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• 11. [Article] Participation in Vessel Buyback Programs: An Option Value Model of the Vessel-Scrapping Decision

  Research Paper

  Citation × Citation Citation Abstract Copy Title: Participation in Vessel Buyback Programs: An Option Value Model of the Vessel-Scrapping Decision Author: Chen, Chin-Chen, Lee, Yao-Hsien, Ching-Ta, Chung Research Paper Title: Participation in Vessel Buyback Programs: An Option Value Model of the Vessel-Scrapping Decision Author: Chen, Chin-Chen, Lee, Yao-Hsien, Ching-Ta, Chung Research Paper Close

• 12. [Article] An Ecological-Economic Simulation Model of Genetic interaction Between Farmed and Wild Salmon

  Abstract only.

  Citation × Citation Citation Abstract Copy Title: An Ecological-Economic Simulation Model of Genetic interaction Between Farmed and Wild Salmon Author: Hindar, Kjetil, Liu, Yajie, Skonhoft, Anders, Diserud, Ola Abstract only. Title: An Ecological-Economic Simulation Model of Genetic interaction Between Farmed and Wild Salmon Author: Hindar, Kjetil, Liu, Yajie, Skonhoft, Anders, Diserud, Ola Abstract only. Close

• 13. [Article] Generalization of Age-Structured Models in Theory and Practice

  A generalization of the harvesting functions and the stock updating functions in age-structured bioeconomic models is outlined. Using this generalization everything from completely uniformly distributed ...

  Citation × Citation Citation Abstract Copy Title: Generalization of Age-Structured Models in Theory and Practice Author: Steinshamn, Stein Ivar A generalization of the harvesting functions and the stock updating functions in age-structured bioeconomic models is outlined. Using this generalization everything from completely uniformly distributed fish to extreme schooling is taken care of. The classical Beverton-Holt model comes out as a special case of the generalized model. Both the theoretical outline as well as practical numerical examples are provided, and the generalization can be applied both for simulation as well as optimization purposes given appropriate software. Here we apply advanced non-linear programming to maximize the net present value in a bioeconomic setting where the new updating and harvesting functions are used as constraints. This is possible thanks to new software, such as KNITRO, for solving highly nonlinear problems. Applications of this generalized model produce interesting new results. One such practical result is that pulse fishing seems to become less and less economically profitable as we move from uniformly distributed fish to schooling species. The main reason why pulse fishing cease to be optimal in schooling fisheries, is that the economies of scale present in search fisheries gradually disappear when we move from search fisheries to schooling fisheries. This may have important implications for how fish stocks ought to be managed in the future, especially with respect to total allowable catches based on bioeconomic criteria. Title: Generalization of Age-Structured Models in Theory and Practice Author: Steinshamn, Stein Ivar A generalization of the harvesting functions and the stock updating functions in age-structured bioeconomic models is outlined. Using this generalization everything from completely uniformly distributed fish to extreme schooling is taken care of. The classical Beverton-Holt model comes out as a special case of the generalized model. Both the theoretical outline as well as practical numerical examples are provided, and the generalization can be applied both for simulation as well as optimization purposes given appropriate software. Here we apply advanced non-linear programming to maximize the net present value in a bioeconomic setting where the new updating and harvesting functions are used as constraints. This is possible thanks to new software, such as KNITRO, for solving highly nonlinear problems. Applications of this generalized model produce interesting new results. One such practical result is that pulse fishing seems to become less and less economically profitable as we move from uniformly distributed fish to schooling species. The main reason why pulse fishing cease to be optimal in schooling fisheries, is that the economies of scale present in search fisheries gradually disappear when we move from search fisheries to schooling fisheries. This may have important implications for how fish stocks ought to be managed in the future, especially with respect to total allowable catches based on bioeconomic criteria. Close

• 14. [Article] Viability of Transboundary Fisheries and International Quota Sharing

  This paper examines the viability of the management of a transboundary resource, the Bay of Biscay anchovy (Engraulis encrasicolus L.). A deterministic model is used to simulate the anchovy dynamics, with ...

  Citation × Citation Citation Abstract Copy Title: Viability of Transboundary Fisheries and International Quota Sharing Author: Curtin, Richard, Martinet, Vincent This paper examines the viability of the management of a transboundary resource, the Bay of Biscay anchovy (Engraulis encrasicolus L.). A deterministic model is used to simulate the anchovy dynamics, with the fish stock consisting of two age groups, “young" and “old", while recruitment follows a Beverton Holt pattern. Two countries, France and Spain, harvest the resource, with two different types of gear, the purse seiner for Spain and the pelagic trawler for France. These technologies impact the different age-groups of anchovy at differing rates. A regulatory agency defines an annual fishing quota and its allocation between the two countries, with the aim of sustainability in the overall allocation design. A set of constraints is defined to describe the sustainability of the system which encompasses the economic, ecological and social aspects of the fishery. The optimal harvest share between the two countries is found and a number of scenarios are then tested in relation to their ability to remain within the set of constraints, or viability kernel. Other scenarios, including the historical trajectory, the optimal harvest share trajectory and the minimum time of crisis trajectory, are examined. Title: Viability of Transboundary Fisheries and International Quota Sharing Author: Curtin, Richard, Martinet, Vincent This paper examines the viability of the management of a transboundary resource, the Bay of Biscay anchovy (Engraulis encrasicolus L.). A deterministic model is used to simulate the anchovy dynamics, with the fish stock consisting of two age groups, “young" and “old", while recruitment follows a Beverton Holt pattern. Two countries, France and Spain, harvest the resource, with two different types of gear, the purse seiner for Spain and the pelagic trawler for France. These technologies impact the different age-groups of anchovy at differing rates. A regulatory agency defines an annual fishing quota and its allocation between the two countries, with the aim of sustainability in the overall allocation design. A set of constraints is defined to describe the sustainability of the system which encompasses the economic, ecological and social aspects of the fishery. The optimal harvest share between the two countries is found and a number of scenarios are then tested in relation to their ability to remain within the set of constraints, or viability kernel. Other scenarios, including the historical trajectory, the optimal harvest share trajectory and the minimum time of crisis trajectory, are examined. Close

• 15. [Article] Market-Based Size Selection in the Bering Sea Pollock Fishery

  Abstract only.

  Citation × Citation Citation Abstract Copy Title: Market-Based Size Selection in the Bering Sea Pollock Fishery Author: Haynie, Alan, Ianelli, James Abstract only. Title: Market-Based Size Selection in the Bering Sea Pollock Fishery Author: Haynie, Alan, Ianelli, James Abstract only. Close

• 16. [Article] From Shark Fin Markets to Shark Populations: An Integrated Market Preference Cohort Analysis Of the Blacktip Shark (Carcharhinus limbatus)

  The increasing demand for shark fins in Asia and the shark s life history pattern of slow growth, late maturity, and few offspring, have generated concerns regarding the sustainability of shark resources. ...

  Citation × Citation Citation Abstract Copy Title: From Shark Fin Markets to Shark Populations: An Integrated Market Preference Cohort Analysis Of the Blacktip Shark (Carcharhinus limbatus) Author: Fong, Quentin S.W., Anderson, James L. Year: 2001 The increasing demand for shark fins in Asia and the shark s life history pattern of slow growth, late maturity, and few offspring, have generated concerns regarding the sustainability of shark resources. Despite this concern, little effort has been spent on understanding the markets for shark fin products and the population dynamics of sharks. This work incorporates the results of a conjoint analysis of dried processed shark fins from Hong Kong into a cohort model of the balcktip shark with the objective of maximizing the utility of Hong Kong shark fin importers/processors. Results show that optimal harvest sizes and ages for all mortality and discount factor scenarios are greater than the maturation sizes and ages for both male and female blacktip. Policy implications for this study are also discussed. Title: From Shark Fin Markets to Shark Populations: An Integrated Market Preference Cohort Analysis Of the Blacktip Shark (Carcharhinus limbatus) Author: Fong, Quentin S.W., Anderson, James L. Year: 2001 The increasing demand for shark fins in Asia and the shark s life history pattern of slow growth, late maturity, and few offspring, have generated concerns regarding the sustainability of shark resources. Despite this concern, little effort has been spent on understanding the markets for shark fin products and the population dynamics of sharks. This work incorporates the results of a conjoint analysis of dried processed shark fins from Hong Kong into a cohort model of the balcktip shark with the objective of maximizing the utility of Hong Kong shark fin importers/processors. Results show that optimal harvest sizes and ages for all mortality and discount factor scenarios are greater than the maturation sizes and ages for both male and female blacktip. Policy implications for this study are also discussed. Close

• 17. [Article] The Stability of Rent Maximization in the Western and Central Pacific Fishery

  The potential for achieving sustainable and efficient harvesting of three species of migratory tuna in the Western and Central Pacific Ocean is examined. The stocks reside in exclusive economic zones (mainly ...

  Citation × Citation Citation Abstract Copy Title: The Stability of Rent Maximization in the Western and Central Pacific Fishery Author: Kennedy, John, Hannesson, Rögnvaldur The potential for achieving sustainable and efficient harvesting of three species of migratory tuna in the Western and Central Pacific Ocean is examined. The stocks reside in exclusive economic zones (mainly those of Pacific island countries) and in the high seas. Most harvesting is carried out by distant water fishing nations, including the USA, Japan, Taiwan, China and Korea. Problems of achieving sustainability and efficiency in the harvesting of the stocks by disparate countries are made more difficult due to changes in the harvesting levels of one fleet affecting the rents of another fleet through changes in the age distribution of stock. These types of problem are under review by the Western and Central Pacific Fisheries Commission. Results from an age-structured steady-state bioeconomic model are used to show: the changes in fleet rents and catches of tuna if all fleets form a cooperative grand coalition to deploy fishing effort to maximize rents over the region; the likely non-stability of the grand coalition; and the inferior Nash Equilibria outcomes if fleets fish non-cooperatively to maximize their own rents. Title: The Stability of Rent Maximization in the Western and Central Pacific Fishery Author: Kennedy, John, Hannesson, Rögnvaldur The potential for achieving sustainable and efficient harvesting of three species of migratory tuna in the Western and Central Pacific Ocean is examined. The stocks reside in exclusive economic zones (mainly those of Pacific island countries) and in the high seas. Most harvesting is carried out by distant water fishing nations, including the USA, Japan, Taiwan, China and Korea. Problems of achieving sustainability and efficiency in the harvesting of the stocks by disparate countries are made more difficult due to changes in the harvesting levels of one fleet affecting the rents of another fleet through changes in the age distribution of stock. These types of problem are under review by the Western and Central Pacific Fisheries Commission. Results from an age-structured steady-state bioeconomic model are used to show: the changes in fleet rents and catches of tuna if all fleets form a cooperative grand coalition to deploy fishing effort to maximize rents over the region; the likely non-stability of the grand coalition; and the inferior Nash Equilibria outcomes if fleets fish non-cooperatively to maximize their own rents. Close

• 18. [Article] Optimal Harvest in a Multispecies Age Structured Fishery Model at Different Level of Density Dependency

  Presentation

  Citation × Citation Citation Abstract Copy Title: Optimal Harvest in a Multispecies Age Structured Fishery Model at Different Level of Density Dependency Author: Poudel, Diwakar Presentation Title: Optimal Harvest in a Multispecies Age Structured Fishery Model at Different Level of Density Dependency Author: Poudel, Diwakar Presentation Close

• 19. [Article] Economics of Fish Harvesting in Nigeria: A Case Study of Yola North Local Government Area of Adamawa State

  Powerpoint Presentation and Research Paper

  Citation × Citation Citation Abstract Copy Title: Economics of Fish Harvesting in Nigeria: A Case Study of Yola North Local Government Area of Adamawa State Author: Adebayo, Elizabeth Powerpoint Presentation and Research Paper Title: Economics of Fish Harvesting in Nigeria: A Case Study of Yola North Local Government Area of Adamawa State Author: Adebayo, Elizabeth Powerpoint Presentation and Research Paper Close

• 20. [Article] Misplaced Concreteness: Prospects and Problems with Interdisciplinary Approaches to the Fisheries

  In an age of increasing complexity, simple answers no longer suffice, but the demand for greater sophistication is itself at odds with an era of growing specialization. Researchers must thus incorporate ...

  Citation × Citation Citation Abstract Copy Title: Misplaced Concreteness: Prospects and Problems with Interdisciplinary Approaches to the Fisheries Author: Tayloe, Joseph E. III Year: 2001 In an age of increasing complexity, simple answers no longer suffice, but the demand for greater sophistication is itself at odds with an era of growing specialization. Researchers must thus incorporate information from specialists in other fields. This trend in interdisciplinary research contains hidden challenges, however, including a necessary familiarity with the development, ideas, major questions, and dominant institutions of those disciplines. Title: Misplaced Concreteness: Prospects and Problems with Interdisciplinary Approaches to the Fisheries Author: Tayloe, Joseph E. III Year: 2001 In an age of increasing complexity, simple answers no longer suffice, but the demand for greater sophistication is itself at odds with an era of growing specialization. Researchers must thus incorporate information from specialists in other fields. This trend in interdisciplinary research contains hidden challenges, however, including a necessary familiarity with the development, ideas, major questions, and dominant institutions of those disciplines. Close