Human-caused mortality
Two cases of predation (one by an Asiatic black bear, the other by a Eurasian lynx) are the only known sources of Blakiston’s fish owl mortality not directly tied to human activity. Unlike Amur tigers, which are poached for commercial gain, most fish owls die needlessly when they become entangled and drown in fishing nets, are captured in hunters’ snares, or are simply shot for sport. Additionally, given their high fat content (particularly in the months leading up to winter), Blakiston’s fish owls were once prized as a food source by the indigenous Udege peoples, but this practice seems to be less common now
Habitat Loss
Habitat loss due to logging in old-growth riverine forest (much of it illegal) is a significant threat. Although a resident pair of Blakiston’s fish owls seems to occupy no more than 10 km2 as a home range, fish owls have very specific habitat requirements. Most known Blakiston’s fish owl nests have been found in natural tree cavities, and many fish owl territories have only a handful of such old-growth trees large enough to support a nest. If these few trees are removed, the owls will not breed. Furthermore, fish owls need productive stretches of river that remains unfrozen throughout the year to provide hunting habitat – not a simple requirement given the Russian Far East’s harsh winter climate. Thus, Blakiston’s fish owls are often tied to stretches of river where warm upflowings keep waters unfrozen in winter.
Blakiston’s fish owls have been recorded in several of Primorsky Krai’s protected areas, but nearly all known nest territories (>95%) fall outside the borders of existing protected areas. Therefore, management of habitat outside protected areas is critical for Blakiston’s fish owl conservation, and any such plans must include the land-use needs of local communities. Education of local populations about the species will also greatly aid Blakiston’s fish owl conservation, as most causes of mortality are human-related and easily avoided.
Read about Blakiston's fish owl ecology.