The Maryland Department of Natural Resources (DNR) recently confirmed the presence of zebra mussels (Dreissena polymporha) in tributaries of the upper Western Shore near Middle River in Baltimore County.
On August 17, 2015, a waterman alerted DNR Biologist Brenda Davis of small zebra mussels fouling their crab gear off the Gunpowder, Bush and Middle Rivers. The next day, DNR Fisheries Habitat and Ecosystem Program biologists found numerous mussels in aquatic vegetation while trawling Middle River.
Past monitoring suggested that zebra mussels had not spread beyond the Susquehanna Flats. However, heavy rainfall in the late spring has led to lower than average salinity in the upper and middle Chesapeake Bay, potentially allowing zebra mussels to spread into habitat where they would normally not survive.
It is not yet known if zebra mussels will persist in these upper Chesapeake Bay tributaries as salinity levels increase around the Baltimore area.
For more information on zebra mussels is available at dnr.maryland.gov/invasives/ZebraMussel.asp, including a fact sheet and reporting form.
DNR asks citizens to report any suspected sightings to firstname.lastname@example.org.
source: Maryland Department of Natural Resources