Do they use dolphins for that?
There's a lot of fascinating archaeology waiting to be done in shallow continental waters as the technology continues to develop. 7,000 years takes us back to the end of the last ice age and the beginnings of agricultural settlements. I gather that there is still considerable debate on the subject, but some researchers believe the Black Sea basin only flooded about 7,000 years ago. There are likely to be some fascinating sites waiting for the right tools for exploration. Unless some Bulgarian or Turkish ancestor worship cult crops up and forbids us to look.