T (Twan) Stoffers, PhD

I am an Assistant Professor of Fish Ecology at the Aquaculture Biology and Fisheries Ecology group (AFI). My work focuses on how fish interact with their environments in large, fragmented river systems. I study fish-habitat relationships, connectivity, and habitat heterogeneity, and how these factors shape fish communities and their resilience to human pressures. A central aim is to inform climate-resilient restoration of river–floodplain systems that support riverine and migratory fishes. I also carry out complementary research on tropical marine species, particularly elasmobranchs in the Dutch Caribbean, which broadens my perspective on the ecological consequences of human activities.

Methodologically, I combine field ecology with fish tagging, stable isotope analysis, environmental DNA, and ecological modelling to understand movement, habitat use, and food-web links across spatial and temporal scales. During my PhD and postdoctoral work I investigated restored floodplains in the lower Rhine as nursery and feeding habitats, showing how ontogenetic habitat shifts and permanent connectivity underpin effective restoration. I have also worked at larger scales to evaluate how measures such as floodplain reconnection, riparian restoration, and bypass channels influence fish communities across diverse river contexts.

I coordinate the Global Swimways Initiative’s migratory fish database, which compiles and standardises information on more than 2400 freshwater migratory species to support international conservation, including a technical report for the Convention on Migratory Species. In Europe, I contribute to science-policy dialogue on restoring free-flowing rivers, including the opportunities and challenges of implementing the EU Nature Restoration Regulation. My overarching vision is to link robust ecological evidence with practical restoration and policy so that river management delivers biodiversity recovery alongside benefits for water quality, flood risk reduction, and society.