The governor of the Primorsky region of Eastern Siberia, the supporter of G.I. Nevelskoy, the admiral. More than 50 years full of work and eventful life he gave to the Russian fleet. In 1848-1850 he carried out marine surveys in the creek of the Amur and near the Sakhalin island. He prepared and carried out the first Amur rafting (1854). He was the military governor of the Primorsky region and the commander of the Siberian flotilla and ports of the Eastern Ocean (1856-1865).
He organized the Nicholay Naval School (from which later graduated the future admiral S.O. Makarov), conducted earth resources surveys on Sakhalin and Primorye, created a library and a literacy school for sailors of the Amur crew, built the first light-houses along the shores of the Sea of Japan. Upon his initiative, a museum was established in Nikolaevsk. In 1861 P.V. Kazakevich led the Russian part of the commission on the determination of the boundaries between Russian possessions and China under the Beijing Treaty. In 1865, for health reasons, he was transferred to the Baltic Fleet.
He was buried in St. Petersburg in the churchyard of the Novodevichy Resurrection Convent, where the ashes of his commander of the “Baikal” transport - G.I. Nevelskoy – are. The bay and the strait in the Sea of Japan, the cape in the Sea of Okhotsk, the village Kazakevichev of the Khabarovsk region and the Kazakevichev arm of the Amur river, and the guard-ship of the Far Eastern regional department of the Border Guard Service of Russia were named in the honour of P.V.Kazakevich.