Untitled - The Future Ocean

objectives. However, the importance of economics in explaining fishing activities and theoverexploitation of resources has, meanwhile, been accepted, and a transition towards anecosystem-based management of marine resources can be observed (Browman and Stergio2004). Traditionally, ecosystem models have been developed to simulate nutrient cycles in theocean with an explicit focus on lower trophic levels (for a review cf. Gentleman 2002). In contrast,models of higher trophic levels have been developed as tools for fishery assessment. Apart from afew exceptions which use simplified mass balance models (Christensen and Pauly 1992), thoseapproaches have not yet been coupled with each other. Wätzold et al. (2006) point outfundamental similarities between ecological and economic approaches. In particular, bothdisciplines use similar methods for the study of the dynamics and stability of systems. Furthermore,ecologists explore the manner in which species maximize reproductive success and survival underfood limitation, while economists examine how humans maximize their well-being under aconstrained budget (Settle et al. 2002). At present, most economic fishery managementapproaches build on equilibrium models, in which the population growth of a single species ismodeled through inverse U-shaped functions. Recent approaches generalize these models byintroducing stochastic parameters (Carson et al. 2005) or introduce new methods, includingviability theory or qualitative differential equations, to deal with knowledge of various qualities (foran overview cf. Luna-Reyes and Andersen 2003). Thus far, state-of-the-art marine ecosystemmodels have not been coupled to economic models.3. Previous and on-going work of the proponentsMajor international and national research projects which address the biological basis forecosystem-oriented marine resource management are coordinated fully or in part at IFM-GEOMAR(Schnack / Froese: GLOBEC, UNCOVER, BECAUSE, INCOFISH). The experimental ecologygroup (Sommer) concentrates on the lower trophic levels (Sommer and Sommer 2005). Climatechange effects are studied within the DFG priority program AQUASHIFT. IFM-GEOMAR hosts theworld's largest compilation of data on fish and fishery (http://www.fishbase.org). The Research andTechnology Center Westcoast (FTZ) in Büsum possesses complementary data on marinemammals and birds. At the CAU Department of Economics, incentives for environmental andresource managing policy instruments are studied. Recently, Moslener and Requate (2006)studied multi-pollution problems. The structure and methodology for dealing with these problems issimilar to multi-species approaches.4. ObjectivesAn examination of the mechanisms of marine resource exploitation indicates that a fundamentalchange in the socio-economic, institutional, and ecological settings is needed to achieve a return tosustainability. Since the majority of bio-economic models draw on single species models and donot reflect dynamic ecosystem interactions or the stochastic nature of processes related to thespecific life strategy of marine organisms, the aim of this JRG is to develop coupled bio-economicmodels which adequately take account of the complexity and the uncertainty of marine65