Fish location data based on PIT

The establishment of hydropower projects have affected the flow regime and
structure of fish habitats. Various habitat restoration measures based on
natural river morphology have been carried out, but the effects of habitat
restoration and the hydrodynamic mechanisms of fish preferred topography
remain unclear. Based on a large ecological test site, we created a
variety of near-natural microtopographic habitats and achieved real-time
monitoring of behavioral characteristics of the test fish habitats by
deploying a Radio Frequency Identification (RFID) system incorporating
Passive Integrated Transponder (PIT) tags. The experimental results
indicate that microtopographies with different structures have a certain
attraction to fish behavior. Among the four selected hydrodynamic
indicators, flow velocity and vorticity have a greater effect on
Onychostoma sima (O. sima). The optimal vorticity for fish habitats ranges
between 1.75 and 10.85 s⁻¹, with suitable flow velocities exceeding 0.545
m/s. The hydrodynamic mechanism of habitat selection for the test fish is
presented according to the Habitat Suitability Index (HSI) and Regression
Tree (CART) methodology. The results have verified by the Receiver
Operating Characteristic (ROC) method showed that the habitat selection
model based on hydrodynamic indicators has a good prediction effect on the
determination of suitable habitat for most test fish. In this study, we
explored the relationship between fish activities and hydrodynamic
indicators in complex terrain, and obtained the utilisation patterns of
fish for different habitats under changing terrain and flow conditions. It
provides theoretical support for flow scheduling and habitat terrain
management under the influence of hydropower projects.