A team of scientists examining weapons with shark teeth from Gilbert Island made an unusual find: some of the teeth belong to two species of sharks that are no longer present in the area. The conclusion they drew? They were wiped out by humans.
The two species of sharks can be found elsewhere in the world today, but for some reason have never been recorded in the island reefs -- yet, the existence of their teeth in Gilbertese weaponry suggests there was once a local population.
The study, titled "Shark Tooth Weapons from the 19th Century Reflect Shifting Baselines in Central Pacific Predator Assemblies," was spearheaded by Joshua Drew from Columbia University and relied on the Field Museum of Natural History for the weapons and extra researchers.
"Using a novel data source, the shark tooth weapons of the Gilbertese Islanders housed in natural history museums, we show that two species of shark, the Spot-tail (Carcharhinus sorrah) and the Dusky (C. obscurus), were present in the islands during the last half of the 19th century but not reported in any historical literature or contemporary ichthyological surveys of the region," reads the study abstract.
Sharks played a vital role in the culture and history of the Gilbertese people, who regularly fished sharks and used their parts for gear. The study team hopes that this case will help highlight the effects that humans have on the wildlife around them. After all, it wasn't too long ago that another team of scientists declared that humans were responsible for a mass extinction of birds.
"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 splendor," Drew says.
You can read the published study at PLOS One.
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