Nick Dulvy, Simon Fraser University (IMAGE) Simon Fraser University Caption SFU marine biodiversity expert Nick Dulvy has co-authored the first research paper to find that one quarter of the world's sharks and rays face extinction. Credit Perry Zavitz Usage Restrictions Please always give credit to photographer License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.