What if the creatures in the lake near you aren’t really supposed to be there? From Hakai Magazine, this is Amorina Kingdon’s article on invasive crayfish in Washington state: Pinch Me.

In Pine Lake, as in many waterways across the Pacific Northwest, native signal crayfish and invasive red swamp crayfish are duking it out, and the red swamps seem to be winning. (To be called “invasive” and not just non-native, a species has to cause ecological damage.) Kuehne and Chunlong are working with University of Washington freshwater ecologist Julian Olden, who has been holding the line at Pine Lake for six years. Along with the study I’m observing today, he’s distributed crayfish traps to the lake’s residents, asking them to release native signal crayfish and “dispose” of any red swamps they catch, trying to see if citizen science can beat back an invasive species and help the signals recover. That’s why Kuehne, Chunlong, and I are disappointed to see the red swamp.

But should we be? Around the world, humans have introduced different species of crayfish into each other’s territories, where they sometimes thrive, sometimes barely survive, and sometimes wipe out the native populations. A species such as the signal crayfish might be the underdog here, but a hostile invader in European waterways. When it comes to crayfish, choosing sides is never simple. Should humans try to correct the damage—or should we leave well enough alone? [continue]