Recent changes of water level in Lake Khanka and their consequences for its fisheries resources

Abstract

Interannual variation of the water level in Lake Khanka is considered on satellite altimetry data; its extreme rising in recent years is noted, with the maximum in 2016. Using a simple balance model, contribution of the main components of its water balance to the modern rise is determined, as precipitation in its basin, evaporation, and water discharge through the Sungacha River. Growth of summer precipitation is defined as the main reason of the level rising. However, the water income to the lake does not correlate with the precipitation volume since 2010 that confirms the hypothesis about artificial influence on the water balance of Lake Khanka by its connection with the Mulin River (China) and worsening of the outflow through the Sungacha. As the result, the lake got additionally about 1.3 km³ in 2014–2015 that promoted the level rise to the highest mark. But before and after this period, the water inflow was lower than its expected values, obviously because of its redistribution. Positive influence of the anomalous water level growth on total abundance of commercial fish species is shown. The high level is favorable for reproduction of phytophilic species (Cyprinus rubrofuscus), whereas abundance of pelagophilic species (Chanodichthys erythropterus) declines.