Helene Marsh is an internationally recognised leader in the field of conservation science. Her leadership in marine mammal population assessment and protected area management has played a key role in shaping the best practice management used in the Great Barrier Reef, northern Australia and in developing countries. She has played key roles in the design of major research programs and published syntheses of mammal conservation science methods that have set global standards. Her work as a teacher and manager of graduate studies, and her contribution to scientific societies and editorial boards of science journals has been outstanding.