The whale shark which was found dead in the Ashtamudi backwaters had a long gash in the abdomen, and its stomach had ruptured, necropsy has revealed. It had landed in the Ashtamudi backwaters and was towed by fishermen towards Kavanadu at Meenatucherry in Kollam on Monday.

By night, the fish died, and the carcass was transported to the Punnala forest region for necropsy on Tuesday. The whale shark is included in Schedule 1 of the Wildlife Protection Act. Capturing and killing the fish is a cognisable offence.

Forest veterinary doctors who conducted the necropsy have collected samples of heart and muscle for a detailed histo-pathological examination. The samples will be sent to the Avian Disease Diagnostic Laboratory, Thiruvalla. There was significant fluid accumulation in the abdomen (ascites), a condition where fluid from an infection collects in spaces in the belly.

"We spotted a long, deep cut in the stomach. The fluid may have originated from a localised infection which then spread to other parts. We need to find out if the rupture was because of a pathogenic infection or a wound due to a sharp, piercing object.

"There was no trace of plastic or any sharp objects inside the abdomen. We also don't think the fish sustained any injury from hook or bait because, normally, in such cases, the presence of objects is confirmed inside the abdomen," a forest vet associated with the necropsy said.

The vets also looked for signs of any external injury due to a boat propeller hit or cut wounds resulting from human interference. "No such wounds were detected. Lab examination would confirm if it was suffering from any disease," the vet said.

The adult male shark measured 17 ft and weighed around 2 tons. The carcass was buried at Punnala as per the request raised by the Department of Museum and Zoo. The museum administration has requested the Department of Forests to preserve the skeleton and exhibit it at the Natural History Museum.

The NH museum now has a model of the whale shark. The officials said they planned to obtain the skull and jawbones of the whale shark for display. A fully articulated skeleton of a false killer whale and jaw bone of an Indian fin whale are already on display at the NH museum.

The Indian fin whale had beached ashore in 1902 at Rajakkamangalam in Kanyakumari. "Usually, we flay the shark's skin or put worms in the ditch to enable faster decomposition. In this case, we were not able to do so.

"We have placed a request with the Forest department, and now an official nod is awaited for further procedure. We may not be able to get a full articulated skeleton, but the skull and jaw bone could be retrieved," said an official with the Museum.