Researchers believe that a shell-dense island off the coast of Culasawani, in the northern part of Vanua Levu Island in Fiji, was caused by human activity from 1,200 years ago, rather than a tsunami as previously assumed.

New Fiji Island Discovered

The island was first discovered during a geoarchaeological survey of the coast of Vanua Levu in 2017. Researchers found the small 32,291-square-foot, low-lying island surrounded by mangroves. After closer examination, they realized the landmass was made of the remains of shellfish mixed with sandy clay.

“These were not merely on the surface,” the team explains in their paper. “In many places, burrowing crabs (Scylla serrata) had brought subsurface materials from depths of 30–50 cm [12-20 inches] to the ground surface, showing that shellfish remains also formed the bulk of these.”

Since its discovery, two different teams have investigated the area. Sitting around 24 inches above the average high tide at its highest points, the island was first believed to be caused by wave mechanics.

“The narrow concentration of ages around 1190 cal BP (760 CE) ± 99 may indicate that this deposit was created when a large (tsunami?) wave once washed across the area with great force,” the team explains. “Perhaps this wave impacted a shell bed, even an ancient midden, on the sea floor west of the island and broke it up, carrying remnants far inland.”

The only problem with this theory is that it’s at odds with the types of shells found in this area. Instead, the team believes they were deposited by a group of early settlers who processed huge amounts of shellfish and discarded the shells over a few hundred years.

Another name for an island made of discarded shells, animal bones, or other waste is a midden. Midden islands are typically found around low-latitude Pacific islands, where shellfish had been a large percentage of the diet for ancient civilizations. If further research confirms the island is a midden, it would be the first found in the South Pacific west of Papua New Guinea.

“In those islands in the western Pacific around which sea level fell during the period of their (early) human settlement, the long-term consumption of shellfish and the discarding of their inedible remains sometimes led to the emergence of shell-dense land suitable for human habitation,” the team explains.

The study is published in the journal Geoarchaeology.