Non-native tropical fish found in Ness Salmon River

Three dead tropical fish have been found in a river in Scotland. Two Jaguar cichlids were discovered by a member of the Inverness Angling Club, before a Silver dollar was discovered by Chris Conroy and a colleague at the Ness District Fishery Board.

The discovery caused a mild media storm as the Silver dollar, Metynnis hypsauchen, was misidentified first as a Piranha, making it perfect tabloid media fodder, and then as a Pacu, which also does the media rounds as supposedly being feared by anglers for its human-like teeth and testicle-eating capability. Pacu do eat nuts, but not those sorts of nuts. And this fish wasn’t a Pacu either. 

Everyone jumped in on the Jaguar misidentification too. Uneducated guesses including American sunfish, Perch (cichlids are Perciformes, however,) Tanganyikan cichlids, Firemouths, Nimbochromis, Archerfish and Dovii, before 300 Facebook comments later the consensus was formed that they were Jaguar cichlids, Parachromis managuensis.

It would take a very hot week in Southern England for those two South and Central American species to survive outdoors, and this wasn’t was one of them, so all three were found dead and by the looks of the fixed glaze of the Silver Dollar’s eye, we’d say they had been dead for some time. These were clearly home aquarium fish and whether or not more fish were released at the same time we may never know. 

Two dead Jaguar cichlids, Parachromis managuensis, and by the looks of it, a sexed pair

Implications

Any release of non-native fish is a bad idea on so many levels. The biggest immediate threat is actually any disease pathogens that those fish may have introduced to a pristine Scottish waterway. If they had survived there are further implications such as predation of native flora and fauna, and those species that could survive a British winter may also become invasive and outcompete non-native species. 

Mr Conroy told the BBC: “Any release of non-native species into the wild is extremely irresponsible and could have significant negative impacts on our native fish stocks.

“The species found to date are all native to a warm climate and so had little to no chance of surviving in the cold waters of the River Ness. They could however pose a significant disease risk.”

The River Ness’s native fauna include Atlantic Salmon, Sea Trout, European eels and two species of Lamprey.

Live Atlantic Salmon parr, left, dead Silver Dollar, right.


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