The Buskin River holds a lot of opportunities for fishing, including salmon. But over the past several years, it’s also become known as a place to capture a relatively new resident — the signal crayfish.
For environmental and cultural groups, it’s become a mission to determine their cause and find a way to manage or mitigate the invasive species, as it presents a potential menace to salmon in the Buskin watershed.
The Sun’aq Tribe of Kodiak and the Kodiak Soil and Water Conservation District have taken ownership of projects, according to Matthew Van Daele, tribal biologist for the Sun’aq Tribe.
“The first report of crayfish was in 2002, and that was just a single crayfish,” Van Daele said. “The following year, Fish and Game sent a few people out and we tried to trap them and weren't successful.”
He said it wasn’t until 2012 or 2013 that a high school student caught a female crayfish laden with eggs and brought it to a science teacher.
“Kodiak Soil and Water Conservation District started a concerted effort to try and trap them,” Van Daele said. Females were finally trapped in 2015, including those with eggs.
“Since then, the reports have become more and more,” he said, “whether it’s because the population has increased or people are learning how to catch them and providing local knowledge.”
The Sun’aq Tribe also launched its own program. The tribe received a grant in 2016 from the federal Bureau of Indian Affairs Invasive Species program to conduct a two-year survey of the signal crayfish population. According to the survey data, 378 crayfish were captured and removed from the watershed in 2016, followed by 708 in 2017.
Mitigating invasive species has been a mission of the Sun’aq tribe, especially when it impacts subsistence resources like fishing.
“This is about as bad as it can get for an impact to subsistence resources,” he said.
He noted the Alutiiq Elders Language Group recently established a new word for signal crayfish: “sisurturta,” or “fish egg eater.”
“This is possibly the first time anywhere in Alaska that a Native language has come up with a name for an invasive species, and demonstrates the importance of protecting cultural heritage and subsistence resources,” Van Daele said by email, “especially considering signal crayfish have likely only been here two decades at the most.”
Another grant followed in 2017 for a 2018 survey season, when 1,299 crayfish were captured in the northeast, southeast and southwest portions of Buskin Lake.
Van Daele called signal crayfish “system engineers” capable of burrowing into the water bed.
“Potentially, they could be very damaging to the ecosystem,” he said. “In other places, especially in Europe where this same species has been introduced, they had a devastating impact on Atlantic salmon from both predation and burrowing into the salmon nests.”
The signal crayfish is native to Oregon, Washington state and Idaho.
Van Daele said that while there are other species in the Buskin watershed that burrow much deeper than signal crayfish, the invasive shellfish can potentially produce more numbers and impact water quality.
“Right now, it’s almost too soon to say if they’re changing the ecosystem,” Van Daele said. “We’re still continuing to monitor and remove as many as possible, just so we don’t have to look back and say we should have done something.”
He added that the survey has yet to provide data sets on population trend or recruitment, “only that there are a lot of them out there.”
A Monday catch, he added, netted 128 crayfish in just three hours of fishing, including 10 egg-carrying females and “one the size of my hand.”
Female signal crayfish typically lay between 200 and 400 eggs, but Van Daele said that might not be the case for those in the Buskin waters.
“The ones we are catching don’t seem to have that many, so once we have a rainy day, we’ll sit down and count every single egg that is in these females,” he said. “There are some strange things we’re seeing that aren’t necessarily aligned with what the literature says about crayfish populations elsewhere in the world.”
Van Daele added that it’s possible “the cold water in the Buskin may be doing something with their life cycle so they may grow more slowly than signal crayfish in more temperate climates.”
According to a 2018 Alaska Department of Fish and Game report, most crayfish can begin reproducing by 3 years of age and can live up to 20 years. Most adults are between 2.5 and 6 inches long, but can grow up to 8 inches.
He noted that juvenile crayfish potentially present the biggest danger to the salmon population.
“Other studies in the world have indicated that the younger ones are looking for more energetically beneficial food with a lot more protein,” Van Daele said. “Not only are they growing more, but they need more food for molting and try to get the most bang for their buck because everyone wants to eat a little crayfish, including the bigger crayfish.”
Van Daele is currently working on a federal grant that, if successful, would conduct a “mark and recapture” study. The study would allow the Sun’aq Tribe to capture and tag a set number of crayfish and release them back into the Buskin watershed.
“That would allow us to have a good solid population estimation based on how many marked crayfish we capture versus unmarked crayfish,” he said.
The grant would also potentially fund a community crayfish derby.
While the Sun’aq Tribe and the conservation district are looking for ways to mitigate the problem, Van Daele said the community can also help in a number of ways — including a good old-fashioned crayfish hunt.
“Get your families out there, it's a great activity especially on these nice hot, sunny days,” he said. “Go flip some rocks to save some baby salmon and get as many out as possible.”
He added the crayfish are edible “and quite tasty.”
“It is a food resource, and one of the mantras in Invasive Species Week is ‘If you can’t beat ‘em, eat ‘em,’” Van Daele said.
Like all fishing in Kodiak, crayfish harvesting requires a permit from the Alaska Department of Fish and Game. People just need a sports fishing license, and there is no set harvest limit as it’s an invasive species, according to department guidelines.
The recommended spots for catching crayfish would be on the south or southwest end of Buskin Lake.
ADF&G recommends using similar methods to what the Sun’aq Tribe have been using — dip nets and snorkeling. Homemade traps used over the years have tended to be inadvertently forgotten, or caused damage to other species.
The Kodiak Soil and Water Conservation District is also looking for information and asks people to send information via email to firstname.lastname@example.org or call 907-486-5574.
The crayfish invasion has risen to such a level of concern that the Sun’aq Tribe has requested support from the Kodiak Island Borough Assembly, a step mentioned by Assembly Member Julie Kavanaugh at last Thursday’s work session.
“They have asked us to declare crayfish as an invasive species in the borough of Kodiak,” Kavanaugh said. “We all know the situation in the Buskin is pretty bad — the amount in there is somewhat unknown but it is growing every year. … It’s a big mess.”
Kavanaugh called the proposed resolution or proclamation “a very forward-thinking thing for us to do” and “not common for a borough to do that.”
If passed, she said, it could inspire other boroughs to take similar actions with invasive species in Alaska.
“There are areas on the mainland that have issues with nightcrawlers due to sports fishing and have no way to eradicate them,” Kavanaugh said. Resolutions, she said, could pave the way for potential grant money to provide services.
She noted that the potential derby that comes from the Sun’aq’ Tribe’s grant application could provide a draw for people in the future “to help eradicate the species.”
“I think it could become a really unique, cliquey thing that brings different people to the community … who might not come here to hunt or fish, but because invasive species is their interest,” Kavanaugh.
Kavanaugh stressed using the word “eradication” lightly “because in some instances in other places, they haven’t been able to completely eradicate an invasive species. Instead, they just suppress their numbers so much that they are not doing as much damage.”
Borough Manager Mike Powers suggested taking the item up as a resolution.
“It would seem to me if we’re going to use it as a basis for funding or activities, passing it as a resolution would be a wise thing to do,” Powers said. “Perhaps later as this evolves, we could do a subsequent resolution declaring July as ‘Crayfish Eradication Month’ and all the tie-ins could occur.”
The borough assembly proposed putting the item on the agenda for the July 1 regular meeting.
Van Daele, who helped work on the proposed resolution, said Tuesday the action could prove essential.
“We’re hoping it can raise awareness and open more doors for grants and collaborative efforts to demonstrate the things going on,” Van Daele said.
Like Kavanaugh, Van Daele also suggested a loose definition of the word “eradication.”
“We’re probably never going to be able to completely eradicate crayfish from the Buskin, they’re probably here to stay,” he said.