Detection and avoidance of tidal turbines by fishes

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My research program focuses on the impact of industrial developments in the coastal zone on migratory fish resources. Complex interactions between fishes and large (large dams, causeways, bridges) and small (culverts, fishways) scale obstructions occur in most freshwater systems, but are difficult to quantify due to a lack of equipment that can provide accurate and precise 3-d data on fish behaviour. A new global challenge for fish migration is the development of tidal energy infrastructure in the marine environment. If there is spatial and temporal overlap between operating turbines and migratory fishes, we need to determine if fishes are able to detect and avoid turbines in their path. If they cannot avoid the turbines what is the impact of fish-turbine interaction on fish health and survival? The type of turbine, current speed and fish behaviour are critical components necessary to accurately construct and validate fish-turbine collision models. In this research program, we will use a collaborative stepwise process to: 1) test new innovative acoustic tagging technology in high noise environments; 2) develop an appropriate array geometry for tracking tagged fishes on a scale of 100s of m with a predicted 3-d positional accuracy of 0.2 m; and 3) tag migratory benthic and pelagic fishes to quantify their ability to detect and avoid operating tidal turbines at varying current speeds. Fish have been shown at low current speeds to change orientation, depth and direction when approaching a turbine. We predict that changes in behaviour will be obvious when data from fish approaching a turbine and data from fish not in the direct vicinity of a turbine are compared. Results will inform predictive models of fish-turbine interactions at variable current speeds. The results of this program will be generally applicable to prediction of effects of tidal energy extraction on species and species groups in high energy environments globally. The proper prediction of negative effects of tidal turbine operation on fish resources is critical to the Canadian economy. For example, in the Atlantic Provinces alone in 2012, 616,944 mt of fish were harvested, with a value of $977 million and employment of 61,256 people. So, the economic effect of reducing the health and abundance of already stressed commercial fish resources is likely to have a large effect on coastal economies, and Canada's economy as a whole. Our inability to effectively predict the negative effects of operation of tidal turbines on migratory fish health keeps us from understanding the full range of biological consequences of tidal power developments. Moreover, the lack of credible scientific data on the potential impacts of tidal power will delay the decision-making process on a technology that shows promise for reducing carbon emissions, and for which Canada could become a global leader in the production of tidal power infrastructure for the coastal zone.