American signal crayfish

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I promised to write about this topic ages ago and then didn’t because I couldn’t find the photo I was sure I had to go with it. I think something @DianneN wrote about prompted me to say I would write this. Still can't find the photo but here's the river! The American signal crayfish is an invasive species in Britain, that was brought in for aquaculture in the 1970s and 80s and predictably escaped. It has now become widespread, colonising rivers all over the UK. It causes problems for three reasons: by outcompeting the smaller native white-clawed crayfish, because it is larger and has a less specific diet; by transmitting the disease crayfish plague, and by creating large burrows in river banks causing them to collapse. One solution to this issue would be to encourage the public to catch them, which some people have been doing, but this is not as straightforward as you might think. Catching them is apparently quite easy in places where they are common, but legally you are not supposed to just chuck a trap in the river anywhere you like, you have to get the right kind of permit from the correct authority, and it isn’t allowed within a certain distance of bridges and the like. All very bureaucratic when you just want to try your luck with an old bicycle wheel and a few bread crusts. And then there is the issue of preparing them. Although British people often go on holiday to countries like France and Spain and come home raving about the delicious seafood (a large proportion of which is exported from Scotland, ironically) they are not so keen on actually preparing and cooking it themselves. One day I happened to be out for an early walk beside the river. And there I saw a narrow-boat (traditional canal boat) with lots of lobster pots stacked up on the roof, and a man in a Canadian-style canoe paddling about. Being nosey I asked what he was doing, and he explained he was catching crayfish. Obviously he wouldn’t be willing to give away his catch, so I asked if there was anywhere I could buy some, but he told me there was not. Apparently one fancy hotel used to take some of the crayfish but they had stopped because it just wasn’t worth all the work necessary to prepare them. Instead the crayfish they caught would be put on an early train to the coast where they would be loaded onto a ship for export. By lunchtime they would be on one of those enormous container ships owned by the worldwide shipping company Maersk and on their way to be enjoyed for dinner somewhere else in the world! Who would have thought that our little river would be the source of someone’s fancy meal? Still it seems like a good way to get rid of them. The snag of course is that the more that are caught, the more difficult it becomes to catch the last ones and thus non-economic meaning that the fishers will go elsewhere and the population will rebound. Hopefully it might help to keep them more under control though. I will have to go for another early morning walk one day and see if anyone is fishing for them these days. All rights reserved. © Text copyright Fleur 2026.