Given the irregular distance between holes and the different angles of the holes, I'd guess something organic. There's still a lot we don't know about even well known fish like sharks, what to talk of fish or marine life that we have yet to discover. Seeing the raised ridge along the entire set of holes makes me wonder if they're from some kind of eggs that hatched after being embedded in the seabed.

It's amazing that there are still so many mysteries like this on Earth.