Pond Boss Forums INTRO Questions & Observations Crayfish Used For Weed Eradication?

A while back there was a discussion about crayfish (crawdads) and there were three posts as I remember about crayfish stripping their pond of vegetation. So my thought’s are why couldn't crayfish be used in place of grass carp to keep down pond weeds? My pond would be the perfect test pond to try this since I don’t have predators that would eat the crayfish but only minnows and six or seven grass carp that aren't keeping up with my vegetation growth. My only problem is getting the crayfish. I set traps in two rivers at three different times of the year and didn't get one crawdad. These rivers contained lots of crawdads when I was young. I suspect farm runoff might be the problem. However I will try seining for them this year and see what happens.

John, I am trying to get crawfish to establish in my pond with only FA and some Rye grain cereal that is now underwater. I just hope to get some to take hold for my RES and later for my LMB. If they take out some of the FA I will be even happier. And like you, I have not been able to trap any. But I am using a fine mesh net on a 6' handle (pole) and dragging the bottom of water holes. I will catch 1 to 50 on each swipe of the net. I find more if I drag it through any green vegetation in the water but keeping contact with the bottom. There u go, finding them in the green vegetation, So they might be keeping it under control in Nature. I have no idea what type or species these native craws are. I hope to get a picture and post it here for Bill Cody, and hope he has a name for them.
Tracy

Just because a pond has crayfish does not mean the weeds will be controlled or eradicated (see below). Many of the crayfish species will consume vegetation. The diet for the range of crayfish species has a lot of variation.
TGW1 - I will probably need to see adults for specie verification, unless you have a unique easy to recognize type of crayfish. Often specie verification requires males, more specifically first form males. IMO for good weed control by crayfish, the pond should not have larger predators who eat numerous adults nor should it have lots of smaller fish that will prey heavily on the newly hatched and youngster crayfish. For instance, a pond with abundant GSF will effectively control crayfish numbers.

For optimum crayfish weed control, lots of young crayfish need to survive to create a type of over population of crayfish - lots of consumers. The best species of crayfish for weed control IMO are the pond dwelling type of crayfish who do not have a strong tendency for migrating out of the pond i.e. primarily pond dwellers. IMO primarily the stream dwelling crayfish species would not be the best candidates for weed control in ponds. Note that some pond adapted crayfish also live in streams.

This whole species selection concept is very similar to fish selection for pond stocking. There are numerous minnow-shiner species that live in streams. A select few can thrive in the habitat of stream and/or pond; for example FHM or spotfin shiner. However most stream dwelling shiners will reproduce only in stream conditions.

I have a large population of Golden shiners and Fathead's so establishing crayfish may be hard. However if I find seining is productive perhaps I can keep stocking the pond all summer with crayfish.

Here in E. central Indiana we are just now entering the 50 degree weather so would I be likely to seine and catch crayfish now in the cold water?

You shouldn't have a hard time getting the crayfish to thrive in a pond with just shiners and FHM especially since you have ample weed cover as protection for the newly hatched crayfish. Developing a quick high number of crayfish this year will need to have them stocked before the eggs hatch this spring. Eggs of papershell crayfish are laid fairly early and are hatched in our region by I think mid May maybe early May. Check a PM.

John, since I seined mine from some backwater, I did not check the water temp there. but we had just had our first snowfall, and sleet storm when I got them. So I would think 50 degree water would be ok. The water temp in my pond at the time was 48. I do know you will not get any setting at the house
Good luck
Tracy

Bill and TG we are in a snow melt and rain right now but as soon as the streams subside I will start seining.

Hoping our crayfish can help with the weeds and also be an additional food source for the trout. Hoping you might be able to tell me what kind they are from these pics.

Sorry for the hijack!

Pictures are way too out of focus to be much help with identification.

I figured they might be. I'll get some better ones next time. Thanks!