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The Crayfish of Nebraska

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24 starting to go bad. They want it to be fresh. Also, in contrast to fishes, if the food runs out, crayfish will find the entrance and leave. So you have to check your traps often and there has to be enough bait to keep them interested. The collection of burrowing crayfishes is another matter altogether. Burrowing crayfishes live most of their lives in burrows where nets and traps don't work. First, you have to find the burrows and then you have to figure out how to get them out. Not all burrows are occupied but the presence of fresh mud is a sure sign that they are. There are some techniques that can be tried. In the spring, the females will go to a nearby pool or waterbody to release her young and you might be able to catch them then. The young live and grow in the waterbody for several weeks before they dig their own burrow. You might be able to collect these in late summer. While they spend most of the time in their burrow, they have to come out sometime to feed and mate. Rainy or humid evenings in the spring is the best time to catch them out of their burrows and can be caught by hand or a small net. If they are in the burrow, you can dig them out. But they may be very deep (up to six feet) and this is hard work. I did it once and never again. The final technique is a lot easier than completely digging out the burrow. After you find a burrow, you dig a depression about the size of a large mixing bowl. Pour water into the burrow until there is a small pool in the bottom of the depression. Reach your hand in and agitate the water vigorously. Then sit back and wait. About half the time, if there is a crayfish living in the burrow, it will come up and see what all the commotion was about. You have to watch carefully because you probably will only see the antennae break the surface of the water. If you are quick, you can stab your hand down and pin the crayfish to the side of the burrow. But be warned, they are very wary and very quick to escape back down the burrow. You can find YouTube videos that show how to do this. There is also a burrowing crayfish trap that you can make and I have used with some success. It is a short length of PVC tubing with a trap door built in. 172 I will first try the agitation technique and, if that fails, I screw one of these traps into the burrow entrance and come back the next day. Some of the time this succeeds in capturing a crayfish. It may be necessary to preserve specimens for accurate identification. For this you will need jars and preservative. Either 8 oz or 16 oz glass jars are adequate for most of your needs and these can be either jars purchased from biological suppliers. On the other hand, the plastic peanut butter jars will work just fine and they can be had for little cost. The usual preservatives used by biologists are 10% formalin and 70% ethanol. Formalin is nasty stuff, hard to get and a known carcinogen. Leave this stuff for professional biologists. 70% ethanol is 200 proof ethyl alcohol diluted with water to 70% (7 parts alcohol and 3 parts water). Full strength ethyl alcohol is expensive and hard to get. The easiest preservative to get is rubbing (isopropyl) alcohol which can be purchased at any drug store. It should also be diluted to 70% for use. When I preserve crayfish I prefer to euthanize them first. I put the crayfish in a jar almost full of water, then add a small amount of alcohol. After 20 minutes or so, they are knocked out and can then be preserved. One final and very important point. If you are collecting and preserving specimens, you

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