A Wealth of Science From a Lowly Source

A few times each month, National Aquarium Conservation Coordinator Taylor Long heads out onto Harbor Wetland as the sun is coming up. She wears tall rubber boots, a bright orange life jacket and latex gloves, and carries a sandwich-size zip-top plastic bag. She opens one of the staff-only gates and steps out onto the grassy wetlands. Her task? Picking up poop. Specifically, she's collecting scat from North American river otters on Harbor Wetland. This dirty job is not a cleanup effort; it's all in the name of science.

Thanks to the frequent presence of otters on Harbor Wetland, the Aquarium is now part of the Chesapeake Bay Otter Alliance, a group brought together by the Coastal Disease Ecology Lab at the Smithsonian Environmental Research Center (SERC). Through the alliance, scientists, educators and community members collaborate to find and learn about river otters in the mid-Atlantic. As an official alliance partner, the Aquarium is contributing to ongoing research about river otters' diets and parasites, which gives researchers valuable information about the environment and human health.

Surprise But Welcome Visitors

It's a common misperception that wildlife can't survive in Baltimore's Inner Harbor. In truth, the harbor is full of life, from microscopic bacteria and algae to swirling schools of silvery menhaden and hefty snapping turtles.

Director of Field Conservation Charmaine Dahlenburg knows better than just about anyone how much life the harbor holds. For the past ten-plus years, she and her team have been collaborating with the Institute of Marine and Environmental Technology and the Baltimore Underground Science Space to analyze biofilms in the Inner Harbor. This allows the team to track even the tiniest aquatic creatures.

"Biofilms are the cornerstone of food webs; diverse biofilms foster healthy ecosystems," Charmaine explains. "Because we've collected baseline information about species in the harbor, we can follow how the environment changes over time and better understand Harbor Wetland's impact."

Observations of easily visible wildlife, such as blue crabs and American eels, are also clear signs that Harbor Wetland is performing as intended and attracting native Chesapeake Bay species. But even Charmaine, Taylor and the rest of the Aquarium's Conservation team were surprised when otters first made an appearance on Harbor Wetland in June 2024, shortly before the exhibit's grand opening in August. The otters have had a steady presence on Harbor Wetland ever since and are particularly active from November to February.

"Because they're here so frequently, the otters on Harbor Wetland give us an opportunity to be curious and learn from them, and we're taking that opportunity because it benefits animals and people alike," Charmaine says.

Shedding Light on Human and Ecological Health

After the otters first visited Harbor Wetland in 2024, Dr. Katrina Lohan, a parasite ecologist who leads the Coastal Disease Ecology Laboratory at SERC, approached the Aquarium about becoming an alliance partner and contributing to the otter study.

Since the partnership officially began in early 2025, the Aquarium has contributed more than 150 scat samples to the lab. Taylor has been giving batches of 30 to 50 samples to SERC a few times a year, labeling and freezing them until it's time for the hand-off. She either packs the samples in a cooler and drives them to the SERC labs in Edgewater herself, or one of the researchers picks them up from her at the Aquarium.

Because the Aquarium's Conservation team has also found river otter scat on the wetlands adjacent to the Fort McHenry National Monument and Historic Shrine in South Baltimore, the team may begin submitting samples from that site to the SERC researchers as well.

Calli Wise, a lead study author and the field program manager at SERC, sums up the study the Aquarium contributes to this way: "We're not studying otter health; we're looking at human and ecological health through the lens of otters."

Otters are a sentinel species, or one that can give scientists a window into ecosystem health and broader environmental conditions. The presence of otters is a sign of good water quality and healthy waterways. And because river otters eat blue crabs, oysters, clams, fish and other seafood that people eat, too, studying their diets can shed light on the parasites, pathogens and pollutants these food sources might be carrying that could impact people.

An Important Sentinel Species

On a recent spring morning, Taylor finds some otter scat in one of the grassy areas of Harbor Wetland, but the samples are not fresh enough to submit to the study. Still, she appreciates knowing that otters have visited recently. She can also see evidence of what these otters are eating from the crab shells and fish scales visible in what they've left behind.

"I love all creatures, but I really love otters," Taylor says. "I knew there were otters around here and that it might be possible to see one on Harbor Wetland one day, but the fact that they flocked here so quickly and have kept returning is amazing."

She also says she appreciates the opportunity to contribute to SERC's work since it helps spread the word about otters and their importance as a sentinel species, adding to our knowledge about ecosystems and our own health.

And you can help with this research, too! The team at SERC encourages anyone who sees a river otter in the Chesapeake Bay watershed to take a photo and track their sighting in the Chesapeake Bay Otter Alliance iNaturalist survey. This helps them map where river otters are living and understand their activity in the region. As of mid-April 2026, more than 600 users reported over 1,200 otter observations through the survey, including a few right outside the National Aquarium.