From a purely selfish and personal point of view, I'd hate to see carp become widely established in Ireland. I can catch plenty of carp at home (and if I wanted a days travel and a ferry journey I'd go to France to catch them[

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If carp were to become established in one of the big river systems (ie the Erne or the Shannon) they will be able to spread throughout the country. I am sure that this will be to the detriment of the native species. Carp are more aggressive feeders than either bream or tench and will almost certainly prosper at the other fishes expense.
Look at the way the roach have spread to almost every body of water in the country and at the same time the rudd has declined to be almost extinct from some waters. If you get a single rudd in a day's fishing on many of the lakes I fish in the Cavan / Monaghan area you've had a 'good' day.
On the other hand I can see how Irish anglers would love the chance to catch decent sized carp (probably barbel and chub too, which I'm sure would prosper in the food-rich Irish rivers)They would have to be introduced to enclosed waters only to prevent them spreading throughout the country (although carp in England do seem to have this amazing habit of walking 100 miles in a single night to reappear somewhere else[V]) and more than likely that would mean paying for a day's fishing.
The big problem is likely to be the low numbers of Irish coarse anglers. For a commercial venture to work it has to get plenty of people fishing there, personally I don't think the visiting angler will bother and there are not likely to be enough 'locals' to keep it going. I can't see the fisheries boards carrying out widespread stocking of non-native fish due to the possible ecological damage.
I (and I would think plenty of other anglers) go to Ireland to fish for 'wild' fish in wild surroundings, catching numbers and weights of fish that can't be done in England (not from natural fisheries anyway)
If a few forty and fifty pound carp start to appear from lakes in Ireland, it won't be long before the 'catch at all cost' bivvy brigade move in, spending days at a time by the water (and probably preventing the locals from getting a look-in).
I've no doubt that the carp WILL become more widespread across the country - I just hope it happens very slowly [

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Tight Lines
Simon