What is the rusty crayfish origin?

Hi! That's a great question, and a lot depends on what it is that you're concerned is being affected. Rusty is a high-metabolism crayfish that hunts during the day (many if not most other crayfish species are nocturnal) and has a fairly "aggressive" nature. In a new territory, there is concern over the rusty's ability to defend against predators (the thinking is that the predators will incrase their eating of the natives instead of tussle with the rusty), the rusty's ability to eat during the day while nocturnal species are in hiding, hence possibly reducing the resources available for the native nocturnal species. Also, the rusty females can hang onto fertilized eggs until conditions are optimal, so she can be transported quite a distance on her own, settle into a new area and start a whole new population from scratch. Now, I don't know yet if other species do this, as well, so it might not be an exclusive trait to rusty.

Interestingly, rusty can also mate with native species, creating hybirds. My question is whether this will eventually be a "good" thing, making a new species that is hardier than the natives were. Since crayfish are scavengers, it's entirely possible that rusty and the hybrids (sounds like a rock band!) will do more to clean up polluted lakes and rivers as they eat algae, aquatic plants (some of which are highly invasive), dead creatures and other detritus. I'm not saying rusty isn't causing problems or hasn't got the potential to cause problems; I'm saying we ought to pay close attention and not allow ourselves too much of a knee-jerk reaction.

Kelly, Director of Black River Action Team

blackrivercleanup@Yahoo.com