We had our last MAPS session at Rock Ridge this morning. It was quite productive, our second-busiest morning there, with quite a number of dispersing young birds. Dan will likely write more about the birds in the next few days.
On our way out, as we were preparing to launch the canoe and paddle back to the car, I noticed a couple of small crayfish in the water just along the shore. They were only about two inches (5 cm) long or so, fairly small by crayfish standards, but were intriguingly washed with blue, and had red rings around their elbows.
I wanted to get a photo up close, but, perhaps due to my double-X genes, was reluctant to stick my hand near those pincers, despite Dan’s attempts at reassurance that even if they did pinch they were too weak to hurt. Dan tried crawling to the front of the canoe to catch one for me, but without any luck. They crayfish continued to sit in the leafy debris at the edge of the shore, so I plucked up the courage to try again; I was able to grab it with a quick snatch at the mud. However, startled that I’d actually succeeded, I reflexively tossed the handful of mud toward the open floor of the canoe – which was also where Dan was sitting. Fortunately, he and the crayfish were both fine.
Upon coming home and browsing the net, I discovered the website CrayfishOntario.ca, which seems to be a site/project set up with the goal of helping increase awareness of Ontario crayfish. It’s a joint project between the Toronto Zoo, Ontario Nature, and Bishops Mills Natural History Centre. There are 10 species of crayfish listed on their brochure, of which all but two are native. However, like so many non-native and invasive species, the two exceptions are causing some problems among native populations. Habitat loss and pollution are also contributing to the decline of some of our native species. However, even in areas where neither of these appear to be a factor, crayfish have disappeared from some lakes. The cause is unknown – disease? competition? pH changes? – and their brochure simply lumps these disappearances under “other mysterious causes”.
After studying their guide, I think this is a Northern Clearwater Crayfish, Orconectes propinquus. They indicate that one of the distinguishing characteristics of this species is the orange tips to the claws, which this one shows. It’s a native species, found through most of northeastern North America. It seems to be a bit of a generalist in the habitats it uses.
I wrote about crayfish last spring; for more on their general ecology and natural history, you can check out the original post.