Food is scarce in the deep sea, so this animal gets creative to snap up any available morsel.

The predatory tunicate (Megalodicopia spp.) lives attached to the rocky seafloor, orienting their cavernous mouth into the currents. Most tunicates are filter feeders. They draw water in through a large oral siphon and use mucus to collect tiny plankton before expelling the water out a second siphon. 

Megalodicopia takes a more active approach to dining. The predatory tunicate’s oral siphon has evolved into a large pair of lips that quickly close to engulf larger prey items. This unique anatomy allows Megalodicopia to capture nutrient-rich crustaceans. Many unrelated deep-sea animals have evolved a similar feeding strategy. Jellies, eels, sea anemones, and even a remarkable swimming sea slug also deploy a broad hood to grab a meal.

Working with our partners at the Monterey Bay Aquarium, we are learning more about the population of predatory tunicates in our blue backyard. Using MBARI’s robotic submersibles, we have mapped where Megalodicopia live in Monterey Canyon. Predatory tunicates are solitary animals, though we sometimes see small clusters in areas where conditions are favorable, like steep, rocky walls. Monterey Bay Aquarium biologists are studying predatory tunicates and even culturing their larvae to understand more about their lifecycle. This species grows very slowly, making Megalodicopia especially vulnerable to a changing ocean.

Threats like fisheries and mining leave an uncertain future for the predatory tunicate and other deep-sea animals. Some fishing gear indiscriminately scrapes along the seafloor, uprooting bottom-dwelling animals. Extracting minerals from the deep seafloor removes rocks where animals have made their home and also kicks up sediments that can smother the inhabitants of the deep seafloor.

MBARI research can help resource managers and policymakers set protections for deep-sea animals and environments. Our unique partnership with the Monterey Bay Aquarium brings the deep sea to land, allowing visitors from around the world to meet the remarkable denizens of the deep face-to-face. Together, we hope to inspire stewardship of the ocean and all the amazing animals that call it home.