A bottle nose dead dolphin was washed ashore at at Bhuigaon beach, Vasai on Tuesday.
The local fishermen found the dolphin floating dead near the shore and pulled it to the shore.
Sources said the dead mammal was 5 feet long weighing 55 kg.
The fishermen informed Marine Police about the dead dolphin. There were injuries on the fins and body of dolphin indicating that it suffered injuries from fishing hooks used by fishermen.
In the past, several incidents of dead dolphins being washed ashore at Vasai, Dadar and Juhu beaches have been reported.
The increasing frequency of dolphins washing ashore or being found in shallow waters is now of deep concern among environmentalists.
The dolphins were declared endangered species in 1996.The Patna high court had in 2011 directed the Bihar government to check dolphin deaths after reports surfaced that they could be poached for their meat, skin and oil. Freshwater dolphins number only 2,000 to 2,500 in India.