The Cetacean Beauties Of Great Nicobar

By Mahi Mankeshwar

Beauty lies in the eye of the beholder and for me, it lies in the shape of the seafloor of the Andaman and Nicobar Islands. For if, from the water’s surface, our eyes could peer deep into the island’s waters, we would find ourselves floating over summits of a mountain range sprawled beneath us! Beginning high up in the eastern Himalaya to the north, these mountains stretch over 1,000 km. southwards, hemming off the Bay of Bengal to the west and nestling in the Andaman Sea to the east.

What initially drew me to the Andaman and Nicobar Islands was not so much the submerged mountains but the possibility of learning more about a group of animals known as cetaceans… dolphins and whales. These are arguably one of the most charismatic animals in the animal kingdom, yet we know so little about them from our waters.

A boat ride around Great Nicobar Island offers a fair chance of sighting a hyperactive pod of spinner dolphins Stenella longirostris. These were not documented in the EIA report for the Great Nicobar ‘development’ project. Photo: Vikas Nairi.

When it came to the islands, we knew even less. And so, one of the first questions I asked when I first arrived on the islands as a researcher in 2016 was, “Are there dolphins and whales in these waters”? The more I talked to island folk and the more we observed the sea with binocular-equipped eyes, the canvas of the waters began to fill up. First, with the languid swims of bottlenose dolphins, then with the most energetic breaches by spinner dolphins, and then with curious orcas ambling around a fishing boat. One by one, through old photos shared by people and new sightings made from our ferries and boats, we learnt that there are at least 15 species in these waters including Omura’s whales, sperm whales and other deep-sea species such as the Fraser’s dolphin and the dwarf sperm whale.

Between the deep, yet vastly homogenous stretches of the Bay of Bengal and the Andaman Sea, these islands seem to offer a refuge to oceanic species. Whether it’s the steep ridges that give way to depths thousands of kilometres below sea level, or seamounts and pinnacles that are magnets of diversity, or the shallow waters off a beach, they all are nooks offered by the mountains that the animals keep returning to – making the island system a haven for cetacean diversity.

This large pod of Fraser’s dolphins Lagenodelphis hosei was spotted in the waters off Nicobar Islands. This deep-sea species feeds on pelagic fish, squid and shrimp at depths where sunlight does not penetrate. Photo: Akshata Karnik.

Cetaceans And The Great Nicobar Island

The Great Nicobar Island (GNI) at the southernmost tip of the island chain is very much a part of the same underwater mountain range more scientifically known as the Andaman and Nicobar Accretionary Ridge (ANAR). Yet, the EIA report for the Great Nicobar Island’s ‘development’ project documented only three marine mammal species from the area, one of which is the dugong, which is not a cetacean! This hardly came as a surprise as EIAs have often been nothing but facilitators for such projects in the past.

What kind of diversity do we really have in the waters of Great Nicobar? Frankly, we do not know enough. Unlike humans, dolphins and whales are free of the name-place mental barrier and to them, Andaman and Nicobar are part of the same seascape as their usual haunts, with thankfully no one asking them to furnish a pass or permit… at least, not yet!

Omura’s whale Balaenoptera omurai is a rare species of rorqual, of which there has been limited sightings and natural history data. Photo: Mahi Mankeshwar.

All the cetaceans we found during the study in the Andaman Islands, with the exception of the bottlenose dolphin and Omura’s whale, were oceanic species. These are free-ranging and quite boundless in their movements, most often in pursuit of fish and squid. So even though they may show preference to certain areas, they also often make lengthy migrations, which may cover an entire sea or ocean basin.

But, if you still do not want to leave it to speculation, take a couple of walks on B-quarry beach in Great Nicobar and you will surely witness the slow-swimming fin of a bottlenose dolphin pierce through the surface of the water. A species that was not documented in the EIA but stands to lose much of its habitat given its preference for shallow coastal waters, just like the dugong. Or take a boat ride around the islands and chances are you will be greeted by a hyperactive pod of spinner dolphins or the pantropical spotted dolphins. Add to this list, beautiful drone footage of Omura’s whale, captured by a fellow researcher from the waters off Little Nicobar, an island just north of Great Nicobar. The orca and Risso’s dolphin have also made their presence felt in these waters.

Sadly, none of these animals were recognised in the EIA report. Cetaceans have been accoladed Schedule I status, making them eligible for the highest protection by Indian law, and if that was not enough, part of the southern Andaman islands has been internationally identified as Important Marine Mammal Areas (IMMAs). But, as has been the case thus far with marine mammals of Great Nicobar, as with so many other species, it will be difficult to protect something whose existence has barely been officially acknowledged.

The false killer whale Pseudorca crassidens is a highly social species of oceanic dolphin. The name ‘false killer whale’ comes from having a skull similar to the orca Orcinus orca, or killer whale. Photo: Akshay Malawi.

After exploring the waters of Andamans, it was always Great Nicobar I wanted to return to. Given their remote and relatively undisturbed status, this island has always had the potential of revealing a lot more to us than is already known. Besides the desire and curiosity to find which species of cetaceans live there, I have also been interested in understanding how different species interact with their habitat. Which of the many nooks offered by these majestic underwater mountains do different species most depend on and why? What role do they play in their life histories at different times of the year? These are the questions that need to be answered before we decide to permanently alter a habitat.

If we knew the answers, we would be very unlikely to condemn these habitats and their inhabitants for short term financial gains through poorly conceived projects… in the name of development.