In April 1983, Wengert and other state Game and Fish Department biologists stocked some 12,000 young trout in the Flaming Gorge Reservoir in southwest Wyoming.

Game and Fish spokeswoman Lucy Wold said Wengert was ice fishing recently on the 146-kilometre-long reservoir and caught a 58-centimetre Mackinaw trout, a type of lake trout.

Mr Wengert noticed the trout's right pelvic fin had been clipped, indicating it was a hatchery fish that had been stocked. Examining historical stocking data, Wengert determined the fish was stocked on April 14, 1983.

'I may have actually clipped the fins on this very fish, and I know I was driving the barge when the fish were stocked, nearly 25 years ago,' Mr Wengert said.

Mr Wengert, a 35-year veteran of the agency, estimated the trout was 26 years old because stocked fish spend a year in a hatchery before being released. But he said it was very skinny, weighing only 1.13 kilograms, compared to another trout released at the same time that weighed 7.7 kilograms when it was caught in 2004.

He said the trout will allow fishery biologists 'an opportunity to learn more about fish genetics, age and growth of lake trout in the reservoir.' -- AP