Evaluation of the Longitudinal Connectivity of Gokseong Stream Aquatic Ecosystem Based on Features of Fish Species and Artificial Structures

Longitudinal connectivity of Gokseong Stream aquatic ecosystem was assessed based on features of fish species and artificial structures. A total of 18,542 individuals, representing 33 species, nine families and four orders were identified downstream of 45 weirs. The dominant species was <i>Zacco platypus</i>, while the subdominant species was Zacco koreanus. Fish surveys indicated a pattern of increasing fish species richness in downstream sites. Based on the movement characteristics of the fishes and features of the weirs, longitudinal connectivity was assessed for each artificial structure: two were continuous, six were damaged, 32 were interrupted, and five were absent. For inclined structures, the main factors influencing interruption were the downstream water depth, whereas for vertical structures, the primary factors were the upperstream water depth and the head drop. For fishways, stream velocity was identified as the principal factor causing interruption in inclined structures, while upperstream water depth was the predominant factor causing interruption in vertical structures. These results are expected to provide fundamental data for future conservation of stream aquatic ecosystems.