Horseshoe crabs, found along Odisha's coastline, are ‘living fossils’ as they have remained relatively unchanged for at least 445 million years, much before dinosaurs existed. More closely related to spiders and scorpions than crabs or lobsters, horseshoe crabs are now on the verge of extinction.
Fakir Mohan University (FMU) and the Association for Biodiversity Conservation and Research (ABCR), both based in Balasore, are using In-Vitro Fertilization (IVF) and also hatching the naturally fertilized eggs in laboratories to protect the endangered species.
While IVF has been used for many years in animals like dogs and cattle, the application of the method to horseshoe crabs is among the first in India. The process is set to increase the number of horseshoe crabs along Odisha’s coastline.
Horseshoe crab eggs are rich in protein, fatty acids, and minerals, making them a vital food source for many birds, animals, reptiles, and fish. Combined with human activities, most eggs do not turn into larvae, endangering the survival of the species.
With the Central Government’s support of Rs 29 lakh, FMU’s Bioscience and Biotechnology Department (BBD) and ABCR have hatched thousands of horseshoe crab larvae and released them into the sea in a process called sea ranching.
The project ‘Stock Enhancement of Horseshoe Crabs by Sea Ranching commenced in 2016 and was wound up in 2019. FMU has now set up the Centre for Research and Conservation of Indian Horseshoe Crabs (CRCIHC) to conserve living fossils.
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How IVF is done in horseshoe crabs
The IVF method used by scientists in the case of horseshoe crabs is different from the one carried out for test tube human babies and other animals.
During IVF, injured and dying male horseshoe crabs are given an electric shock of six to nine volts that leads to sperm secretion. A similar process is implemented in the case of females to induce egg release.
When larvae hatch, they are kept under observation for three months till their tails are formed which is followed by sea ranching.
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Founded this year under the guidance of FMU vice-chancellor Prof Santosh Kumar Tripathy, CRCIHC is working on baseline data to garner detailed information about living fossils’ habitats, their movement and time of hatching.
The Zoological Survey of India (ZSI) has also been roped in under the project ‘Conservation and Management of Horseshoe Crabs along Odisha Coast’ (CMHCOC). The state government has earmarked a budget of Rs35 lakh for this project of which nearly Rs5 lakh was released in the first phase.
“The State Forest Department allowed us to target only injured and dying horseshoe crabs for collecting their eggs and sperms to perform IVF in the laboratory of FMU’s BBD,” says Professor (Dr.) Bishnu Prasad Dash, the present adjunct professor of FMU’s Department of Zoology and principal investigator of CMHCOC.
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Out of four types of horseshoe crabs in the world, ‘Tachyplycus gigas’ and ‘Carcinoscorpius rotundicauda’ are mostly found on the coast between Sundarbans of West Bengal and Bhitarakanika of Odisha, according to Professor (Dr.) Bishnu Prasad Dash, the present adjunct professor of FMU’s Department of Zoology and principal investigator of CMHCOC.
“As horseshoe crabs come under Schedule 2 of the Wildlife Protection Act, we allowed BBD to focus on injured and dying ones along Chandipur coast in Balasore district for research purposes,” says Harsh Bardhan Udgata, former Divisional Forest Officer, Balasore.
“In the natural environment, males usually sit on eggs and release sperm for larvae to hatch in 38 to 42 days. In natural fertilization, the success rate is 60 to 70 percent, while that of IVF is 90 to 92 percent,” points out Dr Dash.
“Retired senior scientist Dr Anil Chatterjee of National Institute of Oceanography, Pune, helped in artificially circulating the incubator continuously for development of eggs and resultant hatching,” he added.
In the second segment of the work, naturally fertilized eggs at estuaries are collected and brought to the laboratory.
Eggs are hatched naturally inside soft sand with mild moisture content when an environment of temperature is 28 to 30 degrees Celsius and salinity is around 31 ppt. This environment is simulated inside the incubator for larvae to hatch.
A female lays 6000 to 8,500 eggs mostly in winter. In other seasons, the frequency of egg-laying comes down.
Awareness around horseshoe crab conservation
Odisha has nearly 12 estuaries like Mahishiali, Khandia, Kantiachitra, Talapada, Talapada and Udabali along its coast. Though all estuaries have now assumed priority for CRCIHC, its main focus would be on those estuaries and sandy patches where the maximum number of horseshoe crabs is found.
“We would first request the government to accord protected status to these areas that ‘forest reserves’ and ‘wildlife sanctuaries’ have,” says Dr Dash.
“In the first phase, 50,000 larvae were released into the sea. Now we will expand the scale of conservation with government support,” says Dr Bharat Bhusan Patnaik, the deputy director of CRCIHC, and associate professor and present head of FMU’s BBD.
“However, the overall change in horseshoe crab numbers can be calculated only after three to four years,” he adds.
A similar step has been taken by ZSI which is working on areas where horseshoe crabs are mostly visible. After demarcating these areas, ZSI will prevail upon the government to declare them protected in two categories—conservation reserve and community reserve.
‘Conservation reserves’ are lands of government departments, people and other agencies that are declared protected. Similarly, ‘Community reserve’ private land is declared protected against payment of compensation to its owner/s,” says senior scientist Dr Basudev Tripathy of ZSI’s Western Region, Pune.
‘We have already initiated ‘tagging’ in which we number horseshoe crabs wherever we stumble upon them,” he adds.
ABCR is conducting public awareness camps in villages along the Balasore coast and organizes art, quiz and debate competitions in schools. On ‘Rakhi Purnima’ (In August) and ‘Snana Purnima’ (In June), villagers and ABCR’s members tie ‘rakhi’ around each other’s wrists, vowing to protect horseshoe crabs.
“We also screen a five-minute ‘A Day for Living Fossil’ to raise awareness about the biomedical and ecological importance of horseshoe crabs,” says scientist Dr Siddartha Pati, the Secretary of ABCR, who received state’s prestigious Biju Patnaik Wildlife Conservation Award this year.
Horseshoe crab is ecologically important, as it has a major role in the food web for migratory shorebirds, finfish and other species. It is biomedically useful because the protein in its blood, called Limus Amebocyte Lysate, is used in pharmaceuticals.
“In 2014 we marked stretches of dead horseshoe crabs along sea beach. People used to kill them out of ignorance. Now I have marked around 50 percent reduction in their mortality,” says artist Keshu Das who belongs to the coastal village Dublagadi in Balasore district.
(Niroj Ranjan Misra a Cuttack-based freelance writer. He writes on rural and tribal life, social issues, art and culture, and sports)
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