1. Department of Biology; Centre for Biodiversity Dynamics; Norwegian University of Science and Technology; Realfagbygget NO-7491 Trondheim Norway
2. Norwegian Institute for Nature Research; Høgskoleringen 9 NO-7034 Trondheim Norway
3. Marine Scotland Science Freshwater Laboratory; Faskally; Pitlochry Perthshire PH16 5LB UK
4. USDA Forest Service Northern Research Station; 201 Holdsworth NRC 160 Holdsworth Way Amherst MA 01003 USA
5. Cromarty Firth District Salmon Fisheries Board c/o CKD Galbraith; 17 Old Edinburgh Road Inverness IV2 3HF UK