1. Department of Aquaculture and Fish Biology; Hólar University College; Háskólinn á Hólum; Sauðárkrókur Iceland
2. Institute of Life- and Environmental Sciences; University of Iceland; Reykjavík Iceland
3. Department of Aquatic Ecology, Eawag; Swiss Federal Institute of Aquatic Science and Technology; Dübendorf Switzerland
4. Institute of Integrative Biology; ETH Zürich; Zürich Switzerland
5. Institute of Zoology; University of Graz; Universitätsplatz 2; Graz Austria