The carcass of a marine mammal that was found stranded on the Puthukurichi beach, near Perumathura, in Thiruvananthapuram on Sunday has been identified as that of a killer whale or Orca ( Orcinus orca ).
Dipani Sutaria of the IUCN Cetacean Specialist Group and A. Biju Kumar, Head, Department of Aquatic Biology and Fisheries, University of Kerala, who examined photographs of the beached body confirmed it as a killer whale.
According to the Marine Mammal Research and Conservation Network of India (www.marinemammals.in) that maintains a database of marine mammal sightings and stranding in India, this is the first report of a killer whale stranded or sighted from Kerala waters.
Important
Dr. Kumar feels that the record of stranding from Thiruvananthapuram is important, especially in realising the distribution of this top predator of the ocean in the Arabian Sea and its migration. The specimen stranded measured 12 feet in length and weighted about 3 tonnes, and is an adult bull (male). The killer whale is robust and streamlined, with a round but not prominent beak. The dorsal fin is very tall and conspicuous, and the flippers (modified forearms) are very large and paddle-like. They also have a distinct colour pattern.
In the specimen stranded in Thiruvananthapuram, however, the colour pattern was not clear, as it had started decomposing. “One of the distinct identification features in such cases is the 12 pairs of large conical, strong, sharp and often recurved teeth in each jaw, the dorsal fin, and their paddle like flippers. No other cetacean has such flippers,” says Dr Dipani.
Killer whales or orcas are efficient swimmers, attaining more than 50 km per hour. Though abundant in cooler waters because of the abundance of prey, they are also common in tropical waters as they migrate across oceans.
Modern technologies make it possible to study their genetic stock structures, kinships, migration and prey preference by collecting data from carcasses, says Prof Kumar. “Considering their importance, there is an urgent need to develop a marine mammal stranding response and participatory observation network with help from fishermen, lifeguards, naturalists, researchers, the Indian Coast Guard and the Forest Department, he says.
