Tidal turbines are designed to be noisy enough to deter marine life but not so noisy that there are detrimental health and ecological effects. Not sure how successful this strategy is, but the scale of deployments is still small and more study and monitoring should be done before the scale makes big impacts from even small effects.

Here’s a blog post from an engineering firm that works on these issues:
…theiet.org/…/designing-tidal-turbines-are-safe-m…