A Guide to SelectedInvasive Non-nativeAquatic Species in

Massachusetts

C. Barre HellquistDepartment of Biology

Massachusetts College of Liberal Arts

North Adams, Massachusetts 01247

James StraubMassachusetts Department ofEnvironmental Management

Lakes and Ponds Program131 Barnum Road, Bldg 3701

Devens, MA 01432

Non-native species are a problem in many Massachusettslakes, ponds, and rivers. Once in a water body, many of theseorganisms can spread aggressively, out-competing and frequentlyeliminating native species. They reduce the health of our waterbodies by disrupting natural ecosystems and altering fish andwildlife habitats. Frequently, they make swimming, boating, andfishing difficult or dangerous. Many plant species produce a densevegetative cover on lakes, and the large amount of decomposingorganic matter accelerates eutrophication in the lake system.

Often, non-native aquatic species spread to new water bod-ies when they are transferred by boats, motors, bait buckets, fishingtackle and trailers. These infestations can be prevented if everyoneremembers to completely clean their boats, motors, fishing equip-ment and trailers before leaving a site. Dispose of all organismsand drain water from your boat on dry land before leaving a waterbody.

YOU CAN HELP!!! Learn how to identify these organ-isms and help prevent their spread throughout Massachusetts.For more information, or to report an infestation, please contact:

Massachusetts Department of Envir onmental ManagementLakes and Ponds Program(508) 792-7716 ext 170www.state.ma.us/dem/

Massachusetts Department of Envir onmental ProtectionOffice of Watershed Management(508) 767-2877www.state.ma.us/dep/

Massachusetts Division of Fisheries and WildlifeNatural Heritage and Endangerd Species Program(508) 792-7270 ext. 163www.state.ma.us/dfwele/dpt_toc.htm

Massachusetts Congress of Lakes and Ponds Association (COLAP)(508) 429-5085 www.colap.com

Revised - May 2002

WATER CHESTNUTTrapa natans

Water chestnut is a majornuisance in the Concord River and Charles Riversystems of easternMassachusetts, and it appears to be spreading rapidly elsewhere in the State. Large populations have been noted in the Connecticut River, andit has been found in Berkshire County. It is believed that ducks andgeese may be the majormeans of dispersal. Canadageese have been observedwith the spiny nutsattached to their feathers.

ESTABLISHED

FANWARTCabamba caroliniana

This southern United Statesnative has been established in the acid water ponds of easternMassachusetts for over 50 years.The plant is separated fromthe small white flowersand leaves that arisefrom a small stem. This gives the leaves a fan-likeappearance.

ESTABLISHED

VARIABLE WATERMILFOILMyriophyllum heterophyllum

This southern and westernU.S. species has long been established in the acidic waters of easternMassachusetts. Thisspecies is identified bythe leaf-whorls beinglocated closely togetheralong the stem and withlarge leaf-like bracts onthe emergent stems thatare longer than the flowersor fruits.

ESTABLISHED

Round tip

EURASIAN WATERMILFOILMyriophyllum spicatum

This Eurasian species isextremely abundant inthe alkaline waters of Berkshire County, but also isaggressive in the eastern counties. It is identified by the widely-spacedwhorled leaves and the tiny emersed bracts that are much shorter than theflowers and fruit.

ESTABLISHED

Blunt tip

CURLY-LEAVED PONDWEEDPotamogeton crispus

The pondweeds are a very common and diverse group ofaquatic plants. Manynative species maybecome a nuisance.Potamogeton crispusis the only non-nativepondweed and is easily identified bythe conspicuous teeth along the leaf margin.

ESTABLISHED

YELLOW WATER LOTUSNelumbo lutea

This species is native to NewEngland and often is used in private water gardens.

Care should be take not tointroduce this species into theenvironment. These plantsreproduce by tuber andseed and can overpopulateshallows of a pond. TheYellow lotus forms largedense mats that are virtuallyimpenetrable. Look for broad,flat leaves floating on thesurface with a large, bright yellow flower. The flowers can be 2 to 3 inches wide.

ESTABLISHED

EUROPEAN NAIADNajas minor

This species isnaturalized in some of the alkaline lakesof BerkshireCounty. It isidentified by thelobed leaf bases andthe conspicuous leafserrations. Densegrowth can crowd outnative vegetation andimpede swimming andboating.

ESTABLISHED

SOUTH AMERICAN WATERWEED Egeria densa

This species was introducedinto the aquarium tradefrom South America and isnow naturalized in a fewareas of easternMassachusetts. Itappears as a robustElodea canadensis.The leaves arewhorled and themargins appearsmooth to the unaided eye.The flowers are approximately1 inch across as compared tothe much smaller Elodea.

ESTABLISHED

YELLOW FLOATING HEAR TNymphoides peltata

This extremely hardyEurasian species spreads rapidly from seed.The leaves appearsimilar to small waterlilyleaves, but the yellowflowers are more showy than the native yellowwaterlilies. The long stems can impede swimming and boating.

ESTABLISHED

PURPLE LOOSESTRIFE Lythrum salicaria

Purple Loosestrife is aninvasive non-native plant fromEurope and Asia that was introduced almost 200 yearsago. When purple loosestrife isintroduced into wetlands, it outcompetes native plants such ascattails, sedges, bulrush andferns. As these wetlandsbecome infested with purpleloosestrife, desirable food andnesting sites for wildlife arelost, there are fewer stopoversites for migrating birds, andkey habitat is lost for other wet-land organisms.

ESTABLISHED

COMMON REED Phragmities australis

The Common Reed is often foundalong roadsides and in wetlandsareas. The reed is able togrow in freshwater, brackishwater and saline marshes. Itgrows in large dense standsthat can reach 15 or morefeet high. This reed out-competes native wetlandspecies in the competition forresources, creating a mono cul-ture. Stands of Phragmitiesarepoor habitat for most wetlandanimals.

ESTABLISHED

ASIAN CLAM Corbicula

This clam is usually less than 0.5cmwide and is a dark beige to browncolor. The major impact of the clamin freshwater systems is befoulingof equipment. Power plants,boat motors, water intakepipes, etc. are all places theAsian Clam prefers to settle.Eventually they will cut offthe flow of water throughthat structure. The clam canalso out-compete nativebivalves for resources.

Juvenile forms of the clam aremicroscopic and can travel in bilgewater, bait buckets or on boat trail-ers. Care shoud be taken to removeand RINSE all equipment when leav-ing a water body and before enteringanother.

THREAT CT, NY

PARROT-FEATHER Myriophyllum aquaticum

This South Americanspecies is established on Long Island, New York.Parrot-feather is commonin the aquarium andwater-garden trade, and cantolerate the harsh conditions ofNew England winters. It is separated from all the other watermilfoils by the presence of conspicuousemergent feathery leaves.

THREAT CT, NY

HYDRILLAHydrilla verticillata

Hydrilla has the potential tobecome a serious problem inMassachusetts. A populationhas been verified on CapeCod. This species is oftenconfused with the nativeElodea. Elodea leaves havevery fine teeth that are noteasily seen with the unaidedeye and the leaves are inwhorls of 3 as compared to 4-6on Hydrilla. If found pleasereport it to one of the agencieslisted on the inside cover of thisbooklet.

THREAT CT

* Established in one pond on Cape Cod.

ZEBRA MUSSELDreissena polymorpha

Zebra mussels get their name from the "zebra-like"stripes that are found on their shells. Usually lessthan 5cm long, zebra mussels can proliferate at analarming rate. They clog water intake pipes for fac-tories, water treatment plants, boat intakes, nuclearfacilities, etc. They can grow to densi-ties of around 500,000 per m2 + andreduce flows through pipes.Zebra mussels out compete other bivalves for food, spaceand other resources. Deadmussel shells are very sharp and can create a swimming haz-ard. The weight from large numbersof mussels has been known to sink channel markers.Young zebra mussels (veligers) are microscopic andcan easily be transported. These young have beenfound in or attached to boat hulls, bait buckets, boatmotors, boat trailers, and fishing tackle. Great careshould be taken when leaving a lake known to beinfested with zebra mussels. Wash all equipment thatmay have come in contact withwater.

THREAT CT, NY, VT

SPINY WATERFLEABythotrephes cederstroemi

Both Cercopagis andBythotrephes have long caudalprocesses with up to threepairs of barbs along the proxi-mal end of the process. Bothspecies occur in brackish andpure freshwater environments.Cercopagidids most commonlyreproduce parthenogenically,which allows them to quicklyestablish new populations witha relatively small seed popula-tion. Caution should be usedwhen transferring bait andfishing tackle from infestedwaterbodies to outside sys-tems. Never keep bait bucketwater from contaminatedlakes. Always flush bilgewater before entering a differ-ent lake.

THREAT NY

FISH HOOK FLEACercopagis pengoi

The spiny water flea, a smallplanktivorous crustacean, aver-ages about 0.25 to 0.50 cm inlength, of which 70% is along, sharp, barbed tail spine.Native to parts of Eurasia, itwas first introduced into theGreat Lakes ecosystem in1984 via ballast water. It hasspread to all of the GreatLakes. Large numbers of theseorganisms form huge cotton-like mats in a waterbody. Theyfoul fishing gear, boat motors,and can impede swimming.The spiny waterflea can alsodramatically alter the foodwebs. It will out-competesmall fish for food. It has fewpredators due to its sharpspines.

FLOWERING RUSH Butomus umbellatus

This plant is well established in the LakeChamplain drainageand along the Connecticut River inConnecticut. In the water, it appears much like the native water-celery, but the leavesarise from a fleshyrhizome. The emergentform is much more common and producesshowy large pinkinflorscences.

THREAT CT, NY, VT

STOP

The Spreadof

Nuisance Fresh Water Organisms

Clean All Organisms off Boats,Anchors, Motors and Trailers

BEFORE LEAVING AN ACCESS AREA

Jane Swift, Governor ● Bob Durand, Secretary, EOEAPeter C. Webber, Commissioner, DEM

Straub, J.R. 2002. Selected text on Dreissena polymorpha and Corbicula.Department of Environmental Mangement; Lakes & Ponds Program