Transmarine is an adjective that means passing over or crossing the sea. 

The Latin prefix TRANS means ‘across.’ We see it in words like ‘transatlantic’ or ‘transfer.’ Marine comes from the Latin word for ‘of the sea.’ It’s often used to describe sea animals, for example:

Those transmarine turtles sure do travel fast. It only takes them a few hours to reach the other side of the Lake we fish on.