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Crayfish in the Northwest

(Photo: a Signal Crayfish posing with an energy bar wrapper)

Most of our crustacean friends– crabs, lobsters, and their kin– call the sea their home. But a few adventurous groups of these hard-shelled, many-legged invertebrates left the sea long ago to take up residence in freshwaters.

The most familiar of the freshwater crustaceans are the crayfish (also called crawdads or crawfish). Of course, crayfish are not fish, but are close relatives of the ocean-dwelling lobsters.

Crayfish creep along the bottom of streams, rivers, lakes, ponds, and swamps, using their claws (the technical terms for a claw is chela, or plural chelae) to pick apart and eat dead and living plants and animals. Crayfish are eaten in turn by predators, such as raccoons and birds. Their roles as consumers and as prey make crayfish important parts of freshwater ecosystems.

There are about 350 crayfish species in the United States, some of which are famous for their tendencies to end up in the cooking pots of folks in Louisiana. Crayfish are also used as live bait by fishermen across the country.

What’s the Deal with Crayfish in Washington and Oregon?

When you see a crayfish in the Pacific Northwest, it might be a native species (awesome!) or it could be an invasive species (bummer!).

The most widespread native species in the northwest is the Signal Crayfish (Pacifastacus leniusculus). Signal Crayfish come in a variety of colors: bright red, dull green-brown, or even bluish. They seem to prefer swiftly flowing waters, rather than lazy pools.

This species can be found throughout Washington and Oregon– from the coastal streams to the rivers of the Columbia Basin.

Recent research based on genetic data found that what we call the Signal Crayfish may actually represent four distinct species, each found in a different part of the northwest:

  • The Olympic Peninsula and Puget Sound area
  • The Okanagan Highlands
  • Central Oregon
  • Everywhere else that the Signal Crayfish lives (but it has been introduced here and there as well)

An invasive species that you might mistake for a Signal Crayfish is the Red Swamp Crayfish (Procambarus clarkii). The latter is the one most often eaten by people. The main way to tell the two species apart is to look at the texture of the ‘shell,’ which is the animals’ exoskeleton, called a carapace. If your crayfish’s carapace is covered with red, white, or dark bumps, you probably have a Red Swamp Crayfish.

The Rusty Crayfish (Orconectes rusticus) is another invasive species that can look like a Signal Crayfish. Rusty Crayfish have a large, rust-colored spot on both sides of their carapace.

The only other native species found within the borders of Washington and Oregon is the Snake River Pilose Crayfish (Pacifastacus connectens). This species lives in southeastern Oregon and Idaho, in desert lakes and in streams that drain into the Snake River. Not much is known about how this animal makes a living or about the status of its populations.

There are six invasive (i.e. alien) crayfish species that have been found in the Pacific Northwest, including the Red Swamp Crayfish and the Rusty Crayfish.

How did these invaders get here? They have gills and must be in water to survive, so they sure didn’t crawl over land (although they can crawl short distances over land– see the comments).

It is humans who move crayfish from place to place, all across the planet, both intentionally and accidentally, for eating and for use as bait. Even our own Signal Crayfish has been introduced to Europe, Japan, and elsewhere!

Live crayfish have been used in elementary and high school science classes for years. The animals are shipped from biological supply companies. Many compassionate kids have opted to ‘free’ their little study animals into local streams or ponds, rather than kill them (see the video below). Unfortunately, once they are turned loose, these non-native crayfish can cause a lot of damage.

The problem with invasive crayfish is that they often crowd out and outcompete the natives. They sometimes kill and eat other native animals or plants.

I look forward to returning to the Drift Creek Wilderness in Oregon, where I have seen many native Signal Crayfish in the stream. I took the photo at the top of this post at Drift Creek. In case you were wondering: I didn’t leave the energy bar wrapper in the wilderness :)

I will keep an eye out for these strange and fascinating animals as I splash around the Pacific Northwest.

Have you had any close encounters with crayfish, native or otherwise?

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25 comments… add one

  • DaveOnFidalgo March 15, 2011, 9:33 AM

    When I lived in Iowa, I found one dirty and wandering up the driveway. This was a good 100 feet from a nearby creek and he wasn’t in very good shape. I scooped him up and dropped him in my tropical fish tank to see if he would revive. He not only revived, he flourished in the clean, warm water. He didn’t bother the fish but fastidiously cleaned up after them. He built himself a burrow under a stone and took on quite a personality. In the clean water, he developed beautiful colors and iridescent markings. He even shed his shell a couple of times. This charming friend lived in that tank for a few years until I moved back here. He was adopted by another tropical fish buddy. This was a nice memory. Thanks.

    • Ivan Phillipsen March 23, 2011, 8:50 PM

      I’m glad you made reference to the fact that these guys can indeed move over land for short distances.

      I would love to have a crayfish in an aquarium. There is one at the Oregon Zoo and I was mesmerized by the movements of its swimmerets and mouthparts.

  • PDX Nature Nut March 16, 2011, 12:26 PM

    I’ve seen crayfish in Oregon streams before, but I didn’t know about the invasive species until I saw that story on Oregon Field Guide. Now I’ll be on the lookout for them. Thanks for the great article – your identification tips for all the various species will be helpful.

  • jill i March 17, 2011, 2:06 PM

    We used to have these in our ponds when I was a kid, we called them “crawdads.” Don’t know if they were native or not, we always were afraid of stepping on them in the mud and algae at the bottom of the pond. A natural spring flowed through the front yard and the previous owners had landscaped to created a couple large ponds w/a waterfall between. We stocked it with rainbow trout. So not sure if they were introduced? Anyway, that was several decades ago…
    interesting post as usual!

    • Ivan Phillipsen March 23, 2011, 8:53 PM

      Thanks, Jill. Until I did the research for this post, I was unclear about native versus invasive crayfish in the northwest. I was happy to find out that the crayfish I had seen along the Oregon coast were native signal crayfish.

      Hard to say if the crayfish in your yard were introduced or not. I think the invasive species have been around for awhile, so maybe…

  • Tom April 17, 2011, 10:00 AM

    Predation as a solution . As in human predation of the non native species.
    Yes this would require sorting by the human predators. If you could
    introduce people in Oregon to the idea that they could be getting something
    good to eat and be doing good for the environment then it might work.
    Human being are the solution of the problems they create.

  • Norm May 13, 2011, 5:12 PM

    What species’ of crayfish would I likely encounter if I were fishing on the Willamette river in Portland Harbor (common and scientific names)? Would you expect there to be one or two species’ that would be frequented more than other? I’m trying to learn more about these inhabitant’s life cycles and histories. Any recommendations? Thanks in advance and thanks for creating this forum! Cheers!

    • Ivan Phillipsen May 15, 2011, 8:43 PM

      Hi Norm,

      I am not sure off hand. I did a little web search and it looks like there is some research going on at Oregon State University regarding the distributions of Signal Crayfish and the Red Swamp Crayfish in the Willamette River. Contact Dr. Tiffany Garcia… and tell her I said, “Hi!”

  • Margie July 23, 2011, 9:35 AM

    note: Pacifastacus spp live under and between rocks in water at depths of up to 5 ft. Western crayfish do not dig burrows as eastern crayfish do. Sorry I couldn’t find the referenence to that fact. Probably from an early natural history text. In the 1950′s in the Willamette Valley, these creatures were very easy to find in the rocky substrates of swift creeks.

  • Gary January 9, 2012, 11:06 PM

    Ivan, I just encountered your website today. I was searching for information about crayfish. My wife and I moved to West Linn and are fortunate to have a creek along one side of our property. I had to remove a lot of Himalaya blackberry and ivy just to gain access to the creek and now I’m in the slow process of removing all the junk that’s been tossed into it as well as pulling more ivy and establishing native plants. While working near the creek this past summer I observed a single small crayfish. It made me think about improving the creekside habitat for crayfish but I’m ignorant about their requirements. Can you steer me to some expertise or just good information on how to make those improvements? The creek does flow year-around but just a few gpm in the summer. It even has a name–Barlow Creek–and flows into the Willamette R.

    • Ivan Phillipsen January 11, 2012, 4:57 PM

      Hi Gary. Thanks for the question. I don’t have personal experience in stream restoration. I suggest you try contacting the Pacific Rivers Council ( http://pacificrivers.org/ ). Also keep in mind that your crayfish might be a non-native species.

    • North West Wild Products June 26, 2012, 10:11 PM

      From what I’ve experienced they need big rocks and algae. The more big rocks and algae present, the bigger the population will be. Once they run out of “housing” the the big ones start eating the small ones.

      They pretty much eat plant material their whole lives and only rarely get the chance to eat meat (dead fish) which is why crayfish traps work so well.

  • Gary January 11, 2012, 6:12 PM

    Thanks for the prompt reply, Ivan. I will follow up on that reference.

  • Kool June 20, 2012, 5:56 PM

    I found a thing that looks like a lobster or crayfish. It is in a lake that goes into a river, it is muddy at the bottom, and is in Hillsboro, Oregon. Help!

    • Ivan Phillipsen June 23, 2012, 8:22 PM

      Thanks for the question. Wish I could tell what your critter was for certain, but I would need more details. It wouldn’t be a lobster– those live in the sea. So it was a crayfish, but I can’t say what species.

  • Judy October 3, 2012, 5:50 PM

    We live along the Molalla River in Oregon and recently have found the bodies of crayfish that appear to have been regurgitated by some bird. They are similar to owl pellets but are just the outer skeleton of the crayfish, compressed into a tube shape about 2 inches long. What bird would be doing this? There are bird droppings all around where we find these pellets so that is why I am assuming it is a bird.

    • Ivan Phillipsen October 4, 2012, 2:59 PM

      Hi, Judy– thanks for the question. My best guess is that you have discovered pellets regurgitated by a Great Blue Heron.

  • Trey October 27, 2012, 7:06 PM

    When I visited Lake Tahoe in California I saw some Signal Crayfish. I think that in this instance, the Signal Crayfish is the invasive, but I could be wrong. They seem like very interesting animals and I would like to keep one in an aquarium or outdoor pond, but I am worried about the latter the raccoon population would either kill them or dig up the pond. Although, I suppose as long as large rocks and other things to hide under are provided they should be able to hide. Also I am wondering are they only cannibalistic when they don’t have enough food or will they always fight over territory? Another thing that intrigues me is their longevity, I read online the Red Swamp Crayfish lives for maybe five years and Signal Crayfish will live for twenty. So if you know about any of these things that would be helpful.

  • Jamyelese Ryer July 9, 2013, 9:16 AM

    My son Dakota loves to find crayfish, pick them up and put them back. We have usually found the Signal Crayfish. Yesterday at Crystal Springs Creek he met a boy who wanted to take four of the crayfish home. We wouldn’t do this, and have wondered about the fate of these four critters. It looks like they can live well in an aquarium, but would otherwise be better off in the stream. We just want your advice for kids who feel the need to take the signal crayfish home.

    • Ivan Phillipsen July 22, 2013, 7:00 PM

      Hi, Jamyelese. Thanks for the question.

      When I was a kid, I wanted to take just about every critter I found home with me. My childhood was enriched by my experiences with wild-caught pets. But, sadly, they would often die after awhile, despite my best efforts to keep them happy (I read a lot of books on how to keep reptiles, amphibians, fish, etc).

      There are numerous problems with taking animals from the wild to be pets. It sounds like you understand that. I would tell kids that want to take animals home that wild animals belong in the wild because that is their home. That’s where they will be the happiest and healthiest. And if every kid took home a crayfish (or whatever), there wouldn’t be any more wild crayfish.

      To satisfy a child’s curiosity, some animals could be captured and observed briefly (e.g. 5-10 minutes), then released where they were found.

  • Art Gray October 16, 2013, 7:22 PM

    Last week, I found a live, what looked like a crawfish on the beach North of Florence, OR. The critter was alive and some distance from a fresh water stream that entered the ocean, North of the location. It was about 6″ to 7″ long and the color was almost black. It reminded me of a young lobster in Maine. What the heck was it?

    Thanks,
    Art Gray

    • Ivan Phillipsen October 31, 2013, 6:12 PM

      That’s pretty interesting, Art. Without getting a good look at your mystery crustacean, I wouldn’t be able to tell you what it was.

      • Art Gray October 31, 2013, 7:12 PM

        Ivan, my wife took a picture of this critter, on her I-phone. Maybe she can send you this picture. All I know, as a novice, is that it sure did not look like a crawfish. Do you have an e-mail address that can be used for the pictures. Don’t have a scale, but it was about 6″ to 7″ in length.

        Art Gray

  • Ryan March 31, 2014, 2:54 AM

    Hello! I am actually quite familiar with crawdads from gathering them down in oregon! I love in puyallup,Washington now and have no idea where to go. Should any clean stream or lake/pond have them? Any idea where they would be around the puyallup area? Thanks!

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