Trout are stocked in about two dozen named lakes and a few unnamed waters in the Seven Devils Mountains of the Hells Canyon Wilderness, but some lakes are not stocked because they have natural reproduction, are too shallow or other factors.
West-side lakes that drain into Sheep and Granite Creeks and ultimately the Snake River generally are stocked with rainbows, which are native to the drainage, said Joe DuPont, Idaho Fish and Game Department regional fisheries manager in Lewiston.
However, cutthroats were planted historically before the agency adopted the policy to stock species native to a drainage. Some cutthroats or cuttbows remain in a few Snake River drainage lakes through natural reproduction or hybridization with rainbows.
For example, the last westslope cutthroats were stocked in Echo Lake in 2004. Sterile triploid rainbows were dropped into Echo – 500 fry at a time – in 2008 and 2011.
East-side lakes that drain into the Rapid River are stocked with cutthroats native to that drainage.
Stocked lakes in the Seven Devils generally get new plants of hatchery trout fry dropped from aircraft every three years.
“Our goal is keeping a relatively low density so the fish can reach an optimum size before they die,” DuPont said, noting that some heavily fished high mountain lakes are stocked more frequently but the fish don’t grow as large.
The Seven Devils waters aren’t as productive as waters in Idaho’s White Cloud Mountains where a few lakes are producing fish up to 25 inches long, he said.
“In the Selway drainage we have lakes we stock very sparsely and the fish get to 20-to-24 inches,” he said.
“But the Seven Devils area is fished more that those areas, so fish getting to the 15-16 inch range would be very good growth.”
For perspective, Baldy Lake, one of the two largest lakes in the Devils, is stocked with 1,000 rainbow fry every three years. “That’s not high for a lake that gets a fair bit of pressure, so the number of fish you catch may be low but the quality should be good.”
A decade ago, Idaho Fish and Game biologists studied stocking records back through the 1960s and eliminated plants in lakes where trout were reproducing naturally, he said.
Researchers monitor those and other lakes to see if trout stocking affects amphibians.
Sheep Lake, for example, also is one of the largest lakes in the Seven Devils yet it has not been stocked since 1987.
Nearby Basin Lake, which is in a popular hiking destination area, continues to be stocked with 500 triploid rainbow fry every three years.