The whale, at least 25 feet long, was spotted just after 9 a.m. Thursday.
Rescue workers from the Riverhead Foundation for Marine Research and Preservation were en route to examine the whale.
They will perform a necropsy to determine what killed the whale. There were no apparent signs of distress or injury.
The whale was spotted on a section of beach known as High Hill. It is two miles east of the Jones Beach Water Tower, east of Field 6 and west of Tobay Beach.
The beaching is close to where a male dolphin washed ashore in West Gilgo Beach last Thursday. That dolphin died less than a day later.
And in April, an ill baby whale washed ashore in East Hampton. Several attempts to euthanize that whale failed before authorities were able to finally put it down.
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