In 1997, he was among the curious crowds watching wildlife filmmaker Mike Pandey shoot Shores of Silence on the species. A 30-foot whale shark had been found dead on the shore near the religious town of Dwarka, Goswami remembered of this first sighting.

The film focused on the plight of the fish, which was being hunted indiscriminately off the shores of Gujarat for liver oil and meat. The liver oil was used to waterproof fishing boats, while the meat was exported.

Pandey’s film won the Panda Award, considered the green Oscar, in 2001, the year in which whale shark hunting was banned.

The fish have a critical ecological role, Pandey said in an interview. At least four of his films have brought about legislation or legislative changes for wildlife protection.

“The whale sharks help in creating equilibrium between nature and our lives,” he said. “By consuming two and half tonnes of plankton every day, these whale sharks remove an equal amount of harmful carbon dioxide from the atmosphere.”

Before the ban, as many as 1,200 whale sharks used to be slaughtered every year in Gujarat during the monsoon. The waters off the state’s coast had the largest population of whale sharks in the world—a little known fact that Pandey’s film brought to light.

Goswami’s first rescue took place in 2004 when the forest department got news of a whale shark that was struggling to free itself from a fishing net. He went to the site and with the help of local fishermen cut the fish loose without harming it.

He has taken part in at least 300 rescues along the coast of Gujarat as a volunteer for the whale shark conservation programme initiated by the Gujarat forest department and the Wildlife Trust of India in 2004. The programme has succeeded in saving more than 350 whales so far, according to a recent media statement by Tata Chemicals Ltd that funded the project.

On 27 April, Goswami was reminded of the 1997 incident as he examined a whale shark that was killed near Kodinar recently. “Some fishermen informed me and my friends about the killing. The shark’s liver was missing,” said Goswami, who documented the dead fish.

“Three years ago, we had learnt of a similar incident where a whale shark was hacked to death for its organs. It is wrong to assume that poaching of these gentle giants has completely stopped. A whale shark liver can fetch anywhere between Rs.75,000 and Rs.1 lakh,” according to Goswami. A state government official in the know of the development confirmed the recent poaching of the big fish. This is probably for the first time in the last one decade that a case of whale shark hunting has come to light.

“We have found out they are being hunted in some parts of Gujarat in significant numbers. I will soon find out who is behind this,” said Goswami, who is investigating the matter with the help of friends in the area and forest officials.

Pandey, whose film inspired Goswami to become a whale shark champion, is impressed by the activist’s achievements.

“Dinesh’s work in conservation has been very inspirational. He has been talking to the fishermen and has created awareness among them, making it a people’s programme. The fishermen hardly made any money by selling these dead fish. It was the meat exporters who pocketed Rs.1-1.5 lakh per kilo,” Pandey said.

Goswami lives with his wife and two children in a one-room rented house at Kodinar, near Porbandar.

“Whenever a whale shark is in trouble, I rush to rescue (the fish). If I am at work, I take a pay cut. I got to know a lot about the fish and why they should be saved by seeing the film,” said Goswami, who can barely read or write.

He has built a strong rapport with the fishermen and uses their boats for rescues. “They (the fish) are gentle giants and unless you rattle them, they will never attack,” he said.

Goswami said there aren’t too many risks associated with the conservation work, although one rescue bid threatened to go sour when the animal that was trapped turned out to be a 65-foot sperm whale, which then tried to attack the team. None of them were hurt and the whale was successfully returned to the ocean.

One of the biggest challenges is rescuing whale sharks caught in nets. While the government will compensate the fishermen, the real challenge is to rescue the fish at the spot. This is where having a close relationship with the fisherfolk help.

“About five whale sharks have been caught in my net so far. Earlier we used to sell them, but now we call Dineshbhai and he helps us rescue them,” said Babubhai Savai, president of a fishermen’s association in Mul Dwarka. “Moreover, he also helps in documenting the rescue operation and we get compensation from the forest department.”

Goswami and his team have been alerting the forest department about whale shark movements and accompanying personnel during rescue work, said Aradhana Sahu, deputy conservator of forests, Junagadh.

In August 2012, the state government launched a ‘self-documentation scheme’ by using water-proof cameras to ensure minimum stress to whale sharks by speeding up rescue operations.

Contrary to the widespread belief that whale sharks have their habitat in Australia and migrate to Gujarat during winter in search of food, it has been found that as many as 700 are residents of Indian waters and do not migrate, Goswami said. The number was arrived at from data collected after talking to fishermen in Porbandar and nearby areas. The whale sharks have found a new habitat in Gujarat, he said.

Goswami is also working for the conservation of sea turtles and has formed a non-government organization known as Prakruti Nature Club. His team, which has about 200 members, raises funds by organizing awareness programmes at private schools and colleges, and hasn’t sought any help from the government yet.