Photo: M. Troell/Azote

Photo: M. Troell

Marine system dynamics

This theme aims to provide a broader and deeper understanding of the resilience and dynamics of marine social-ecological systems

Research within the theme explores and analyses the dynamics of the marine social-ecological systems, and how they are connected to markets and processes that act across different spatial and temporal scales. We aim to synthesize information across case studies that span the tropics (around Australia, Hawaii, the East coast of Africa, South East Asia, and Latin America), the Arctic, as well as temperate systems including the Seas of Norden (e.g. Baltic Sea, Norwegian Sea).

Important research areas within the marine theme include:
- Social-ecological cross-scale interactions
- Global seafood production systems and their links to food security, human wellbeing, and sustainable seafood.
- Transformations of seafood supply chains and consumption patterns.
- Exploring adaptive management approaches.
- Testing regime shifts and CAS theory across marine case studies using modelling and advanced statistics.
- Exploring alternative sustainable development transformations.

Research topics include, for example, coral reef dynamics, fisheries governance, sustainability of aquaculture, marine food-web dynamics, social-ecological health assessments, management implications of global trade dynamics and geopolitics, and sustainable seafood supply chains and fisheries improvements.

The theme uses and tests theories and transdisciplinary methods, including agent based modelling, complex adaptive system modelling, social network analysis, spatial analyses, and qualitative comparison analysis. Researchers of the theme collaborate closely with several other themes and streams at the Stockholm Resilience Centre as well as colleagues at the Stockholm University and other leading international research institutes around the world, including Princeton and Stanford Universities.

Theme contact

Staff details

Theme contact

Theme contact

Thorsten Blenckner



Stepwise function of natural growth for Scylla serrata in East Africa: A valuable tool for assessing growth of mud crabs in aquaculture

Moksnes, P.-O., D.O. Mirera, E. Björkvik, M.I. Hamad, H.M. Mahudi, D. Nyqvist, N. Jiddawi, M. Troell

2015 - Journal / article

Predicting growth is critical in aquaculture, but models of growth are largely missing for mud crab species. Here, we present the first model of natural growth in juvenile and adult mud crabs Scylla serrata from East Africa using a stepwise growth function based on data on intermoult periods and growth at moult from field mark-recapture, pond and laboratory studies. The results showed a sigmoid growth pattern in carapace width and suggest that S. serrata in East Africa will reach 300 g and sexual maturity ~9.9 months after settlement, and a commercial size of 500 g after 12.4 months. Analyses of the literature identified several issues with the common praxis to compare standard growth measures between aquaculture studies with different initial size or growing periods. Using the new growth function to estimate the proportional difference between modelled and obtained growth as an alternative method, we show that growth rates of S. serrata cultured in cage systems, which are dominant in East Africa, was <40% of the estimated natural growth and growth obtained in pond systems. The analysis also indicated that growth rates of S. serrata in Southeast Asia was over 50% higher compared with similar culture systems in East Africa, and that different species of mud crabs had large differences in growth rates. This study shows that growth in the present mud crab aquaculture systems in East Africa is below their expected potential. Further work is needed to identify the factors behind this observation.

Marine regime shifts around the globe: Theory, drivers and impacts

Möllmann, C., C. Folke, M. Edwards, A. Conversi

2015 - Journal / article

This theme issue ‘Marine regime shifts around the globe: theory, drivers and impacts’ has the goal to make a step change towards a more unified understanding of regime shifts in marine ecosystems. Towards this purpose we define ecological regime shifts as ‘dramatic, abrupt changes in the community structure that are persistent in time, encompassing multiple variables, and including key structural species—independently from the mechanisms causing them’. Our definition deliberately includes regime-like changes without evidence of multiple alternative stable states (or multiple basins of attraction), as we think emphasis on this theoretical aspect often hinders progress in considering abrupt changes in marine ecosystem-based management. Our definition is hence more practical for marine management purposes and can be used for both benthic and pelagic regime shifts, even where the link with the mathematical theory is not yet fully established. This special issue brings together experts from different marine science disciplines and trophic level expertise (i.e. benthic ecology, pelagic ecology, fisheries, marine conservation and management), from diverse marine ecosystems, and from a mixture of geographical areas around the globe. More than 80 authors from six continents have contributed to the 16 papers in this issue, around the following themes: (i) advances in marine regime shift theory, (ii) drivers of marine regime shifts and (iii) management of marine regime shifts.

Combining system dynamics and agent-based modeling to analyze social-ecological interactions - an example from modeling restoration of a shallow lake

Martin, R., M. Schlüter

2015 - Journal / article

Modeling social-ecological interactions between humans and ecosystems to analyze their implications for sustainable management of social-ecological systems (SES) has multiple challenges. When integrating social and ecological dynamics, which are often studied separately, one has to deal with different modeling paradigms, levels of analysis, temporal and spatial scales, and data availabilities in the social and ecological domains. A major challenge, for instance, is linking the emergent patterns from individual micro-level human decisions to system level processes such as reinforcing feedbacks determining the state of the ecosystem. We propose building a hybrid model that combines a system dynamics with an agent-based approach to address some of these challenges. In particular, we present a procedure for model development and analysis that successively builds up complexity and understanding of model dynamics, particular with respect to feedbacks between the social and ecological system components. The proposed steps allow for a systematic increase of the coupling between the submodels and building confidence in the model before deploying it to study the coupled dynamics. The procedure consists of steps for (i) specifying the characteristics of the link between the social and ecological systems, (ii) validating the decoupled submodels, (iii) doing sensitivity analysis of the decoupled submodels with respect to the drivers from the respective other subsystem and, finally (iv) analyzing the coupled model. We illustrate the procedure and discuss opportunities and limitations of hybrid models against the background of an archetypical SES case study, namely the restoration of a turbid lake. Our approach exemplifies how a hybrid model is used to unpack SES complexity and analyze interactions between ecological dynamics and micro-level human actions. We discuss the benefits and challenges of combining a system dynamics models as an aggregated view with an agent-based model as a disaggregated view to improve social-ecological system understanding.


Baltic Health Index

The Baltic Health Index is a regional study under the global Ocean Health Index framework. The aim is to provide a tool for decision-makers to guide management of the Baltic Sea region towards increased sustainability. Read more here

Sustainable Poverty Alleviation from Coastal Ecosystem Services (SPACES)

SPACES aims to understand the complex relationship between ecosystem services and the wellbeing of the poor in coastal Kenya and Mozambique. Read more here

Stockholm Resilience Centre is a collaboration between Stockholm University and the Beijer Institute of Ecological Economics at the Royal Swedish Academy of Sciences

Stockholm Resilience Centre
Stockholm University, Kräftriket 2B
Phone: +46 8 674 70 70

Organisation number: 202100-3062
VAT No: SE202100306201