Kodiak Island’s invasive crayfish population has reached levels that make it too difficult to completely eradicate. That’s according to a biologist running a program to remove signal crayfish from Buskin Lake.
Daniel Smith is the biologist with the Sun’aq Tribe of Kodiak. He says signal crayfish were first observed in the Buskin River more than two decades ago in 2002, near Kodiak’s airport.
“Unfortunately due to the rapid expansion and the myriad of invasive traits that signal crayfish have, here in Kodiak the population has reached a level where a complete eradication is rather unfeasible,” Smith said.
Female crayfish carry several hundred eggs at a time, have a high reproductive rate or fecundity and can easily avoid predators by burrowing, which has allowed them to thrive in the Buskin watershed.
Smith gave an update on the invasive crayfish during this week’s Board of Fisheries finfish meeting in Kodiak. Most of Sun’aq’s eradication efforts have involved using traps and hand capture while snorkeling in the eastern side of Buskin Lake.
“Over the last three years we have boosted our control efforts and became more efficient in capturing crayfish. We removed a total of 2,821 crayfish in 2021, 6,048 in 2022 and 4,300 in 2023,” Smith said.
Board of Fisheries Chair John Wood pointed out that these numbers pale in comparison to crayfish populations in Louisiana and the bayou country areas of the Lower 48. Still these crawdads are not native to Alaska, and since they are invasive to Kodiak, the question is how did they get to the island?
According to Smith, there are a few theories but no clear answers.
“Some likely ones probably are, maybe a science experiment for crayfish and then when they were done with them, someone might have thrown them into the lake. It’s rather unknown, but it was definitely introduced sometime probably in the late 1990s or early 2000s,” he explained.
Biologists believe that Kodiak is the only place in the state where crayfish are currently established; although Smith with the Sun’aq Tribe of Kodiak warns that other areas of Alaska should be on the lookout for non-native crayfish, from areas extending all the way north to Denali National Park and south to Homer.
The Sun’aq Tribe has introduced community eradication efforts over the years, like local crayfish derbies at Buskin Lake. Smith expects those efforts will continue this summer.
He hopes that as crayfish are removed from the Buskin watershed, the local sockeye salmon population will be able to recover since crayfish prey upon juvenile salmon and other food sources. According to data from the Alaska Department of Fish & Game, the Buskin River sockeye return last year was significantly below the average returns of previous years and fell very short of the escapement goal.