1. Department of Ecology and Vertebrate Zoology, Faculty of Biology and Environmental Protection; University of Łódź; 12/16 Banacha Str. 90-237 Łódź Poland
2. Salmon & Freshwater Team; Centre for Environment, Fisheries and Aquaculture Science, Pakefield Road; Lowestoft NR33 0HT U.K.
3. Centre for Conservation Ecology and Environmental Science; Bournemouth University, Poole; Dorset U.K.