Pine Lake Invasive Crayfish Removal

Cumulative_RSRemoved_12312016Washington State is host to several aquatic invasive species, which pose significant threats to local ecosystems. Of significant concern is the recently introduced red swamp crayfish, (Procambarus clarkii). The substantial ecological effects of red swamp crayfish and possible financial costs to recreational fisheries necessitates rapid management efforts. Though likely established in only 10 lakes in western Washington, without control efforts these lakes may over time become local source populations for future spread. Lakes in Washington are ideal places to attempt removal and eradication of invasive crayfish, but the potential for volunteer-based removals is a largely unexplored. In the last two years we provided equipment and trained resident volunteers to trap, identify, and remove red swamp crayfish in Pine Lake; the site of its first discovery in 2000. This represented the first ever whole-lake volunteer-based removal effort for invasive crayfish. Volunteers in nearly 80 households have participated between 2013-2016 , amounting to over 175,000 reported trapping hours and removal of more than 8,600 red swamp crayfish from the lake! Moreover, this volunteer effort has enhanced environmental literacy about Washington’s freshwater ecosystems and highlighted the innovative efforts of Pine Lake residents through local and regional media. The project has been featured in the Sammamish Review, Issaquah Reporter, The Seattle Times, College of the Environment News, and by National Public Radio. We are continuing trapping efforts for red swamp crayfish in 2016 as well as lake-wide sampling to determine if removal of red swamp crayfish can help increase populations of native crayfishes and fishes. You can learn more about our progress in our 2013 and 2014 letters to Pine Lake residents, as well as a community study on invasive species awareness completed in 2016. Please check back for ongoing project updates!

FOR VOLUNTEERS Link to enter data Link to print more datasheets Link to (color) Volunteer Field Identification Guide  (also see bottom of page for Frequently Asked Questions) Link to instructions on Measuring Crayfish Carapace Length using calipers


Powerpoint presentation from March 10th workshop at Pine Lake Community Center

Oregon PBS story on invasive crayfish in the Pacific Northwest


1.      What can I do to make this control effort successful? Simple, make sure you are trapping regularly, record all the data accurately, and have don’t be discouraged if you don’t catch many crayfish. The success of this effort depends on having those traps in the water as much as possible. I suggest that you establish a routine of trapping. For example, at a minimum it would be great if you could trap 1 or both nights over the weekend. If you have the time, then add an additional night of trapping during the week (set a day). Finally, if you are really ambitious then trap continuously by retrieving traps and the re-setting every 2 days. Most importantly, have fun! Don’t worry if you don’t catch any crayfish. Crayfish are not always active, and therefore they do not always enter the traps. Crayfish activity increases with water temperature, so you are likely to catch more and more with time. You can also trap from a different location on your dock or shoreline (or using a boat if you have one). Just keep trying.

2.      Can I recruit a new volunteer? Definitely yes! I kindly request that the volunteer is a lakeshore resident of Pine Lake and that you ask them to contact me for additional information and to obtain the necessary materials. I am required to have all the names of the volunteers.

3.      What should I do with the crayfish that I capture? First, separate native signal crayfish and invasive red swamp crayfish (you can use each half of the trap as a holding area). Second, measure and sex each signal (native) crayfish and release back to the lake. Third, measure and sex all red swamp crayfish and deposit into a Ziploc bag. Then you can either freeze the red swamp crayfish and place directly into garbage (we previously announced that we would be collecting the crayfish, but this is not necessary) OR cook and use in your favorite Cajun recipe.

4.      How do I measure crayfish again? Please see the instructions by clicking here.

5.      What is the deepest that I should set traps? Less than ten feet is recommended, but you could try up to 15 feet – just keep track on your datasheet.

6.      I have a juvenile crayfish, but am having trouble identifying it? Juvenile signal crayfish look just like the adults, with the same smooth surface/shell, brown in color, and without spotting. Juvenile red swamp crayfish are not red like the adults but brown, but will have spotting (flecks) on their carapace. Juvenile red swamp crayfish will also have the same ‘V’ pattern on the top of their carapace. If you are really in doubt about a juvenile, don’t remove it.

7.      What should I do with the data that I collect? After ending your information, please file the datasheet in a safe location. We request that you either mail your datasheets to Julian (Julian Olden, School of Fisheries, Box 355020, Univ. Washington, Seattle, WA 98105) or scan and email them to Please do this at the end of each month starting in May until November. We would be VERY appreciative if you also enter your data using the on-line form at: By doing this I can routinely provide updates on the total number of crayfish removed and volunteer leaders (!). If you enter data online, still keep your datasheets for collection at the end of the summer.

8.      Can I use bait other than dry dog food? Yes, you can use other types of bait (i.e., dry cat food, chicken, old fish, etc …). However, wet dog or cat food is not recommended because it will dissolve quickly in the water.

9.      I ran out of bait, how do I get more? Please purchase a bag of dry dog food and keep your receipt if you would like to be reimbursed.

10.   Can I use my own traps and set more than 2 traps? Yes. Please enter this data the exactly the same way on the datasheets (just use additional datasheets) and on-line.

11.    Can I catch crayfish by hand or using a net? Yes, put please make note of this on your dataset by writing “Caught by hand” at the top of the dataset.

12.   Can I get more datasheets? Yes, please click here to print more sheets.

13.   What should I do with my traps at the end? We will be collecting all the traps and floats on a specific date at the end of the summer. We will likely ask everyone to put the traps on the end of your dock for pick-up. For folks interested in participating next year (we sure hope so!), we will re-distribute traps.