AIS: Methods of Introduction

Methods of Introduction

​Invasive species are primarily spread by human activity, often unintentionally. 
 The main way AIS like zebra mussels and Eurasian water milfoil spread to new waters is by hitching a ride on boats, trailers, and equipment. Similarly, other AIS are introduced into lakes and streams through intentional releases.  AIS pathways are the means and routes by which invasive species are imported or introduced into new environments. Pathways can generally be classified as either natural or man-made.

Natural pathways are forms of natural dispersal that can bring species to a new habitat such as via wind, current, floating debris, and run-off. Example: Purple loosestrife seeds can move with storm water run-off. 

Man-made pathways are those which are created or enhanced by human activity and are either unintentional or intentional.

  • Intentional introduction of an non-native species is the result of a deliberate movement of a species by humans outside of its natural range. For example, intentional release of unwanted aquatic pets and aquaria plants.
  • Unintentional, which is the inadvertent or unintentional movement of a non-native species as an indirect result of some other human activity. For example, zebra mussels and Eurasian water milfoil can hitch a ride on boats, trailers, and mud on an anchor.


“Happy” the Golden Retriever, loves floating in the inflatable inner tube. Happy’s human is Oneida County AIS Coordinator, Stephanie Boismenue.

Common and not so common pathways of introduction:

All Watercrafts: 

  • Boats, jet boats, wake boats, canoes, kayaks, fishing kayaks, rowboats, paddle boats, fishing, inflatables with solid floors, and other recreational watercrafts. 

Watercraft Equipment: 

  • Hulls, motors, propellers, lower units, intake grates, bilge, livewells, bait containers, anchors, ropes, downrigger cables, trailer axles, bunkers, and boat carpet. 

            Here are some examples:

  • AIS can spread by hitching a ride in ballast water of oceangoing ships.
  • A few drops of water left in bait buckets and livewells can move spiny water fleas.
  • Invasive plants can hide in mud and sand in canoes, kayaks, boat anchors, and on boat trailers. 
  • Zebra mussels can attach to boat hulls, motors, and bilges.

Fishing Gear:  

  • Nets, waders, footwear, dip nets, fishing lines, and tackle. 


  • Purple Loosestrife seeds, Zebra Mussels, New Zealand Mud Snails, and organisms can attach to felt sole waders, hunting clothes, equipment, and even dog fur. 

Hunting and Trapping Gear: 

  • Hunting dogs, clothing, traps, waders, hip boots, boats, motors, trailers, ATV’s, push poles, decoys, decoy lines and anchors (use elliptical and bulb-shaped anchors to help avoid snagging aquatic plants).  

            Examples include: 

  • Huntings dogs can accidently transport invasive species. This happens when seeds (including burrs, stickers, foxtail seeds, etc) and mud (containing seeds, mussels, or organisms) gets tangled in dogs fur, including the fur between the paw pads. 
  • Invasive plant seeds, insects, and diseases can be moved on equipment, such as mud on tires or seeds with burrs on clothes and shoes.

Schools and Teachers:

  • As a teacher, you need to be sure you are not spreading AIS through common classroom activities. 
  • Be careful when acquiring live specimens from biological supply companies. Try to stay away from exotics and properly dispose of the specimens when finished with them.
  • Avoid buying exotic fish, plants, mollusks, or other species to lessen the chance of AIS introductions.
  • Many AIS introductions are linked to schools and households dumping aquarium contents into lakes or rivers. Aquarium fish, plants, mollusks, and water can be invasive, or hold invasives so proper disposal is very important.
  • Never allow your students to bring captured fish or other aquatic creatures into your classroom. This is especially important to emphasize to all students that they should never capture something somewhere else and bring it home. Too often these species end up getting dumped in a local water.
  • Teach students the importance of not moving water or species from place to place. It is illegal to move aquatic species from one waterbody to another. The water that fish are transported in may also hold AIS.

Trade Industries/Other: 

  • Bait shops, marinas, dock and boat lift installers, aquarium trade, landscapers, garden centers, water gardening, aquaculture, shipping, seaplanes, and scuba gear.  

            Examples include: 

  • Some ornamental plants can escape into the wild and become invasive.
  • For example: Mud and debris on tires, lawn mowers, and construction equipment can move invasive plant seeds, insects, and diseases.
  • Example: Wood products such as garden mulch, firewood, Christmas wreaths, and shipping pallets can move invasive insects, plants and pathogens.
  • Example: Intentional and accidental release of aquaculture species, aquarium specimens, and other means.