National Geographic is doing a feature on Megafishes and just recently got around to the world's largest trout, Hucho tiamen of Mongolia.
This fish is not like other trout and salmon species," said Zeb Hogan, a fisheries biologist with the University of Reno in Nevada.
Waist-deep in the clear, fast-moving waters of the Eg, Hogan prepared to release a newly tagged, 44-inch-long (112-centimeter-long) taimen back into the river.
The fish, which takes up to nine years to fully mature, can live for 50 years, said Hogan, who is a National Geographic Society Emerging Explorer. (National Geographic News is owned by the National Geographic Society.)
"We only see a few animals this size per mile in the river, so if you remove one of them, it's going to take a long time before it can be replaced," he said.
For additional information and a unique view on fly fishing for Tiamen check out the AEG Media blog, Trout Bum Diaries, which chronicles the making of their latest film.