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Vertical Slot Fishway Passage Efficiency for River Connectivity Restoration in China: A Case Study

Author(s): Jiang-Hui Bao; Wei-Wei Li; Ming Duan

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Keywords: Fishway; Passage efficiency; Monitoring and evaluation; PIT; River Connectivity Restoration

Abstract: Fishway as an ecological compensation project for the negative ecological impacts on the river by construction of hydroelectric power station has been widely used in China. According to technical reports, over 21 fishways were constructed during the past 15 years. However, how to fully and accurately assess the passage efficiency and river connectivity restoration are critical problems. Zhentouba I Hydropower Station is the first vertical slot fishway on the Daduhe River built in 2015, which is designed for passing native, listed, and economic fish species, and meanwhile maintaining fish gene exchange. This study was conducted during the fish breeding season from June to August in 2017. Firstly, we investigated the fishery resources in three different places near the entrances of the fishway downstream the dam to quantify the upstream fish species; Secondly, we used video system installed on the fishway to monitor the movements of the passing fish, and analyzed the number and rhythm of the fish individuals; Finally, Passive Integrated Transponder (PIT) telemetry method was used to assess the upstream-directed movement process of PIT implanted resident Schizothorax in the fishway. In the present study, 1) 646 fish individuals were totally captured in the downstream, affiliated to 3 orders, 9families, 27 genus, and 40 species. The dominant species were Schizothorax preuanti, Slabeo prochilus, Hemiculter leucisculus, Misgurnus anguillicaudatus, Liobagrus marginatus, and Euchiloglanis davidi; Fish closest to the entrance tended to have longest standard length (SL) than those further from the entrance. 2) 114 fish were observed at one entrance and 82 fish at exit, passage efficiency was 71.9%. Five species could be identified, nine species could be recognized as genus, six species were unidentified. The dominant species were Liobagrus marginatus, Euchiloglanis davidi, Hemiculter sp., Saurogobio sp., and Silurus sp. In contrast, there was a 33% overlap between actually passed species and target species. The number of fish during night time (19:00~07:00) was significantly more than that during day time (07:00~19:00), and the most monthly passing number was in June. 3) Four PIT antennaes records show that passage efficiency decreased with the detection site away from the entrance, with the ratio 73.9%, 49.3%, 39.1%, 20.3%, respectively. Conversely, returning ratio increased with ratio 72.5%, 85.3%, 85.2%, 100%, respectively. This research is a first attempt to evaluate fishway passage efficiency on the Daduhe River, which indicated that the fishway formed a effective component for the river connectivity restoration.


Year: 2018

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