Connoquenessing Creek Watershed Conservation Plan - Western ...

Connoquenessing Creek Watershed Conservation PlanChapter 4. Biological ResourcesDCNR in 2004 on affected hemlock trees in central and southern Pennsylvania. DCNR is also in theprocess of establishing sites for chemical applications against the hemlock woolly adelgid (Spichiger,2004).Zebra MusselZebra mussels were brought to the U.S. in the 1980s in the ballasts of European ships. Since thattime, they have colonized many lakes and streams in the Great Lakes region and also the entire stretch ofthe Mississippi River. These thumbnail-size mussels impose damage by removing all of the microscopicfood, including plankton and zooplankton, depriving other organisms, and altering the food chain(Pennsylvania Sea Grant, 2003).The Pennsylvania Zebra Mussel Monitoring Network was established in 1990–1991 to monitor thespread of zebra mussels in the state. Volunteer personnel from a variety of agencies report sightings of thespecies to DEP. Due to its ecological requirements; the species is restricted to slow-flowing rivers,impoundments, reservoirs, and lakes. For instance, it has been identified in the Monongahela, Ohio, andAllegheny rivers, and in French Creek above an impoundment(Shaw, personal communication, 2006).The zebra mussel is most commonly transported in shipballasts and on recreational boats that utilize multiple waterways.Boaters should always clean their vessels thoroughly beforetransporting to another waterbody to prevent the spread ofmussels, invasive aquatic plants, and other nuisances. According tothe Connoquenessing Creek Watershed Mussel Survey (Lang,2002) report, no zebra mussels were detected within the watershed,although the species has been detected in the Ohio River drainage.Asiatic ClamIt is unknown, exactly where and when this exotic, bivalvemollusk was introduced to the U.S. or Pennsylvania. The Asiaticor Asian clam has a yellow show with pronounced ridges and canreach lengths of 55 mm. Although this species is native to Asiaand Africa, it adapts well to the stream bottoms of theExotic Asiatic clam shells scatteredalong the bank of ConnoquenessingCreek represent a large invasivepopulation which may be outcompetingnative freshwater mussels in thewatershedConnoquenessing watershed. Immature Asiatic clams are very small and hard to see, and unlike manynative species, they do not require host dependency for dispersal. These factors, combined with its highertolerance to pollutants, enable the species to reproduce and spread aggressively. Because of their nature,Asiatic clams can out-compete native freshwater mussels for resources and space.The shells from hundreds, even thousands, of dead clams can litter the stream bottom andstreambanks of local waterways. As the organisms decompose, ammonia byproducts may kill otherfreshwater organisms, this is particularly threatening in lake environments. The main consequence of thepresence and abundance of this invasive species is its tendency to clog pipes and cause disruption ofindustrial processes and water treatment plants.In order to prevent further spreading of Asiatic clams, boots, boats, and other watercrafts should bethoroughly rinsed with hot water after use in Asiatic clam infested waters. Bait buckets should also becleaned and thoroughly dried before transporting to another stream or watershed (Aquatic InvasiveSpecies of Pennsylvania).4-29