Invasion of an Exotic Species:
Stop the Zebra Mussel!
Activities and Resources
For Grades 8 - 12

By

Vicki P. Clark
Thomas J. Miller

Virginia Sea Grant Marine Advisory Program
School of Marine Science
Virginia Institute of Marine Science
The College of William and Mary
Gloucester Point, Virginia 23062
VSG-94-03, VIMS-ES-41-3, Download Edition

VSG 94-03-EE-96 1
Susanna Musick, Editor

This work is a result of research sponsored by NOAA Office of Sea Grant, U.S. Department of Commerce, under federal Grant No. NA 90AA-D-SG045 to the Virginia Graduate Marine Science Consortium and the Virginia Sea Grant College Program. The U.S. Government is authorized to produce and distribute reprints for governmental purposes notwithstanding any copyright notation that may appear hereon.


[INTRODUCTION] [TEACHER'S GUIDE]
[ RESOURCES] [STUDENT ACTIVITIES]


INTRODUCTION

Invasion of an Exotic Species:

Stop the Zebra Mussel!

Activities and Resources
For Grades 8 - 12

Thousands of exotic plants, animals, and microbes have been introduced into the United States. Some of these organisms were intentionally imported for use in agriculture, the pet industry, and fish and wildlife management. Others accidentally found their way to the United States in ships' ballast water, in packing materials, or as hitchhikers on other plants and animals. Many exotic species, such as soybeans and wheat, have been beneficial. Others, such as the Japanese beetle and kudzu, have had a negative impact. In addition, plant and animal species from the Americas have been exported to other parts of the world, with similar effects. Many exotic species displace native plants and animals, alter ecosystems, cause disease, and interfere with human activities in industry, agriculture, and recreation.

The zebra mussel is an exotic freshwater mollusk from Europe which was accidentally introduced into the United States in the Great Lakes area in 1985 or 1986. The mussel larvae were most likely transported in the ballast water of a ship and released into Lake St. Clair. The mussels reproduce rapidly in suitable habitats and have created serious environmental and economic problems in many parts of the country. Zebra mussels are spreading toward the mid-Atlantic states. Where and how will they be most likely to invade Virginia? How can the zebra mussel invasion be controlled?

The activities and resources presented in this lesson will guide students in a study of the zebra mussel and the possibilities of its invasion of Virginia. Actual scientific research data are introduced as a critical part of group problem-solving activities. Students are challenged to use the scientific data and other information to design action plans to help prevent the introduction and spread of zebra mussels into the state. Additional follow-up activities extend the study of zebra mussels and encourage the investigation of the impact of other exotic plants and animals.

Acknowledgments

The information used to develop the data cards in the activity "Where Will the Zebra Mussel Invade?" was obtained from personal communications with Patrick Baker, a graduate student at the Virginia Institute of Marine Science, and from the following research reports:

Baker, Patrick, Shirley Baker, and Roger Mann. 1993. Criteria for predicting zebra mussel invasions in the mid-Atlantic region. Virginia Sea Grant College Program, Virginia Institute of Marine Science, VSG-93-03.

Baker, Patrick, Shirley Baker, and Roger Mann. 1993. Potential range of the zebra mussel, Dreissena polymorpha, in and near Virginia. Virginia Sea Grant College Program, Virginia Institute of Marine Science, VSG-93-04.

Supplementary materials provided by:

  • North Carolina Sea Grant
  • Ohio Sea Grant
  • Virginia Sea Grant
  • Virginia Department of Game and Inland Fisheries
  • Zebra Mussel Information Clearinghouse, New York Sea Grant

Editorial Review:

  • Bland Crowder
  • Jan Hodges
  • Lee Larkin
  • Carol Rideout


TEACHER'S GUIDE

Instructions
Activity 1:


Where Will the Zebra Mussels Invade?

OBJECTIVE
Students will work in small groups to communicate and analyze scientific data on zebra mussels and water quality. Using this information, each group will predict the likelihood of zebra mussels becoming introduced and established in various aquatic sites in Virginia.

STUDENT PREPARATION
Students should have a basic understanding of pH, temperature, and calcium content as measurable characteristics of the water in aquatic habitats. They should understand that "parts per thousand" and "parts per million" refer to the concentration of chemical substances present in a body of water.

Time Needed

1 class period (45 - 50 minutes)

Materials Needed (for each group of 4 - 6 students)

From the "Student Activities" section:

  • Zebra Mussel Biology

  • Zebra Mussel Optimum Habitat Needs

  • Zebra Mussel Impacts

  • Zebra Mussel Study Site Data Cards (one set of 6 data cards per group)

  • Zebra Mussel Study Site Report

    Optional: Virginia highway map (one per group) or other state map showing rivers, lakes, towns and cities

    Teacher Preparation

    1. Read the information in the "Student Activities" section and the supplementary reference materials provided in the packet to familiarize yourself with zebra mussels and their impact.

    2. Duplicate the Zebra Mussel Study Site Data Card sheets. (You will need one set of 6 cards for each student group.) Cut the data cards apart and put each set of six in a separate envelope, or paper clip them together. (It's a good idea to duplicate each set of data cards on a different color paper. This makes it easier to sort the cards if they become mixed together.

    3. For each group, duplicate one copy of the other four pages ("Zebra Mussel Biology," "Zebra Mussel Critical Habitat Needs," "Zebra Mussel Impacts," and "Zebra Mussel Study Site Report"). If you wish, give the "Biology" sheet to each student to read before class. You may want to make overhead transparencies of the "Critical Habitat Needs" and "Impacts" sheets and display them for reference during the activity.

    4. If students are not already familiar with the concept of exotic species, decide how you will relate the zebra mussel issue to other concepts that they have studied, such as animal adaptation, species competition, impact of human activities on ecosystems, etc.

    Conducting the Activity

    1. Divide the class into groups of four to six students each. Assign roles within the groups as follows:

    Materials Manager: Obtains activity materials from teacher, distributes them to group, and returns all materials to teacher in good order after activity is finished.

    Recorder: Keeps written notes on group discussions and observations. Records group responses to questions on activity worksheets. Reads written information back to rest of group for their approval.

    Reporter: Gives verbal report to the class summarizing the group's conclusions, using the activity worksheets and other notes from the Recorder.

    Research Technician(s): Provide(s) additional information to the group during the problem-solving activities by consulting supplementary handouts and reference materials.

    2. Introduce students to the information from the "Zebra Mussel Impacts," "Zebra Mussel Biology," and "Critical Habitat Needs" sheets. You may lead a class discussion, or each small group may read and discuss the information and review it with the teacher and the rest of the class. Explain that they will be working in groups to analyze scientific information in order to predict whether or not various places in Virginia are suitable habitat for zebra mussels.

    3. Give each Materials Manager a set of Zebra Mussel Study Site data cards and a copy of the Zebra Mussel Study Site Report form. The Materials Manager should distribute the data cards one at a time to all group members (some students may get more than one card if groups have fewer than six students). In turn, the students read aloud the information on their data cards to the other group members. The Recorder reads the Study Site Report form to the group.

    4. Based on this information, each group develops a prediction about the likelihood that its study site will be affected by zebra mussels. The questions on the Study Site Report form will guide their discussion. The Recorder writes the predictions and supporting information on this form

    5. Once all groups have completed their report forms, each group's Reporter shares the results with the rest of the class. To facilitate discussion as the class compares the sites, the Recorders can post on a chart or the chalkboard the predictions for their sites, along with water quality data and other important facts.

    6. If you plan to follow this activity with Developing a Zebra Mussel Action Plan," have the Recorders keep their Site Report forms to use as reference.

    Summary and Evaluation

    1. Based on the information known about each study site, did each group make a reasonable prediction about the zebra mussel's introduction and establishment? (See chart below for scientists' predictions.) If students disagree, remember that all of the facts are not yet known, and that there is some room for debate.



    Study Site        Chances for Introduction    Chances for Establishment
    1. James River		   high			high                             
    
    2. Potomac River	   high			high              
    
    3. Smith Mountain Lake	   high			moderate              
    
    4. Rappahannock River	   moderate		moderate
    
    5. Kerr Reservoir and	   high			high
    
     Lake Gaston                                  
    
    6. Mattaponi and	   moderate		low
    
     Pamunkey Rivers                       
    
    7. Lake Anna		   high			low                                  
    
    8. Claytor Lake		   high			moderate                                
    
    9. South Holston Lake	   high			high 

    2. Rank the study sites from "lowest risk" to "highest risk" for the successful establishment of a zebra mussel population. Which site is closest to your school?

    3. Overall, what human activity might be most likely to contribute to the introduction of zebra mussels in Virginia?

    4. Locate the study sites on a Virginia highway map. How could the location and geography of each study site contribute to the introduction of zebra mussels? Once the zebra mussel becomes established, how far away from each study site do you think the mussel could spread?

    5. At which study site might zebra mussels have the most serious economic impact?


    Activity Instructions

    Developing a Zebra Mussel Action Plan
    Objective

    Students work in small groups to design and communicate action plans to help prevent the introduction and spread of zebra mussels in areas which are at risk.

    Student Preparation

    Students should have already completed the "Where Will the Zebra Mussel Invade?" activity and be divided into small groups.

    Time Needed

    Two 45-50 class periods or more, depending on number of groups (students may need additional time outside of class to prepare group presentations)

    Materials Needed

    • Zebra Mussel Action Plan Outline (in "Student Activities" section)

    • Supplementary zebra mussel publications included in this packet

      (See "Resources" section for list of titles. You may duplicate these so that each group has a copy, or groups can share materials.)

    • Posterboard, markers, and other art materials

    Optional: Additional zebra mussel articles

    (See "Resources" for bibliography)

    Teacher Preparation

    1. Read the "Zebra Mussel Action Plan Outline" for information on how the activity is done.

    2. For each group, duplicate one copy of the "Zebra Mussel Action Plan Outline" and the supplementary publications. These publications contain background information the students will need to develop their action plans.

    3. Divide students into small groups and assign roles, as in the previous activity. Groups may remain the same, or students may rotate into another group. NOTE: You may decide to have the class develop action plans only for those study sites which are at a high or moderate risk. If so, students from "low-risk" groups can be moved into "high-risk" groups.

    Conducting the Activity

    1. Give each Materials Manager copies of the "Zebra Mussel Action Plan Outline" sheet and the supplementary publications.

    2. Briefly introduce the activity, and give students the timeline for the completion of their plans and for their class presentations (5-10 minutes each). Encourage the groups to use charts, posters, and any other creative methods to make their presentations effective.

    3. On the day set aside for presentations, assign a timekeeper to help keep the activity on schedule. Each group should allow time for questions and comments from the rest of the class when its presentation is finished.

    Summary and Evaluation

    1. Have a small group of students serve as an evaluation team, and let them choose which plans are the most creative, comprehensive, practical, effective, etc. Alternatively, have the entire class discuss and evaluate the merits and shortcomings of each plan.

    2. How do the groups' action plans compare to the efforts which Virginia and other states are making to control the zebra mussel? Students may want to contact zebra mussel specialists to get their reactions to the student plans. (See "Resources" for contact people.)


    RESOURCES

    Zebra Mussel Publications

    1. Baker, Patrick, Shirley Baker, and Roger Mann. 1993. Criteria for predicting zebra mussel invasions in the mid-Atlantic region. Virginia Sea Grant Program, Virginia Institute of Marine Science, VSG-93-03.

    2. Baker, Patrick, Shirley Baker, and Roger Mann. 1993. Potential range of the zebra mussel, Dreissena polymorpha, in and near Virginia. Virginia Sea Grant Program, Virginia Institute of Marine Science, VSG-93-04.

    3. Baker, Shirley, Patrick Baker, and Roger Mann. 1993. Zebra mussels in Virginia's future. Virginia Sea Grant Program, Virginia Institute of Marine Science, VSG-93-05.

    4. Doll, Barbara. 1993. Mid-Atlantic zebra mussel fact sheet. University of North Carolina Sea Grant, North Carolina State University.

    5. Heath, Robert T. 1993. Zebra mussel migration to inland lakes and reservoirs: A guide for lake managers. Ohio Sea Grant College Program, OHSU-FS-058.

    6. Kelch, David O. 1994. Boaters: Slow the spread of zebra mussels, and protect your boat too. Ohio Sea Grant College Program, OHSU-FS-054.

    7. Ohio Sea Grant College Program. A Great Lakes Sea Grant resource list on zebra mussels and other nonindigenous species. 1993. Ohio Sea Grant College Program, OHSU-FS-052.

    8. O'Neill, Charles R. Jr., and David B. MacNeill. 1991. The zebra mussel (Dreissena polymorpha): An unwelcome North American invader. New York Sea Grant.

    9. Snyder, Fred L., David W. Garton, and Maran Brainard. 1994. Zebra mussels in NorthAmerica: The invasion and its implications. Ohio Sea Grant College Program, OHSU-FS-045.

    10. New York Sea Grant. 1996. North American Range of the Zebra Mussel.(map)

    11. University of Wisconsin Sea Grant. 1995. aquatic eXotic: Sea Grant Resources on Zebra Mussels.

    12. Dreissema! Zebra Mussel Information Clearinghouse. New York Sea Grant. (newsletter)


    Selected Bibliography

    For more information on zebra mussels and other exotic species, check local libraries for the following publications:

    Bruenderman, Sue, and Lisie Kitchel. 1992. A hitchhiking terror: The zebra mussel. Virginia Wildlife, Vol. 53, No. 4, April 1992, pp. 11-13.

    Culotta, elizabeth. 1991. Biological immigrants under fire. Science, Vol. 254, No. 5037, 6 December 1991, pp. 1444-1447.

    Doll, Barbara, and Jeannie Farris. 1993. Invasion of the killer mussels. Wildlife in North Carolina, Vol. 57, No. 3, March 1993, pp. 21-23.

    Fleming, C.B. 1991. Unwelcome immigrants: Ballast water stowaways. Sea Frontiers, Vol. 37, No. 3, June 1991, pp. 22-25.

    Neves, Richard. Brooding over mussels. 1994. Virginia Wildlife, Vol. 55, No. 1, Jan. 1994, pp. 4-9.

    Raloff, Janet. 1992. From tough ruffe to quagga. Science News, Vol. 142, No. 4, pp. 56-58.

    Ross, John. 1994. An aquatic invader is running amok in U.S. waterways. Smithsonian, Vol. 24, No. 11, Feb. 1994, pp. 40-51.

    Stolzenburg, William. 1992. The mussels' message. Nature Conservancy, Vol. 42, No. 6, Nov./Dec. 1992, pp. 16-23.

    Virginia Sea Grant. 1992. Dreissena polymorpha, the unwelcome colonizer. Virginia Marine Resource Bulletin, Vol. 24, Nos. 1 and 2, Spring and Summer 1992, pp. 22-23.

    Carlton, Reid & vanLeeuwen. 1995. The Role of Shipping in the Introduction of Nonindigenous Aquatic Organisms to the Coastal Waters of the United States (other than the Great Lakes) and an Analysis of Control Options. National Sea Grant College Program /Connecticut Sea Grant Project, Report No: CG-D-11-95.

    Additional curriculum materials may be ordered from the following sources:

    "Alien Invaders: A Case Study on Zebra Mussels" (curriculum unit with student activities)
    The Rivers Project
    Southern Illinois University
    Box 2222
    Edwardsville, IL 62026

    "Saving America's Pearly Mussels" (video, script, and poster)
    Virginia Tech Extension Distribution Center
    112 Landsdowne St.
    Blacksburg, VA 24061-0512


    Mid-Atlantic Contacts for Zebra Mussel Information

    Delaware

    Tracey Bryant
    Delaware Sea Grant Program
    University of Delaware
    Marine Communications Office
    263 East Main Street
    Newark, DE 19716-3530
    (302) 831-8185

    Jim Falk
    Delaware Sea Grant Program
    Marine Advisory Services
    700 Pilottown Road
    Lewes, DE 19958-1298
    (302) 645-4235

    Maryland

    Dan Terlizzi
    Sea Grant Extension Service
    NOAA Chesapeake Bay Office
    410 Severn Avenue, Suite 107A
    Annapolis, MD 21403
    (410) 267-5660

    New Jersey

    Eleanor Bochenek
    New Jersey Sea Grant
    Rutgers Cooperative Extension
    1623 Whitesville Road
    Toms River, NJ 08755
    (908) 505-1210

    New York

    Charles O'Neill, Jr.
    Zebra Mussel Information Clearinghouse
    New York Sea Grant Extension
    250 Hartwell Hall
    SUNY College at Brockport
    Brockport, NY 14420-2928
    (716) 395-2638
    sgbrockp@ccl.cornell.edu

    North Carolina

    Barbara Doll
    North Carolina Sea Grant
    Box 8208
    North Carolina State University
    Raleigh, NC 27695
    (919) 515-5287

    Virginia

    William DuPaul
    Vicki Clark
    Virginia Sea Grant Marine Advisory Program
    Virginia Institute of Marine Science
    P.O. Box 1346
    Gloucester Point, VA 23062
    (804) 642-7164

    Virginia Department of Game and Inland Fisheries
    Fisheries Division
    P.O. Box 11104
    Richmond, VA 23230-1104
    (804) 367-9231

    Louis A. Helfrich
    Department of Fisheries and Wildlife Services
    Virginia Polytechnic Institute and State University
    Blacksburg, VA 24060
    (540) 231-5059
    lhelfric.async.vt.edu


    Other Zebra Mussel Contacts

    Ohio Sea Grant College Program
    The Ohio State University
    1314 Kinnear Road
    Columbus, OH 43212
    (614) 292-8949
    ----------------------------------------

    Michigan Sea Grant College Program
    Zebra Mussel Information Office
    University of Michigan
    20200 Bonisteel Blvd.
    Ann Arbor, MI 48109
    (313) 764-1138
    ----------------------------------------

    Minnesota Sea Grant
    Zebra Mussel Information Center
    208 Washburn Hall
    University of Minnesota
    Duluth, MN 55812
    (218) 726-8712
    ----------------------------------------

    Tennessee Valley Authority
    1101 Market Street
    Chattanooga, TN 37402
    (800) 538-2526
    ----------------------------------------

    Zebra Mussel Information Clearinghouse
    New York Sea Grant Extension
    250 Hartwell Hall
    SUNY College at Brockport
    Brockport, NY 14420-2928
    (800) 285-2285


    STUDENT ACTIVITIES

    See "Teacher's Guide" for activity instructions.

    Master copies of student activity pages included in this section are as follows:

    Zebra Mussel Biology

    Zebra Mussel Optimal Habitat Characteristics

    Zebra Mussel Impacts

    Zebra Mussel Site Report

    Zebra Mussel Action Plan Outline

    Zebra Mussel Study Site Data Cards (9 pages)

    Follow-Up Ideas

    NOTE TO TEACHERS AND STUDENTS:

    It is against Virginia state law to import live zebra mussels into the state. No activity in this curriculum involves the use of live zebra mussels. Due to the danger of accidental introduction and the strict laboratory controls required for their use, live exotic species are not recommended for student research.


    Zebra Mussel Biology

    The zebra mussel is a freshwater bivalve mollusk, originally found in Europe in the Caspian, Aral, and Black seas. Adult zebra mussels range from 0.5 to 3.5 cm long. The zebra mussel's scientific name is Dreissena polymorpha. The name polymorpha refers to the many individual variations in the color and pattern of the shell. Most zebra mussels have striped shells, but some are solid black or brown.

    Zebra mussels feed on plankton, including algae, bacteria, larval animals, and other tiny particles of organic matter suspended in the water. The mussel pumps water into its body through a siphon tube and filters out the food. The water is pumped out through a second siphon. An adult zebra mussel filters an average of one liter of water each day.

    Although they are freshwater animals, zebra mussels can survive in slightly brackish water (0.5 parts per thousand). Some adult zebra mussels have survived for several days in water with salinities as high as 12 parts per thousand under controlled laboratory conditions.

    Zebra mussels grow and reproduce best in water which is 12 to 26C with a calcium content of at least 20 parts per million. The calcium is important for the growth and maintenance of the shell.

    Zebra mussels are either male or female. Mature females can produce 30,000 eggs each year.

    Some females have produced as many as one million eggs per year. Spawning occurs when water temperatures warm to 12 to 23C. If the water temperature remains suitable, spawning may occur several times during the season.

    A fertilized zebra mussel egg becomes a microscopic, planktonic larva. The larval mussel spends two to three weeks swimming about, feeding on phytoplankton. During this stage, downstream currents can easily transport the larval zebra mussel from one body of water to another.

    About two to three weeks after hatching, the larva begins to settle to the bottom. To survive, it must settle on a hard surface. Almost anything will do, including rocks, pier pilings, boats, concrete, another animal's shell, aquatic plants, or submerged logs. It attaches to the surface with strong fibers called byssal threads. Zebra mussels frequently grow in large colonies, with hundreds of individuals attached to an object and to each other.

    Zebra mussels can crawl from place to place by secreting temporary byssal threads which the mussels attach and detach as they move along.


    Zebra Mussel Optimal Habitat Characteristics


    water temperature   6 -28C     (spawn at 12 - 23C; die above 32C)


    pH   7.4 - 9.4


    salinity   less than 5 parts per thousand (ppt)


    calcium (from CaCO3)   greater than 20 parts per million (ppm)


    substrate   need firm surface for attachment


    NOTE: Larval forms are more sensitive than adults, especially to cold water temperatures.

    Zebra Mussel Impacts

    Zebra mussels can reproduce in large numbers in suitable habitats. Although individual zebra mussels are small, they attach to each other to form large colonies which grow on almost any solid underwater material. These colonies can grow to contain as many as 100,000 mussels per square meter!


    Zebra Mussel Site Report

    Location of zebra mussel study site:

    Names of study team members:

    1. The chance that zebra mussels will be introduced to this site is (circle one)

        [low]		[moderate]		[high]

    What specific facts and information about zebra mussels and about the study site led you to this conclusion?

    2. If zebra mussels are introduced, the chance that they will survive and successfully reproduce in this site is (circle one):

        [low]		[moderate]		[high]

    What specific facts and information about zebra mussels and about the study site led you to this conclusion?

    3. List three specific actions which your group feels people should take to prevent the introduction of zebra mussels into this site.


    Zebra Mussel Action Plan Outline

    Names of team members:

    Location of zebra mussel study site:

    Chance that zebra mussels will become introduced at this site (see your "Zebra Mussel Site Report" form):

        [low]		[moderate]		[high]

    Chance that zebra mussels will survive and successfully reproduce in this site:

        [low]		[moderate]		[high]

    Your team is responsible for developing an action plan which will help reduce the chances that zebra mussels will be introduced in your study site. As a team, discuss the following questions (be sure to have your team's recorder take notes during the discussion):

    What groups of people (your "target audience") will need to know about zebra mussels?

    What will each group of people need to do to help keep zebra mussels out of the area?

    How will you communicate this information to each group in your target audience?

    How will you pay for developing and conducting your activities?

    What can you do to find out if your action plan is successful?

    Use your answers to these questions to develop your action plan. Prepare a 5 - 10 minute presentation to give to the rest of the class which describes what your group wants to do. Include a written summary of the plan as well as charts, posters, or other items which will help explain your ideas.


    Follow-Up Ideas

    Classroom Activities

    1. Work with your group to design a method to remove zebra mussels from one of the following areas:

    Small lake used for swimming, fishing, and boating

    Water treatment facility which provides water for an entire community, including homes, schools, businesses, hospitals, and industries

    Stream which supports a population of a freshwater mussel which is important to the local economy (its shells are exported to Japan for use in the cultured pearl industry)

    Information on zebra mussel control can be obtained from supplementary materials listed in the "Resources" section.

    As you design your control method, consider the following:

    Some control methods which kill zebra mussels may also be harmful to native freshwater mussels, fish, aquatic plants, and other organisms. How will you make sure your method will not be harmful to other organisms in the area?

    What will you do with the zebra mussels that you destroy?

    If drinking water supplies are affected, how will you avoid contaminating the water with chemicals and with dead zebra mussels?

    Describe your control method in writing, or present a report to the class. You may want to draw diagrams and pictures or build a model to show how your control method will work.

    2. Design a poster which educates recreational boaters, fishermen, and other users of lakes and streams about the zebra mussel problem. In addition, develop a bumper sticker or T-shirt design using the zebra mussel theme.

    3. Produce a public service announcement for television which informs people about the zebra mussel problem. Videotape or present the announcement live to the rest of the class.

    4. Write a short play or skit with a zebra mussel as the main character.

    5. If you have access to a computer and a telecommunication network, contact students who live in an area where zebra mussels have become established (see range map in "The Zebra Mussel: An Unwelcome North American Invader"). Find out what people in their community are doing about the problem. If you cannot use a computer to communicate, write letters.


    Field Activities

    1. Visit your local water treatment facility or electric power plant to find out how the operators keep the water intake areas free of debris, animals, plants, etc. It is usually possible to schedule a tour for a group if you call in advance.

    2. Take a walk around your school, a local park, or your yard. List the plants and animals which were introduced from another part of the United States or another country. A horticulture teacher, science teacher, botanist, or garden club member might be able to help you with the survey.

    3. Call a local greenhouse or plant nursery and ask if your class can schedule a visit to learn about the types of plants which are grown and sold there. How many of these are native plants? What different parts of the world have provided us with some of our most common house and garden plants? What are the advantages and disadvantages of cultivating native versus exotic plants?

    4. Many exotic animals have been intentionally brought into the United States. These animals may have been imported for pets, for hunting, or for control of other species. Contact state and federal wildlife and agriculture departments for information on regulations which control the importation of exotic animals into your state. Local pet stores should also be able to explain how they are required to follow regulations concerning the sale of exotic species.

    5.Many plants which orginated in the Americas, including corn, tomatoes, and "Irish" potatoes, have been introduced to Europe and Africa. What impacts have these exotic species had on the economies and ecosystems of these areas?

    6. Get involved in a water quality monitoring project to learn how to measure mineral content, pH, temperature, and other water conditions. Many communities have organized groups which monitor water quality in specific sites on a regular basis. Contact the following organizations for information on citizen water quality monitoring:

    Jay West
    Save Our Streams (SOS)
    Izaak Walton League of America
    1401 Wilson Blvd. Level B
    Arlington, VA 22209
    (703) 528-1818

    Marjorie Adkins, Monitoring Coordinator
    Alliance for the Chesapeake Bay, Inc.
    6600 York Road, Suite 100
    Baltimore, MD 21212
    (301) 377-6270

    Global Rivers Environmental Education Network (GREEN)
    721 East Huron
    Ann Arbor, MI 48104
    (313)761-8142


    DATACARDS

    Zebra Mussel Study Site #1:

    James River at Richmond, VA

    The land area which drains into the James River has many large lakes and reservoirs with heavy recreational use. There are over 90 public boat ramps in the area, mostly on lakes.

    ------------------------------------------------------------------------------------------------------------------------

    Zebra Mussel Study Site #1:

    James River at Richmond, VA

    Each year, professional bass fishing tournaments are held near the city of Richmond on the tidal freshwater portions of the James. Many of the fishing boats, which are brought to these tournaments on trailers, have been used in lakes and rivers throughout the country only a day or two earlier.

    -------------------------------------------------------------------------------------------------------------------------

    Zebra Mussel Study Site #1:

    James River at Richmond, VA

    In areas where the mussels thrive, adult zebra mussels frequently attach to boats and trailers. These mussels can sometimes survive out of the water for 2 to 3 days.

    --------------------------------------------------------------------------------------------------------------------------

    Zebra Mussel Study Site #1:

    James River at Richmond, VA

    The deep water port in Richmond is visited regularly by large ships which have traveled from freshwater ports in Europe. There is also heavy barge and boat traffic between the James River and other estuaries in the Chesapeake Bay.

    --------------------------------------------------------------------------------------------------------------------------

    Zebra Mussel Study Site #1:

    James River at Richmond, VA

    The water monitoring site closest to Richmond is near Cartersville. The pH of the James River at this site in August is 8.1. The calcium content of the river near Cartersville is about 22 ppm.

    -----------------------------------------------------------------------------------------------------------------------

    Zebra Mussel Study Site #1:

    James River at Richmond, VA

    Free-swimming zebra mussel larvae can survive in bilge water and in water contained in bait buckets, boat hulls, trailer frames, etc.


    DATACARDS

    Zebra Mussel Study Site #2:

    Potomac River at Alexandria, VA

    Large vessels travel regularly into the Potomac River from the Great Lakes area. For example, according to officials at one dock terminal, cargo ships from Quebec City on the St. Lawrence River arrive in Alexandria six or seven times a year.

    ------------------------------------------------------------------------------------------------------------------------

    Zebra Mussel Study Site #2:

    Potomac River at Alexandria, VA

    Quebec City is on a portion of the St. Lawrence River that is populated by a large number of zebra mussels.

    ------------------------------------------------------------------------------------------------------------------------

    Zebra Mussel Study Site #2:

    Potomac River at Alexandria, VA

    Alexandria is the largest port in the freshwater portion of the Potomac River. The amount of ballast water exchanged by ships in the port at Alexandria is unknown.

    ------------------------------------------------------------------------------------------------------------------------

    Zebra Mussel Study Site #2:

    Potomac River at Alexandria, VA

    The pH of the Potomac River near Alexandria is 8.1 - 8.4 from May to September. Calcium content of the Potomac River near Alexandria is 32 - 40 ppm.

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    Zebra Mussel Study Site #2:

    Potomac River at Alexandria, VA

    Commercial and recreational traffic into the Potomac estuary from adjoining estuaries is very high.

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    Zebra Mussel Study Site #2:

    Potomac River at Alexandria, VA

    The Potomac is the closest Virginia estuary to the Susquehanna River. Reproducing

    populations of zebra mussels have been found in the Susquehanna River in the vicinity of Johnson City, NY.


    DATACARDS

    Zebra Mussel Study Site #3:

    Smith Mountain Lake

    Smith Mountain Lake is a large reservoir on the headwaters of the Roanoke River near the city of Roanoke.

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    Zebra Mussel Study Site #3:

    Smith Mountain Lake

    Smith Mountain Lake is heavily used for recreational boating and fishing. There are 17 public boat ramps and a very popular state park located on the lake.

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    Zebra Mussel Study Site #3:

    Smith Mountain Lake

    There is a large professional bass tournament held annually on Smith Mountain Lake. Participants travel from all over the country to compete, and bring their own boats in on trailers.

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    Zebra Mussel Study Site #3:

    Smith Mountain Lake

    The pH of Smith Mountain Lake in the summer ranges from 7.6 - 9.1.

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    Zebra Mussel Study Site #3:

    Smith Mountain Lake

    The calcium level of Smith Mountain Lake is about 15 - 17 ppm.

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    Zebra Mussel Study Site #3:

    Smith Mountain Lake

    Adult zebra mussels, which frequently have been found attached to boats and trailers in areas where the mussels thrive, can live outside of the water for two to three days under certain environmental conditions.


    DATACARDS

    Zebra Mussel Study Site #4

    Rappahannock River

    Upstream from the Rappahanock there are several reservoirs, and there are 11 public boat ramps in the freshwater portion of the river's drainage area.

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    Zebra Mussel Study Site #4

    Rappahannock River

    Boat traffic into the Rappahannock from other estuaries is low to moderate. There are several large, private reservoirs in the Rappahanock drainage which are surrounded by residential development.

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    Zebra Mussel Study Site #4

    Rappahannock River

    Free-swimming zebra mussel larvae can survive for several days or even weeks in the ballast water of ships, and in water contained in bait buckets, live wells, boat trailer frames, and other enclosed areas in boats and ships.

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    Zebra Mussel Study Site #4

    Rappahannock River

    Near Fredericksburg, the Rappahannock River has a pH of 7.8 (measured in August).

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    Zebra Mussel Study Site #4

    Rappahannock River

    Calcium levels of the Rappahannock in August have been measured at 5.2 ppm.

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    Zebra Mussel Study Site #4

    Rappahannock River

    Larval zebra mussels can easily be transported by currents moving downstream from one body of water to another.


    DATACARDS

    Zebra Mussel Study Site #5

    Kerr Reservoir and Lake Gaston

    Kerr Reservoir and Lake Gaston are on the Roanoke River. Both lakes are heavily used for recreational boating and fishing.

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    Zebra Mussel Study Site #5

    Kerr Reservoir and Lake Gaston

    Larval zebra mussels can easily be transported by currents moving downstream from one body of water to another.

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    Zebra Mussel Study Site #5

    Kerr Reservoir and Lake Gaston

    Both lakes are located downstream from several public-access reservoirs, which have a total of at least 80 public boat ramps.

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    Zebra Mussel Study Site #5

    Kerr Reservoir and Lake Gaston

    Water chemistry data varies from place to place in both Lake Gaston and Kerr Reservoir. Both lakes, however, have regions in which pH readings of 6.9 - 9.3 have been found.

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    Zebra Mussel Study Site #5

    Kerr Reservoir and Lake Gaston

    Calcium levels in Lake Gaston have been measured at 24 - 44 ppm.

    Data on calcium levels in Kerr Reservoir is not yet available.

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    Zebra Mussel Study Site #5

    Kerr Reservoir and Lake Gaston

    Adult zebra mussels, which frequently have been found attached to boats and trailers in areas where the mussels thrive, can live outside of the water for two to three days under certain environmental conditions.


    DATACARDS

    Zebra Mussel Study Site #6

    Mattaponi and Pamunkey Rivers

    The Mattaponi and Pamunkey Rivers flow together at West Point to form the York River. The York River has a salinity of about 5 ppt at West Point.

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    Zebra Mussel Study Site #6

    Mattaponi and Pamunkey Rivers

    Large barges and ships travel up and down the York River to and from a large paper mill in West Point. The barges travel between West Point and the eastern shore of Virginia. The ships travel from a number of ports in northern Europe, Canada, and South America.

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    Zebra Mussel Study Site #6

    Mattaponi and Pamunkey Rivers

    The Mattaponi River has several freshwater reservoirs upstream from West Point which are used for boating and fishing.

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    Zebra Mussel Study Site #6

    Mattaponi and Pamunkey Rivers

    Lake Anna, a large freshwater reservoir in the Pamunkey River drainage, is used heavily for recreational fishing and boating.

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    Zebra Mussel Study Site #6

    Mattaponi and Pamunkey Rivers

    At the Beulahville monitoring site, which is northeast of Mangohick, the pH of the Mattaponi in July is about 6.9. Calcium content is about 3.7 ppm.

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    Zebra Mussel Study Site #6

    Mattaponi and Pamunkey Rivers

    At the Hanover monitoring site, the pH of the Pamunkey in June has been measured at about 6.9 ppm. Calcium content has been measured at about 9 ppm.


    DATACARDS

    Zebra Mussel Study Site #7

    Lake Anna

    Lake Anna, the largest reservoir in the Pamunkey River drainage, is used heavily for recreational fishing and boating. There are nine public access boat ramps on the lake.

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    Zebra Mussel Study Site #7

    Lake Anna

    The pH of Lake Anna has been measured at 7.9 in some branches of the lake during the summer.

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    Zebra Mussel Study Site #7

    Lake Anna

    The maximum calcium content of Lake Anna waters has been measured at 6.0 ppm.

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    Zebra Mussel Study Site #7

    Lake Anna

    Larval zebra mussels can easily be transported by currents moving downstream from one body of water to another.

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    Zebra Mussel Study Site #7

    Lake Anna

    There is a nuclear power plant located on Lake Anna which requires large amounts of water for its operation.

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    Zebra Mussel Study Site #7

    Lake Anna

    Adult zebra mussels, which frequently have been found attached to boats and trailers in areas where the mussels thrive, can live outside of the water for two to three days under certain environmental conditions.


    DATACARDS

    Zebra Mussel Study Site #8

    Claytor Lake

    Claytor Lake has heavy recreational use. There are eight public boat ramps on the lake, and eight more are located on the New River upstream.

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    Zebra Mussel Study Site #8

    Claytor Lake

    Claytor Lake hosts numerous fishing tournaments. Participants travel with their boats to Claytor Lake from many areas outside of Virginia.

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    Zebra Mussel Study Site #8

    Claytor Lake

    Surface waters in Claytor Lake are normally alkaline, with a pH of 7.3 - 9.3 in June.

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    Zebra Mussel Study Site #8

    Claytor Lake

    The calcium level in Claytor Lake is usually low, around 9.0 to 10.0 ppm. However, in some years, the calcium has been measured at 30.0 ppm.

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    Zebra Mussel Study Site #8

    Claytor Lake

    Claytor Lake was built as a reservoir to provide a source of water for a hydroelectric power plant.

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    Zebra Mussel Study Site #8

    Claytor Lake

    Adult zebra mussels, which frequently have been found attached to boats and trailers in areas where the mussels thrive, can live outside of the water for two to three days under certain environmental conditions.


    DATACARDS

    Zebra Mussel Study Site #9

    South Holston Lake

    South Holston Lake is located near Abingdon on the South Fork of the Holston River, a tributary of the Tennessee River.

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    Zebra Mussel Study Site #9

    South Holston Lake

    South Holston Lake is within a few hours drive of other lakes in the Tennessee River system. Zebra mussels have become established in the Tennessee River.

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    Zebra Mussel Study Site #9

    South Holston Lake

    There are sixteen public boat ramps on South Holston Lake, and two more upstream on

    Hungry Mother Lake.

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    Zebra Mussel Study Site #9

    South Holston Lake

    The pH of South Holston Lake has been measured at 6.9 to 8.6 in June and July.

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    Zebra Mussel Study Site #9

    South Holston Lake

    Calcium levels in South Holston Lake have been measured at 18 to 30 ppm.

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    Zebra Mussel Study Site #9

    South Holston Lake

    Adult zebra mussels, which frequently have been found attached to boats and trailers in areas where the mussels thrive, can live outside of the water for two to three days under certain environmental conditions.

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