Scientists Discover Island Formed Entirely From Shellfish Left by Early Humans

General presumption of the aboveground of the Culasawani ammunition island. Credit: Patrick D. Nunn / CC BY-NC 4.0

A small, unremarkable land disconnected the coast of Fiji has turned retired to beryllium thing scientists had ne'er documented successful this portion of the Pacific. Researchers accidental it is an land formed wholly from shellfish near down by communities that lived determination much than 1,000 years ago.

The land lies adjacent Culasawani, a lightly inhabited country connected the bluish seashore of Vanua Levu, Fiji’s second-largest island. It covers astir 3,000 quadrate meters (32,000 quadrate feet) and rises up to 60 centimeters (24 inches) supra the precocious tide line. Between 70 and 90 percent of its creation is shellfish remains embedded successful a sandy-clay matrix.

Patrick D. Nunn of the University of the Sunshine Coast successful Queensland, Australia, led the study, published successful the diary Geoarchaeology. His squad concluded the tract is simply a “midden island,” a landmass that grew from the accumulated shellfish discards of past settlers.

Radiocarbon dating of 10 ammunition samples placed their enactment astatine astir 760 CE, with dates ranging from astir 420 to 1040 CE.

How an land formed wholly from shellfish successful Fiji

The astir apt explanation, according to Nunn’s team, is that aboriginal settlers built stilt-platform homes implicit the shallow coastal waters astatine the site. Over generations, discarded shells piled up connected the seafloor beneath them.

A Fijian land formed wholly from shellfish discarded near by past settlers has been identified by researchers, marking a unsocial archaeological find successful the Pacific. pic.twitter.com/2CMNlLDxjb

— Tom Marvolo Riddle (@tom_riddle2025) April 3, 2026

As oversea levels gradually fell, the accumulated debris roseate supra the waterline, and an land formed wholly from their shellfish discarded dilatory took shape. Researchers besides considered the anticipation that the tract served lone arsenic a shellfish-processing spot, wherever radical removed the nutrient and carried it elsewhere for consumption.

Every shellfish taxon recovered from the deposit was edible, including Anadara antiquata and Gafrarium tumidum, some communal nutrient sources successful the region.

Pottery fragments were recovered passim the site, pointing to repeated quality activity. The lack of food bones and chromatic tools led the researchers to thin toward the processing-site mentation alternatively than imperishable habitation.

Edible taxon and pottery corroborate past quality presence

The squad initially examined whether a tsunami had deposited the shells successful a azygous event, since the furniture showed nary evident interior stratification. They dismissed that anticipation aft uncovering the shell-dense sediment confined strictly to the island, with nary thinning toward its edges, a signifier inconsistent with question deposition.

Today, the land sits wrong a ringing of mangrove forest. Researchers judge the mangroves took clasp lone aft the settlement was abandoned, erstwhile falling oversea levels and sediment from cleared inland areas built up astir the stream mouth.

Future enactment volition survey the surrounding seafloor for akin deposits and stitchery section oral histories astir immoderate ample waves that whitethorn person struck the coastline successful the distant past.