The Colne Valley Regional Park has more than 200km of rivers and canals, and 60 lakes, home to 16 native fish species including Dace, Pike and European Eel. Large proportions of these species are migratory and need free and easy passage along watercourses to reach different habitats they need at crucial stages of their lifecycle, e.g. spawning sites, sheltering from predators and recruitment of juveniles into the population. Migratory distance varies from species to species. Dace (Leuciscus leuciscus), for example, travel up to 16km between freshwater streams throughout their lives. The European Eel, (Anguilla anguilla), a ‘critically endangered’ species, travels more than 5,000km from its spawning grounds in the Sargasso Sea to European river systems. Maintaining free passage is crucial to the long-term survival of coarse fish species.
The Colne Valley Regional Park has more than 35 man-made structures, such as weirs and sluices built to serve watermills dating back to the industrial periods. To mitigate their negative effect on fish migration, the Landscape Partnership Scheme includes a ‘fish passage’ project. Its aim is to improve migration routes for fish in the Colne Valley by modifying historic man-made structures along the river to include special highways known as fish passes.