I am very sad to say that I recognize this dive site.
the title of the movie mentions Futo, and sure enough I have been to Futo and this is what it looks like, I recognized all the features of the site.
I had heard that dophin fishing had taken place at many of the fishing spots in the Izu peninsula here near Tokyo. As it was described to me, this practice was stopped in the last decade. It is hard to tell, but the cars and clothes in this video look pretty recent. I will make some inquiries at Futo and I will ask on the Zen Divers forum...
JAg