Lots of dolphins showing up in the Chesapeake Bay

The effort to better track movement of dolphins through the bay and its tributaries began last June, and since then, over 900 sightings have been reported.

“We were only expecting maybe 25 to 30 [dolphin sightings] a year,” said Helen Bailey, a research professor at the University of Maryland Center for Environmental Science. “We had over 900 reported last year, and we were able to verify nearly 450 of those.”

To report a dolphin sighting, go to the Dolphin Watch website.

Scientists say dolphins used to visit the bay more frequently. Published reports of sightings date back into the 1800s. But as pollution degraded the Chesapeake’s water quality through the 20th century, they became more rare.

Researchers are exploring whether more dolphins are swimming up the bay, possibly invited by clearer waters, abundant submerged grasses and rebounding fisheries. Through a website they set up to collect sighting reports — and a smartphone app that will launch soon — the researchers are learning that the beloved creatures venture miles upstream in rivers such as the York and Potomac, and as far north as Annapolis and the Bay Bridge.

“It’s very likely they’re following fish into the bay. Hopefully, that’s a good sign,” Bailey said. “It doesn’t look like it’s just amusement from the coast into the bay.”