The Ganges river shark is so rare that there has been no confirmed record of the species for a decade 鈥� and very few ever. But a series of photographs taken at a fish market in Mumbai, India, show the species is still around, and in a unexpected place.
鈥淚t鈥檚 a species that鈥檚 never really been seen in the western Indian Ocean,鈥� says , founder and lead scientist of the 鈥� a shark research and conservation organisation 鈥� in the United Arabic Emirates.
A student of hers, Evan Nazareth of St Xavier College in Mumbai, snapped shots of a Ganges shark (Glyphis gangeticus) in the Sassoon Docks fish market of Mumbai in February 2016. Jabado, Nazareth and colleagues have now published a paper describing the find.
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As their name implies, Ganges river sharks are thought to spend much of their lives in freshwater or estuarine environments. Some researchers think that the Ganges river sharks can live their entire lives without saltwater, but a previous genetic suggests some degree of oceanic mobility.
We know hardly anything about them. 鈥淭here is so little information about these species,鈥� Jabado says, adding that much of their behaviour isn鈥檛 so much known as extrapolated from a related river shark in northern Australia. And even the Australian species is very rare and seldom caught.
There have been very few reported sightings of river sharks over the past couple decades in Southeast Asia, and these sightings are most likely actually of bull sharks 鈥� an oceanic shark that can survive in fresh water and often travels far up rivers. But Nazareth鈥檚 photos clearly show a river shark.
Unfortunately, Nazareth, who was visiting the docks as part of a study on shark landings, only had time to snap a few pictures before the traders took the body away for processing in the market. He didn鈥檛 manage to get a sample from the shark.
Extremely rare
The researchers don鈥檛 know for sure where the shark was caught, but Jabado says that fishermen usually go north of Mumbai. She thinks it was likely caught in the estuary of the Indus River in north of India closer to Pakistan. There is just one previous jawbone finding from this area.
鈥淭here are so few specimens of river sharks from around the world that pretty much all the information we have is based on either preserved specimens from the last century, or from jaws that were found at some point in remote villages and were identified as river sharks,鈥� Jabado says.
The Ganges river shark is a protected species in India but more needs to be done to enforce the regulations, including teaching people recognise these rare sharks, the paper says.
Rare species do occasionally turn up in fish markets. In fact, David Ebert of the Pacific Shark Research Center in California has named 10 new species of shark from specimens he found for sale in a single Taiwanese fish market.
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