Browsing by Author "Soares, Muri"
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- ItemRestrictedAssessing the adequacy of current fisheries management under changing climate: a southern synopsis(Oxford University Press, 2011) Plagányi, Éva E; Weeks, Scala J; Skewes, Tim D; Gibbs, Mark T; Blamey, Laura K; Soares, Muri; Robinson, William M L; Poloczanska, Elvira S; Norman-Lopez, AnnaClimate 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 individual to population responses, as well as ecosystem ramifications. Examples 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 climaterelated 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
- ItemMetadata onlyAssessing the adequacy of current fisheries management under changing climate:a southern synopsis(ICES Journal of Marine Science, 2012) Plagányi, Éva E; Weeks, Scala J; Skewes, Tim D; Gibbs, Mark T; Blamey, Laura K; Soares, Muri; Robinson, William M L; Norman-Lopez, AnnaClimate 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 individual to population responses, as well as ecosystem ramifications. Examples 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 climaterelated 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
- ItemOpen Access
- ItemOpen AccessA model of a rangeland grazing system within a management procedure approach framework(2007) Soares, Muri; Plagányi, Éva; Hoffmann, Timm; Richardson, David MarkA model describing livestock grazing system dynamics was developed and fitted to available data. This study preliminarily explored the use of a formal management procedure (MP) approach to determine appropriate annual offtake in a terrestrial system. This approach has been applied in marine systems with great success, but has never been tried in terrestrial ecosystems. Rangelands and marine systems have in common the fact that there is often an offtake component to them and so stakeholders in those systems need knowledge of optimal harvesting strategies within defined management strategies. Three models were developed that described the growth of female goats in Paulshoek. The first (basic livestock model) depicted the growth of livestock as a logistic equation with an adult survival term and an annual growth term. The second model (rainfall-livestock model) added a rainfall component, with livestock productivity modelled as a function of rainfall. The final version of the model (vegetation-rainfall-livestock model) added a vegetation component that interacted with rainfall and livestock. The rainfall-livestock model provided a statistically significant better fit to the data, followed by the vegetation-rainfall model. The vegetation-rainfall-livestock model provided a reasonable representation of livestock population changes through time, with the largest deviations evident over the period 1975-1980. Results show that environmental factors alone are unable to fully explain observed system dynamics because anthropogenic factors for which no data are available may also play a role. Preliminary exploration with a simple MP suggested that a low offtake rate of 10% provided the highest average annual offtake. Our study has shown that a rangeland stocking system can be reasonably described by a simple model that uses only rainfall data and a rainfall-vegetation-livestock interaction. Rangeland livestock systems would benefit greatly from adopting an MP approach as it would allow stakeholders to make informed decisions on stocking rates and annual offtake.