[10] De Vos had served as a senior programme officer in the marine and coastal unit of the International Union for Conservation of Nature.

She discovered through her research that an unrecognized unique population of blue whales, previously thought to migrate every year, stayed in waters near Sri Lanka year-round.

De Vos is an invited member of the IUCN Species Survival Commission's Cetacean Specialist Group.

[12][13] She is the founder and director of the non-profit Oceanswell, Sri Lanka's first marine conservation research and education organization.

She argues that "parachute science", the practice of Western scientists collecting data in developing countries and then leaving without training or investing in the locals or region, is unsustainable and cripples conservation efforts.