Failure to rein in global temperature rises could cause the marine food web to collapse, devastating the livelihoods of tens of millions of people who rely on fisheries for food and income, scientists have warned.

Warming oceans restrict vital energy flows between different species in the marine ecosystem, reducing the amount of food available for bigger animals — mostly fish — at the top of the marine food web, according to a study in the journal PLOS Biology published on Tuesday.

This could have "serious implications" for fish stocks, said Ivan Nagelkerken, a professor of marine ecology at Australia's University of Adelaide and one of the study's authors.