tailieunhanh - Bioeconomic model of eastern baltic cod under the influence of nutrient enrichment

The ob jective of this paper is to study the economic management of Eastern Baltic cod (Gadus morhua) under the influence of nutrient enrichment. Average nitrogen concentration in the spawning areas during the spawning season of cod stock is chosen to be an indicator of nutrient enrichment. | N AT U R A L R E S O U R C E M O D E L IN G Vo lu m e 2 6 , N u m b e r 2 , M ay 2 0 1 3 BIOECONOMIC MODEL OF EASTERN BALTIC COD UNDER THE INFLUENCE OF NUTRIENT ENRICHMENT NGUYEN VIET THANH ∗ Centre for Fisheries & Aquaculture Management & Economics (FAME), Department of Environmental and Business Economics, University of Southern Denmark, Denmark Faculty of Development Economics, VNU University of Economics and Business, Vietnam E-mail: thanhmpa@ Abstract. The objective of this paper is to study the economic management of Eastern Baltic cod (Gadus morhua) under the influence of nutrient enrichment. Average nitrogen concentration in the spawning areas during the spawning season of cod stock is chosen to be an indicator of nutrient enrichment. The optimal cod stock is defined using a dynamic bioeconomic model for the cod fisheries. The results show that the current stock level is about half of the estimated optimal stock level and that the current total allowable catch (TAC) is about one-fourth of the optimal equilibrium yield. The results also indicate that the benefit from a reduction in nitrogen very much depends on the harvest policies. If the TAC is set equal to the optimal equilibrium yield, the benefit of a nitrogen reduction from the 2009 level to the optimal nitrogen level would be about 604 million DKK over a 10-year time horizon, given a discount rate of 4% per year. However, if a recovery management plan is chosen, the benefit would only be about 49 million DKK over a 10-year time horizon. Key Words: Bioeconomic model, Eastern Baltic cod, eutrophication. 1. Introduction. The objective of this paper is to study the economic management of Eastern Baltic cod (Gadus morhua) under the influence of nutrient enrichment. This fish stock inhabits the regions East of Bornholm in the ICES’ (The International Council for the Exploitation of the Sea) subdivisions 25–32, and its spawning season begins in early March and ends in September–October (Bagge and Thurow .