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Chapter 14: Slide 2 of 17

1. Introduction and Spread of AIS

Introduction and spread of AIS involves a number of vectors, or means of introduction, as well as various pathways, or sources. We humans play a large role in mediating introduction and subsequent spread of AIS as active vectors—both accidentally and intentionally—through several pathways.

Introduction to New Locations


  • Natural means of movement
    • Carried
      • water
      • Air
      • On or in animals
    • Simply move to new areas
      • Animals
    • Individuals dispersing may be
      • Adults
      • Larvae
      • Young
      • Seeds
      • Clones/fragments
  • Unnatural means of movement (with human help)
    • Carried (includes "hitchhiking")
      • Vehicles (boats and other watercraft and boat trailers)
      • Ballast water
      • Nursery plants
    • Escape
      • Aquaria (fish, snails, other aquatic animals)
      • Other pets (e.g., turtles)
      • Aquaculture (aquatic invasives)
    • Intentional release
      • Pets
      • Biological control
      • Sport fishing
      • Bait bucket transfers
      • Food source
    • Horticulture
      • Ornamental pond plants


  • Natural
    • Rivers and streams
    • Migrating birds (some plants)
  • Unnatural (human-mediated)
    • Aquaculture (aquatic invasives)
    • Horticulture
    • Aquarium trade
    • Recreation

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