Greg Stone is chief ocean scientist at Deep Green. Stone’s Pew fellowship focused on reducing marine mammal bycatch in the South Pacific. He collaborated with fishers, environmentalists, and scientists in New Zealand to test the effectiveness of pingers—acoustic devices that emit sounds—to warn away the endangered Hector’s dolphin and thus prevent entanglement and unintended death. As a result, Stone developed a course on marine mammals and bycatch mitigation for the University of the South Pacific. In addition, he explored funding mechanisms to expand use of such mitigation measures throughout the region.