He trained as a marine biologist and specialized in kelp forest ecology and the impacts of illegal fishing. He retired from active science in 2004 to pursue a life dedicated to environmental photojournalism after he realized that he could have a greater conservation impact with photographs than statistics.
He is a Fellow of the International League of Conservation Photographers and believes that photographs are one of the most effective weapons in conservation today. He has photographed stories/campaigns about shark finning, marine reserves, manta ray exploitation and oil pollution. Thomas believes that the combined force of photojournalists and conservation NGOs is very powerful and in the past has worked as a staff photographer for WWF and the Save our Seas Foundation. Today he continuous to collaborate with a diverse group of committed NGOs and is a founding director of the Manta Trust.
His photojournalism endeavors have earned him many accolades, including 7 awards in the in the BBC/Veolia Wildlife Photographer of the Year Competition. In 2011 he won the nature/environment category at the World Press Photo Awards.
Thomas has published four books: Currents of Contrast: Life in Southern Africa’s Two Oceans, Great White Shark, Wild Seas Secret Shores of Africa and Lost World. His forthcoming book Sharks and People chronicles the relationship between humans and the most feared fish in the sea.
Thomas lives in Cape Town, South Africa but spends most of the year in the field on assignments.