Integration of Hydrodynamics and Acoustic Telemetry for Predictive Species Distribution Modelling in a Dynamic Marine Environment: Implications for Marine Renewable Energy Development

Tidal stream energy has the potential to greatly contribute to the expansion of marine sources of renewable energy and the reduction of greenhouse gases, but carries a potential environmental cost in the form of detrimental interactions with marine life. The greatest potential threat from tidal stream turbines is generally perceived by stakeholders and regulators as physical collisions between marine animals and turbine blades that may result in mortality. The ability to estimate the potential encounter rate between marine species and tidal power devices is crucial in assessing the potential environmental impacts of tidal power development. Here we demonstrate an exposure time population model approach to estimate the encounter rate of striped bass (Morone saxitilis) with a hypothetical tidal stream turbine at two sites in Minas Passage, Nova Scotia, a highly sought-after tidal channel for the development of tidal stream energy. Model inputs included striped bass presence probability from a species distribution model derived from acoustic telemetry detections, fish depth distribution data from pressure sensors carried by a subset of the tagged striped bass, local population estimates from the Fisheries and Oceans Canada stock assessment for Bay of Fundy striped bass, and measurements of vertical encounter area of the turbine based on the extent of the blades on a vertical plane. These parameters provided an estimate of the number of striped bass per hour occurring within the encounter area of the turbine during each tide stage. This approach will provide baseline estimates of encounter rate that will be useful in assessing the potential impact of tidal power development projects on fish populations.