Leonid Pshenichnov, a prominent Ukrainian biologist, was arrested in Crimea by Russian authorities, accused of high treason for opposing industrial krill fishing in Antarctica. His research has been vital in advocating for marine protected areas, and he was set to attend a conference on Antarctic conservation when detained. The charges stem from his support for proposals that would limit krill harvesting, which Russia claims threatens its economic interests. The international community, including Australia and the UK, has expressed grave concern over his detention, highlighting the potential implications for Antarctic marine conservation. Fellow scientists describe Pshenichnov as an outstanding researcher whose work is crucial for understanding the Southern Ocean ecosystem. His arrest has sparked a diplomatic row, with calls for action against Russia's treatment of scientists.