Monday, July 28, 2008

Crayfish

Jody and her partner collecting crayfish near our dock.

One of our visitors during our stay on the island this summer was Jody Peters, a doctoral candidate at the University of Notre Dame who is researching crayfish. Specifically, her research focuses on "species coexistence and invasion" in northern lakes. In the Great Lakes region, the native crayfish species, northern crayfish (orconectes virilis), has faced increasing competition from an invasive species, the rusty crayfish (orconectes rusticus), which was introduced into our waters as escaped bait. In some places, as in the waters around our island, the two species are able to coexist. In other places, the rusty is driving out the native crayfish. Rusty crayfish (pictured at right), native to the Ohio River basin, were first found in Minnesota lakes and rivers in 1967. In addition to competing with the native species, they are responsible for a decrease in aquatic plants in many lakes, and may contribute to a decrease in fish populations by overfeeding on fish eggs. In the area around our dock, crayfish (both rusty and northern) provide food for minks, who leave the discarded exoskeletons inside our boat.

4 comments:

Jim H. said...

Escaped bait. Could that not in some wise describe us all?

Bleeet said...

Have you ever put a crayfish in your nose?

Try it some time.

The northern and rusty varieties can easily live side-by-side, one nasal condo to each.

Christopher Tassava said...

That last photo gives me a bad case of the heebie-jeebies, and Bleeet's comment doesn't help. When I was a kid at the other end of the U.P., we'd catch tiny little "crawfish" in the creek - they were shorter than my 12-year-old fingers. That, that, that LOBSTER in someone's hand makes me want to run in terror. Or get some boiling water and butter.

Jim H. said...

Mmmmm...jambalaya.

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