India, March 18 -- Marine conditions in the North Pacific have significantly reduced suitable habitat for Japanese chum salmon over the past 25 years, according to new research from Hokkaido University.

Known in Japan simply as "shirozake," or salmon, chum salmon can be recognised by their faint vertical stripes and silvery sides.

Today, most of the salmon consumed in Japan is imported from countries like Chile and Norway, according to the Ministry of Agriculture, Forestry and Fisheries. But just two decades ago, Japanese chum salmon made up a much larger share of domestic salmon consumption, according to a statement by the university.

Researchers from the Arctic Research Center at the university found that suitable marine habitats for...