The Economics of Marine Ecosystem Services - the Fisheries Case

PhD defence

Lars Ravensbeck


The thesis “The Economics of Marine Ecosystem Services − the Fisheries Case” focuses on some of the issues in marine resources economics that have attracted significant interest in recent years. Historically, the central issue has been fisheries economics and how to management fish stocks to obtain maximum resource rent. Since the late 1990s, focus has tilted towards a broader scope drawing the attention to the importance of ecosystems for human welfare by viewing ecosystems as capital assets. This approach is the point of departure for the thesis. By focusing on fish stocks as a major component in the formation of flows of ecosystem services from the oceans it is possible to integrate classical fisheries economics with a broader ecosystem approach. The core element of the thesis is the combination of fisheries economics, an ecosystem approach and extended, applied bioeconomic models. The thesis consists of five papers, but additionally five other documents have been authored or co-authored in relation to the thesis.

The first document is a book chapter that surveys the state of art in some main areas related to green accounting and the links to economic value of ecosystem services particularly those related to fish stocks. The second paper develops a framework for assessing green growth in fisheries. It explains and analyses fisheries role in “green growth” and how rebuilding fisheries stocks play a role in “greening” the economy. Also it highlights the importance of using an incentive-based management system which is able to take into account all benefits provided by the ecosystem.

The third document, a working paper, applies an ecosystem based management perspective on the exploitation of the marine resources using a modelling approach. A general framework and bioeconomic model are developed and it is analysed how ecosystem services will influence the methodologies used for assessing the resources as well as the possible regulation of the fisheries and other marine resources. The model applied takes a broader range of ecosystem services as well as species interactions into account. A numerical version of the model is created in order to analyse the relative complex settings. In general, the analyses show that if species interaction, external damage and non-market values linked to the fish stocks are taken into account, fishing effort should be reduced compared to the effort levels recommended by models that operate in a single species framework. Particularly a conventional MSY (maximum sustainable yield) based policy seems less useful in this context. The review in the paper gives the background for integrating relevant elements into the bioeconomic model.

The fourth document is an interdisciplinary paper that assesses the increasing conflict between public interests to conserve natural resources and commercial fisheries. The grey seal-fishery case in the Baltic Sea is a textbook example of such a conflict. The approach is a combination of bioeconomics and standard cost-benefit analyses. Direct costs associated with grey seals are large compared to the indirect costs of forgone fishing opportunities. The benefits outweigh the indirect costs, but are significant lower than the direct costs. The results indicate that it would be socio-economic beneficial to reduce the seal population, but difficulties in evaluating all economic benefits from the grey seal population make a final conclusion about the socio-economic optimal grey seal population difficult to draw. The consequence of the absence of a common Baltic Sea management plan for grey seals may in the long run force fishermen using passive gear to either leave the industry or shift to fishing methods with active gear types. Alternatives management options are discussed.

The focus in last paper is on the complicated case where several pelagic stocks are exploited by different fleets from various countries. A static model is developed to analyse the long term welfare effects of different management strategies and applied to estimate gains by reallocating quotas between fleets and countries. Furthermore, the paper assesses the importance of taking the value chain into consideration and not focus on resource rent creation alone. The model is applied to the pelagic fisheries in the Northeast Atlantic. The analysis shows that the main source for welfare improvement by a better management of the North Atlantic pelagic fisheries is the linked to the harvest sector (rent gains) and less is obtained through gains in the value chain.

The papers examine and outline how the management of marine resources can include a broader set of ecosystems services and environmental goals whilst maintaining objectives of efficiency and sustainability through green accounting and application of green growth. Furthermore, the papers give new insights into the research field “the economics of marine ecosystem services” and the applied model work extends the present trend in the field. In particular, the models demonstrate how species interaction and range of ecosystem services can be included and assessed using a relatively simple approach.


Peder Andersen, Professor, Deputy Head of Department, Department of Food and Resource Economics, University of Copenhagen, Denmark

Assesment Committee

Jesper Levring Andersen, Associate Professor, Department of Food and Resource Economics, University of Copenhagen, Denmark

Berit Hasler, Head of Section, Senior Researcher, Aarhus Univeristy, Denmark

Simon Mardle, Researcher and Independent Consultant and Director, Fishor Consulting Ltd,  UK.