By Amy Werner
Today is World Fish Migration day, a day best celebrated by raising awareness of the importance of open rivers and migratory fish, exactly what Rock Creek Park did at a 2016 BioBlitz fish identification on May 20.
The urban oasis of Rock Creek Park in Washington D.C., is often viewed as containing only squirrels, deer, and butterflies, but this 126-year-old park is swimming with wildlife.
“A BioBlitz like this does a great job of letting people know what’s here,” said Daniel Ryan, Fisheries Research Branch Chief at the Department of Energy and Environment. “Most of the people have no idea there are any fish here, much less 30 different species of fish.”
Park rangers, scientists, and D.C. residents met at the historic Peirce Mill and Barn to learn how to identify different fish species. A team of scientists from the Department of Energy and Environment, clad in waders and used backpack electrofishers, or in the words of Ryan, their “ghostbuster machines,” to collect fish then deposit them back into the stream.
Ryan explained to the inventory participants crowded around him that American Eels are catadromous, meaning they live in freshwater rivers and spawn in the ocean. American eels are the only catadromous fish in North America, unlike the two common species of fish that use Rock Creek, the alewive and blueback herring. Alewives and blueback herrings are anadromous fish, or fish born in freshwater that migrate to the ocean where they grow into adults, before migrating back into freshwater to spawn.
Park Ranger, Bill Yeaman explained the migration season for alewives and blueback herrings is from the beginning of March to the end of May, the season when they return to their birthplace to lay eggs. These fish are as sentimental as college students homebound for summer holidays, as schools of alewives and blueback herrings will make the spring trek back to their hometown streams where they were born from the Atlantic Ocean.
Inventory participants were able to use iNaturalist, an app used to record observations in nature and share with other naturalists, to record fish like the spotfin shiner and central stoneroller. Among the pumpkinseed sunfish, snakes and bluegills, Ryan noted those on the inventory also had the opportunity to discover the wildlife that’s in danger of being lost.
“When you introduce the public to what’s in their backyard, it creates a desire to protect what’s there.”