Unravelling socio-material complexities in river connectivity restoration: Understanding fishways as heterogeneous networks

In the context of river connectivity restoration, fishways play a crucial role in facilitating the migration of fish past barriers, but their form and functionality are often determined by various sociomaterial complexities. This study uses the case of fishway development in the Waterschap Brabantse Delta management area of the Netherlands to explore such complexities. Taking a network approach, we investigated the implementation and management of fishways as a process of assembling heterogeneous networks that involve both human and nonhuman actors. Using data from interviews, field observations and document analysis, the research revealed fishways to be networks of actors that included fish, engineers and maintenance personnel. We further demonstrate that fishways are embedded as actors, or 'nodes', within broader networks that exert a reciprocal influence on their functioning. By following fishways across different phases of their development trajectory and tracing the participation or withdrawal of actors, we explore changes in the networks and their subsequent impact on fishway design and performance.