Kolkata: Two cyclones–Amphan and Bulbul--that hit the Bengal coast within six months have severely damaged the habitat of horseshoe crabs, a living fossil that has remained unchanged for millions of years.
Out of the four species of horseshoe crabs in the world, two are found in India. Their habitats in India are confined to the beaches of West Bengal and Odisha in areas such as the Sagar Island and Bhitarkanika. The total length of the habitat in Odisha and West Bengal is around 150 km
Forest officials and researchers are now trying to restore this habitat and also relocate some of the animals to three new islands in the Sunderbans to save them. Plans are also afoot to tag some of the animals so that they could be tracked with the help of satellites.
“The horseshoe crab habitat on the Sagar Island has suffered extensive damage because of two consecutive cyclones--Amphan and Bulbul. We have identified three beaches at Kalash, Haliday and Bakkhali where a section of the population of the horseshoe crab will be released,” said S Kulandivel, joint director of the Sunderban Biosphere Reserve.
Amphan hit on May 20 with winds gusting up to 185 km per hour and Bulbul close to Sagar Island in November 2019.
“Satellite pictures clearly show that its mangrove habitat on Sagar Island has been damaged. Ground reports say that it is littered with debris including plastic that was brought in the storm. Also, the water is having a lot of a ‘ghost nets’ which are basically fishing nets that got ripped in the storm and have now been abandoned,” said Punyasloke Bhadury, who heads the Centre for Climate and Environmental Studies at the Indian Institute of Science Education and Research (IISER).
Forest officials and researchers from IISER and Wildlife Trust of India (WTI) will soon start restoring the habitat, first removing the debris and nets. The local fishermen will be involved as Cyclone Amphan has also affected their livelihood. A threshold population will be allowed to stay on the Sagar. Talks are also on to tag the habitat as an ecologically sensitive zone.
“While hundreds of Indian horseshoe crabs (Tachypleus gigas) come ashore particularly during the monsoon to breed, the mangrove horseshoe crabs (Carcinoscorpius rotundicauda) usually stay in the mangrove areas to feed,” Bhadury said.
The researchers will intercept some of the injured horseshoe crabs and treat them before releasing them again in the wild.
As of now, they want to give them some kind of tag that will help identify them in the future. In the next stage, satellite tagging is planned so that they could be monitored.
“We first need to assess the damage. More than the cyclone, it was the storm surge and the heavy rain that could have inflicted the damage on the habitat which comprises mangrove and mudflats. Some might have got washed further inland and their tails might have been broken,” said BC Choudhury, executive trustee of WTI.
The pharmaceutical industry depends on this animal’s blood to test bacteria in vaccines. The creature’s copper-rich blood clots have the presence of bacterial endotoxins and hence have long been used to detect contamination in shots and infusions.