Question: what are you going to do to make sure that a population of crayfish do not escape?

Zara Gladman answered on 13 Jun 2011:

Hello! That is a really important question in crayfish science at the moment! Once crayfish get into a lake or river, it’s VERY difficult to get rid of them… so preventing new populations from reaching freshwater is essential.

Crayfish are very good at escaping… they can easily climb out of tanks (I have to be very careful and make sure tanks are covered when I’m working on them at uni!) and can walk on land too. They can squeeze through the mesh of traps as well, if the holes are big enough. They’re the ‘Houdini’s of the animal world!

In Scotland, there’s a big project going on at the moment to try and stop crayfish escaping from the River Clyde (which has a massive crayfish population) into the River Annan (which has no crayfish). The RIver Clyde and the RIver Annan are two separate rivers, but after heavy rain, there is sometimes flooding which joins them – this is dangerous because it might increase the chance of crayfish crossing into the Annan. To try and stop this happening, workmen are building a big “crayfish barrier” out of concrete… they’re still building it now, I have some photos on my phone which I can upload for you if you like! Hopefully the barrier will keep the River Annan crayfish-free.

Other than putting in physical barriers, educating people on the dangers of introducing crayfish is very important. Crayfish escape and spread themselves to new places naturally but very often they are moved because of the actions of humans. People don’t understand how dangerous crayfish are for native plants and animals – if we can educate the public on these dangers, then hopefully we can slow down the spread of invasive crayfish!

Hope that answers your question 🙂