Latest Baltimore fishkill leaves tens of thousands of dead menhaden floating around the harbor
The Baltimore Harbor Waterkeeper says her teams have been there documenting algae blooms, rotten-egg odor and deoxygenated water, but cautions against normalizing fishkills: “They are not inevitable”
Above: An estimated 25,000 dead fish have appeared in Baltimore Harbor, including next to the tourist promenade at Pratt and Light streets. (Waterfront Partnership)
The Waterfront Partnership and others today posted photos of what’s become an increasingly familiar waterfront scene – mounds of small, silvery menhaden floating in Baltimore Harbor from downtown to Canton and across the water at Locust Point.
The lifeless fish, mixed with some dead crabs, are currently lapping along the shorelines of Fells Point, Harbor Point, Harbor East, Tide Point and the tourist Inner Harbor, reports the Maryland Department of the Environment.
MDE estimates the death toll at 25,000 fish.
Likewise, parts of the harbor have turned bright green and smell of rotten eggs. The phenomenon, known as a “pistachio tide,” is caused by sulfur bacteria from decomposing algae rising from the bottom of the harbor to the surface.
The algae die-off results in low dissolved oxygen in the water.
Fish get stressed when dissolved oxygen falls below 2 mg/L, which is known as a “dead zone.” That is most likely what happened over the last two days as dead zones spread across the harbor, according to MDE spokesman Jay Apperson.
“We do not have any reason to believe the low dissolved oxygen was caused by any specific pollution event,” he added.
Dead fish today spread across the water near the Harbor East Marina. (Blue Water Baltimore Facebook)
Third in a Month
This is the third major fishkill in Baltimore Harbor in four weeks.
On August 28, MDE observed at least 120,000 dead fish floating between Harbor Point and Fort McHenry, Apperson said.
“We found low levels of dissolved oxygen in the surface waters throughout that area and some water discolored green. We suspect this was caused by a weather-related ‘turnover’ event in which water from the bottom of the harbor, which contains little or no oxygen, mixes with the surface water.”
MDE also recorded a fish kill that started around August 22, with an estimated 61,000 dead fish. “We believe this fish kill was also weather related,” Apperson stated.
Alice Volpitta, Blue Water Baltimore’s harbor waterkeeper, said her staff is now taking water samples to obtain oxygen levels and other data to estimate the scope of today’s kill. Her team has documented a large brown algae bloom off the Canton waterfront, with dissolved oxygen levels of 20 mg/L and a saturation level of 245%.
“That’s crazy high,” she said, noting that MDE’s current fishkill estimate “might be an undercount.”
From Inner Harbor fish kill video posted by Mr. Trash Wheel on Reddit.
Lack of Shallow Water
Volpitta said she was very concerned about the latest event because it comes on top of an unusually large number of fishkills this year, suggesting that there are larger factors than dying algae and the seasonal changes in water temperature at work.
“This is not inevitable. We don’t have to view fishkills as the status quo,” she said. “We can probably intervene in the process that’s causing fish to die.”
In an interview with The Brew, Volpitta noted that environmental advocates and harbor boosters have been meeting to rethink how to approach pollution in the harbor and to consider ways to possibly physically alter the waterfront to reduce fishkills.
She noted that such incidents appear to occur more frequently in deep, man-made areas of the harbor.
“It’s these areas that become very stagnant and don’t have a lot of circulation. So the low dissolved oxygen events and the turnovers seem to be trapping the fish and crabs in specific areas,” she said. “And there’s no shallow water refuge for fish and crabs that get caught up in these events.”
The subject needs more data-gathering and analysis, she said, but these early insights suggest that one solution may be to make the harbor less of “a deep channel hardscape” and “more like a living coastline.”
Another important step, she observed, is to get rid of the self-defeating narrative that says, “Oh, this is Baltimore. It’s polluted, and these things are always going to happen.”
Harbor Swims Scratched
Poor water quality thwarted two attempts this summer by the Waterfront Partnership to hold an organized swim in the harbor.
In June, and again in July, the Harbor Splash event was canceled because of heavy rains that washed harmful pollutants from city streets and from sanitary sewer overflows into the harbor.
Despite having to cancel the event, organizers were upbeat. “Our commitment to making Baltimore a swimmable city hasn’t changed,” WP’s vice president Adam Lindquist said at the time.
On the group’s blog, Lindquist commented on the latest fishkill.
“Today was a heartbreaking day for people like me who love our city’s marine ecosystem and spend every day working toward its restoration,” he wrote, below a photo of dead fish with the historic ship, the USS Constellation, visible beyond.
“This week Baltimore’s Inner Harbor experienced one of the worst fish kill events in recent memory.”