1. Å. Ø. Pedersen (aashild.pedersen@npolar.no) and E. Fuglei, Norwegian Polar Institute, Fram Centre, N
2. M. Hörnell-Willebrand, Hedmark Univ. College, Dept of Forestry and Wildlife Management, Elverum, Nor
3. J. U. Jepsen, Norwegian Inst. for Nature Research, Fram Centre, Tromsø, Norway. Present address for
4. M. Biuw, Inst. of Marine Research, Tromsø, Norway