24 Signal Crayfish have been captured on the RiverTill to date. 

Since an angler captured a Signal Crayfish in his landing net in September, the Tweed Foundation  has been busy trapping on the Till to discover how far upstream and downstream they have colonised.  In the last month, Shaun Robertson, our temporary assistant, has captured 24 Signal Crayfish using the standard method of setting baited traps which the crayfish crawl into but find it difficult to escape from.  Water temperatures are starting to drop now, which reduces their activity and the more frequent Winter spates don’t help matters. 

Different sizes of Signal Crayfish have been caught, which suggests that the population is well established and they also appear to be spread over a number of kilometres of river, so they have probably been in the Till for at least 10 years now.   The biggest frustration is that it may well be too late to get rid of them since there is no established means of eliminating them once established.  Trapping just captures the larger specimens, which are typically the main predator of smaller individuals (just like Pike).  Remove the main predator and you end up with lots of smaller ones! JH

See the attached photo of one of the Signal Crayfish captured from the River Till