant change in the views of students before the evolution course and thereafter, for questions that challenged religious ideologies about creation, bio ersity, and intelligent design. Given that students only appreciably changed their views when presented with "facts," we suggest that teaching approaches that focus on providing ex les of experimental evolutionary studies, and a strong emphasis on the scientific method of inquiry, are likely to achieve greater success. This study also reiterates the importance of engaging with students' prior conceptions, and makes suggestions for improving an understanding and appreciation of evolutionary biology in countries such as South Africa with an inadequate secondary science education system, and a dire lack of public engagement with issues in science.
Publisher: Springer Science and Business Media LLC
Date: 25-07-2020
Publisher: Elsevier BV
Date: 02-2023
Publisher: Elsevier BV
Date: 10-2020
Publisher: Wiley
Date: 26-02-2019
DOI: 10.1111/GCB.14573
Publisher: Oxford University Press (OUP)
Date: 10-03-2015
Abstract: Quantitative methods are needed to evaluate the ecological effects of fishing forage species upon which predators depend. African penguin Spheniscus demersus numbers at the Robben Island colony rose during the 1990s co-incidental with a marked increase in sardine Sardinops sagax and anchovy Engraulis encrasicolus abundances, but decreased appreciably during the 2000s as sardine suffered a series of poor recruitments. A population dynamics model is developed which relates penguin adult annual mortality to local sardine biomass, and is fit to penguin moult counts and re-sightings of tagged penguins. The predator–prey interaction is best explained by a sardine–penguin mortality relationship with average penguin survival decreasing only when the local sardine biomass is less than approximately one-quarter of the maximum observed. Results suggest that the rapid growth of the colony during the 1990s was driven primarily by immigration. Penguin projections are generated by linking to future sardine abundances predicted under the operational management procedure used to set catch limits for these sardine and anchovy fisheries, and compared with equivalent scenarios without fishing. Results indicate that fishing is likely to have a relatively small impact on penguins, especially when compared with uncertainties that arise from the variable spatial distribution of the sardine population.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 03-2019
Abstract: Assessment of past fisheries productivity helps to predict and manage future changes
Publisher: CSIRO
Date: 2022
DOI: 10.25919/YNH8-TM70
Publisher: Wiley
Date: 24-09-2023
DOI: 10.1002/EAP.2913
Abstract: Integrated pest management (IPM) leverages our understanding of ecological interactions to mitigate the impact of pest species on economically and/or ecologically important assets. It has primarily been applied in terrestrial settings (e.g. agriculture), but rarely been attempted for marine ecosystems. The crown‐of‐thorns starfish (CoTS), Acanthaster spp . , is a voracious coral predator throughout the Indo‐Pacific where it undergoes large population increases (irruptions), termed outbreaks. During outbreaks CoTS act as a pest species and can result in substantial coral loss. Contemporary management of CoTS on the Great Barrier Reef (GBR) adopts facets of the IPM paradigm to manage these outbreaks through strategic use of direct manual control (culling) of in iduals in response to ecologically based target thresholds. There has, however, been limited quantitative analysis of how to optimise the implementation of such thresholds. Here we use a multispecies modelling approach to assess the performance of alternative CoTS management scenarios for improving coral cover trajectories. Scenarios examined varied in terms of their ecological threshold target, the sensitivity of the threshold, and level of management resourcing. Our approach illustrates how to quantify multidimensional trade‐offs in resourcing constraints, concurrent CoTS and coral population dynamics, stringency of target thresholds, and the geographical scale of management outcomes (number of sites). We found strategies with low target density thresholds for CoTS (≤0.03 CoTS.min ‐1 ) could act as “Effort Sinks” and limit the number of sites that could be effectively controlled, particularly under CoTS population outbreaks. This was because a handful of sites took longer to control which meant other sites were not controlled. Higher density thresholds (e.g. 0.04‐0.08 CoTS.min ‐1 ), tuned to levels of coral cover, diluted resources amongst sites but were more robust to resourcing constraints and pest population dynamics. Our study highlights trade‐off decisions when using an IPM framework and is informing implementation of threshold‐based strategies on the GBR.
Publisher: Springer Science and Business Media LLC
Date: 16-02-2016
Publisher: Wiley
Date: 23-11-2016
DOI: 10.1111/FME.12186
Publisher: Informa UK Limited
Date: 07-2002
Publisher: Wiley
Date: 09-10-2018
DOI: 10.1111/FAF.12326
Publisher: Springer Science and Business Media LLC
Date: 28-07-2020
DOI: 10.1038/S41598-020-69466-1
Abstract: Population outbreaks of Crown-of-Thorns Starfish (COTS Acanthaster spp.) are a major contributor to loss of hard coral throughout the Indo-Pacific. On Australia’s Great Barrier Reef (GBR), management interventions have evolved over four COTS outbreaks to include: (1) manual COTS control, (2) Marine Protected Area (MPA) zoning, and, (3) water quality improvement. Here we evaluate the contribution of these three approaches to managing population outbreaks of COTS to minimize coral loss. Strategic manual control at sites reduced COTS numbers, including larger, more fecund and damaging in iduals. Sustained reduction in COTS densities and improvements in hard coral cover at a site were achieved through repeated control visits. MPAs influenced initial COTS densities but only marginally influenced final hard coral cover following COTS control. Water quality improvement programs have achieved only marginal reductions in river nutrient loads delivered to the GBR and the study region. This, a subsequent COTS outbreak, and declining coral cover across the region suggest their contributions are negligible. These findings support manual control as the most direct, and only effective, means of reducing COTS densities and improving hard coral cover currently available at a site. We provide recommendations for improving control program effectiveness with application to supporting reef resilience across the Indo-Pacific.
Publisher: Elsevier BV
Date: 11-2015
Publisher: National Inquiry Services Center (NISC)
Date: 06-2004
Publisher: Elsevier
Date: 2017
Publisher: Public Library of Science (PLoS)
Date: 30-12-2016
Publisher: National Inquiry Services Center (NISC)
Date: 02-11-2010
Publisher: Elsevier BV
Date: 09-2017
Publisher: Elsevier BV
Date: 02-2014
Publisher: Elsevier BV
Date: 02-2017
Publisher: Springer Science and Business Media LLC
Date: 10-11-2016
Location: Australia
No related grants have been discovered for Eva Plaganyi.