For approximately 40 years, Tongue River Reservoir (TRR) was known as perhaps the best crappie fishery in Montana.

But recent years have seen a steep decline in the crappie population at TRR. Natural reproduction is still occurring, indicated by low young-of-the-year (YOY) catch rates, but trend sampling in 2024 showed a new historic low catch rate for all gear types.

The decline is likely due to a combination of many factors over several years, including habitat changes due to higher reservoir levels after rebuilding Tongue River Dam in 1999, changes to annual water management practices discharging water over the spillway, and possibly storage of high-conductivity water from upstream sources (natural and industrial).

“There isn’t any one reason for the crappie declines,” said FWP Region 7 fisheries manager Mike Backes. “It’s clearly a combination of many complex factors over the last 20 years. The habitat in the reservoir changed after the dam was rebuilt and continues to evolve through 2025. The settlement of the MT-WY Water Compact lawsuit in 2018 has also impacted water management practices and resulting habitat on the reservoir.”

Montana Fish, Wildlife & Parks has put considerable effort into determining how to boost crappie populations while still providing some angler opportunity. Backes is optimistic that Region 7 staff have found a partial solution through stocking and management efforts.

This past April, FWP collected nearly 200 adult white and black crappie from Spotted Eagle Lake in Miles City and put them in ponds at the Miles City Hatchery for natural spawning. The YOY crappie they produce will be stocked into TRR in October.

FWP has already seen some success with this method. This is the third year of efforts to rebuild the once-popular pan fishery at the reservoir. In 2023 only white crappie broodstock were used, yielding 9,800 YOY for stocking into TRR. In 2024, both white and black crappie were utilized in 13 hatchery ponds separated by species. When those ponds were drained that fall, fisheries staff were delighted to discover more than 265,000 YOY crappie (214,683 black and 50,824 white). The fish, ranging from 1.5 to 4.5 inches long, were stocked in TRR over a couple of weeks in October.

“I’m not sure what to expect for hatchery production moving forward,” Backes said. “I would have been happy with any YOY crappie produced. So, it was quite impressive to see the number of YOY crappies produced in each hatchery pond. Their average size exceeded expectations, and the increased growth of the brood adults that were stocked into the ponds in April was noteworthy.”

YOY crappie are extremely sensitive to mortality from being handled, so the hatchery crafted a careful timeline for optimal survival rates. They cannot be collected until water temperatures fall below 60 degrees, usually in October. The five-month delay for stocking also makes for larger fish that are less vulnerable to predation and more likely to survive winter.

The larger white crappie broodstock from 2023 and a batch of young crappie from the 2024 spawn were also stocked back into Spotted Eagle to supplement that fishery. Backes has been very pleased with spawning activity at the small man-made lake. In 2024 each fyke net contained ample adult crappie plus 100-200 YOY crappie (predominantly whites) that averaged three to four inches long.?There were also two noteworthy-sized black crappie, one at 10 1/8 inches and another at 14 inches, which were released back into Spotted Eagle for future production.

Overall crappie goals for the reservoir are to improve abundances, sustain the popular fishery and bolster the forage base (including crappie) for other predatory species like walleye and northern pike.