The Delaware River is critical to the health of many animals, and for the people of Philadelphia! It’s the source of our drinking water, and home to all the animals painted on our mural. Many rivers along the east coast have been dammed, but not the Delaware – It’s the longest free-flowing river in the Eastern United States! This makes it incredibly valuable for many fish, like Fishtown’s namesake fish, the shad, who live most of their lives in the ocean then come up stream to breed. People have lived on the banks of the Delaware River for over 10,000 years. The turtle clan of the Lenni-Lenape had been the caretakers for the Delaware for centuries, and continue to hold pow wows in Penn Treaty Park annually. We hope you take a moment to appreciate what the river does for us and our animal neighbors. Learn more about what you can do to support river health here!
Fishtown got its “fish” from the shad! In the 1800s, Fishtown was a major hub for the Delaware River estuary’s shad fishery. Eventually overfishing and river pollution tanked their populations, but some shad still live here today. Much like salmon, shad spend most of their lives in the ocean, then swim up rivers like the Delaware to breed. Dams in rivers prevent fish like the shad from reaching their spawning grounds. The Delaware is undammed making it a wonderful place for restoration of this historically and ecologically important fish!
North America has more species of Freshwater mussels than anywhere else on earth! Freshwater mussels are an incredibly important member of the river ecosystem because of the multiple services they provide. Mussels bury themselves in the sediment where they help to stabilize the riverbed. This prevents stormwater washing much of the riverbed away during large influxes of water. They also remove particulates from the water from their filter feeding. The Philadelphia water department is raising freshwater mussels in their small-scale hatchery at the Fairmount Water Works! They currently raise and reintroduce about 10,000 mussels back into our water ways every year. They hope to scale up their operations in coming years to introduce 1 million mussels a year! The mussel life cycle is delightfully strange- when mussels are first born they need to find a fish "host" that they latch onto. They specifically grab onto the gills of fish (including our buddy the shad!) where they hang out and get nutrients from the fish's blood, then eventually hop off the fish to settle on the riverbed. Many freshwater mussel species are currently at risk for extinction due to pollution and habitat destruction, so this is super important work in restoring a native species.
We have the beaver to thank for much of the freshwater landscape in North America. Beavers may be seen as nuisances when they live near humans and cut down trees, but the beaver is an essential habitat creator for many other animals. Their characteristic tail is used to store fat and slap the surface of the water to signal danger to other beavers. Their dam-building is critical for keeping rain water on land. In areas where beavers have disappeared, rivers often run straighter, the water moves faster, more erosion of riverbeds occurs, and ultimately fresh water runs into oceans faster. This doesn't give water enough time to seep into the ground and replenish water tables. Here in Philadelphia, we generally have enough water, but in other regions this is a huge problem. In Penn Treaty Park, beavers began being seen again a few years ago. It's an excellent sign for the health of the Delaware!
Sturgeon are ancient, armored, endangered fish that have been known to breed under the Ben Franklin Bridge! Unlike many other fish, sturgeon have bony plates in their skin called "scutes" that make them look like they're covered in armor. The population within the Delaware River used to be the largest on the entire Atlantic coast, and Philadelphia was even known for production of sturgeon caviar until the late 1800s. We have multiple species in our region, including the Atlantic sturgeon that can grow up to 15 ft long, and the shortnose sturgeon which are "only" about 4-5 feet. Much like the shad, they breed in freshwater streams, then go out to the ocean. The Atlantic sturgeon goes farther out to sea to live its adult life, whereas the shortnose sturgeon hangs around in estuaries. The whisker-like barbels on their face (depicted in our mural) are used to find food in the sediment. Major threats to sturgeon are river pollution and the resultant decrease of oxygen that some kinds of pollution can cause. Unfortunately, the one-two punch of overfishing and pollution has resulted in their populations plummeting. Today, the U.S. Geological Survey reports that .1% of the original population is still around today.