The washing ashore of carcasses of five dolphins, and finless porpoises, both protected species, along the Mumbai coastline in a short span of two months has baffled marine conservation experts.

As many of the carcasses were disposed of before conducting a post mortem study, there is no clarity on why these animals are being washed ashore and the exact cause of death.

On April 21, a dolphin was found dead at Marine Drive in South Mumbai, which was directly taken to the Deonar dumping ground by BMC officials, according to activists. Another one was found dead at Nariman Point a week later, and a finless porpoise was found dead at Dadar Chowpatty seashore in central Mumbai a fortnight later.

The dolphins, identified to be humpback dolphins, are protected under Schedule 2 under Wildlife Protection Act, 1972.

Although the Bombay Society for Prevention of Cruelty to Animals (BSPCA) claimed that a post mortem report was sent to the Forest and Wildlife Department, officials in the department’s control room refused to provide further details about the report.

Marine biologists unanimously believe that these marine animals were killed deep in the ocean before they hit the shores. However, without any accessible medical autopsy, experts and biologists are forced to analyse the deaths only using theoretical concepts. There is a variety of reasons presented by them.

“With investigation and a subjective autopsy, we could have evaluated the situation better”, said Dr. N.V.K Ashraf, senior director and chief veterinarian at the Wildlife Trust of India.

Different factors including water pollutants, radio-active toxins, factory effluents and climatic changes are among the many possibilities that could have lead to the spotting of these dead animals. According to Dr. Ashraf, the Wildlife Conservation Act and the forest departments concentrate most of their force on terrestrial wildlife, and neglect marine biodiversity.

“Before the monsoon, the benthic levels start becoming high, and currents in the sea begin to gain momentum”, said Nitin Walmiki, marine biologist and researcher from the environment NGO, Eco Echo.

“Based on Darwin’s survival-of-the-fittest theory, the marine animals that are incapable to cope with these changes die”, he said.

Mr. Walmiki added, “Another possibility is that the migration pattern of marine life is undergoing changes.”

Pawan Sharma, president of Resqink Association Wildlife Welfare (RAWW), suggested possible illegal activity causing the death. “When our team found the carcasses in Nariman Point, the dolphin had a rope tied around it. I find this extremely suspicious as it could imply poaching or smuggling activity. Even when two dolphins and four olive ridley turtles were spotted in Manori beach last month, the carcasses of the dolphins went missing.”

Sharma has written letters to the Brihanmumbai Municipal Commissioner, the State Forest department, and the Mumbai police commissioner Rakesh Maria demanding scientists and expert teams for marine conservation following the incidents.

Another marine biologist, Dr. Abhay Hule, said that changes in water levels, oxygen levels, pressure and temperature of the ocean, caused due to urbanisation and sea traffic, may have created unsuitable environmental conditions for these animals.

“It is also possible that fishermen equipment may have hurt the animals”, he said. Dr. Ashraf agreed that since the oceans are open to fishermen more than it must be, the marine ecosystem is not protected enough.

If this quandary could have a solution, Dr. Hule said, “There is not enough awareness about marine life. The government officials and conservation departments are not equipped with experts. They take it too lightly, and they don’t care enough about marine life."