Fish and Turbines in the Bay of FundyMany sustainable, green technologies are touted to replace fossil fuels. One such technology is in-stream turbines that obtain power from the Bay of Fundy tides. Turbines raise the possibility of adverse interactions with fish.
Let us review the problem of fish-turbine interaction in the scientific way, that is by breaking it down into elementary components that can be independently measured and then assembled together for a complete calculation. Following along the lines of others, we might break things down this way:
The effort is ongoing to measure these things in the Bay of Fundy. In the meantime, it's difficult to conclude much.
- Co-occurrence is the extent to which fish are observed at the turbine site.
- Encounter is the extent to which fish would be swept by currents through the area that is swept by the turbine --- assuming that fish take no corrective action to avoid the turbine.
- Avoidance is the extent to which encounters are offset by fish detecting a turbine from a position sufficiently far upstream and thence changing their path so as to avoid the turbine (ie not pass through the area swept by the turbine blade).
- Evasion is the ability of a fish to evade turbine blades if it passes through the area swept by the turbine blades.
- Survivability is the likelihood of various levels of damage (including fatality) that a fish will suffer if it is hit by a turbine blade or subjected to pressure and shear stresses during its passage through a turbine.
At least we can see how the above factors might be related to assess impacts of instream tidal turbines on fish: