Carcass of Risso’s dolphin washed ashore

CHENNAI: Volunteers of TREE Foundation have identified a carcass of Risso’s dolphin, which was washed ashore in Chinnandi Kuppam beach in Chengalpattu district on Saturday.

Post-mortem examinations revealed the sub-adult dolphin might have died due to drowning, likely due to entanglement in fishing gear.

Supraja Dharini, chairperson of the TREE Foundation, said that the carcass of Risso’s dolphin (Grampus griseus) measured about 115 inches in length and weighed over 480 kilograms. The sea mammal exhibited characteristics indicative of a sub-adult. “Post-mortem examinations revealed an absence of external wounds or marks on the dolphin’s body. The likely cause of death is ascribed to drowning, with entanglement in fishing gear emerging as a plausible contributing factor,” she added.

Following a comprehensive external examination, the dolphin was buried 50 metres above the high tide line to prevent scavenging by jackals and crows in the presence of forest guard.

“The TREE Foundation has recorded an unusual number of cetacean strandings this year, with 12 dead dolphins and 148 dead sea turtles along the Chennai and Chengalpattu coasts. While certain cases suggest fisheries interactions as the most probable cause of death, further investigation is required to determine the exact causes,” she opined.

Grampus griseus is a widely distributed species, inhabiting deep oceanic and continental slope waters from the tropics to temperate regions in both hemispheres. Known for their slow surfacing behavior and preference for squid, these dolphins often bear scars from squid bites.