Spear-toting robot can guard coral reefs against invasive lionfish

August 27, 2018

Lionfish are threats to not only fragile coral reef ecosystems, but the divers who keep them in check. They not only take advantage of unsuspecting fish populations, but carry poisonous spines that make them challenging to catch. Student researchers at Worcester Polytechnic Institute may have a solution: robotic guardians. They've crafted an autonomous robot (below) that can hunt lionfish without requiring a tethered opera tor that could harm the reefs.

The bot attaches to an existing submersible robot and relies on computer vision (trained with thousands of photos) to spot examples of the invasive species and jab them with one of its eight spears. Each spear tip is detachable and buoyant, so any successful kill sends the fish to the surface. The machine is well-suited to the realities of the ocean, too -- it's both resistant to saltwater corrosion and uses an airtight chamber to maintain buoyancy after every spear use.

WPI's automaton isn't ready for service yet. A follow-up group of students will work on a navigation system that can help the robot create a 3D search grid. If that's successful, though, the robot could become a valuable part of reef defense that spares humans from getting involved until (and unless) they have no other choice.

WPI's autonomous lionfish-hunting robot