Ecology Action Centre tosses a lifeline, or is it an anchor?

The Ecology Action Centre has stated it's position with regards to the Cape Sharp Tidal Demonstration Project in the Bay of Fundy. It's a balanced position in as much as the Ecology Action Centre "supports the development of tidal electricity" just so long as "it has a net environmental benefit and minimizes the impact on surrounding ecosystems".

There's the rub. There is no measure for "a net environmental benefit". Such things reflect values, not science. Increased atmospheric CO2 is something that you can measure. Whether or not it is viewed as a benefit depends upon what you value.

The Ecology Action Centre (EAC) mostly rehashes material from reviews made by the Department of Fisheries and Oceans (DFO). I'll restrict myself to considering just one of the things that the EAC would require.

The EAC requires: Monitoring species specific fish mortality due to interactions with turbines. Does the EAC have any idea how difficult it would be to do that? Such things can (sort of) be done for fish going through turbines in dams. It's impracticable for in-stream turbines deployed in the ocean. (How would the EAC harmlessly contain the fish for evaluation on the downstream side of the turbine?)

No! The EAC seems to have missed the whole point of having in-stream turbines instead of turbines within a barrage (dam). The EAC is oblivious to the scientific literature. A different approach is used for in-stream marine turbines, as outlined here.

So what is being done in the Cape Sharp Tidal EEMP? For one thing, they are using active acoustic sensors to provide real time detection and near-field tracking of fish and marine mammals. That's a long-winded way to say using acoustic imaging system to look upstream and watch fish as they approach the turbine. (Acoustic methods have greater range --- but less resolution --- than video.) If it works, acoustic imaging should enable, to some degree, a calculation of encounters of fish with turbines and the extent to which they totally avoid the turbine.

This is not to say that there isn't a major ommission from the EEMP. Elsewhere, video cameras have been installed on the side of the turbine with a view across the face of the turbine. The results from that experiment have been reported here. The authors did not observe fish at the face of the turbine whenever the current was fast. (I have reservations which I will report later.) Reservations aside, this underscores the point that if all fish avoid the turbine when it is in a potentially dangerous state then there is no need to monitor mortality.

I was surprised that DFO did not require that video cameras be installed to look across the face of the turbine at the Cape Sharp Tidal installation. Video data would provide near-field observations to complement the longer range observations made by the acoustic imaging system.