Co-management constitutes a certain type of institutional arrangement that has gained increased attention among both policy makers and researchers involved in the field of natural resource management. Yet the concept of co-management is broad, and our knowledge about how different kinds of management structures affect the ability to deal with challenges pertinent to the commons is limited. One of these challenges is to foster an adaptive management process, i.e., a process in which rules are continuously revised and changed according to what is known about the ecological system. We aim to address the relationship between different kinds of co-management structures and adaptive management. To this end, we conducted a comparative case study of two Fishery Conservation Areas in Sweden. The concept of networks and the formal method of social network analysis are applied as theoretical and methodological devices. Building on previous research, we propose that adaptive management processes occur in co-management networks consisting of a heterogeneous set of actors that are centrally and densely integrated. Networks of this kind are believed to promote a management process in which actors with disparate perspectives and resources formulate a common view regarding the condition of the ecosystem, the basic problem to be solved, and what measures to adopt. The empirical findings support the existence of such a relationship. Nonetheless, the restricted empirical material, an inability to control for hidden variables, and a lack of success in determining causality among variables are all factors that call for more research.

The challenge of establishing adaptive management systems is a widely discussed topic in the literature on natural resource management. Adaptive management essentially focuses on achieving a governance process that is both sensitive to and has the capacity to continuously react to changes within the ecosystem being managed. The adoption of a network approach that perceives governance structures as social networks, searching for the kind of network features promoting this important feature, has been requested by researchers in the field. In particular, the possibilities associated with the application of a formal network approach, using the tools and concepts of social network analysis (SNA), have been identified as having significant potential for advancing this branch of research. This paper aims to address the relation between network structure and adaptability using an empirical approach. With the point of departure in a previously generated theoretical framework as well as related hypotheses, this paper presents a case study of a governance process within a fish management area in Sweden. The hypotheses state that, although higher levels of network density and centralisation promote the rule-forming process, the level of network heterogeneity is important for the existence and spread of ecological knowledge among the actors involved. According to the empirical results, restricted by the single-case study design, this assumption is still a well-working hypothesis. However, in order to advance our knowledge concerning these issues and test the validity of the hypotheses, more empirical work using a similar approach in multiple case study designs is needed.

Social robustness is a neglected but crucial component of fisheries management. We present a conceptual framework for evaluating social robustness and we apply it to the analysis of four case studies. We understand social robustness to be a combination of two factors that allow a management regime to adapt to a broad range of potential ecological, economic and political situations: acceptance by stakeholders, reflected in how they perceive and respond to management, and capacity for institutional learning, the process in which institutions change in reaction to internal or external socio-economic or ecological pressures. We apply five hypotheses about social robustness to four European case studies of innovations in fisheries management in the Baltic Sea, the Faroe Islands, the North Sea and the Western Shelf. The innovations represent a range of systems that incorporate both rights-based management, including transferable effort allocations, and participatory governance. The overall conclusions are that the innovations of the Faroe Islands and the North Sea are socially robust with relatively high degrees of stakeholder acceptance and the ability, in many situations, to institutionally learn. In the Basque fisheries, innovations seem to be socially robust with high institutional learning, but low in stakeholders' acceptance. The Baltic innovations seem to be less socially robust compared to the other cases.

The aim of this paper is to provide insights into how implementation of co-management systems can be a way in building trust between authorities and the users of a CPR. It is shown that a new co-management system can be developed and "triggered" by an ecological crisis and that trust and social networks are crucial factors for successful institutional development.The trawl fishery for vendus (Coregonus albula) in the northern part of the Gulf of Bothnia, has been top-down regulated by the State. At the beginning of the 1990s, catches started to decrease dramatically. In response to the poor performance of the fishery, a co-management system, with sharing of power and responsibilities between the authorities and the trawl fishermen, was implemented.It is concluded that managing fisheries with unexpected changes and complexity in linked social-ecological systems requires actors who learn from failures and, when necessary, initiate and achieve institutional change. The creation of social-ecological resilience can be looked upon as a process - a socially generated collective good - which is likely to result in better governance systems. In this context, the role of institutions in building adaptive capacity and supporting collective rationality is important.