Shark Tooth Weapons Reveal Two Lost Species in Central Pacific

An analysis of weapons made from shark teeth that were used by 19^th century islanders has revealed two species of sharks that vanished from the reefs of Kiribati, even before scientists could discover their existence, reports LiveScience.

According to researchers, the two shark species, namely the dusky (Carcharhinus obscrus) and the spotfin (Carcharhinus sorrah), once existed around the Gilbert Island reefs in the Central Pacific. Presently, spotfin sharks are found near Australia and Indonesia, while the dusky sharks are seen near Fiji, but neither of the species can be seen in the waters of Kiribati, reports LiveScience.

According to the study, published in the journal PLOS One, it is evident from tracing the historic records that sharks were culturally significant to the Gilbertese Islanders; and there existed a complex ritual system surrounding shark fishing and the making of tools and weapons from shark teeth.

In the present study, Joshua Drew from Columbia University and colleagues from the Field Museum of Natural History examined a collection of close to 120 shark tooth weapons that were preserved in the museum, including some weapons that shared a close resemblance to clubs, daggers, swords, spears and lances.

Based on the teeth used in the weapons, they identified eight species of sharks, of which two species have never been documented in historic records.

"When we looked we found this shadow biodiversity, hints and whispers of what these reefs used to be like. It's our hope that by understanding how reefs used to look we'll be able to come up with conservation strategies to return them to their former vivid splendour," Drew said in a press statement.

Though the species are common in other areas, the researchers state that it may be residing in undiscovered areas of the Gilbert Islands. They also hope that the discovery will help in future conservation efforts in the region.

"I think it would be great to use this [study] as a way to help encourage the Gilbert Islanders to make strong marine conservation a priority, so that future generations can experience the same sorts of reefs that past generations have," Drew concluded.