Dr. Holcer is a senior curator of mammalogy, ichthyology and marine invertebrates collections of Croatian Natural History Museum (1996-present). He was a founder and president of Blue World Institute (2000-2019). He is also a director of Marine Institute (2019-present) and remains a close collaborator. In his early days, he studied small mammals and bats, but his main professional work is focused on cetaceans and other large marine vertebrates (sea turtles and cartilaginous fish), their biology and ecology, social organization, population genetics, abundance estimates, spatial modelling of habitat use and distribution, satellite telemetry, evaluating threats and population management and conservation. Dr Holcer is active in education and training of Cetacean researchers and engaged in conservation awareness raising. He teaches a course on Conservation Ecology of Marine Mammals for graduate students and course on Conservation Biology of Large Marine Vertebrates for postgraduate students on University of Primorska, Koper (Slovenia).