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• 1. [Article] The cost of fisheries induced evolution. An example using data for North-East Atlantic cod

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  Citation × Citation Citation Abstract Copy Title: The cost of fisheries induced evolution. An example using data for North-East Atlantic cod Author: Reithe, Siv Abstract only. Title: The cost of fisheries induced evolution. An example using data for North-East Atlantic cod Author: Reithe, Siv Abstract only. Close

• 2. [Article] Growth Overfishing

  Growth overfishing squanders large parts of the potential rents in fisheries. Many of today’s fisheries are characterized by a severely truncated age-distribution, which in addition may have irreversible ...

  Citation × Citation Citation Abstract Copy Title: Growth Overfishing Author: Diekert, Florian K. Growth overfishing squanders large parts of the potential rents in fisheries. Many of today’s fisheries are characterized by a severely truncated age-distribution, which in addition may have irreversible ecological consequences. Nevertheless, the implications of age-differentiated harvesting for management have received surprisingly little attention in the literature. In the present paper, optimal and non-cooperative exploitation paths for a generic age-distributed resource are derived. We show that, in the case of perfect selectivity, competition between two agents is sufficient to dissipate all rents. Akin to the classical Bertrand competition in prices, each agent has an incentive to target fish at a younger age. That is, the “race to fish” extends to the dimension of age. This observation is crucial also with respect to management: Individual quotas are not able to restore efficiency unless accompanied by gear regulation. Moreover, it turns out that quotas specified in terms of numbers are far superior to those specified in terms of volume or value. Title: Growth Overfishing Author: Diekert, Florian K. Growth overfishing squanders large parts of the potential rents in fisheries. Many of today’s fisheries are characterized by a severely truncated age-distribution, which in addition may have irreversible ecological consequences. Nevertheless, the implications of age-differentiated harvesting for management have received surprisingly little attention in the literature. In the present paper, optimal and non-cooperative exploitation paths for a generic age-distributed resource are derived. We show that, in the case of perfect selectivity, competition between two agents is sufficient to dissipate all rents. Akin to the classical Bertrand competition in prices, each agent has an incentive to target fish at a younger age. That is, the “race to fish” extends to the dimension of age. This observation is crucial also with respect to management: Individual quotas are not able to restore efficiency unless accompanied by gear regulation. Moreover, it turns out that quotas specified in terms of numbers are far superior to those specified in terms of volume or value. Close

• 3. [Article] Fisheries induced evolution. A review

  Abstract only.

  Citation × Citation Citation Abstract Copy Title: Fisheries induced evolution. A review Author: Primicerio, Raul, Reithe, Siv Abstract only. Title: Fisheries induced evolution. A review Author: Primicerio, Raul, Reithe, Siv Abstract only. Close

• 4. [Article] Appreciating the value of age: An evaluation of efficiency gains from controlling gear selectivity under various scenarios

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  Citation × Citation Citation Abstract Copy Title: Appreciating the value of age: An evaluation of efficiency gains from controlling gear selectivity under various scenarios Author: Diekert, Florian Abstract only Title: Appreciating the value of age: An evaluation of efficiency gains from controlling gear selectivity under various scenarios Author: Diekert, Florian Abstract only Close

• 5. [Article] Age-Structured Ecological-Economic Multi-Species Models for Baltic Sea Fisheries

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  Citation × Citation Citation Abstract Copy Title: Age-Structured Ecological-Economic Multi-Species Models for Baltic Sea Fisheries Author: Quaas, Martin Abstract Only Title: Age-Structured Ecological-Economic Multi-Species Models for Baltic Sea Fisheries Author: Quaas, Martin Abstract Only Close

• 6. [Article] The Spawners' Shadow price: Joint Production of Recruitment and Growth in Agestructured Fish Populations

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  Citation × Citation Citation Abstract Copy Title: The Spawners' Shadow price: Joint Production of Recruitment and Growth in Agestructured Fish Populations Author: Voss, Rudi, Quaas, Martin Abstract Only Title: The Spawners' Shadow price: Joint Production of Recruitment and Growth in Agestructured Fish Populations Author: Voss, Rudi, Quaas, Martin Abstract Only Close

• 7. [Article] Age, Period, of Birth Cohort: What Determines Demographic Differences in Seafood Consumption?

  Research Paper

  Citation × Citation Citation Abstract Copy Title: Age, Period, of Birth Cohort: What Determines Demographic Differences in Seafood Consumption? Author: Lund, Eiliv, Trondsen, Torbjorn, Scholderer, Joachim Research Paper Title: Age, Period, of Birth Cohort: What Determines Demographic Differences in Seafood Consumption? Author: Lund, Eiliv, Trondsen, Torbjorn, Scholderer, Joachim Research Paper Close

• 8. [Article] Optimal Management of the Baltic Sea Fishery Under Climate Change: An Ecological-Economic Age-Structured Multi-Species Model Analysis

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  Citation × Citation Citation Abstract Copy Title: Optimal Management of the Baltic Sea Fishery Under Climate Change: An Ecological-Economic Age-Structured Multi-Species Model Analysis Author: Voss, Rüdiger, Neuenfeldt, Stefan, Quaas, Martin F., Schmidt, Jörn O. Abstract only. Title: Optimal Management of the Baltic Sea Fishery Under Climate Change: An Ecological-Economic Age-Structured Multi-Species Model Analysis Author: Voss, Rüdiger, Neuenfeldt, Stefan, Quaas, Martin F., Schmidt, Jörn O. Abstract only. Close

• 9. [Article] Determining Optimal Catch in Age-Structural Multispecies Fisheries

  This study investigates optimal catch of Barents Sea stocks, namely Northeast Arctic Cod and Capelin in multispecies ecosystem. We solve a multispecies age structured bioeconomic model for predator-prey ...

  Citation × Citation Citation Abstract Copy Title: Determining Optimal Catch in Age-Structural Multispecies Fisheries Author: Steinshamn, Stein Ivar, Poudel, Diwakar This study investigates optimal catch of Barents Sea stocks, namely Northeast Arctic Cod and Capelin in multispecies ecosystem. We solve a multispecies age structured bioeconomic model for predator-prey interaction. Barents Sea stock data from ICES are employed for model application. Among others, we also include sustainability constraint in the model that contributes towards ecosystem based management of fishery. Our preliminary result suggests that a conservative harvest is optimal for capelin compared to the single species model and a higher harvest is possible in cod in multispecies model. Furthermore, we found that a pulse fishing yields higher value in cod (predator) compared to the uniform (current) fishing policy. Title: Determining Optimal Catch in Age-Structural Multispecies Fisheries Author: Steinshamn, Stein Ivar, Poudel, Diwakar This study investigates optimal catch of Barents Sea stocks, namely Northeast Arctic Cod and Capelin in multispecies ecosystem. We solve a multispecies age structured bioeconomic model for predator-prey interaction. Barents Sea stock data from ICES are employed for model application. Among others, we also include sustainability constraint in the model that contributes towards ecosystem based management of fishery. Our preliminary result suggests that a conservative harvest is optimal for capelin compared to the single species model and a higher harvest is possible in cod in multispecies model. Furthermore, we found that a pulse fishing yields higher value in cod (predator) compared to the uniform (current) fishing policy. Close

• 10. [Article] Contribution of Children in Artisanal Fisheries to Households’ Poverty Alleviation in Ondo State, Nigeria

  Despite the global clamour for the eradication of child labour in agriculture, children in developing countries continue to be prominent actors in the fisheries sector though their contribution is unrecorded ...

  Citation × Citation Citation Abstract Copy Title: Contribution of Children in Artisanal Fisheries to Households’ Poverty Alleviation in Ondo State, Nigeria Author: Mafimisebi, Taiwo Ejiola, Fasina, Oluwatosin Despite the global clamour for the eradication of child labour in agriculture, children in developing countries continue to be prominent actors in the fisheries sector though their contribution is unrecorded in the national income accounts of many countries. The study examined the involvement of children in artisanal fisheries in Ondo State, Nigeria. Simple random sampling procedure was used to select 90 children aged 9-18 years who were involved in artisanal fishing activities. Descriptive statistics were used to present the data gathered for the study. Pearson Product Moment Correlation and the Chi-Square analysis were used to test the study hypotheses at the 0.05 level of significance. Respondents were mostly males (70%) with mean age of 15 ± 2 years. Fishing experience for two-thirds was over 7 years. Major economic activities engaged in by children were fishing (100.0%) and fish marketing (97.8%). All respondents fished more on rivers, lakes, creeks and canals with friends mostly in the mornings (70.0%) between 4-5am (43.3%). Mean daily catch per caput per day amounted in monetary terms to N317. Income increased significantly with age of children (r = 0.27, p< 0.05). Respondents’ major constraint was lack of capital to purchase nets and boats of their own (97.8%). Sustainable involvement of children in artisanal fisheries can help alleviate poverty as the children remitted their incomes to their parents for food, school fees or other school needs. Children’s capacity for production can be boosted through capacity building and greater access to fishing equipment and capital assets used in fishing. Scholarship programmes should be put in place to encourage children who do well at both school and fishing to further develop the quality of future manpower available for fishing in the coastal areas. Title: Contribution of Children in Artisanal Fisheries to Households’ Poverty Alleviation in Ondo State, Nigeria Author: Mafimisebi, Taiwo Ejiola, Fasina, Oluwatosin Despite the global clamour for the eradication of child labour in agriculture, children in developing countries continue to be prominent actors in the fisheries sector though their contribution is unrecorded in the national income accounts of many countries. The study examined the involvement of children in artisanal fisheries in Ondo State, Nigeria. Simple random sampling procedure was used to select 90 children aged 9-18 years who were involved in artisanal fishing activities. Descriptive statistics were used to present the data gathered for the study. Pearson Product Moment Correlation and the Chi-Square analysis were used to test the study hypotheses at the 0.05 level of significance. Respondents were mostly males (70%) with mean age of 15 ± 2 years. Fishing experience for two-thirds was over 7 years. Major economic activities engaged in by children were fishing (100.0%) and fish marketing (97.8%). All respondents fished more on rivers, lakes, creeks and canals with friends mostly in the mornings (70.0%) between 4-5am (43.3%). Mean daily catch per caput per day amounted in monetary terms to N317. Income increased significantly with age of children (r = 0.27, p< 0.05). Respondents’ major constraint was lack of capital to purchase nets and boats of their own (97.8%). Sustainable involvement of children in artisanal fisheries can help alleviate poverty as the children remitted their incomes to their parents for food, school fees or other school needs. Children’s capacity for production can be boosted through capacity building and greater access to fishing equipment and capital assets used in fishing. Scholarship programmes should be put in place to encourage children who do well at both school and fishing to further develop the quality of future manpower available for fishing in the coastal areas. Close