The mucus now covers a huge area of the fjord. "We are talking about millions of cubic metres," says Roger B. Larsen, who teaches at the Arctic University of Norway in Tromso. "The images we are picking up from the echo sounders and other equipment are totally atypical," he tells the NRK broadcaster , adding that the substance has a consistency similar to margarine. Mr Larsen, a fisheries expert, says he has been taking annual trips to the area and has "never seen anything like this in these fjords".