Modelling Eco-System Services using AGE-structured approaches (MESSAGE)

Population and economic growth result in increased greenhouse gas emissions that affect the productivity of our oceans as well as the services provided by ecosystems. Analysis of ecosystem services must be performed by ecosystem modelling. Ecosystem modelling is much more than traditional multi-species modelling, as some may think. For one thing, in order to include a large variety of ecosystem services, it must also include more stakeholders than traditional bioeconomic models, which typically include only those who are directly involved in the harvesting activity, consumers of marine products and possibly managers. A good ecosystem model should look at the problem from the viewpoint of the society as a whole. In particular, it should involve the aquaculture sector, the land-based processing industry, recreational fishers and tourism in addition to the harvesting sector. It must also include external effects of the economic activities such as pollution and direct and indirect pressure on biodiversity. Indirectly, it therefore includes the whole population. We will adaptat existing models at SNF and NHH to the research questions mentioned above which is the aim of the proposed project. Another important objective in this project is to analyze how, and to what extent, different types of fisheries, vessels and gear contribute to or challenge sustainability of fisheries and ecosystems. Deliverables from the project include advice both on the degree of exploitation and type of exploitation with respect to gear as well as type of fishery (commercial versus recreational, industrial versus artisanal, etc.) In the reporting period 2016/2017 there have been published 10 scientific articles, of which 9 in international journals and one Norwegian. These articles have covered areas such as effort-quotas (WP1), uncertainty and fishermen behavior (WP1), ecology and fisheries-induced evolution as factors of dynamic development (WP2) and economic multi-species models where the interaction between species is taking place in the market and not in the biology (WP4). In addition, there have been given 9 presentations at seminars/conferences, of which 8 international (English) and one Norwegian. These have been on the same subjects as mentioned above. One highlight among the results this period is that by integrating multi-species modelling in the management instead of the traditional MSY (maximum sustainable yield) and MEY (maximum economic yield) approaches, net return can be increased by some 25 percent. During the reporting period 2017-2018, 4 new international articles have been published and 17 lectures given at international workshops and conferences. Themes have varied from more biological aspects such as the effect of size-selective mortality on maturation and growth and the effect of density on recruitment and growth through bioeconomic effects of artificial reefs to game-theoretic approaches to possible collaborative constellations and coalition structures before and after Brexit. An analysis of productivity and profitability in the purse seine fleet was presented at the Directorate of Fisheries. This study shows that profitability has increased due to higher prices, but productivity has decreased. The reason is that the large investments have not contributed to higher catches. An important result of the latter work is that the possibility of having stable coalitions declines with the number of players and therefore decreases as a result of Brexit since the UK has to be considered as an additional player and no longer as part of the EU's common fisheries policy. Also in the period 2018 - 2019, 4 new articles were published in international journals, and 17 presentations were given at workshops and conferences around the world. An international workshop was also held in Bergen in May. The topics of the international publications have varied from continuous age-structured modeling and analysis of pulse fishing to the study of density-dependent regulation and rebuilding of fish stocks. In the former, it is found that continuous age-structured modeling complements the discrete age-structured models as they make the analysis more transparent and produce results that would be difficult to find in the classical models. The latter shows that the decline in many of the North Atlantic fish stocks before the year 2000 is due to lack of, or poor management. After 2007, one has seen the opposite trend where improved management has accompanied growth in the stocks. There is, however, still room for further improved management. In the final phase of the project, a major report on Northeast Arctic cod and a doctoral dissertation on game theoretic aspects were completed and a closing workshop was held.

A pervasive feature in many of the articles is how economic performance of various fisheries can be increased and management improved by replacing existing management practices with more sophisticated ones. For example, for the NEA cod fishery by taking multi-fleet aspects into account in an age-structured model, or for selected pelagic fisheries by redistributing quotas or using active multi-species modelling, to mention a few examples. We believe that this line of thinking will gradually be absorbed by decision makers as well. We will continue the effort to convey these messages to politicians, bureaucrats and other decision makers by publishing the results as much as possible, and present them both at large conferences and more exclusive meetings and seminars at the Ministry of trade, industry and fisheries, and the Directorate of fisheries. In addition to the articles already published, there are several recently submitted articles with final decision pending.

Analysis of ecosystem services must be performed by ecosystem modelling. Ecosystem modelling is much more than traditional multi-species modelling, as some may think. For one thing, in order to include a large variety of ecosystem services, it must also include more stakeholders than traditional bioeconomic models, which typically include only those who are directly involved in the harvesting activity, consumers of marine products and possibly managers. A good ecosystem model should look at the problem from the viewpoint of the society as a whole. In particular, it should involve the aquaculture sector, the land-based processing industry, recreational fishers and tourism in addition to the harvesting sector. It must also include external effects of the economic activities such as pollution and direct and indirect pressure on biodiversity. Indirectly, it therefore includes the whole population. During the period 2012-2015 two projects were performed at SNF financed by NFR called AGAMEM and "International Management of Pelagic Fisheries in the Northeast Atlantic". Both projects have been highly successful and resulted in a large number of international publications, reports, working papers and presentations at international conferences. Important research tasks have been further development of age-structured models, for example by making them continuous in time and age. This facilitates both analytical and numerical study. These models are well suited for adaptation to the research questions mentioned above which is the aim of the proposed project. The project is divided in four work packages: 1 Fishers behavior and response to environmental and economic changes. 2 Linking market and marine ecosystem through fish prices. 3 Analysis of different fleet categories and gear types and their contribution to ecosystem services. 4 Multi-species age-structured models.