Mystic Aquarium officials said they're investigating after receiving a report of a dolphin spotted in the Thames River in Norwich.
The aquarium said they've been in contact with the National Oceanic and Atmospheric Administration (NOAA) and they're being advised to monitor the dolphin.
As a result of the sighting, Norwich Police advised fishermen to pull all of their lines from the area of the river where the dolphin was spotted.
Volunteers from Mystic Aquarium were dispatched to the area to monitor the dolphin.
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Video of the sighting was shared on social media. The dolphin appears to be jumping out of the water.
No one has spotted the mammal since its initial sighting.