As it turns out the lone dolphin that's been spotted close to the city shores this week could be in danger. It's believed to be an offshore bottleneck dolphin, which is typically spotted in groups about 75 miles offshore, according to the NY Times. The director of the Riverhead Foundation's rescue program, Kimberly Durham, told the paper that seeing the dolphin close to shore "can be an indication that something is not right."

It is less alarming, according to Durham, to see regular bottlenose dolphins closer to shore—which is why when sightings were happening in 2009, it was more of a cause for celebration.

Riverhead has received several reports of what is described as a nearly seven-foot-long dolphin in the Hudson, from 14th Street to 225th Street. Durham believes the dolphin could be alone and close to shores due to a "bacterial infections, injuries from passing boats and brain damage from parasites that can impair a dolphin’s ability to use sonar."

If you spot the dolphin, then call the Riverhead Foundation at (631) 369-9829.

SAD UPDATE: A dolphin was found dead in the Hudson today, and Riverhead is trying to determine if it's the same one that was being spotted all week.