Special to WCS by science writer, Amy West
After the mutineers left Captain William Bligh to steer his own course, Bligh probably didn’t realize he’d passed so close to an astonishing seamount rising nearly straight up from the seafloor. Of course how could he, when cannibals were most likely chasing him from Fiji? In recognition of his plight, this popular dive spot has been christened Mt. Mutiny.
Plowing through calm waters between the two large islands of Fiji – Vanua Levu and Vitu Levu – where it feels like open ocean, “land” abruptly stops you in your wake: the seamount’s peak is visible at the surface. During low tide, you could theoretically walk on it. Just a few hundred feet off its edge, the depth reaches down to 600 meters—a sheer drop.
Seamounts are usually rife with life. These undersea mountains are prime features for currents to swoop around and carry food to the diverse filter feeders such as corals and sponges. The stony and soft assemblages in turn attract an entire ecosystem of marine life that rivals most regions of the ocean. These volcanic structures can be uplifted mountains that are unhurriedly inching their way to the surface, such as the emerging island Lo’ihi in the Hawaiian Islands. Or they could be islands that have slowly eroded and sank like northern Hawaii’s Meiji seamount. We don’t know the history of Mt. Mutiny without drilling into it, but one thing is clear– it does not seem to be teeming with life. Many of the larger fish and top predators seemed to be out to lunch, or perhaps more likely, became lunch.
Seamounts are hotspots for fish, which is why fisherman love them- the suspected reason that they are missing. With support from the Waitt Foundation and Institute to help create offshore-protected areas, the first item on the agenda was to document marine life below diver depths. The Institute’s contribution of their research vessel and camera-equipped robot allowed us a quick glimpse. This steep mountain had seemingly discrete bands of life: reef-building corals for about 30 meters, then softer corals below it, and different species like larger sea fans and encrusting algae and sponges below it. After 60 meters the seamount appeared more barren and so vertical that tracks of rubble flows were noticeable- as if someone had driven an ATV up its side.
An astonishing amount of ambient light was still apparent at 150 meters, but not a lot of fish. Whether it was due to the loud, whirring vehicle or our limited field of view, dives near the surface also appeared devoid of large and abundant fish. Interestingly though, at 180 meters we found banner fish amongst saddleback snapper. One references notes a banner fish’s range to only 75 meters.
Additional dives will give us a better snapshot of the diversity. Yet, whatever this seamount’s patterns, bringing Fijis’ deeper underwater seascape to the surface is imperative. The release of oil exploration licenses around these islands calls for urgency to discover what might need protected before it could be destroyed.
On board the Waitt Institute research vessel, we are fortunate to have coral spotting guru, Dr. Don Potts from UCSC, as well his former PhD student, Dr. Stacy Jupiter, who has been WCS Fiji’s program director for the past five years. WCS’s Sea and Sky director Claudio Campagna, who specializes in the creation of Argentina’s pelagic marine protected areas, also aids in the conservation goals of this research leg.
Click on the link below to see exciting video footage from the ROV: Fiji seamount survey video
Amy West has traveled worldwide as a marine scientist, specializing in fisheries and deep-sea ecology. Now as a science communicator she brings stories about ocean realms to the public through radio, video, photography, and writing. She’s usually diving into adventurous stories that take her on or below the water.