Blakiston fish owls mainly frequent riparian forests and primary coniferous forests. They are found mainly along rivers and streams that have a high water flow and are never covered by ice during the harshest periods of winter.
In the Ussuri region, they live in the dense mixed forests of conifers and deciduous trees of the plains crossed by large rivers. Often the clusters of trees where they reside are located on small islands in the midst of fast flowing rivers.
In the Kuril Islands, these large birds of prey inhabit the dense forests of fir and spruce mixed with some deciduous trees along the shores of lakes, river mouths or sea coasts. In the far north, they also go fishing along the rocky shores.
Blakiston's fish owls are native to the northeastern regions of the Asian continent. Their range extends through eastern Siberia from Vladivostok to Sakhalin and along the coasts of the Okhotsk Sea, continuing westwards almost to Lake Baikal.
To the south, these nocturnal birds of prey occupy the mountainous regions of western and northwestern Manchuria, pushing south to the border between the Korean peninsula and Heilongjiang in China. Blakiston fish owls are also found in Hokkaidō and the southernmost islands of the Kuril archipelago.
This species is rare and its future is seriously threatened. In Siberia, including Sakhalin and Kurils, the total population does not exceed a few hundred specimens. There are probably fewer than 50 pairs left in Hokkaidō. Along 350 km of rivers in Manchuria, no more than 30 individuals have been found.
In Siberia, these birds are concentrated near ventilation holes in the ice, making them extremely vulnerable to fishermen, hunters and fur seekers. However, specific protection measures have been adopted, which also include the installation of nest boxes, and the first encouraging signs of this conservationist policy are already beginning to be perceived in the form of a recent population growth.
Blakiston fish owls feed mainly on fish, sometimes even of considerable size. The list of prey includes Amur pike, catfish, barbel, trout and salmon, but also shrimp. These birds also eat frogs, which are sometimes caught in large numbers to be given to the young.
In winter, Blakiston's fish owls hunt mammals that can grow to the size of a hare, marten, or small dog. They catch prey by entering the water, wading in shallow water and stopping before jumping on the victim.