Seasonal habitat utilization and movement patterns of the threatened Brachymystax lenok tsinlingensis in a Korean river

Abstract

Threatened fish species that utilize riverine environments are faced with critical habitat degradation caused by various disturbances. Brachymystax lenok tsinlingensis, has been designated as a threatened species by the South Korean Ministry of Environment. In this study, we evaluated the movement patterns and seasonal habitat utilization of this species was monitored by radio telemetry during the overwintering and spawning periods. Within each period, no statistical difference in total distance travelled and linear range was identified between years (two-way MANOVA, Wilks’ lambda = 0.971, f = 0.271, P = 0.896). However, the mean total distance and linear range were longer during the spawning period compared to the overwintering period. Less movement was recorded during the overwintering period. A total of 8 tagged fish (24.2 %) moved upriver to the Songjeongri or the Byeongo streams (tributaries of the Nakdong River) for spawning. Movement to the spawning grounds was started with increased discharges, which were caused by rainfall and melting snow (following a rise in water temperature in late February). The fish returned to the Nakdong River after spending 2–3 weeks at the spawning grounds. The fish inhabited deep pools with low water velocity during the overwintering periods. In comparison, the spawning grounds tended to be located in shallow running water dominated by gravel-beds. This study clarified the habitat use and movement patterns of B. lenok tsinlingensis, contributing useful information toward establishing appropriate conservation and management plans for this threatened species.