Use of Passive Integrated Transponder (PIT) Technology for Passage Efficiency Estimating on the Angu Fishway (Dadu River), China

Restoration of fish populations at dammed rivers using the fishways and other fish passage facilities for fish migration is demanded in China. The requirement of performance monitoring and evaluation of fishway post-construction was highlighted by the fact that fishway frequently do not perform as intended points. Fish passage efficiency (FPE), a quantitative descriptor of fishway performance, defined as the percentage between the numbers of successful migrants related to the fish numbers willing to migrate below the dam. Passive integrated transponder (PIT), one of the ideal tagging technologies for behaviors and movements monitoring, has been extensively applied into the FPE studies. Prior to this application, the survival of tagged fish (especially the juvenile) and reading efficiency is required to be determined. This study used the PIT (Oregon RFID) to estimate the passage efficiency of vertical slot fishway on the Angu Hydropower Station on the Dadu River, Southwest China. This study aims to reveal the effects of PIT tag on the juvenile survival and the reading abilities of those tags on the vertical slot of fishway, subsequently conclude the FPE of fishway. A total of 215 individuals of juvenile fish (TL ranged from 9.7-26.6 cm; mean TL=15.8 cm) from three species, namely, Hemibarbus labeo, Onychostoma sima and Pelteobagrus fulvidraco, were tagged with a PIT tag (12 mm long) by implanting in the body cavity. Besides, six receiving antennas (2.0 m long and 0.4 m wide matching the size of vertical slot) were manufactured and separately installed in the fishway the from entrance through exit. The surgical wounds of the tagged fishes were entirely recovered after five days. Out of total fish tagged, 199 juvenile fish survived with a survival rate of 74.42%. Moreover, for 172 tagged fish that released in the river near the entrance, 83 tagged fish entered the fishway and fourteen swam out of fishway, including one swam back to the fishway from the exit. The FPE of this fishway is ultimately determined as 7.56%. This study illustrated a successful application of the PIT technology on the FPE monitoring of juvenile fish. Further studies are still required for improvements of the PIT reading efficiency so as to conclude the accurate evaluation of the passage efficiency.