A biologist in hip waders stands knee deep in the Buskin River on Kodiak Island. She's pulling a wire mesh cage from the water - a crawdad trap, and she's caught some of the fresh water crustaceans, which look like small lobsters. She's not happy about her success.
Crawdads, also known as crayfish and crawfish, are an invasive species in Kodiak's Buskin River and Buskin Lake. Crawdads are not native to Alaska, and they are potential harmful. Invasive species can damage native habitat. Burrowing crawdads can affect vegetation in lakes. Biologists are also concerned crawdads could eat salmon eggs in rivers.
The species of this crustacean found in Kodiak, the signal crayfish, are originally from the Pacific Northwest. It's not clear how they got to Kodiak. They could have been shipped live to Kodiak for eating, school projects, as pets, or as bait. The small crustaceans were spotted occasionally in Kodiak waters since the early 2000s, but in the past, only about one per year was found. In the summer of 2015, a couple dozen were caught. That changed in 2016 - as of August 2016, 228 crawdads have been caught in Buskin River and Buskin Lake - including newly hatched young. Signal crayfish are successfully breeding in both in Buskin River and Buskin Lake.
Biologists are concerned that if the crayfish population continues to flourish, it could spread from the Buskin River into other systems. They're trying to solve this issue before it expands into something that is more difficult to control.