Invasive Species

Bad ‘dads: Crawdads of Kodiak

A conversation about crayfish in Alaska

U.S.Fish&Wildlife Alaska
Jun 19 · 8 min read

Adapted from a conversation with Matt van Daele (Sun’aq Tribe of Kodiak), Jeff Woods (crayfish fisherman), and Tammy Davis (Alaska Department of Fish and Game). Listen to episode 24 of “Fish of the Week!

a crayfish next to a ruler
A signal crayfish caught on Kodiak Island, Alaska. 📷 Blythe Brown/Kodiak Soil and Water Conservation District

Arrival of Crayfish in Alaska

Matt: Back in 2003, I was a brand new high school intern with Alaska Department of Fish and Game’s Sport Fish division in Kodiak. My buddy and I got sent out to try to trap these crayfish.

We got a lot a lot of crushed traps by bears checking them out and trying to get to the bait inside.

Fortunately as years have gone by, folks have gotten very adept at catching crayfish. Jeff was the first student to successfully catch crayfish, including females with eggs.

crayfish on its back with eggs in its tail
A female signal crayfish with eggs caught on Kodiak Island. 📷 Blythe Brown/Kodiak Soil and Water Conservation District

Jeff: I caught the first one back in high school, completely by accident. I was out with my dad fishing silver salmon by the outlet of Buskin Lake. There was another gentleman sitting next to us who saw something under a rock — he was too scared to grab it. It turned out to be a fairly good-sized signal crayfish, which I later took to my high school natural resource teacher, Jane Iseman.

Signal crayfish are fast-growing and can live up to 20 years. Females start reproducing by age three and have clutches of up to 400 eggs

Why Are They Called Signal Crayfish?

crayfish in someone’s hand
A gravid female signal crayfish from Kodiak’s Buskin River waves her claws. Note distinctive white patches (signal) at the claw joint. 📷 Lisa Hupp/USFWS

Where Are They Found Naturally?

Have Other Crayfish Species Made it to Alaska?

Sun’aq Got a Tribal Wildlife Grant to Look at Their Distribution, Movement and Diet, Right? What Are You Finding?

young man holding a crayfish
young man holding a crayfish
Sun’aq Tribal Youth Intern D. Smith with signal crayfish. 📷 Matt van Daele/Sun’aq Tribe of Kodiak

What’s Your Biggest Fear About the Introduction of These Crayfish?

Signal crayfish also carry specific pathogens, namely “crayfish plague.” Since we don’t have native crayfish, we don’t need to worry about that, but it’s a good reminder that anything you release into the wild could carry pathogens and negatively impact native species.

bucket full of crayfish
Signal Crayfish captured on Kodiak Island. 📷 USFWS

What’s the Crayfish Fishing Situation on Kodiak?

The most efficient way I found to catch crayfish is diving. I’ve caught them as shallow as two inches of water and as deep as 20 feet. I’ve tried walking with just my Xtratufs down the first little portion of Buskin River every year since probably 2017. That year I caught 16 around April. This year: 103 in about three hours.

someone holding a crayfish
A Buskin Lake signal crayfish 📷 Matt van Daele/Sun’aq Tribe of Kodiak

They Do That Backward Scuttle?

I’ve caught all sizes, from as small as you can see to longer than my hand and wrist from claw tip to the base their tail.

Are They Just in the Buskin River Watershed?

Just the other week, Jeff was telling me he observed strange little holes in another river that looked very much like crayfish burrows. If we get an eDNA monitoring technique going here on Kodiak, when we receive reports from concerned citizens and citizen scientists, we’d be able to do something about it rapidly.

Environmental DNA (eDNA) is found in the environment and comes from cells shed from a kin, excrement, etc.

The problem with crustaceans is they don’t shed as much DNA into the water as other taxa might. So it’s going to take some refining and figuring out the best timing.

How Are People Preparing Crayfish/What’s a Crayfish Boil?

boiling crayfish
cooked crayfish, corn and potatos
person removing tail from cooked crayfish
Invasive American signal crayfish trapped in waterways around London. 📷 Chris Young/ CC-BY-4.0

I’ve actually done quite a lot of crayfish boils since 2012. In fact, we had a crayfish boil at our wedding reception. I’ve taken conservatively 800 to 1,500 crayfish out of the Buskin.

It also depends on who you’re talking to — one of the gals in at the Soil and Water Conservation District very much likes the more Swedish method with lots of dill. For me, I take a dozen lemons, cut them in half, put them with some onions and plenty of Tony Chachere’s and call it good.

Tammy: I always like when the invasive species can be turned into food sources, that idea “if you can’t beat it, eat it.”

Do You Suck the Heads?

Matt: You know, this is a really cruel conversation to be having right before lunch.

What’s Your Take-home About Kodiak’s Crayfish?

Matt: The Buskin supports the per capita most important subsistence sockeye fishery here in Kodiak and certainly on the Kodiak road system. There have been multiple times in the past when even the subsistence fisheries had to be shut down because of low escapement. Now whether this has anything to do with the crayfish is definitely debatable, but it highlights the importance of this salmon resource for the entire community of Kodiak, and also the fragility of this essential fishery. Introducing something like a crayfish is just one more thing to upset the balance.

What’s the Likelihood of Reducing or Eradicating Crayfish on Kodiak?

Tammy: We have an invasive species hotline (1–877 INVASIV) and you can also report invasive species sightings online. You can also contact the ADF&G invasive species program if you’re interested in doing citizen science. During Alaska Invasive Species Awareness Week in June, look for opportunities to engage with your community to learn about invasive species and participate in local events. We ask that you share what you learn with your family, friends and neighbors.

Compiled by Katrina Liebich, Alaska Digital Media Manager for the U.S. Fish and Wildlife Service’s External Affairs. Listen to episode 24 of “Fish of the Week!Thanks to our guests and Deb Kornblut.

As the Service reflects on 150 years of fisheries conservation, we honor, thank, and celebrate the whole community — individuals, Tribes, the State of Alaska, sister agencies, fish enthusiasts, scientists, and others — who have elevated our understanding and love, as people and professionals, of all the fish.

In Alaska we are shared stewards of world renowned natural resources and our nation’s last true wild places. Our hope is that each generation has the opportunity to live with, live from, discover and enjoy the wildness of this awe-inspiring land and the people who love and depend on it.

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