Here is my tuppence worth ;
To my mind there is no doubt they are already breeding in UK rivers & as was already mentioned they are well established in rivers in Northern France & I don’t see great deal of difference between the habitat there and in southern England. The only surprise for me is that they are not already more established than they are. Perhaps the UK has been right on the cusp and threshold for them, just a little too far north for them to get a proper grip but what with global warming it may provide the extra little increase in temperatures to make the difference. For that reason, I do believe we will continue to see an increase in their numbers in the UK.
Despite my efforts to avoid them I catch, quite a few each year as a number of my venues hold good stocks of them. I am not a fan but my opinion of them has changed. Somewhat over time.
Based on nothing scientific, just what I see with my own eyes I now think Catfish like anything else once in a water will find a balance. They will not destroy a water as people think but it will change the ecology of it. What I have seen, & this is across a number of venues, is that some species thrive alongside them while others suffer. To my mind two species that suffer allot are first Bream which are the ideal Catfish meal and the other is Pike which I assume occupy too close a niche in the food chain and just cannot compete
Contrary to what people may think Roach I do not think get affected anything like as much as people might believe and in fact, due to the Cats decimating the Bream stocks I think the Roach can actually thrive. It is worth pointing out that the Roach catches I have been posting of late have come from two venues & both with Catfish in them. The Ebro is another example of a water throwing up some unbelievable catches of Roach but with a huge head of Cats too. Chub as well do not seem to be greatly impacted and my very amateur guess at why is simply that fish like Bream being slower and less maneuverable are a far easier target for Cats than the more mobile Chub and Roach. If you think about it, why would a Catfish go chasing after a say 3 nimble pound Roach or Chub when it can nobble one 3lb Bream allot more easily….
Another fish that also seems to be able to live alongside them are Zander. I have never really understood this but I see and catch enough to know that they do not seem to have any problems living in the same water.
Although I do not like them, the Cats themselves can be impressive fish. They are very powerful but I find their fight dour and dogged. The nearest fish I can liken them to in terms of how they fight is an Eel…that sort of deep thump thump. However if anything I find them easier to land than say a Carp of the same size. Netting them can be interesting as they as adept at swimming backward as forwards so pull the head right to the spreader block before you lift.
The other bit of kit that is handy is a rubber net. You will be hard pressed to find something more slimy and smelly and the stink will linger on fabric nets for weeks after.
