Sea rancher
In agriculture, a sea rancher was a type of farmer who practiced ranching in the open sea.
Ruth Bonaventure, one of the women Harry Mudd had recruited for wiving settlers on Ophiucus III, came from a pelagic planet, populated by sea ranchers, all of whom lacked the necessary requirements for being a potential husband. (TOS: "Mudd's Women")
In the final draft script of "Mudd's Women", these laborers were instead called "sea farmers."