Krasheninnikov spent ten years on the Second Kamchatka Expedition. On his return to St Petersburg, he wrote and defended his doctoral thesis on ichthyology in 1745. He was appointed adjunct at the Academy of Sciences, and later head of the Academy's Botanic Garden and professor of natural history at the university. He was one of only 26 Russians to become Academy members in the 18th century. In 1752, Krasheninnikov went on his last expedition to the tracts of Lake Ladoga and Novgorod to investigate the flora. He died before being able to publish his observations, which instead were published by David de Gorter.