Ep22of24. Freshwater eels are explored this week, as Sian Griffiths reports from the Ottawa River Valley in Canada where hydropower dams are disrupting the American eel's migration paths, and Brett Westwood speaks with David Bunt from the Sustainable Eel Group to discuss similar issues with European eels. Joanna Pinnock looks the furry clawed invasive species; the Chinese mitten crab and the problems they cause for British habitats. Also in the programme - news from around the world with our regular news reporter, Kelvin Boot. Presenter: Brett Westwood. Producer: Sheena Duncan. Editor: Julian Hector.