The dolphin became stuck in mud in Manhasset Bay at about 5:30 p.m. on Tuesday, March 30, said the Nassau County Police.
It was moved about two hours later by police officers and a. Good Samaritan, and members of the Great Neck Alert Volunteer Fire Company and the Manhasset-Lakeville Fire Department worked for hours attempting to guide the animal into deeper waters.
But a check by marine biologists determined that the animal was too sick to swim in open waters.
Maxine Montello, rescue program director for the New York Marine Rescue Center in Riverhead the animal, who weighed out 220 pounds, was "was a very comprised older adult and was severely underweight."
After being found dead, the animal was retrieved by the center.
The dolphin will be necropsied by officials with the Atlantic Marine Conservation Society of Hampton Bays.
Montello urges the public to report sick, injured, or stranded marine mammals to the New York Stranding Hotline by calling 631-369-9829.
"Animals in these situations are already under extreme stress and unnecessary handling or attention can further worsen their condition," she said.
Dolphins are federally protected animals and require trained response teams to evaluate and assist the animal, she added.
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