News Oceans ‘Jet packs’ and ultrasounds could reveal secrets of pregnant whale sharks Until now, our knowledge of pregnancy in the world’s largest living fish came from one female Two researchers scuba dive beside a female whale shark in the Galápagos Islands to learn more about how the world’s largest fish reproduces. S. Pierce Share this:EmailFacebookTwitterPinterestPocketRedditPrint By Brianna Randall April 7, 2023 at 7:00 am How do you know if the world’s largest living fish is expecting babies? Not by her bulging belly, it turns out. Scientists thought that an enlarged area on the undersides of female whale sharks was a sign of pregnancy.