Below average temperatures in November has many anglers scrambling to get their ice fishing gear ready: Old man winter is arriving early in Idaho, and the hardwater is already here on parts of Lake Cascade (ice update). For anglers itching for an update on the status of the fishery prior to hitting the ice, Fish and Game has plenty to offer from a number of studies conducted over the past year.
Lake Cascade is one of the most popular ice fisheries in Idaho, and it is also one of the most intensively surveyed by Fish and Game staff. Biologists in McCall have been busy wrapping up several large fish surveys on Lake Cascade, in addition to other large ongoing projects on the lake. Some of these surveys are conducted annually to follow fish population trends, while others are conducted less frequently but answer specific questions.
Overall, the news is good: recent studies suggest that there are still lots of perch swimming around in Lake Cascade, and plenty of big ones. Perhaps the hottest tip for anglers heading onto this ice fishing season is to stay mobile and move around until you find fish. Throughout a recent harvest study, we observed that 10% of ice anglers caught 73% of the perch last winter. This is probably because big perch tend to school, and they move around a lot. To be successful on Lake Cascade, staying mobile and using electronics will help you become one of the 10%.
Anglers can read more about the recent studies on Lake Cascade below and should stay tuned for more updates. Good luck to all of you that can get out on the ice this season. Remember to be safe and enjoy your time in Idaho’s great outdoors.
Harvest study: Popularity has increased, but harvest remains within historical range
Biologists in McCall recently wrapped up a year-long creel survey of anglers, which gathered information about angler preferences, effort, and harvest. This information helps fishery managers assess performance and determine if changes in management strategies are needed to increase fishery quality.
If you fished Lake Cascade last year, you may have been asked a few questions at the boat ramp by our creel technicians -- like which fish species you were after, how long you fished, and how many fish you caught. To get a good summary of angler experiences, large numbers of interviews are required. In fact, throughout the year, fisheries staff in McCall spent a total of 116 days conducting almost 1,500 interviews – rain or shine.
Although the popularity of Lake Cascade has increased in recent years, harvest remains within historical ranges. In this study, we estimated that 66,780 Yellow Perch, 3,953 Rainbow Trout, and 1,678 Smallmouth Bass were harvested between May 2021 and 2022 in Lake Cascade. Those are really big numbers, so it’s extremely important to put our estimates in context with past harvest studies conducted on Lake Cascade (see figure below).
Estimated angling effort (hours) and perch harvest by study year at Lake Cascade
While we saw an increase in angling effort (hours spent fishing) compared to our two most recent harvest studies in 2009 and 2016, our effort and harvest estimates remained well within historic ranges. Anglers that are new to fishing Lake Cascade may not realize that in the 1980s and early 1990s, Lake Cascade was the top sport fishery in terms of effort and harvest in Idaho – and we have some phenomenal fisheries in this state.
Many anglers that ice fished Lake Cascade in late-January and February in 2022 will remember the tough fishing conditions created by a large Chironomid (AKA bloodworm) hatch. It was like a light switch – the bite got tough, even though anglers were still finding, or “marking” plenty of fish. We picked this up in our data when we looked at catch rates by month (see figure below).
Catch rates by month during 2021-2022 harvest study at Lake Cascade
While catch rates can be very high during the ice fishery, most of the fishing effort (73%) and harvest (92%) actually occurs during the open water fishery. The average catch rate (fish per hour) across 2021-2022 for perch was 1.6 and 1.1 for ice fishing. Except for the bloodworm hatch, these catch rates are actually higher than most previous years, like 2016 (0.3 fish per hour), and are more similar to the 1980s, when catch rates hovered around 1.3. That said, catch rates are not always indicative of fish abundance, as many factors like food availability, weather, water conditions, and experience can influence angling success. Like I mentioned before, 10% of anglers caught 73% of the perch during last year’s ice fishery, which illustrates how variable catch rates can be among anglers.
What does this mean?
At this time, harvest is not a significant factor affecting the abundance of perch in Lake Cascade. Current and past research suggests that the main factor influencing the quality of the sport fishery has been periods of poor juvenile perch survival (previous update). This is occurring well before those perch make it to a harvestable size. While fishery managers work with partners at the University of Idaho to better understand factors affecting juvenile perch survival, biologists will continue to closely monitor the status of the fishery through annual netting and tagging studies.
Fall gillnetting survey shows juvenile perch numbers are up
Biologists also just wrapped up an annual fall gillnetting survey on Lake Cascade used to monitor trends in the fish community. This survey consisted of a three-boat crew that sets, pulls, and re-sets nets for an entire week; capturing and measuring enough fish (over 1,500) to closely follow annual trends in the fish population.
Perch numbers have remained stable since 2020 after increasing from the lows observed between 2017 and 2019 when the population was comprised almost entirely of large perch. This year, we saw many more perch in the 5-to-7-inch range than we have seen in years, which is very encouraging. Overall, the size of perch caught in our 2022 survey remains extraordinary and unrivaled by other Western reservoirs.
Biologists also use these annual trend data to keep tabs on the Northern Pikeminnow population. An abundance of large pikeminnow can predict a future decline in the quality of the perch fishery. Therefore, trends in pikeminnow abundance and size structure are closely monitored to determine when management intervention should be considered, to help improve the quality of the fishery. In 2022, we are seeing an increasing trend in the numbers of small pikeminnow in the lake (see figure below).
Fortunately, work is underway with partners at the University of Idaho to better understand the impact this may have on the sport fishery (stay tuned for an update!). In the meantime, fishery managers will continue to keep a close eye on fish numbers and angling effort in Lake Cascade and will update anglers if any management interventions appear necessary in the coming years.
Learn more about Lake Cascade
For more information on Lake Cascade or other fisheries in the McCall subregion, visit idfg.idaho.gov or contact the McCall Fish and Game office at (208) 634-8137, Regional Fisheries Biologist mike.thomas@idfg.idaho.gov, or Regional Fisheries Manager jordan.messner@idfg.idaho.gov