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What is Rotenone?

Sept. 1, 2026

In a remote corner of Southcentral Alaska, state biologists carried out a dramatic restoration: they treated an entire lake with rotenone, a plant-derived piscicide, to wipe out an invasive population of northern pike.

About Rotenone:

  • It is a naturally occurring compound derived from the roots of tropical plants in the genus Derris, Lonchocarpus, or Tephrosia.
  • It is commonly used as an insecticide and a pesticide.
  • It has been used for decades in fisheries management to remove unwanted fish from lakes and streams.
  • When applied at carefully calculated concentrations, it blocks oxygen uptake in fish gills, killing fish while leaving most other aquatic organisms unaffected.
  • The chemical breaks down relatively quickly in sunlight and warm water.
  • Currently, rotenone is commercially available as either a wettable powder or liquid.

Key Facts about Northern Pike: 

  • It is a freshwater predatory fish belonging to the pike family (Esocidae).
  • Scientific Name: Esox lucius
  • Habitat and Distribution:
    • They are native in all of the circumpolar regions.
    • They can be found through much of the northern reaches of the USA, parts of Alaska, Canada, Europe, and Asia in both rivers and lakes as well as the brackish waters of the Baltic Sea.
    • Unfortunately this hearty fish species is often found out of its northern native range, where they can become a nuisance because they devour other native fish such as trout, perch, and bass.
  • Features:
    • Their elongated slender bodies help them hide in weeds and among logs and rocks to ambush prey half their size.
    • They have a long head and flattened snout. Their mouths are enormous, with a one-way road of teeth.
    • These aggressive fish are striking in appearance, usually brownish green on top and sides covered with whitish bar-like spots.
    • The fins are dashed with red and brown streaks and darker dots, and the belly is cream-colored and white.
  • Conservation Status:
    • IUCN Red List: Least Concern

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