Modeling the Probability of Fish Encounter with a Tidal Energy Turbine

The extreme tidal currents in Cobscook Bay make it increasingly attractive for tidal power development. However, fish species also utilize tidal currents to move on- or off-shore. Little is known about the effects of installed marine hydrokinetic (MHK) devices on fish behavior. The dynamic physical characteristics of the bay make it impractical to use conventional monitoring tools, such as trawling. We used two hydroacoustic systems to examine fish behavior in the presence of one MHK device. Seasonal data collected from 2011-2013 using stationary down-looking hydroacoustic surveys were used to characterize the temporal variation of relative fish density and vertical distribution. Mobile hydroacoustic surveys, carried out in summer 2014 (more than 300 transects spanning from 200 m upstream to 200 m downstream of the device), were used to characterize the spatial variation of fish responses to the device. Using a Bayesian Generalized Linear Model we modelled the probability of fish encounter with a turbine using the preliminary data from both datasets (and the full dataset will be applied in near future). This model only estimates the encounter probability with one device, but the results can be extended to characterize fish response to a commercial MHK array which may have Bay-wide implications.