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The First 365 Days of Harbor Wetland®
The National Aquarium's newest exhibit in the Inner Harbor is an impressive sight, but how did it perform during its first full year of operation?
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We're not too shy to say it: National Aquarium Harbor Wetland presented by CFG Bank is big, beautiful and impossible to miss. The expansive outdoor exhibit is a re-created salt marsh designed to support native wildlife species, educate people about ecosystems, promote healthy water, and withstand extreme conditions. It's also the first floating wetland of its kind anywhere in the world, and it's free and open to all in Baltimore's Inner Harbor.
Harbor Wetland is the culmination of 14 years of research and planning, four prototypes, nine months of construction, and more than 32,000 hand-planted grasses and shrubs.
But all that work was just the beginning. Since the exhibit opened on August 8, 2024, we've been counting, tracking, measuring and recording, and now we're reporting on Harbor Wetland's first 365 days of operation.
Animal Visitors
What do monarchs, menhaden and muskrats have in common? They all visited Harbor Wetland during its first year. In total, more than 120 community scientists documented 496 observations of 139 different species of wildlife and plants on and around the exhibit from August 2024 to August 2025. These species included 31 birds, 24 insects, 12 fish, eight arachnids, six mammals, four reptiles, two mollusks and one amphibian. All observations are tracked on the National Aquarium Harbor Wetland and Waterfront Park iNaturalist page.
Human Guests
In addition to our winged, finned and furry visitors, we welcomed 120,000 people to Harbor Wetland in its first year. These guests included more than 1,000 participants in the first annual Harbor Wetland BioBlitz during the 2025 City Nature Challenge, as well as 813 Baltimore City sixth graders who took part in our What Lives in the Harbor education program.
Water Quality
During low-oxygen events in the Inner Harbor from August 2024 to August 2025, Harbor Wetland provided healthier oxygen conditions 34% of the time. The Aquarium collects live Inner Harbor water quality data every 15 minutes, 24 hours a day, 7 days a week, in partnership with the Maryland Department of Natural Resources' Eyes on the Bay project. We measure temperature, salinity, dissolved oxygen, chlorophyll, turbidity and pH.
What do these measurements sound like? Local musicians Jessica Keyes and Patrick McMinn, who created the sound installation for Harbor Wetland, compiled a 10-track playlist of musical interpretations of Inner Harbor water quality.
Exhibit Resilience
Mother Nature really put Harbor Wetland to the test, almost from day one. The exhibit successfully weathered multiple storms and events throughout its first year, including Tropical Storm Debby in August 2024, a massive fish kill caused by a pistachio tide in September 2024, zero precipitation for 38 consecutive days (the longest dry streak in 150 years!) in fall 2024, and a tornado in May 2025.
Awards and Honors
Now that it's been open for more than a year, Harbor Wetland is being recognized with awards and honors. The exhibit was among the Association of Zoos and Aquariums' (AZA) 2025 honor and award winners, receiving top honors in the Facility Award category at the AZA annual conference in September. It also received the 2025 Baltimore WaveMaker Award from the Urban Land Institute, which celebrates visionary urban development projects, and the Outstanding Civil Engineering Achievement Award from the American Society of Civil Engineers' Maryland chapter.
The Future in Front of Us
There's much more ahead for Harbor Wetland. Because we see American river otters so frequently on and around the exhibit, the Aquarium recently joined the Chesapeake Bay Otter Alliance. Our team is supporting a study of river otters' diets and parasites by providing scat samples to the Smithsonian Environmental Research Center.
We're also in the process of patenting the floating wetlands used in the exhibit to safeguard the technology we invented and invested in. We continue to field inquiries from groups interested in using our technology, including for a project in Newtown Creek, a Superfund site in Brooklyn, New York.
"I'm really looking forward to what's to come for Harbor Wetland," said Director of Field Conservation Charmaine Dahlenburg. "It feels like we're just getting started."