Montana's Tongue River Reservoir Shows Good Sportfish Populations
Sampling efforts by Fish, Wildlife & Parks Region 7 crews at Tongue River Reservoir yielded good news for sport-fish populations and anglers.
A variety of sampling methods is used to determine relative abundance of different species in the reservoir. Sampling is done using overnight trap-sets, gill-net sets, seine hauls and electrofishing. Catch-per-net rates for all of the fish sampled show that numbers are trending upward.
2016 Tongue River Reservoir Sampling Results
Crappies – both black and white – are the most abundant sport-fish in TRR, and the primary focus of management for the fishery is to provide a recreational family fishing opportunity for crappie. There is no stocking of crappie in TRR, as they reproduce naturally.
The five-year average catch rate (2012-2016) in gill nets for crappie is just under 14 fish per net. In 2016, trap nets captured more than 60 crappie per net, almost double 2015 rates and above a seven-year average. The catch-rate report summarizes that the increase is likely a result of a smaller size class of crappie that has become catchable by both trap nets and anglers' tackle. The report notes that this year class of fish is a good sign that younger fish are recruiting to adulthood and replacing older, larger fish that are harvested or die of natural mortality. But the representation of crappie in each size category up to 15 inches is a good sign that the liberal harvest limits on crappie at TRR are sustainable and not eliminating larger size classes of fish.
Walleye are the second most abundant sport-fish in TRR, and management efforts aim to provide a recreational fishery with emphasis on harvest. Annual stocking of walleye is used to augment natural recruitment.
Gill nets captured more than 10 walleye per net in 2016, well above the 20-year average of 4.6 walleye per net. Walleye numbers continue to be above long-term average, and size structure indicates harvest is not eliminating larger size classes.
Northern pike numbers are slowly and consistently on the rise. Although their numbers are trending up, they are still found in low densities compared to crappie and walleye, with about two pike per gill net caught in recent years.
Night-time electrofishing sampling showed smallmouth bass are abundant, but the majority sampled are less than seven inches. The juvenile fish are important for forage for adult sport fish, however.
Seine hauls this summer suggest a poor year for production of young-of-the-year (two to three inches) for the four principle forage species of yellow perch, crappie, largemouth bass and smallmouth bass. Poor recruitment of an individual year class is fairly common and only of concern if sustained for several years. Recruitment from the 2015 year class was strong for all four species and is believed to have contributed to a fickle walleye bite for anglers in late 2015 through early 2016. The silver lining is that adult fish should be more aggressive in taking the bait until spawning in the spring of 2017 contributes a new year class of easy prey to the fishery.