The Phantom Menace - Signal Crayfish
I had a rather sobering experience on Sunday that made me sit up and think about what's happening to the local river - the Wharfe.
This season has been tough - but more worrying the hatches have been less - and the usual 'stone turning' have shown very few nymphs clinging to stones. Unlike previous years where there have been dozens. Now - is this due to the weather? - I don't think so - we have always had hot summers - this has been a bit exceptional but nothing to write home about. But . . .
On Sunday evening I was having a chat to another angler - who told me about the numbers of Signal Crayfish in the river - now I knew that there were some (I have even cuaght them on a nymph) -but when he explained that he had caught some via other means I didn't believe him. - So he demonstrated. - After 1 hour the 'other means' contained some 30-40 signal crayfish - and big ones at that.
I'm not gettiing into a debate about whether he should have put a net out - but that number of Signals in the river can only be a problem. The signals are a big problem in that they eat fish eggs, nymph larvae and undercut the banks with their burrowing. - Also their constant digging causes cloudy water etc. This cannot be good.
Does this explain the lack of nymph life and the poor hatches?
It's certainly food for thought.
What can be done about this widespread problem? - I believe that the Signal is not only having a detrimental effect to the native species - but is also ruining the fishing!
It's also the case that we are getting bigger river trout - over 6lbs in places - but is it worth it? - And what will the impact be on the Grayling - which are not stocked!
This season has been tough - but more worrying the hatches have been less - and the usual 'stone turning' have shown very few nymphs clinging to stones. Unlike previous years where there have been dozens. Now - is this due to the weather? - I don't think so - we have always had hot summers - this has been a bit exceptional but nothing to write home about. But . . .
On Sunday evening I was having a chat to another angler - who told me about the numbers of Signal Crayfish in the river - now I knew that there were some (I have even cuaght them on a nymph) -but when he explained that he had caught some via other means I didn't believe him. - So he demonstrated. - After 1 hour the 'other means' contained some 30-40 signal crayfish - and big ones at that.
I'm not gettiing into a debate about whether he should have put a net out - but that number of Signals in the river can only be a problem. The signals are a big problem in that they eat fish eggs, nymph larvae and undercut the banks with their burrowing. - Also their constant digging causes cloudy water etc. This cannot be good.
Does this explain the lack of nymph life and the poor hatches?
It's certainly food for thought.
What can be done about this widespread problem? - I believe that the Signal is not only having a detrimental effect to the native species - but is also ruining the fishing!
It's also the case that we are getting bigger river trout - over 6lbs in places - but is it worth it? - And what will the impact be on the Grayling - which are not stocked!
posted by Crabacle at 8:55 AM
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