Invasive Species

A gypsy moth hanging from a tree.
A gypsy moth hanging from a tree.

ADF&G

What are Invasive Species?

An invasive species can be an animal, a plant, an insect, or any other living thing that is:

  • not native to an area
  • able to pervade a region because of insufficient checks (such as natural predators or diseases).
Invasive species can be found in all kinds of areas, including forests, waterways, and urban environments.

Why Are Invasive Species Bad?


They can take over a habitat, crowding out important local species that other plants and animals depend upon.Invasives change what can grow and thrive in an area, which affects the whole food chain. They affect how many and what kind of fish are available to eat for both us and other animals.They affect how we experience nature (e.g. it's hard to canoe or kayak in overgrown waterways covered in plants that aren't supposed to be there).

Some examples of damage invasives can (and have) caused include:
  • killing wildlife,
  • damaging boats and gear,
  • clogging water pipes and hydropower facilities, and
  • chewing wiring.

How are Invasive Species Introduced?


Most invasive species are introduced to a new region through human activity. Some are intentional actions, such as:
  • agricultural crops,
  • landscaping and ornamental plants,
  • released or abandoned pets, and
  • bait fish.

Others arrive through unsuspecting human carriers.

  • They hitchhike on visitors’ clothes, shoes, gear, or transport.
  • Boaters move invasive species that have attached to their equipment or clothing to new bodies of water.
  • Hikers and hunters move invasive species around through mud on boots and other equipment.
  • Drivers move invasive species that catch in their wheel wells, tires, or grills.
 
A pike fish is seen being dumped from a bucket, with a prohibited icon atop.
If you catch an invasive species in the water, don't put it back!

NPS/anch

Several Invasive Species in Alaska

  • Atlantic Salmon - these could compete with native salmon and trout for spawning and rearing habitat. Because Atlantic salmon are held in large, overpopulated net pens, they are treated for disease and parasites. Treated fish may not show signs of pathogens but can be carriers. ADF&G is concerned that Atlantic salmon that can escape or are released from aquaculture net pens may introduce disease or parasites to valuable Pacific salmon fisheries.
  • Northern Pike (in southcentral Alaska) - Illegal stocking of northern pike is reducing the quality of fishing in Southcentral Alaska and threatening both wild and stocked fisheries. The northern pike is native to most of Alaska, but it does not naturally occur south and east of the Alaska Mountain Range except for a small, remnant population near Yakutat.
  • Norway Rat - Because rats have a wide diet, they can prey on a lot of Alaskan wildlife (for example, bird eggs). They also carry parasites, pathogens and diseases that can be harmful to other species as well as humans.
  • Rock Dove - These can be crop pests. Because they live in large numbers, they can displace native birds in developed areas. But the largest concern is that rock doves carry a variety of parasites and pathogens that could suppress the health of native birds in Alaska.
If you see any of these (or other) invasive species, please report them immediately.
 

Preventing the Spread of Invasives

There are many different, easy things you can do help protect from invasives. Whether you're an avid outdoor person or you just like to take the occasional stroll, each time you go outside you have the opportunity to make a difference.

 

VIDEO - Dalton Discoveries: Uninvited Guests

In 2004 the BLM discovered white sweet clover, an invasive species, was pushing out native plant life along the Dalton Highway. While non-native plants are often found along highway corridors throughout Alaska, this plant has also made its way along some of the waterways that branch off from the highway.

Last updated: December 7, 2023

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