Ecological characteristics of Rhynchocypris deogyuensis inhabiting the Gucheondong Valley in the Deogyusan National Park: its population size, health condition, and predation pressure

This study analyzed the population size, ecological health condition and predation pressure of Rhynchocypris deogyuensis, which is geographically restricted to the Gucheondong Valley in the Deogyusan National Park. A mark–recapture survey conducted at four sites revealed that R. deogyuensis occurs in relatively smaller populations (N = 808 ± 186 individuals) than closely related Rhynchocypris oxycephalus (N = 1,447 ± 245) within a limited section of the valley, suggesting its potential vulnerability to environmental disturbances. Indicators of ecological health, such as condition factor and length–weight relationship, were relatively lower, indicating that R. deogyuensis is under unfavorable ecological conditions. Furthermore, genetic analysis of stomach contents from introduced species Oncorhynchus mykiss detected R. deogyuensis’s DNA, confirming its feeding on R. deogyuensis. These findings indicate that predation pressure from introduced species would pose significant threats to the survival of R. deogyuensis.