The Economics of Multispecies Harvesting

The aim of this study is twofold: to provide a theoreti cal and an applied analysis of multispecies fisheries. The theoretical part will include concepts and analysis which, hopefully, will be of interest not only to economists, but also to biologists and ecologists. The application of the theoreti cal model and analysis to the Barents Sea fisheries gives empiri cal content to the analysis, which is important for the advance ment of fisheries management science. It is also my firm belief that this kind of work in the end will be beneficial to the people trying to make a living from harvesting marine resources. For thousands of years man has been whaling, sealing and fishing in these cold and harsh surroundings. The relative importance of the different species in the ecosystem has changed throughout history. In the seventeenth century the abundant, slow-swimming Greenland right whale and the Biscayan right whale in the Barents Sea area were so valuable, especially to English and Dutch whalers, that the intensive exploitation of these common property resources probably were the main reason for the extinction of these two stocks. The two species are, however, still present in other parts of the North Atlantic Ocean. Except for these two stocks of whales there is no knowledge of other stocks of sea mammals or fish in this area being extinct in historical time.

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This book is about the economics of multispecies harvesting of renewable resources. The aim is to provide both a theoretical and an applied analysis of multispecies fisheries. The applied part is devoted to the North Atlantic fisheries of the Barents Sea area, and special emphasis is put on the interactions between sea mammals and fish. The theoretical part of the book includes discussion and analysis of the effect on the optimal stocks from changes in the prices, costs and the discount rate. Among the new results is the possibility of an increased optimal resource stock from a rise in the discount rate. Also, a method is derived for the computation of the maximum sustainable yield frontier (MSF) in the three species case. The applied part comprises the paradoxical result of higher levels of fish stocks in the optimal regulated fisheries than under open access. The fish stocks should be even higher than they were in the pristine ecological system before man started his exploitation. This is possible because of the reduced stock of sea mammals at the optimum. The book should be of interest to economists, ecologists and other academics with an interest in resource management, and to managers of marine resources.

Contenu

1. Introduction.- 2. A Two Species Model.- 3. A Three Species Model.- 4 The Maximum Sustainable Yield Frontier.- 5 The Ecological System of the Barents Sea.- 6 Estimating Biological Parameters of the Three Species Barents Sea Model.- 7 Economic Aspects of Multispecies Fisheries.- 8 Estimating Economic Parameters of the Three Species Barents Sea Model.- 9 Optimal Solutions of the Three Species Barents Sea Model.- 10. Open Access Solutions.- 11. Summary and Conclusion.- Appendices.