yes, a funny and serious topic. For an experiment in a swiss lake where we played test sounds including orca sounds, we had to get permissions and do lengthy risk assessment, including the question whether fish would be disturbed. The lake is very noisy due to pumps, chains, boats, UW-communications, echo sounders etc. It was no problem at the end, and permission is only required if you do a scientific experiment. In Switzerland even (scientifically) recording birds in the wood needs a permission. 
Then in Norway, no permit was required, because it was considered as "non-invasive". After some discussion we got a written statement that no permit is needed.
The industrial fishing boats in Norway use very powerful sonars, and when I asked the fishermen if they need a license, they asked me where I am from...