Abstract
The effect of tidal in-stream energy conversion (TISEC) devices on fish remains largely unknown and long-term fish monitoring is essential to assess such effects. The goal of this project was to quantify relative fish distribution changes associated with the presence of a deployed TISEC device in Nova Scotia, Canada. Mobile active acoustic surveys (n=6) were performed before (n=3) and after (n=3) the turbine deployment and included a reference site for comparison. Relative fish densities differed in each month of the survey but there was no statistically significant effect of the site (impact or reference) or turbine presence. May and November surveys had the highest density of fish, probably associated with seasonal migrations of certain species. In August and October, fish were more concentrated in the 10 m layer above the seafloor. The proportion of fish at the depth of the turbine, based on data collected adjacent to the turbine varied greatly, ranging from 2 and 51%, depending on the time of year. This survey is preliminary and the site will continue to be monitored to examine longer-term influences of turbine presence.