Applying a simple model for estimating the likelihood of collision of marine mammals with tidal turbines

A E Copping,M E Grear

doi:10.36688/imej.1.27-33

Abstract

As tidal turbine deployments continue at test sites and in commercial areas, the potential risk for injury or death of marine mammals from colliding with rotating turbine blades continues to confound efficient consenting (permitting) of devices. Direct observation of collisions is technically very challenging and costly. Estimates of collision risk to date have been derived from complex collision risk models that depend on estimates of the number of marine mammals found in the area. Using a simple collision model, the risk of collision was examined at three real-world sites, each of which featured an indigenous marine mammal. Two different turbine designs were examined at each site to extend the range of the estimates. The results of the model runs allow for comparison of risk at a range of tidal sites for a variety of the marine mammals thought to be at potential risk.

Highlights

As tidal turbines are deployed at test sites and in commercial areas, the potential risk for injury or death of marine mammals from colliding with rotating turbine blades continues to challenge efficient consenting of devices
Estimates of risk are derived from complex collision risk models that depend on estimates of the number of marine mammals found in the area
The collision risk model presented here indicates that the proportion of three indigenous species of marine mammals likely to be seriously injured in a collision with a tidal turbine ranges from 0.035% for harbour seals in the relatively shallow and constricted Lashy Sound to 0.006% for harbour porpoise and 0.011% for killer whales in the deeper wider channels in the Bay of Fundy and Puget Sound, respectively

Summary

Introduction

As tidal turbines are deployed at test sites and in commercial areas, the potential risk for injury or death of marine mammals from colliding with rotating turbine blades continues to challenge efficient consenting (permitting) of devices. This paper explores the application of a simple collision risk model for marine mammals interacting with tidal turbines at three potential tidal sites in the US, the UK, and Canada to provide a first-order estimate of the risk of serious injury or death to the animals. This paper examines the model applied to two different turbine types at each location using species of indigenous marine mammals for each site This approach allows us to explore collision risk based on the unique characteristics of the channel and the species of concern. This model focuses on the fate of a single marine mammal traversing a tidal channel with installed tidal turbines. Additional steps are needed to bridge the gap to understanding potential impacts on marine mammal populations

Methods

Results

Conclusion