Dolphins in Fredericksburg? Chesapeake DolphinWatch finds bottlenose sightings far upstream
By MADISON BROWN
Featured photo courtesy of Beth Pence via Chesapeake DolphinWatch.
When you think of Fredericksburg’s wildlife, you may imagine the river otters highlighted in the Otter-ly Amazing Public Art Project or the great blue herons that fly in from their rookery in Stafford. You may not picture a bottlenose dolphin swimming in the river near Sophia Street, but crowdsourced data from the University Maryland Center for Environmental Science have led some to speculate online that dolphins may swim as far west as Fredericksburg.
UMCES’ Chesapeake DolphinWatch project collects data on the location of bottlenose dolphins in the Chesapeake Bay and its tributaries, an area spanning from Baltimore to Virginia Beach. This data is crowdsourced from “citizen scientists” who report dolphin sightings to DolphinWatch’s app or website.
During the 2022 season, researchers at DolphinWatch have been following an unusually high number of dolphin sightings in Chesapeake Bay tributaries. One citizen scientist spotted a dolphin far up the James River in Richmond. Weekly updates from DolphinWatch from the past two weeks also showed reports of dolphin sightings deep in the Rappahannock and Potomac Rivers, including an unverified sighting from Fredericksburg during the week of July 20. The posts caused users to wonder whether dolphins might truly swim so far upstream.
So, will bottlenose dolphins really visit Fredericksburg? We spoke with Jamie Testa, the project coordinator at UMCES’ Chesapeake DolphinWatch project, to find out.
The work of dolphin-watchers
Prior to 2017, there was little data on the spatial distribution of dolphins in the Chesapeake Bay. Dr. Helen Bailey set out to learn about dolphins’ whereabouts in the bay after picking up dolphin detections while testing gear for another project.
“Being that the [Chesapeake] Bay is quite large, and there’s so many tributaries, they developed this app so that people could report their own [dolphin] sightings opportunistically,” Testa explains. “By crowdsourcing, by using volunteers, we’re able to cover a lot more ground. There’s so many eyes on the water.”
The DolphinWatch team quickly found that people were eager to assist in their research. The app was a quick success, and in June 2022 they had surpassed 10,000 registered users.
“We’ve received emails from folks who clearly sit on their back deck everyday on the waterfront, and they’re really good reporters because they’re out there everyday, looking for dolphins.”
Sightings are verified using descriptions, photos and videos provided by the citizen scientist, and biases are controlled with outside data. The weekend of July 4th tends to be the peak period for dolphin sightings, according to Testa. While increased human activity during Independence Day festivities may create a bias in reported sightings, Testa says these reports do correspond with DolphinWatch’s regional acoustic detections showing that dolphin activity also peaks in early July.
DolphinWatch can also filter out duplicate sightings based on the average swim speed of dolphins thanks to the work of graduate research assistant Lauren Rodriguez. This allows researchers to reduce biases created by the spatial distribution of citizen scientists.
The data produced by these citizen scientists is used to improve dolphin conservation efforts in the Chesapeake Bay region by reducing potentially harmful human activity when and where dolphin activity is expected. According to Testa, DolphinWatch’s data has informed the Navy’s environmental impact statements and the creation of a noninvasive construction plan for a bridge between Newburg, MD and Dahlgren.
Freshwater dolphin sightings
DolphinWatch’s weekly “Where on Wednesday”’ update from the week of July 20 showed dolphin sightings far up the Potomac and Rappahannock Rivers, including a sighting from a user in Fredericksburg and several in Northern Virginia and Washington, D.C.
The “Where on Wednesday” maps show both verified and unverified reports from the week, and people can submit reports from any location. There were likely no sightings in Fredericksburg this week.
That said, researchers have found that this year’s dolphins are traveling farther upriver than usual across many tributaries.
“We have been seeing that across multiple tributaries,” Testa says. “This year, our interest has peaked in really low salinity and very far upriver areas where sightings have been reported. Not all of those have been validated, but many of them have.
“What’s likely happening is some individuals are kind of scouting out. They have these big pods that are linked together, but they’ll often splinter off and come back together, so maybe they’re just sending individuals out and they’re rejoining the pod. Maybe they’re just chasing food. Maybe they’re like, ‘I’m just going to keep following this fish,’ and then once the fish are gone or they’re full, they come back out.”
Testa says the team are unsure whether these freshwater sightings will continue into next season.
“For right now, in these unique locations, we’re taking note of it, collecting the data, and seeing if this is an anomaly, if this year is just a curious data point, or if it becomes a trend in future years.”
Though this year’s data is unexpected, Testa emphasizes that there is no need to panic. “A dolphin being seen in a rather fresher, low salinity area in and of itself isn’t cause for concern. I know it worries a lot of people.
“What we know about bottlenose dolphins is that they can spend time in freshwater and be okay, and as long as they have access to leave those areas, they’re not trapped, they’re not forced into that area by any circumstances, and they can leave the area when they want to, then they’re okay.”
Will we see dolphins in Fredericksburg?
“That’s a really good question,” says Testa. “[Fredericksburg] is very far upriver. I am inclined to make a wild guess that no, we shouldn’t expect dolphins to show up in Fredericksburg. However, they are wild animals. I certainly can’t tell them what to do, and they do surprise us sometimes. If you look at the number of miles upstream in the next tributary up, in the Potomac River, they are going pretty far up.”
While dolphin sightings in downtown Fredericksburg may be improbable, they may venture nearby to Stafford and King George, where the wider and deeper Potomac River provides more favorable conditions for dolphins than the Rappahannock does.
What happens if you spot a dolphin?
“We really encourage responsible wildlife viewing,” Testa says. “The more people know that dolphins are in the area, the more likely they are to try to see them, so we encourage using the SMART acronym.”
The SMART acronym for dolphin-viewing etiquette was developed by the National Oceanic and Atmospheric Administration to ensure the safety of both the humans and dolphins involved in an interaction.
“A big one is refraining from feeding, following, chasing, approaching the dolphins,” Testa emphasizes. “You just want to give them their space to be their regular, wild dolphin selves.”
After ensuring yours and the dolphins’ safety, you can choose to send a description and any images or videos of the dolphin to Chesapeake DolphinWatch.
Photos courtesy of (left to right) Ashley Haines, Captain Pete Sengenberger, and Jeff Varnon via Chesapeake DolphinWatch.