THE NEW-MEMBER PROBLEM IN THE COOPERATIVE MANAGEMENT OF HIGH SEAS FISHERIES

This paper discusses the threat that new members pose to the cooperative agreements in the management of straddling and highly migratory fish stocks and the possible solutions to this problem. In particular, the main solutions proposed in the fisheries literature are explored-namely the "transferable membership," the "waiting period" and the "fair sharing rule." The analysis is illustrated by a typical highly migratory species: the northern Atlantic bluefin tuna. The application of the analysis to the bluefin tuna fishery case study shows that, at present, the threat of the new members is not sufficient for the breakdown of the cooperative agreement. The simulation results for this case study show that both the "transferable membership" and the "fair sharing rule" solutions solve the potential new member threat.Resource /Energy Economics and Policy,

OPTIMAL MANAGEMENT OF THE NORTHERN ATLANTIC BLUEFIN TUNA

This paper analyzes the optimal management of the Northern Atlantic bluefin tuna, both eastern and western stocks. The analysis is based on a deterministic multi-gear and age-structured bioeconomic model. In order to assess the importance of the gear structure in this fishery, the model is optimized in two scenarios. In the first, the strategies are restricted to the gear mix of the base year, whereas in the second, the optimal gear mix is estimated. For both scenarios, optimal constant strategies are determined. The corresponding optimal use is then compared with an open-access scenario. Also, optimal non-constant strategies are explored. As expected, the gear structure of the fishery proved to be highly relevant in the optimal payoffs. In particular, the unrestricted strategies yield rents substantially higher than the restricted ones. Also, the optimal management of the bluefin tuna fishery, in both the East and West Atlantic, would imply significant reallocation of the gear shares.Resource /Energy Economics and Policy,

MANAGEMENT OF THE NORTHERN ATLANTIC BLUEFIN TUNA: AN APPLICATION OF C-GAMES

This paper considers the prospects for cooperative multilateral management of the North Atlantic bluefin tuna fisheries in accordance with the United Nations (UN) Agreement on Straddling Fish Stocks and Highly Migratory Fish Stocks signed in December 1995. A three-players characteristic function game (c-game) is used to analyze the cooperative agreements. The analysis focuses on the sharing of total net returns from cooperation. Three sharing rules are calculated; namely, the Nucleolus, the Shapley value, and the Nash bargaining solution. The analysis is based on simulation and optimization results from a multi-gear, age-structured, bioeconomic model developed for the North Atlantic bluefin tuna fisheries, East and West stocks. The results show, as expected, that significant gains can be attained from cooperation. The different sharing rules for the distribution of gains provide different returns to each player. Nonetheless, the basic transfer payments structure is rather stable. This case study points out some particular situations where these solutions are not enough to guarantee cooperation between all the coastal states.Resource /Energy Economics and Policy,

Forest vintages and carbon sequestration

In the current paper we examine the role of forest carbon sequestration benefits in optimal forest management. When carbon benefits are considered not only the forested area is relevant, but also the flow of carbon between land and the atmosphere through the carbon cycle. To account for all these impacts a multi-vintage forest setting is used, following Salo and Tahvonen (2004). The model is extended to three different carbon accounting methods to measure the benefits form carbon sequestration: carbon flow regime, tonne-year crediting and average storage. In the case of the carbon flow regime, the impact on the optimal management and allocation of land will depend upon the amount of carbon released when the forest is harvested. Under the other two accounting systems optimal steady state forest area will be increased, and in cases where optimal management imply cyclical harvesting, considering carbon benefits will always increase cycles dimension.

The Hyperbolic Forest Owner

This paper examines the implications of quasi-hyperbolic inter-temporal preferences to the Faustman model. The use of decreasing discount rates leads to dynamically inconsistent behavior. To solve this problem a two-stages optimization decision model is developed. The resulting actual cutting time will be anticipated compared to the Faustman optimal cutting time. If, alternatively, the equivalent constant rate of discount is the empirically observed discount rate, then the optimal cutting time is the same, but the present value of profits for the hyperbolic forest owner is always higher than the one resulting from the equivalent constant discount rate. All these results apply to both the single and the multiple rotation problems.Hyperbolic discounting; time preference; dynamic inconsistency; Faustman model; optimal rotation

Continuous versus Discrete Time Forest Management Models with Carbon Sequestration Benefits

Forest literature uses both continous and discrete time models to study forest management problems, and when carbon sequestration benefits are considered, the results obtained in both approaches are not always equivalent. This issue is relevant from a policy point of view if credits are to be allocated to forest owners within the implementation of the Kyoto Protocol. This note explores the impact of different carbon sequestration accounting methods on both settings. It studies the specific conditions for optimal rotation period and the value of a marginal unit of bare land on a one stand model and compare them with the long run optimal stationary steady state of a forest vintage model.N/

Forest Vintages and Carbon Sequestration

In the current paper we examine the role of forest carbon sequestration benefits in optimal forest management. When carbon benefits are considered not only the forested area is relevant, but also the flow of carbon between land and the atmosphere through the carbon cycle. To account for all these impacts a multi-vintage forest setting is used, following Salo and Tahvonen (2004). The model is extended to three different carbon accounting methods to measure the benefits form carbon sequestration: carbon flow regime, tonne-year crediting and average storage. In the case of the carbon flow regime, the impact on the optimal management and allocation of land will depend upon the amount of carbon released when the forest is harvested. Under the other two accounting systems optimal steady state forest area will be increased, and in cases where optimal management imply cyclical harvesting, considering carbon benefits will always increase cycles dimension.N/

The Role of Forests as Carbon Sinks: Land-Use and Carbon Accounting

The use of forests as carbon sinks is examined by introducing carbon sequestration benefits’ accounting in a multi-vintage land allocation model. Following the IPCC, three carbon accounting methods are considered. We compare the results in each case with those without carbon sequestration, as well as the performances of the ton-year and the average methods (second-best) to the carbon flow (first-best) concerning optimal land allocation between forestry and alternative uses, total carbon sequestered, timber production and social welfare. A full proof of long-run optimality of steady state forest is provided. Numerical simulations are performed and results discussed illustrating the setup’s potential.Land Allocation Model, Forest Vintages, Carbon Sequestration, Carbon Accounting, Optimal Rotation, Transition/steady-state

The Hyperbolic Forest Owner

This paper examines the implications of quasi-hyperbolic inter-temporal preferences to the Faustman model. The use of decreasing discount rates leads to dynamically inconsistent behavior. To solve this problem a two-stages optimization decision model is developed. The resulting actual cutting time will be anticipated compared to the Faustman optimal cutting time. If, alternatively, the equivalent constant rate of discount is the empirically observed discount rate, then the optimal cutting time is the same, but the present value of profits for the hyperbolic forest owner is always higher than the one resulting from the equivalent constant discount rate. All these results apply to both the single and the multiple rotation problems.N/

Leaf mineral element content and soil characteristics on in vitro antioxidant and enzymatic inhibitory activities of aqueous fennel extracts

his study was conducted to evaluate the biochemical characterization of three harvested Foeniculum vulgare plants collected from two bioclimatic zones in order to investigate the soil growing conditions effect. The results showed a great variability of the phenolic amounts and biological properties of samples rely on localities. FvSEN contained the highest amounts of phenolic compounds. These amounts were accompanied by the greatest antioxidant ability through almost studied assays. FvSEN and FvZO were significantly different. In addition, the samples exhibited a significant and variable enzymatic inhibition activity with values ranging from 30 to 50 mu g/mL for lipoxygenase assay. But these extracts did not revealed significant differences on their tyrosinase abilities. On the other hand, the levels of mineral elements were also estimated. These contents varied depending on sample and locality. The growing soil conditions of samples in terms of different parameters is likely related to their antioxidant and enzyme inhibition potentialities added to their mineral composition which settled by Spearman's correlation. These data may confirm the interesting potential of F. vulgare as a valuable source for natural antioxidant molecules but the growing soil conditions can affect all the potentialities of these plants set for human consumption and other uses.UID/O/00350/2020, UIDB/05183/2020info:eu-repo/semantics/publishedVersio