India begins geotagging horsheshoe crabs
ZSI and Odisha forest department tag horseshoe crabs to study their population and habitat.
The Zoological Survey of India (ZSI) and the Odisha forest department have begun a novel exercise: tagging horseshoe crabs to understand the population and habitat utilisation of this globally recognised living fossil.
India is home to two species of horseshoe crabs (which are actually not true crabs), Tachypleus gigas and Carcinoscorpius rotundicauda (mangrove), and both are found along the country’s eastern coast. In Odisha, they are found along the coasts of Balasore and Kendrapara districts.
Over the years, however, their numbers have dwindled due to destructive fishing practices and illegal harvesting for biomedical testing.
In a bid to understand the species’ behaviour in the wild, ZSI and the Odisha forest department has tagged 12 horseshoe crabs in the Khandia Muhan estuary of the Balasore coast.
“This is an extremely important species. We need to come up with a conservation plan,” said Dhriti Banerjee, director, ZSI.
The exercise is set to be completed over the next three years.
The plan involved tagging hundreds of crabs to determine their population pattern and the threats to the population, said senior ZSI scientist Basudev Tripathy.
“All the tags are marked with a serial number, mobile number and has Zoological Survey of India mentioned. Tags will help us to track the migratory routes of the marine species,” he said.
The blue blood of crabs can clot in the presence of bacteria, rendering them harmless. This clotting ability has been extensively utilised in testing injectable medicines, vaccines, and sterile medical equipment. The outer layer of horseshoe crabs consists of chitin that enhances wound healing and serves as a crucial component in treating burn wounds.
Although there are no estimates of their population decline, scientists in Odisha say in the 1990s and early 2000s, there were around 40 specimens in a 200-square metre area, and now one can hardly see them. There are only a few estuaries left in Odisha, including one in Balasore where horseshoe crabs can be found.
“Destructive fishing practices are major threats to horseshoe crabs, and there are reports of illegal smuggling of the species from the Odisha and West Bengal coasts. Horseshoe crabs are a Schedule 2 species under the Wildlife Protection Act, 1972,” said Tripathy.
With the tagging exercise, experts hope to understand the reproductive biology and growth rate of the species, which emerged 250 million years ago, and has not changed in appearance since, which explains why many refer to it as a living fossil.
“Tagging is most often conducted to obtain information on reproductive biology, movement and growth rate. The tagging will help us in studying the horseshoe crab’s migratory route and areas of foraging. Tagging data will also prove interconnection of horseshoe crab population in Odisha coast,” said BC Chaudhury, former wildlife biologist and scientific adviser of Wildlife Trust of India (WTI).
Banerjee said ZSI plans to propose to the Union ministry of environment, forest and climate change to conduct advanced research using modern techniques like satellite telemetry to gather more information about these fascinating creatures.
