Abstract
To date there are limited laboratory studies on the interaction of marine life with marine renewable energy devices. The Aquatron Laboratory at Dalhousie University is designed to study marine life in a controlled marine lab environment. The 15.24 m diameter pool tank is equipped with four 75-HP circulation pumps that can generate tidal currents up to 2 m/s velocities using salt water. The process for modifying the facility to study the impact of hydrokinetic turbines on fish is presented. The installation of a 0.9m diameter 3-blade vertical axis turbine is described (Figure 1). The performance of the turbine was first validated against previous towing tank experiments at NRC St. John’s. Tests were then performed for 3 weeks to monitor the impact of the turbine on Striped Bass (Morone saxatilis) behavior and to measure cortisol levels in the fish blood for different scenarios. The test protocol provided flow in the tank at 2 m/s continuously for 3 weeks with the turbine rotor locked during the first week, the rotor rotating at a tip speed ratio of 1.5 in the second week, and the rotor locked again in the third week. The intent of this study is to demonstrate the feasibility of using the Aquatron facility for turbine-fish interaction studies. The test protocol was kept relatively simple for this test series. Striped Bass (Figure 2) varying in age from 2 to 3 years were used for these tests. The turbine had a cage around the frame to prevent fish strikes in this first phase of tests. There was a second net placed across the centre of the tank to train the fish to pass by the turbine rotor to access food on the other side of the tank as fish passage behavior near the turbine is of prime importance. Within the tank three nets were placed at different distances (2m, 5m, 10m) away from the turbine and were hung in place by ropes tied to the bridge. Fish behaviour was monitored by counting fish passage as they swam to specific locations in the tank. Fish blood cortisol levels, velocity and location as well as general observations were recorded. Results presented should not be considered as definitive fish behaviour when encountering an operational
turbine.