A subsea production system on a sea floor has a pump flowline jumper with a straight intermediate portion and two end portions. Each end portion has a connector for ROV assisted connection between production units. A submersible pump assembly is mounted in the straight portion of the flowline jumper and is lowered along with the flowline jumper into engagement with the production receptacles. The pump assembly boosts pressure of fluid flowing from one of the receptacles to the other. A gas separator may be mounted in the same flowline jumper or in a separate flowline jumper.