Slideshow and Curriculum Chapter 2

Biology of Zebra and Quagga Mussels, and Other AIS


For this module you will need:mussels

  • Biology PowerPoint presentation
  • AIS props to pass around in class at the appropriate time of the presentation.
    • ZQM adults
    • ZQM settlers
    • Asian clams (to compare with ZQM)
    • Other AIS Props (as desired)
  • Boat(s) prepped for outdoor session
  • Flip charts and markers


The purpose of this module is for students to understand what they are looking for on watercraft and why it is important to keep invasive species from being introduced into our lakes and reservoirs.  The biology module is divided into four activities in a strategic order.

  1. Presentation on zebra and quagga mussel biology
  2. Outdoor session – How many mussels can you find?
  3. Presentation on other AIS Biology
  4. Group activity – Repeat

In this module, we reinforce the concept of life cycle and go into greater detail about mussel’s habitat preference.  This is not only important to understand how biology influences where mussels are likely to hide on a boat (e.g. dark places because they are light sensitive) but also helps the student begin understanding the importance of draining standing water and feeling the hull for bumps.  Of course, don’t go into the triggers for standing water decontaminations just yet – that’s much later in the agenda – remember we are planting seeds and by the time you get to decontamination the students will understand the reasons why, which means they are more likely to do it in the field. 

Another main reason to teach this module and be sure that inspectors understand mussel biology is that a large part of their job is educating the public.  Part of the inspection protocol includes education, and they will have to answer a ton of questions.  The better this module prepares the inspector, the better their contacts with boaters will be.

Lastly, this module is the first change that the students have to get hands on a boat and start looking for mussels!

PowerPoint Presentation - Zebra and Quagga Mussel Biology

The presentation goes through species identification, the three characteristics that make them invasive (byssal threads, filter feeders, prolific reproduction) and their negative impacts.  This has the scare factor in the slideshow - we want them to see how bad the mussels can be and motivate them to do good inspections to keep mussels and other AIS out of our waters.  We also want them to understand that mussels are bad for everyone – homeowners, municipalities, agriculture, energy, recreation, fisheries – everyone! 

Outdoor Session – How Many Mussels Can You Find?

The purpose is to demonstrate that it’s not as easy as one might think to find hiding mussels on watercraft, and that mussels come in many different sizes.  The chaotic nature of having all the students’ scourer the watercraft looking for mussels will reinforce the reality that inspectors need to follow a systematic procedure to actually find mussels on boats – it’s not as easy as it looks!  Later in the afternoon, we remind students of this when teaching the importance of following the step-by-step inspection procedure and doing inspections the same way every time to be sure you are going to find the mussels.


This activity requires that a boat be prepped for students to search for invasive mussels in advance.  It is recommended that a co-trainer or assistant prep the boats while the other trainer is doing the presentation. 


Teachers have often used different materials for this activity.  Felt sticky pads, pistachio nut shells, fake plastic fingernails, sunflower seeds and actual dead mussel and clam shells have all been used.  Some trainers have also used 3M washable glue spray and sand or pepper to create an area on the underside of the hull that resembles settlers that don’t rub off.  Regardless of what is used, remember to put them in places where mussels are most likely to be (e.g. underside of boat, hidden in trailer, in live wells, on anchor, on bumper, on anchor rope, in through hull fittings, in bilge plug, in engine compartments, in prop, etc.)  Don’t put ‘mussels’ on the deck in direct sunlight.  Write down exactly where you hid your ‘mussels’ so after the activity you can show students where the mussels are hiding.


When students go outside for this activity, break them up at various boats so the groups aren’t too large. Have them bring their book and a pen or pencil to write down where on the boat they found ‘mussels’.  Watch the clock so you don’t go over time.  Once the time is reached, have students gather around and show them all the places mussels are on the boat.  They will ‘grade’ themselves. 


PowerPoint Presentation – Other AIS Biology

The other AIS slideshow should be adapted by the trainer for their audience.  The species profiles provided in the student book and in the PowerPoint’s are common invaders, but the specific group being taught may be interested in other species.  Trainers should personalize this section to their audience. 

The other AIS slideshows are much shorter than zebra and quagga mussels and go over the basics of origin, identification, habitat, impacts and locations.  They also stress the cleaning recommendations for anglers and other recreationists. 

Group Activity – Repeat

The biology module is concluded with an opportunity for students to share what they have learned, and for instructors to evaluate if students understand the important concepts.  Engage the class in a brief facilitated session in which students tell instructors one thing they learned about mussel biology and one thing they learned about other AIS.  Write these down on separate flip charts and post them on the wall for the duration of the class.  This time should also be used for questions and answers before moving onto the next module.


Students should learn the following in the biology module:

  • Zebra and Quagga Mussels
    • What zebra and quagga mussels look like – smooth, striped shells with byssal threads
    • The three stage life cycle of mussels – veliger, settler, adult
    • Habitat preferences of mussels – light sensitive, live deep in water, right edges, etc.
    • Where mussels are from and how they have been introduced into new waters
    • The three main invasive characteristics – reproduction, byssal threads, filter feeders
    • Impacts – Ecological, Recreational, Economic, Infrastructure
    • There are no control methods in open waters and mussels cost us a ton of money
  • Other A.N.S.
    • First mention of the motto – No plants, No mud, No water, No mussels
    • ZQM is the poster child but WID protects against a lot of harmful species.
    • How to tell the difference between Asian clams and zebra/quagga mussels.
    • Origin, identification, habitat, pathways of spread, impacts for highest priority species
  • Main Points
    • It’s important to prevent the introduction of zebra or quagga mussels, or other AIS.
    • AIS can be moved in water and it’s important not to move water
    • AIS can be plants and it’s important not to move plants
    • AIS can sometimes be bait and it’s important not to dump bait