A device for use in cutting plugs of submerged substrate and particularly seagrass plugs for the purpose of transplanting using a corresponding transport receptacle and method. The device utilizes a hollow cutting member with a serrated bottom edge capable of being placed over a targeted area and forced into the submerged substrate, created vacuum pressure in the hollow cutting member, and compressed air injected between the exterior of the hollow cutting member and the submerged substrate to accomplish cutting of a submerged substrate unit. Vacuum pressure in the hollow cutting member is released to transfer the collected unit to the corresponding transport receptacle with a removable bottom. A corresponding method for transplanting a collected seagrass plug is further accomplished by creating a hole at recipient site using the device and removing the transport receptacle's removable bottom to release the plug into the created hole.