I agree with you ToneBender.
This apparently took place between 1986 and 1992 following teachings of an obstetrician/ psychotherapist who pioneered the method of water birth in 1963.
To re-quote in full...
"Father shows exciting photos of the birth of their 4 children in the sea
Births of babies are always exciting, especially when they happen in an environment so special and full of life as in the ocean. Russian Vladimir Bagrianski registered in fantastic photos pregnancy of his wife, and the birth of her four children in the sea, which took place between 1986 and 1992. The series was named “Sunrise at sea.”
The births took place in different locations, but always with the ocean as the main scenario. The family is very attached to the teachings of the obstetrician and psychotherapist Igor Tcharkowsky, pioneered the method of water birth in 1963."