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AN OPTIMAL MANAGEMENT MODEL FOR INTENSIVE AQUACULTURE - AN APPLICATION IN ATLANTIC SALMON AgEcon
Hean, Robyn L..
In this paper the optimal management strategy for intensive aquaculture is viewed in terms of a combined strategy of releasing the optimal number of recruits and harvesting those recruits at the optimal harvesting time. A model which can be used to determine the optimal management strategy is developed. In the model the optimal harvesting model documented by Bjorndahl (1988, 1990) in which harvesting and feed costs are considered, is extended by including release costs and how they influence the optimal number of recruits. The model forms the basis for an empirical analysis in which the optimal management strategy for a yearclass of Atlantic salmon farmed in Australia during 1989-91 is considered.
Tipo: Journal Article Palavras-chave: Environmental Economics and Policy; Research Methods/ Statistical Methods.
Ano: 1994 URL: http://purl.umn.edu/22426
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Carbon-accounting methods and reforestation incentives AgEcon
Cacho, Oscar J.; Hean, Robyn L.; Wise, Russell M..
The emission of greenhouse gases, particularly carbon dioxide, and the consequent potential for climate change are the focus of increasing international concern. Temporary land-use change and forestry projects (LUCF) can be implemented to offset permanent emissions of carbon dioxide from the energy sector. Several approaches to accounting for carbon sequestration in LUCF projects have been proposed. In the present paper, the economic implications of adopting four of these approaches are evaluated in a normative context. The analysis is based on simulation of Australian farm–forestry systems. Results are interpreted from the standpoint of both investors and landholders. The role of baselines and transaction costs are discussed.
Tipo: Journal Article Palavras-chave: Resource /Energy Economics and Policy.
Ano: 2003 URL: http://purl.umn.edu/116186
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Downstream benefits vs upstream costs of land use change for water-yield and salt-load targets in the Macquarie Catchment, NSW AgEcon
Nordblom, Thomas L.; Hume, Iain H.; Finlayson, John D.; Kelly, Jason A.; Welsh, Rob; Hean, Robyn L..
The net present value (NPV) of downstream economic benefits of changes in water-yield (W) and salt-load (S) of mean annual river flow received by a lower catchment from an upper catchment are described as a 3-dimensional (NPV,W, S) surface, where dNPV/dW > 0 and dNPV/d(S/W) < 0. Upstream changes in land use (i.e. forest clearing or forest establishment, which result in higher or lower water-yields, respectively) are driven by economic consequences for land owners. This paper defines conditions under which costs of strategic upstream land use changes could be exceeded by compensations afforded by downstream benefits from altered water-yields and/or lower salt loads. The paper presents methods, and preliminary calculations for an example river,...
Tipo: Conference Paper or Presentation Palavras-chave: Policy markets upstream downstream water; Salinity Land Economics/Use.
Ano: 2007 URL: http://purl.umn.edu/10355
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Minimising costs of environmental service provision: water-yield, salt-load and biodiversity targets with new tree planting in Simmons Creek Catchment, NSW, a dryland farming/grazing area. AgEcon
Nordblom, Thomas L.; Hume, Iain H.; Cresswell, Hamish; Glover, Mark; Hean, Robyn L.; Finlayson, John D.; Wang, Enli.
Although dryland farming and grazing have been practiced for over 130 years in the 17,000 ha Simmons Creek catchment without surface salinity problems, the area has been identified as a significant source of salt seepage to Billabong Creek in the NSW Murray catchment. Groundwater movement and salinity levels are spatially heterogenous at Simmons Creek. Groundwater of the upper catchment is relatively fresh and seemingly unconnected with the highly saline groundwater of the lower catchment. However, fresh surface water does flow from the upper to the lower catchment. This spatial diversity provokes the question of where high-water-use forest habitats might be placed to achieve different combinations of environmental services (greater water yield, lower...
Tipo: Conference Paper or Presentation Palavras-chave: Optimisation; Opportunity costs; Forest-habitat; Environmental services; Environmental Economics and Policy.
Ano: 2007 URL: http://purl.umn.edu/10357
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OPTIMAL MANAGEMENT OF GIANT-CLAM FARMING IN SOLOMON ISLANDS AgEcon
Hean, Robyn L.; Cacho, Oscar J..
Giant-clam farming is undertaken by coastal villagers in Solomon Islands as part of a research and development project of the International Center for Living Aquatic Resources Management (ICLARM). The production technology is simple and does not require a large capital investment. The main inputs are clam seed, labour and time. Labour is used for activities such as seeding, cleaning, thinning and harvesting. In this paper, a bioeconomic model is used to explore optimal farm management. The theoretical basis for this analysis is found in the economic theory of optimal forestry exploitation. The management variables considered are husbandry applied to cleaning and the frequency with which thinning is undertaken. The optimal cycle-length is determined...
Tipo: Working or Discussion Paper Palavras-chave: Bioeconomics; Giant clams; Subsistence mariculture; Farm Management.
Ano: 1999 URL: http://purl.umn.edu/12935
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Temporary carbon storage and discount rates AgEcon
Hean, Robyn L.; Cacho, Oscar J.; Menz, Kenneth M..
Several approaches have been proposed for accounting for temporary carbon sequestration in land-use change and forestry projects that are implemented to offset permanent emissions of carbon dioxide from the energy sector. In a previous paper, we evaluated the incentives provided by some of these approaches. In this paper, we investigate further what we call the “ideal” accounting system, where the forest owner would be paid for carbon sequestration as the service is provided and redeem payments when the forest is harvested and carbon is released back into the atmosphere. We demonstrate how discounting affects the net present value of the forest when carbon sequestration is taken into account under this ideal system. Not all carbon is released back into the...
Tipo: Conference Paper or Presentation Palavras-chave: Carbon accounting; Reforestation; Discounting; Bioeconomics; Environmental Economics and Policy; Land Economics/Use.
Ano: 2003 URL: http://purl.umn.edu/57888
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The Potential Role of Farm Forestry in the Wheat-Sheep Zone of NSW AgEcon
Hean, Robyn L.; Cacho, Oscar J.; Signor, Anthony; Mullen, John D..
The focus of this paper is the role of farm forestry in farming systems in the NSW wheatsheep zone. The wheat-sheep zone suffers from significant land degradation problems, and the environmental and economical sustainability of many farming systems is in question. Farm forestry provides the opportunity to diversify farmer incomes, increase agricultural productivity and provide environmental solutions. It is therefore proposed that the potential role of farm forestry in the wheat-sheep zone is to provide an environmentally and economically sustainable future for farming systems, through tree planting for multiple benefits. A general model is developed for the purpose of economic analysis of agroforestry systems in the wheat-sheep zone using a bioeconomic...
Tipo: Presentation Palavras-chave: Farm forestry; Farming systems; Bioeconomics; Resource /Energy Economics and Policy.
Ano: 2000 URL: http://purl.umn.edu/123659
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