The Sawfish harvester is a submersible robot produced by the Triton Logging Inc. It is designed for cutting down submerged trees and popping them to the surface, with large pincers and a chainsaw. Such trees are generally submerged when dams are built near existing forests, and their wood remains good while underwater for long periods.
External links News report on the Sawfish Triton Engineering page: details on the Sawfish