Mission: Crayfish

Regular readers of this blog know that my research usually involves plants and/or water: what plant species grow where, and how they grow, and about the relationship between plants and the hydrology of wetlands. Although that work will likely continue, I’ve been pulled in another direction of late…as if claws have grabbed me, and won’t let go.

It’s crayfish.

It began in my ecology classes: catching crayfish as a matter of course, trying to sample populations and differentiate habitats and so forth. Just another species to find and put on the data form.

But these animals are lively, and a little scary, and sometimes quite colorful. In other words, they are charismatic. I was baffled by their seemingly random appearance—many many sites appear to have none, but at some sites you can find them in droves. That makes them ecologically interesting.

So I tried to read up on our crayfish, especially their biogeography and conservation…I recommend a recent publication from the Illinois Natural History Survey, Field Guide to Crayfishes of the Midwest by Taylor, Schuster and Wylie. The book has terrific photos and range maps, an identification key, and a solid introduction to the biology of these animals.

Interestingly, the book lists seven publications that review the crayfish of the eight States included in the region. Guess which State is missing….? Yup: Iowa. In fact, that last review of Iowa crayfish is from…1981. “But Paul,” you say. “Aren’t we overdue for a crayfish survey in Iowa? Shouldn’t ‘Somebody’ do one?”

I’m not sure yet where I’m going with this, something not all that unusual in science! I’m reading publications and corresponding with other researchers. I do have a State collecting permit and a little experience now. Hopefully my 99wetlands travels will also give me some ideas on how to do this work??

My initial research goals are basic: determine which species are found in Iowa today, and how to study them effectively. Later, I may be able to estimate population size and structure, or particulars of their lifecycle, or how they use habitats.

Crayish sampling using wire-mesh “torpedo” trap, similar to the trap used to catch minnows

Eventually, I may understand these animals well enough to let them tell me about the condition of our wetlands, ponds, streams and lakes. I imagine that their unique biology makes them a useful indicator of conditins and functions of our aquatic and semiaquatic systems. After all, they are really large aquatic Arthropods, are voracious omnivores while themselves being important prey items, and although generally aquatic are in some cases terrestrial (primarily subterranean, living in burrows).

They are also really tricky to study—hard to catch, only reliably identified as males and at certain portions of life cycle, and mainly nocturnal. So, dear Reader, I make no promises…but I promise to eventually share what I learn.

Any ideas or suggestions? Leave a comment! Thanks for reading.