He is a professor at the Department of Biology at the Norwegian University of Science and Technology (NTNU) in Trondheim, Norway, where he is the leader of the animal physiology section.

[4][5][6][7] In 2006 he graduated with a PhD at the University of Gothenburg, Sweden, with the thesis The intestinal epithelium of salmonids : transepithelial transport, barrier function and bacterial interactions.

[8] After finishing his PhD, he was a postdoc at the University of Gothenburg in collaboration with the Norwegian Institute of Marine Research in Bergen, Norway.

[12] It had earlier been suggested that coral reef fishes were threatened by ocean acidification causing severe behavioural abnormalities.

They recently performed a large artificial selection experiment, published in Proceedings of the National Academy of Sciences of the United States of America (PNAS), showing that evolution of tolerance to warming can occur in fish.