Fish & Water - Sounds Wild
Signal Crawfish

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Signal Crawfish

On an overcast summer day, a biologist is wading in Buskin Lake on Kodiak Island. She heard that an invasive species has been introduced to Buskin Lake, the signal crawfish, and she's flipping over rocks in the shallows. She finds one immediately, and then another, and another. After a few hours, it's clear that there are a lot of crawfish at the south end of Buskin Lake.

More than 300 different species of crawfish, also called crayfish or crawdads, are found across North America, but they are not native to Alaska. The Signal crayfish is native to the Pacific Northwest, and as an invasive species, it's particularly aggressive. Introduced to California, it outcompeted and essentially replaced every native California crawfish. The story was similar in Europe - the introduced signal crawfish also carried a crawfish disease that reduced native European crawfish species. Their commercial value is less than half of what native European crayfish would be worth. In addition, signal crayfish can dig extensive burrows in river banks and, in England, have been identified as a cause of river bank collapse and increased flooding risk. Biologists with Fish and game, and with the Sun'aq Tribe of Kodiak, are monitoring the invasive crawfish in Buskin Lake and working to remove them from Kodiak Island.