A United States researcher has used shark tooth weapons to prove the waters around Kiribati were once home to species of three shark which are no longer found there.
Joshua Drew, a Lecturer at Columbia University, looked at 124 of the weapons from between 1840 and 1880 which are kept in the Field Museum of Natural History in Chicago.
He says they compared the teeth in the weapons with some stored samples and found the spottail, dusky and bignose sharks would have been found in the waters around the Gilbert Islands.
"The teeth were fairly easy to identify but they were from species that weren't supposed to be there. The species were found either in the Solomons, in some cases Fiji or in some cases on the west coast of the United States but nowhere near the Gilbert Islands. They were showing up often enough that it wasn't just a one off thing that these animals were probably fairly common within these reefs."
Joshua Drew says sharks were prone to be overfished and this could explain why the species are no longer found near Kiribati.