Alien Crayfish

[FourwingsJNR]

In my local brook we have these crayfish from america which were in a research centre that got forgot about and got in the water and you can now find them from one end to the other. Thay are about 3 times the size of Native Crayfish, red and have massive claws and the have ate all the Native crayfish in our brook. has anybody seen these before?

[Chiltern Chris]

Hi,

The crayfish you've seen are called signal crayfish. They carry the crayfish plague which is killing the majority of our native white-clawed crayfish. They are now endemic across the whole of the southern Britain and can be found in most areas with neutral or alkaline water. Most have escaped from ponds which were stocked with them in the 1970's for commercial purposes but they weren't financially viable and so must crayfish 'farms' closed. As crayfish introductions were deregulated by the government during the 1990's it means that there are no proper records of where the main ponds holding these crayfish are. As they can easily walk across considerable distance overland, once a pond reaches its carrying capacity the crayfish just march off to the local river and off they go into the wild. It means that our native crayfish will now be limited to a few 'fortress' locations where we either stop the signals from getting to or where the conditions are not suitable for them - an analogy would be the spread of grey squirrels and the demise of our native reds.

The latest research seems to indicate that it is nearly impossible to get rid of signals once they become established and removing adults by trapping just leaves the juveniles to run rampage as it's the adults cannibalising the juveniles that is the main limiting factor on even faster expansion.

There are a number of other alien crayfish about including, Turkish and spiny cheeked which don't seem to be as much of a problem yet.

This is a good example of why when dealing with ecological matters more deregulation must not be allowed to be championed by the government.

Cheers, Chris

[FourwingsJNR]

Cheers Chris thats really interresting

[nightshade]

Seeing as how you are interested
crayfish