There is global interest in marine renewable energy from underwater tidal turbines. Due to overlap in animal habitat with locations for tidal turbines, the potential for collisions has led to concern around strike risk. Using data from tagged harbor sealscollected before construction and after operation of the SeaGen tidal turbine in Northern Ireland, this study quantifies risks of an operational turbine to harbor seals by taking into account turbine characteristics, tidal state, and seal behavior. We found 68% spatial avoidance (95% C.I., 37%, 83%) by harbor seals within 200 m of the turbine. When additionally accounting for variation in seal occupancy over depth and tidal flows, there is an overall reduction in collision risk from 1.29 to 0.125 seals per tidal cycle (90.3% reduction; (95% C.I., 83%, 98%)) compared to risk calculated under assumptions of uniform habitat use. This demonstrates the need to incorporate environmental conditions to properly assess strike risk.
Empirical measures of harbor seal behavior and avoidance of an operational tidal turbine
Title: Empirical measures of harbor seal behavior and avoidance of an operational tidal turbine
November 01, 2018
Journal: Marine Pollution Bulletin
Joy, R.; Wood, J.; Sparling, C>; Tollit, D.; Copping, A.; McConnell, B. (2018). Empirical measures of harbor seal behavior and avoidance of an operational tidal turbine. Marine Pollution Bulletin, 136, 92-106.