‘Plague’ of invasive fish ruining rivers

This huge haul of Rainbow Trout were caught at Newtownstewart at the weekend.

THE hundreds of Rainbow Trout which were pulled from the River Mourne on the opening day of the new fishing season (April 1) are being seen as perfect evidence of the new “plague” facing local waterways.

At a time when anglers were preparing to celebrate all that is good about fishing at the North West Angling Fair this weekend, a member of Strabane and Lifford Anglers has even suggested that one of Europe’s finest Salmon rivers could have been ruined irreparably by last summer’s leak from a fish farm near Newtownstewart.


Back in August hundreds of thousands of Rainbow Trout entered the waterways after the Rocks Lodge Trout Farm on the Bunderg Road was significantly damaged by flooding from the River Strule.

At the time a spokesperson for Scottish firm Dawnfresh said the firm was not in a position to offer any estimation of how many of the 80 tonnes of fish based at the facility flowed into the river, though one local source told the Chronicle that at least 800,000 had been lost. Other angling experts in the area put the figure in excess of one million fish.

Now, over half year later the scale of the problem has yet to be fully quantified.

“You couldn’t underestimate how big a disaster this is,” Barney Winters of Strabane and Lifford Anglers said. “This is massive. There is real potential here for these Rainbow Trout to ruin one of the best Salmon rivers in Europe.

“Various statutory bodies played down what happened at the fish farm but with what we’ve been seeing, since the start of the season, things are only going to get worse.

“Two fishermen from Newtownstewart caught 400 fish between them. I fished for an hour and caught 25. This might sound good, but no-one wants to catch Rainbow Trout. And more importantly no-one is going to want to come here to fish for Rainbow Trout.”

According to the local angler, the crux of the ecological problem is that, whilst the escaped Rainbow Trout are sterile and cannot breed, they are aggressive eaters and have been competing with the native Brown Trout and Atlantic Salmon for food. This, he says could result in indigenous fish stocks being decimated.


Moreover, hundreds of sea birds have started coming on to the Mourne to feed on the invasive trout and are thus expected to damage populations of migratory smolt (young salmon) in the coming weeks.

Previously a spokesperson for Scottish firm Dawnfresh had said, “We do not believe they (Rainbow Trout) pose a risk to the local ecosystem.”

Barney Winters continued, “This is a combination of things which has the potential to wipe out the Salmon cycle for three or four years.

“It’s a plague. It’s unprecedented anywhere around the world; how do you quantify the damage? It’s like a type of pollution.

“The bottom line is: The whole balance of the river’s eco-system is already gone.”

Commenting on the situation this week a spokesperson for Dawnfresh explained,  “As we informed the Loughs Agency, the unprecedented weather conditions and flooding in August 2017 regrettably resulted in an escape of 387,000 juvenile fish from our Rocks Lodge hatchery site in Newtonstewart.  These fish are triploids which means they sterile and therefore unable to breed and form a new local population.  Following the event, we have commenced works to significantly improve the flood defences at the site including adding to and increasing the height of existing flood defence and improving screening.  This was a highly regrettable event caused by a once in a century storm but we acted quickly and are confident the improvements we have made will make the site even more secure in the future.”

 The Loughs Agency were also contacted about the latest situation on how many fish escaped and what work has since been done, at the time of going to press, no responses were forthcoming.

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