This article explores the history of fishing on Lake Baikal in an effort to understand the fish-human nexus, to expand our understandings of the Russian relationship to the environment before the twentieth century, and to think about the colonial encounter in Siberia from an environmental angle. Fishing has long been a crucial, life-sustaining, and culturally important component of life at Baikal; and fish and people have long existed in mutually influential and intertwined webs of relations. Fish populations declined markedly in Baikal from the late eighteenth century on-a drop with which Soviet fishers and policymakers continued to struggle throughout the twentieth century. The fate of Baikal's fish was the result of 1) the tax-farming, market-based economic structures of tsarist colonialism and 2) the new fishing technologies that Russian settlers brought with them to the practice of fishing-both of which were "revolutionary" transformations from the pre-colonial Buriat and Evenk fishing methods and systems. Notably, this massive fish population decrease came about before any industrial change affected the area. Humans, this story shows, do not need to have industrial machines with their extractive capabilities and pollution by-products in order to bring about systemic ecological and evolutionary changes.