A sign the Chesapeake Bay is getting slightly healthier? Dolphins are returning.

Mike Damas began exploring the Chesapeake Bay in the early 1990s. But 15 years passed before he first saw a dolphin playing in the water.

Now, as Damas pilots his boat through the waters of the Chester River and into the bay, he encounters dozens of them in summer: feeding, leaping out of the water and generally appearing to enjoy themselves. He once came upon a pod of 50 dolphins congregating in the water just south of the Bay Bridge.

“Sometimes you see a few and then you see a few more and then you realize you’re in the middle of a big group,” he said. “They look so relaxed, so graceful.”

It’s only been in the past six years, since the creation of a citizen science program, that researchers have been able to study the prevalence and behavior of marine mammals in the bay. Thanks to an app created by the University of Maryland’s Center for Environmental Science’s DolphinWatch program in 2018, some 13,000 users have logged more than 8,700 sightings.

“There are so many people on the bay, so many urban areas around the bay and yet somehow this was a complete mystery,” said Helen Bailey, the DolphinWatch program’s founding director. Under Bailey’s leadership, the program launched a website to track dolphin sightings in 2017 and released the app the following year.

The results are astonishing, given that just a few years ago scientists believed the marine mammals only occasionally explored the bay, which extends from Havre de Grace to Virginia Beach, Virginia, before merging with the Atlantic Ocean. Citizen scientists reported seeing dolphins — alone or in a pod with others — around 2,000 times in the bay in 2022.

Doug Myers, the Chesapeake Bay Foundation’s Maryland senior scientist, said the resurgence of dolphins in the bay is tied to improvements in water quality.

“They’ve always been here, but they haven’t been here in these noticeable numbers,” he said. “Old-timers who have been around the bay for a long time remember them from their youth, and then they remember a long period of time when they were either absent or very, very rare.”

Myers said that about 50 years ago, when the foundation started, the bay was heavily polluted by runoff of excess nitrogen, phosphorus and sediments that clouded the water and fostered the growth of phytoplankton — tiny floating algae — which in turn pushed out aquatic grasses. Moreover, oysters, which act as living water filters, were overharvested. Decomposing algae also deprived them of oxygen, he said.

“It became a green soup out there,” Myers said. “The bay just couldn’t produce enough seafood, or dolphin food.”

The foundation has successfully lobbied for policies that curb runoff and discharges from wastewater treatment plants, Myers said. It also supports programs to restore oyster reefs and replant bay grasses.

While the bay is still in poor health — the foundation gave it a D+ on its 2022 State of the Bay report card — there are significantly more oysters and dissolved oxygen in the bay compared to 2000. These improvements have led to a greater diversity of fish in the water. And where fish go, so do dolphins.

“Dolphin behavior is driven by where the fish are,” Myers said. “They learn fish-capture techniques from their parents.”

Dolphins are complex and social creatures, the descendants of land-based mammals that decided to head back into the water some 50 million years ago. Their front flippers conceal a similar bone structure to our hands and arms, but shaped by evolution for swimming.

Bottlenose dolphins, the species seen in the bay, live for 40 to 60 years. Like all mammals, female dolphins nurse their young and calves spend nearly a decade with their mothers. Like bats, they use echolocation to find food, sending out a series of clicks that help them determine the location and species of fish. Bottlenose dolphins are highly intelligent, using tools and, much like the humans peering at them, possessing self-awareness. Each has its own signature whistle.

Myers said he sees many more dolphins now than when he started working on the bay a decade ago. He has witnessed dolphins mating in the southern bay, near Virginia’s First Landing State Park. “It’s really interesting,” he said. “Their bellies turn pink. They do a lot of leaping in the water and rushing at each other, and you can kind of tell they’re getting frisky.”

Myers said he saw a pod of about 100 dolphins in the South River near Annapolis this summer, including many calves, a sign that dolphins feel safe bringing their young into the bay.

The profusion of data from the app has enabled researchers to detect annual trends in the dolphins’ movements.

“We’re seeing a seasonal pattern,” said Jamie Testa, Chesapeake DolphinWatch’s project coordinator. Sightings are rare in the winter, then pick up in late spring. Dolphins appear most frequently in June and July, making their way up the bay as far north as Havre de Grace. Then they begin heading south, making appearances near the Bay Bridge in early fall as they head back toward the ocean.

Dolphins explore the bay’s tributaries, grazing on fish (which they swallow whole) and birthing and tending young in the calm waters where sharks, their only real predator, are rare. Dolphins were even spotted twice in the Inner Harbor last month.

Misty Kercz, a stained glass artist from Hampden, was walking around Fort McHenry with her husband and 12-year-old son in early September when they spotted a dolphin gliding through the water. “Oh my God,” she can be heard saying in a video she captured of the event. “It’s Harbor dolphins!”

A few bottlenose dolphins usually appear in the Inner Harbor each summer before swimming back out to the bay, said Kate Shaffer, the National Aquarium’s stranding response and triage manager. In 2019, a dolphin calf from another species, which typically lives in deep offshore waters, was spotted in the harbor and later died, Shaffer said in an email. The calf, a Risso’s dolphin, was “very young” and should have still been with its mother, Shaffer said.

For Steve Coffman, who has spent much of his 48 years boating on the bay, the profusion of bottlenose dolphins is a revelation.

“Growing up, I never saw dolphins in the bay,” said Coffman, who spent childhood summers boating with grandparents near Edgewater. But about eight years ago Coffman spotted a pod of dolphins in the South River near Annapolis while aboard a charter boat. “It was pretty crazy. The kid with us started screaming, and I was screaming too.”

Coffman, who has a captain’s license and spent years piloting charter boats, downloaded the app in July 2018. Since then, he has logged 47 sightings of dolphins, sometimes in groups of as many as 100. “That was just a huge pod of dolphins that never seemed to end,” he said. “There was a line of different groups and 10 to 15 dolphins in each group. They were swimming out of the South River into the bay.”

The idea for the dolphin-tracking app sprang from a fortuitous accident. Bailey, a marine biologist who had completed her doctoral degree studying dolphins off the coast of Scotland, was evaluating the potential effects of a planned offshore wind farm near Ocean City in 2015. She plopped some aquatic listening devices in the Patuxent River to test them. To Bailey’s amazement, she discovered the waters were full of the squeaks and whistles that dolphins use to communicate.

That led Bailey to wonder just how many dolphins were in the bay. She had seen data indicating there were about 20 sightings a year. But she wondered about a better way to track them in such a vast and complex waterway. Then it occurred to her — why not tap the observational power of the many people who live, work and boat on the bay?

Bailey launched the website in 2017 with grant funding from the Chesapeake Bay Trust, which raises money from Maryland’s Save the Bay license plates. The app launched the following summer. Users log where and when they saw the dolphins and how many they saw. Scientists review the data and contact users to confirm sightings. They discard about one-quarter of the reports for being incomplete or invalid, Testa said.

“What really, really surprised us when we launched the app was just how many dolphins were out there,” said Bailey, who currently lives in England.

The DolphinWatch project exists on a shoestring budget, supported by donations and sponsorships, Testa said. The JES Avanti Foundation pledged $60,000 this summer to support the program for three years.

Researchers said it is unclear if rising water temperatures play a role in drawing dolphins to the bay. Water temperatures have risen 1 to 2 degrees since the 1980s, according to the Maryland Department of Natural Resources, and fish associated with warmer waters, including the red drum and Florida pompano, have appeared in the bay. A manatee, an aquatic mammal more often found in subtropical climates, was splashing around the St. Mary’s River in August.

Damas, the owner of a Queen Anne’s County wealth management firm, downloaded the app soon after it launched. He lives in Chester, just over the Bay Bridge, and frequently explores the water on his boat, The Victim of Comfort.

Damas took some Baltimore Banner journalists on a tour of his favorite dolphin-watching spots this month: a cluster of fishing nets in the Chester River, a rusty old lighthouse near Kent Island, the remains of Bodkin Island, where dark cormorants swooped over posts jutting from the water.

In addition to logging dolphin sightings, Damas has ferried DolphinWatch scientists to research sites. He brought Lauren Rodriguez, who earned her master’s degree from UMD’s Marine-Estuarine-Environmental Science Program, to sites where she drew water samples. Rodriguez then extracted environmental DNA samples from the water, which enabled her to determine which species were present without disturbing marine life.

Rodriguez not only found dolphin DNA in these spots, but she found genetic material from some of their favorite fishy snacks: menhaden, bay anchovies and striped bass. Rodriguez also created a map while at Maryland that shows the annual movements of dolphins in the bay. She is working on a doctorate in biology at the University of Innsbruck in Austria, scouting the northern Atlantic for the DNA of dolphins and whales.

DolphinWatch researchers said it is unclear how dolphins know to head out of the bay in autumn. Perhaps they can sense the days getting shorter. Or perhaps the fish on which they feed are also heading in that direction.

But Myers, the scientist from the Chesapeake Bay Foundation, said the sheer number of dolphins in the bay is a sign that humans are actually doing something right.

“What we’re doing to clean up the bay is working, and we need to keep doing it,” Myers said. “The dolphins are the proof.”

julie.scharper@thebaltimorebanner.com

Julie Scharper

julie.scharper@thebaltimorebanner.com

Julie Scharper is an enterprise reporter for The Baltimore Banner. Her work ranges from investigations into allegations of sexual harassment and abuse to light-hearted features. Baltimore Magazine awarded Scharper a Best in Baltimore in 2023 for her series exposing a toxic work culture within the Maryland Park Service.

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