Nineteenth Century tools made from sharks' teeth suggest that two species of shark used to populate the Central Pacific but are no longer present.
Using artefacts from museums, a team of US researchers found that spot-tail and dusky sharks used to inhabit the reefs surrounding the Gilbert Islands.
The unusual historical data would help evaluate the success of ecological conservation measures, they added.
The findings have been published in the scientific journal PLoS One.
In their paper, the team from the Field Museum of Natural History, Chicago, and Columbia University, New York, said indigenous artefacts often represented an "under-utilised source of data". Read the full article