Originally Posted by 4peace1piece
You sound like you know something about the stocking history of the Tongue? I'm interested in anything additional you can tell me about those efforts? Are the Yellowstone cutts native and the Snake River cutts stocked?
Yellowstone Cutthroats are almost certainly native to the headwaters Tongue River drainage. While there's no scientific documentation of their presence prior to the stocking of non-native fish, General George Crook made reference in his diary in June 1876 to his men catching numerous spotted trout, and this would seem to predate any stocking in the region. (As an interesting side note, had Crook's men not been enjoying themselves fishing, they might have made it to the Battle of Little Bighorn a few days sooner, and you might never have heard of George Custer).
Though it's possible that the cutthroat may have made it into the Tongue via a headwaters transfer, the prevailing theory is that during a cool period they migrated down the Yellowstone River to the Tongue, before migrating back up to the mountains. When the climate warmed, they became isolated.
Anyway, some time near the end of the 19th century (stocking records aren't completely clear), non-native, hatchery cutthroats (likely a combination of YSC and Snake River Finespotted Cutthroats) and brook trout were stocked into the Tongue drainage, and the native fish began to disappear. For the first several decades of fish stocking, there was rarely any distinction between cutthroat varieties, and Snake River Cutts made up a big chunk of hatchery-raised cutthroats (they take better to hatchery conditions than any of the other subspecies). Also, beginning in the late '30s, rainbows began to be stocked into at least some tributaries of the Tongue River.
Only recently has the WGFD ceased the stocking of non-native trout and begun stocking only "native" Yellowstone Cutthroats. Two years ago, for example, the river was stocked with 10,000 YSCs as part of an attempt to essentially overrun the non-native fish with replacement natives.