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Signal Crayfish

by jimirst published on


I'm a student going into 3rd year and have started preparing for my dissertation.  My current title is "Why Have Attempts to Control Signal Crayfish in the UK Failed?"

I am looking to conduct interviews with various stakeholders regarding the current situation, assessing the reasons for the failure of all methods of control.  I will also look into possible solutions to the problem, linking my research topic with Hugh's fish fight.  

There is a market in the UK for crayfish, simply look at restaurant menus across the country, as well as the sale of crayfish in supermarkets, for example M&S, and companies such as Pret a Mange. As an alternative 'fish' product, I believe there is potential to create a UK market, and create a cost-effective method of depleting Signal crayfish numbers nationally.  I realise crayfish plague is a huge concern for the native crayfish population, and taking larger Signal specimens from UK waters allows the smaller Signal population to boost.  However, if appropriate education was put in place to distinguish between species and how to deal with caught crayfish and contain plague spores, and if enough demand (which is there), enough funding and community support was given, this national biodiversity threat could be seriously diminished.  

I aim to get an interview with Hugh as I feel it would benefit my project hugely, however I am finding it very difficult to contact him as the 'contact us' page has no option for this type of enquiry.  I hope someone sees this, Hugh in particular! If anyone has any comments or questions regarding my project, I would appreciate it.



2 replies
Replied on

Hi Jimirst,<BR><BR>You need a licence to set traps for Signal crayfish and can do so only in certain parts of the country ie those areas where native crayfish are extinct. If you apply for an Environment Agency licence you also get a map showing you where you can set your traps. I'd recommend you apply for one so you can read the paperwork.<BR><BR>Although it's true that removing large adult Signal crayfish can boost the number of juveniles recent research indicates that these populations are less likely to spread, see:<BR>'The effect of manual removal on movement distances in populations of signal crayfish' by TOM P. MOORHOUSE, DAVID W. MACDONALD 2011<BR><BR><A onclick="javascript: = '_blank'" href=""; target=_blank><;/A><BR><BR>Small Signal crayfish also do less damage to river banks through burrowing and are predated more heavily by fish (eels in particular). <BR><BR>There are concerns within the EA about the trapping of Signals, the chief one being that people will attempt to introduce them to their local waters in order to create a fishery.<BR><BR>It seems inevitable that Signals will spread through our river systems and isolated 'ark sites' are being found for native crayfish in an attempt to preserve them.<BR><BR>It would seem sensible to harvest local Signals since most crayfish eaten in the UK is imported from the Far East.<BR><BR>Hope this helps.<BR><BR>

Replied on

Hello jimirst
I am no expert on signal crayfish,but as an angler I have some experience that you may find interesting.
A couple of seasons ago (2009) I fished the River Lea at Fishers Green & it is full of signal crayfish,so much so that it was almost impossible to fish with any type of soft bait as you would just catch them.
I would throw them in a bucket and take them home to eat-lovely when flash fried with olive oil & garlic.
My understanding is that the law regarding catching them is bizzare.
I believe it is illegal to intentionaly catch them but also illegal to release them if you do catch them.
Trapping them requires a licence,which I do not think are issued freely.
At no time did I see anybody from the EA attempting to catch them,which is strange as they are considered to have an adverse effect on fish stocks,which the EA are supposed to protect.
As far as identification is concerned,I'm sure you're aware that the signal crayfish is easily distinguished from the native variety,not only because of it's red claws,but because the natives are essentialy nocturnal ,whereas the signals are active at all times.
Hope this is of some help.

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