In the Amur-Heilong Basin well-being of most salmon runs depends on conditions in forest streams in mountainous areas, where it spawns. In this respect condition of salmon runs of particular streams serves as useful indicator of integrity of entire watershed ecosystem.
In Russian Far East most extensive research on the subject was completed by cooperation between forest hydrologists and ichthyologists, mostly on rivers of Sakhalin Island in the 1960s-1980s, and then it’s results were for decades shelved as contradicting logging policies of Russia. Summary of research results were collected and published by NGOs “Sakhalin Watch,” “Wild Nature of Sakhalin” only in 2005. (Soloviev, Mezhennaya editors. Forest and Salmon. Yuzhno-Sakhalinsk.2005)
Logging in watersheds has very complex influence on surface flow, erosion patterns, temperature, and thaw patterns in rivers of the Far East. Substantial change in forest cover leads to degradation of soil cover and negative changes in local microclimate. According to comparative research natural forest cover in a watershed of spawning river cannot be reduced below 50 percent without detrimental consequences for spawning salmon. Low technological discipline in real-life logging operations leads to inevitable damage to salmon runs despite well-meaning protective measures prescribed in logging plans. Increasing water turbidity, use of streambeds for transportation and storage, spills of petrochemicals were observed at all researched sites. If adhering to better standards is impossible in practice, the most cost-effective solution is to abstain from logging in watersheds of spawning rivers, thus preserving economically valuable fish stocks. Reproduction rate (efficacy) of pink salmon in similar unaffected rivers was compared to Nerpichia River where logging lasted for 10 years and Peskovskaya River with three years of logging operations. Reproduction on Nerpichia River was 13.6 percent, and on Peskovskaya river 36.4 percent of that on rivers with unaffected watershed. Accelerated sedimentation during post-spawning period in the fall was considered the most obvious factor limiting reproductive success of salmon.
Following this research stricter control measures were declared by national and provincial authorities and one-kilometer wide “spawning river protection forests” put into a special management category exempt from logging. However inspections conducted in 2002 disclosed that on the majority of spawning rivers these regulations were never observed by logging companies. In 2001 salmon fisheries in Sakhalin contributed 60 percent of local budget, while forestry accounted only for 1.6 percent, therefore logging in salmon watersheds was incurring huge losses to local economy at large.
Such evidence spurred thinking in other RFE regions and a set of recommendations for watershed forest protection was developed for rivers of Sikhote-Alin Mountain ridge in Primorsky Province. (Opritova R.A. Influence of logging on river hydrology in Primorsky Province. Vladivostok. Institute of Biological and Soil Sciences FEBRAS.1988). These recommendations allow for logging in 25 percent of the elementary watershed area, but put forward very detailed instructions regarding distribution of logging areas, limits of annual cut, size of logging patches and many other technical detail. Watersheds smaller than 300 sq. km should be excluded from logging. This science-based guidelines were never incorporated into any legally-binding regional logging regulations.
Logging (Photo by V.Solkin)