PROSPER 101105250 - MSCA Post Doc European Fellowship 2022 - (Phenotypic diversity and resilience to environmental change in freshwater fish)

Europe's rivers are highly fragmented by human constructed barriers that block the movement of fish, with this fragmentation driving substantial declines in freshwater fish diversity and abundance. The EU Biodiversity Strategy aims to remove riverine barriers wherever possible so that 25000 km more river will be free-flowing in Europe by 2030. However, barrier removal is only occasionally feasible and so engineered fish passes provide alternative re-connection tools. The passes provide an easier route for fish to use to bypass the barrier. Although these fish passes are frequently on rivers with a diverse fish assemblage, they tend to be constructed to primarily facilitate the passage of diadromous fishes, especially anadromous salmonid fishes, despite most fish species being impacted by the fragmentation. This inter-specific selectivity of fish passes is potentially compounded by their intra-specific selectivity, where only specific phenotype groupings are able to use the pass successfully. Thus, while fish passes are used frequently to provide river reconnection in Europe, the extent to which they impose new selection pressures on fish communities - and the associated consequences - remain high uncertain.

Our project overcomes this high uncertainty in fish passage selectivity by bringing together an outstanding European researcher with potential to develop into a global science leader with a research group with strong competencies in fish tracking technologies and fish behaviour assessment. Together, we generate new knowledge on the performance of fish populations and communities using fish passes on the lower River Severn in western Britain through application of the latest biotelemetry methods. We use these data to then build novel agent based models that predict the ecological consequences of barriers and fish passes. These results provide river managers with the knowledge to better resolve river fragmentation that works for all species.