Bioeconomic advice on TAC - the state of the art in the Norwegian fishery management

The total allowable catch (TAC) is a key instrument in the management of several important fish stocks in the Barents and the Norwegian Seas, and advice on TAC levels used to be based purely on biological information and guidelines from the International Council for the Exploration of the Seas (ICES). In 1991, ICES Advisory Committee on Fisheries Management (ACFM) stated that its objective was to provide the advice necessary to maintain viable fisheries within sustainable ecosystems, leaving the actual choice of management strategy and corresponding TAC for stocks within safe biological limits to managers. In arriving at such a choice, managers should ideally state their objectives in exploiting their fish resource, and analyse the relevant consequences of different levels of TAC. Norway is one of the major 'share-holders' in the fish stocks in the Barents and Norwegian Seas and the country's fishery policy reflects several national objectives, as well as international commitments. In the light of these objectives, the 'state of the art' advice on management strategy and corresponding TAC levels given by experts in the Norwegian fishery management is described. Two transboundary stocks, northeast Arctic cod (Gadus morhua) and Norwegian spring spawning herring (Clupea harengus), serve as examples. The advice is built on analyses of biological and economic consequences, and prognoses for 5 and 10 years are used for cod and herring respectively. In the analysis of the cod fishery, we will show how the optimal management strategy or harvest control rule will change when calculating private economic yield rather than social economic yield. Uncertainty attached to the recruitment model of the Norwegian spring spawning herring and the inclusion of such uncertainty in the advice is dealt with explicitly. The objective of this paper is to illustrate some means of applying existing biological and economic knowledge in practical advice on the choice of TAC. (C) 1998 Elsevier Science B.V. All nights reserved.