Cass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. The Leech Lake Band of Chippewa Indians operates a commercial fishery for lake whitefish and cisco on the Cass Lake chain. A limited subsistence fishery for game species is also allowed for Band members. The only MN-DNR special fishing regulation currently in effect is a ban on winter spearing for Cass Lake proper (excluding the remainder of the chain of lakes). A U.S. Environmental Protection Agency (EPA) Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The EPA has placed a consumption advisory on lake whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species.
\n
\nPresent Fish Population Status
\nThe walleye population of Cass Lake is healthy and is comprised of good numbers of fish distributed among numerous size and age classes. The 2010 gill net catch rate was 9.5 fish per net, and slightly below the long-term median catch rate (13.3 fish/net). Historic data indicate that overall walleye biomass was slightly higher during the 1990's than in recent years. Ten consecutive year classes of walleye were sampled in 2010 (ages 0 to 9), with the oldest fish representing the 1994 year class (age 16). The strong 2002 year class has provided good numbers of fish from 20 to 24 inches and about 13% of the gill net catch was greater than 20 inches in length. The 2006 year class is the second strongest year class on record (2002 was the strongest) and fish from this year class averaged 16 inches in length during fall gill netting. Approximately 51% of the walleye sample consisted of fish between 14 and 19 inches. These fish should provide good fishing opportunities for the next few years and there is also good representation of the 2008 year class which suggests the future is bright.
\n
\nThe gill net catch rate for yellow perch (37 per net) was less than the long-term median (49 per net). Nearly 30% of the sample consisted of perch 8 inches or larger, and 5% were 10 inches or larger. There is some evidence that quality of this population has decreased over the past 30 years, as indicated by an overall gradual decline in average fish size. However, the current size structure should provide ample angling opportunities in the short-term and, given the number of 8 to 9 inch fish in the sample, there is good potential for the number of quality-sized fish to improve in the next few years.
\nThe 2010 northern pike catch rate of 3.2 fish per net was slightly greater than the long-term median of 2.9 fish per gill net. The size structure of the pike population is good with approximately 25% of the sample was composed of northern pike greater than 26 inches with 10% greater than 30 inches. Muskellunge are not sampled effectively with gill nets and few are seen during annual gill net assessments.
\n
Cass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. The Leech Lake Band of Chippewa Indians operates a commercial fishery for lake whitefish and cisco on the Cass Lake chain. A limited subsistence fishery for game species is also allowed for Band members. The only MN-DNR special fishing regulation currently in effect is a ban on winter spearing for Cass Lake proper (excluding the remainder of the chain of lakes). A U.S. Environmental Protection Agency (EPA) Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The EPA has placed a consumption advisory on lake whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species.
\n
\nPresent Fish Population Status
\nThe walleye population of Cass Lake is healthy and is comprised of good numbers of fish distributed among numerous size and age classes. The 2009 gill net catch rate was 14.3 fish per net, and slightly above the long-term median catch rate (13.3 fish/net). Historic data indicate that overall walleye biomass was slightly higher during the 1990\u0019s than in recent years. Ten consecutive year classes of walleye were sampled in 2009, with the oldest fish representing the 1999 year class (age 10). The strong 2002 year class has provided good numbers of fish from 20 to 24 inches. About 10% of the gill net catch was greater than 20 inches in length. The 2006 year class is the second strongest year class on record (2002 was the strongest) and fish from this year class averaged 14 inches in length during fall gill netting. Approximately 60% of the sample consisted of fish between 12 and 16 inches. These fish should provide good fishing opportunities for the next several years.
\nThe gill net catch rate for yellow perch (67 per net) was greater than the long-term median (48 per net). Approximately 31% of the sample consisted of perch 8 inches or larger, and 8% were 10 inches or larger. The length distribution of yellow perch in 2009 was similar to the long-term median distribution, but contained a greater percentage of fish in length groups greater than 8 inches. There is some evidence that quality of this population has decreased over the past 30 years, as indicated by an overall gradual decline in average fish size, however the current size structure should provide quality angling opportunities.
\nThe 2009 northern pike catch rate of 3.2 fish per net was slightly greater than the long-term median of 2.9 fish per gill net. The size structure of the pike population is good with approximately 30% of the sample was composed of northern pike greater than 26 inches with 10% greater than 30 inches. Muskellunge are not sampled effectively with gill nets and few are seen during annual gill net assessments. The 2009 creel survey showed the muskellunge angler catch rate to be similar to previous surveys (0.019 fish/angler hour). The average length of a released fish was 39 inches with the largest fish recorded during the survey measuring 48 inches.
\n
Background
\n
\nCass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. The U.S. Forest Service modified the dam during winter 2015-2016 to a fixed-crest rock-arch structure with a gated bypass channel that will increase outlet capacity during high water events and aid in lowering water levels during winter to increase water storage capacity for the spring season.
\n
\nThe Leech Lake Band of Chippewa Indians operates a commercial fishery for Lake Whitefish and Cisco on the Cass Lake chain. A limited subsistence fishery for game species is also allowed for Band members.
\n
\nA U.S. Environmental Protection Agency (EPA) Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The EPA has placed a consumption advisory on Lake Whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species.
\n
\nAll species in Cass Lake are managed under statewide regulations, except sunfish, for which a chain-wide five fish bag limit was implemented on March 1, 2021. The possession limit for sunfish remains at 20 fish.
\n
\nPresent Fish Population Status
\n
\nThe Walleye population of Cass Lake is healthy and is comprised of good numbers of fish distributed among numerous size and age classes. The 2021 gill net catch rate was 12.7 fish per net, similar to the long-term median catch rate (13.1 fish/net). Captured fish ranged from ages 0 to 13 with most fish ages 0 to 8. Sixty percent of the population was between 13 and 16 inches, most of which belong to the strong 2018 year class. These fish will provide good catch rates and fish for the frying pan for the next several years. The record-strong 2013 year class is still prominent in the population and providing anglers with quality-sized fish that average about 22 inches. The clearer-than-usual water is due to the well-established zebra mussel population and this trend is expected to continue. As a result, Walleye anglers should focus their effort around low light periods or when there is a chop on the water as the clear water tends to keep fish deeper during the day. The catch rate for age-0 Walleye (approximately 6 inches) during fall electrofishing was average. Cass Lake has a history of producing strong year classes every two or three years and this trend is expected to continue. The modest year classes between the strong ones help provide anglers with a wide size range of fish and reduces fishing mortality on the stronger ones.
\n
\nThe gill net catch rate for Yellow Perch (69 per net) was above the long-term median (45 per net). Growth rates have increased remarkably which has increased the number of keeper-sized fish in the population compared to recent years. The catch rate for fish over 9 inches in 2021 (13.3 fish/net) was the record high catch since annual monitoring began in 1983. The portion of the gill net catch over 8 inches (41%) was the highest ever observed. The largest fish exceeded 12 inches in length and anglers continue put together some impressive catches.
\n
\nThe 2021 Northern Pike catch rate of 3.4 fish per net was similar to the long-term median of 3.2 fish per gill net. Average to below average gill net catch rates for Northern Pike over the past few years is encouraging as modest densities tend to result in faster growth rates and larger fish. Remember, Cass Lake lies in the North Central Zone for Northern Pike so the daily bag limit is 10 fish per day with a 22- to 26-inch protected slot limit and no more than two fish can be over 26 inches. About one-quarter of Northern Pike in the 2021 gill net assessment were below the protected slot limit, one-third within the size restriction, and 40% of fish were larger than 26 inches. This gives anglers a nice opportunity to put together a meal of pike comprised of fish both above and below the protected slot limit.
\n
Cass Lake is a nearly 16,000 acre lake and is the largest lake in the Cass Lake chain, which altogether includes over 25,000 acres of connected waters. The lake has a mix of expansive, shallow flats and deeper water with lots of underwater structure. Walleye, Yellow Perch, and Muskellunge are the most sought-after species.
\n
\nThe Walleye population of Cass Lake is healthy and is comprised of good numbers of fish distributed among numerous size and age classes. The 2023 gill net catch rate was 12.4 fish per net, slightly less than the long-term median catch rate (13.1 fish/net). Captured fish ranged from ages 1 to 13 with most fish ages 1 to 8. Half of the catch was between 12 and 17 inches, the smaller fish belonging to the upcoming 2021 year class and the larger fish belonging to the strong 2018 year class that will provide the nicer eating-sized fish this summer. These fish will provide good catch rates and fish for the frying pan for the next few years. The record-strong 2013 year class is still present in the population and providing anglers with quality-sized fish in the mid-20-inch range.
\n
\nThe clearer-than-usual water is due to the well-established zebra mussel population and this trend is expected to continue. As a result, Walleye anglers should focus their effort around low light periods or when there is a chop on the water as the clear water tends to keep fish deeper during the day. The catch rate for age-0 Walleye (approximately 6 inches) during fall electrofishing was poor. Cass Lake has a history of producing strong year classes every two or three years and this trend is expected to continue. The modest year classes between the strong ones help provide anglers with a wide size range of fish and reduces fishing mortality on the stronger ones.
\n
\nThe gill net catch rate for Yellow Perch (40 per net) was similar to the long-term median (45 per net). Growth rates have increased remarkably which has increased the number of keeper-sized fish in the population compared to recent years. The catch rate for fish over 9 inches in 2023 (10.4 fish/net) is among the highest since annual monitoring began in 1983. The largest fish exceeded 13 inches in length and anglers continue put together some impressive catches.
\n
\nThe Northern Pike catch rate of 3.0 fish per net was similar to the long-term median of 3.0 fish per gill net. Average to below average gill net catch rates for Northern Pike over the past few years is encouraging as modest densities tend to result in faster growth rates and larger fish. Remember, Cass Lake lies in the North Central Zone for Northern Pike so the daily bag limit is 10 fish per day with a 22- to 26-inch protected slot limit and no more than two fish can be over 26 inches. About one-quarter of Northern Pike in the gill net assessment were below the protected slot limit, one-third within the size restriction, and the balance of fish were larger than 26 inches. This gives anglers a nice opportunity to put together a meal of pike comprised of fish both above and below the protected slot limit.
\n
\nAll species in Cass Lake are managed under statewide regulations, except sunfish, for which a chain-wide five fish daily bag limit was implemented on March 1, 2021. The possession limit for sunfish remains at 20 fish.
\n
\nCass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. The U.S. Forest Service modified the dam during winter 2015-2016 to a fixed-crest rock-arch structure with a gated bypass channel that will increase outlet capacity during high water events and aid in lowering water levels during winter to increase water storage capacity for the spring season.
\n
\nThe Leech Lake Band of Chippewa Indians operates a commercial fishery for Lake Whitefish and Cisco on the Cass Lake chain. A limited subsistence fishery for game species is also allowed for Band members.
\n
\nA U.S. Environmental Protection Agency (EPA) Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The EPA has placed a consumption advisory on Lake Whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species.
\n
\n
Temperature and dissolved oxygen measurements were collected from the deepest basin in Cass Lake, which is located wholly within the Leech Lake Reservation, on August 7th, 2025, to evaluate the quantity and quality of cold, oxygenated water (oxythermal habitat) available to Lake Whitefish, the most sensitive coldwater species present in this lake (Cisco, also known as 'Tullibee', are also present). The Leech Lake Band of Ojibwe (LLBO) holds Clean Water Act jurisdiction over waters within the exterior boundaries of the Leech Lake Reservation, which allows LLBO to establish water quality standards to protect Reservation waters and culturally important aquatic resources.
\n
\nDuring the summer, Lake Whitefish require a layer of oxythermal habitat that contains water temperatures below 17.2 degrees C (63.0 degrees F) and dissolved oxygen concentrations above 3.0 mg/L. Based on the profile from the deepest basin (maximum sampled depth 114.8 feet), the water temperature decreased below 17.2 degrees C (63.0 degrees F) at 37.9 feet and the dissolved oxygen concentration decreased to 3.0 mg/L at 79.8 feet at the time of sampling. The thickness of this layer of water in the water column was 41.9 feet, indicating that oxythermal habitat was present for Lake Whitefish.
\n
\nFurther, the temperature at which dissolved oxygen decreased to 3.0 mg/L (i.e., TDO3, a single variable to characterize oxythermal habitat) was 9.0 degrees C (48.2 degrees F). TDO3 values cooler than 17.2 degrees C (63.0 degrees F) indicate that oxythermal conditions were suitable for Lake Whitefish at the time of the survey.
\n
\nData collected by the Minnesota Department of Natural Resources during the late summer period of maximum oxythermal stress (July 26th to August 24th) in 2024 the thickness of the layer of water in the water column was 29.2 feet, indicating that oxythermal habitat was present for Lake Whitefish. When inadequate oxythermal habitat is available, Lake Whitefish and Cisco are squeezed into unfavorable, warmer water conditions and experience higher levels of stress.
\n
Cass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. The Leech Lake Band of Chippewa Indians operates a commercial fishery for lake whitefish and cisco on the Cass Lake chain. A limited subsistence fishery for game species is also allowed for Band members.. A U.S. Environmental Protection Agency (EPA) Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The EPA has placed a consumption advisory on lake whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species. There are currently no special fishing regulations in effect on Cass Lake. All species are managed under statewide regulations.
\nPresent Fish Population Status
\nThe walleye population of Cass Lake is healthy and is comprised of good numbers of fish distributed among numerous size and age classes. The 2012 gill net catch rate was 13.1 fish per net, slightly below the long-term median catch rate (13.2 fish/net). Fish representing thirteen different age classes were sampled (ages 0 to 13, except 12). Approximately 61% of the walleye sample consisted of fish between 12 and 17 inches. These fish should provide good fishing opportunities for the next few years. The strong 2008 year class averaged 15.1 inches in length during the fall assessment and should provide good numbers of eater-sized fish. The 2011 year class also appears to be strong and averaged 10.3 inches last fall which means the future is bright for the Cass Lake walleye fishery.
\nThe gill net catch rate for yellow perch (39 per net) was similar to the long-term median (47 per net), but the number of fish over 8 inches increased by 68% compared to 2011. Thirty two percent of the sample consisted of perch 8 inches or larger, and 5% were 10 inches or larger. There is some evidence that quality of this population has decreased over the past 30 years, as indicated by an overall gradual decline in average fish size. However, the current size structure should provide ample angling opportunities and with a little bit of sorting, catches of nice-sized fish are possible.
\nThe 2012 northern pike catch rate of 3.8 fish per net was slightly greater than the long-term median of 2.9 fish per gill net. The size structure of the pike population is good with approximately 16% of the sample greater than 28 inches and 7% greater than 30 inches. It is rare for a male northern pike in Cass Lake to reach 28 inches.
\nA two-year muskellunge assessment was initiated in 2011 and a total of 157 fish were captured during the two-year survey. Fish ranged in length from 33.3 to 53.7 inches with female fish averaging 46.2 inches and males averaging 40.5 inches in length. Thirty seven percent of female muskellunge were greater than 48 inches in length and 17% were greater than 50 inches. All male muskellunge were less than 47 inches in length.
\n
THE WALLEYE POPULATION APPEARS TO BE ABUNDANT WITH CONSISTENT RECRUITMENT FOR ALMOST A DECADE. THE NORTHERN PIKE POPULATION APPEARS TO BE STABLE WITH ABUNDANCE FLUCTUATING AROUND A MEAN OF 2-3/LIFT. MEAN SIZE OF NORTHERN PIKE INCREASED DURING THE EARLY 1980'S BUT HAS APPEARED TO STABILIZE IN RECENT YEARS. ABUNDANCE OF CISCO HAS BEEN ABOVE AVERAGE FOR THE LAST THREE YEARS. ABUNDANCES OF OTHER SPECIES APPEARS TO BE WITHIN RANGES PREVIOUSLY OBSERVED.
","surveyID":"100639","surveyDate":"1996-09-15","surveyType":"Standard Survey","headerInfo":{"county":"Beltrami","wb_id":"04003000","wb_type":"Lake","id_date":"1996-09-15","wb_name":"Cass","survey_id":"100639","wb_alt_name":"","survey_type":"Population Assessment"}},{"surveyDate":"1997-09-15","surveyID":"100641","surveyType":"Standard Survey","headerInfo":{"id_date":"1997-09-15","wb_id":"04003000","wb_type":"Lake","county":"Beltrami","wb_name":"Cass","survey_type":"Population Assessment","wb_alt_name":"","survey_id":"100641"},"fishCatchSummaries":[{"gear":"Standard gill nets","quartileCount":"0.5-5.2","totalWeight":85.4,"averageWeight":"0.53","quartileWeight":"0.4-1.0","totalCatch":160,"CPUE":"8.00","gearCount":20,"species":"TLC"},{"quartileCount":"3.0-7.9","totalWeight":138.4,"gear":"Standard gill nets","CPUE":"2.90","averageWeight":"2.39","quartileWeight":"1.7-2.8","totalCatch":58,"gearCount":20,"species":"NOP"},{"gear":"Standard gill nets","totalWeight":0.3,"quartileCount":"0.2-1.1","averageWeight":"0.30","quartileWeight":"0.2-0.5","totalCatch":1,"CPUE":"0.05","gearCount":20,"species":"BLC"},{"gear":"Standard gill nets","quartileCount":"0.5-4.1","totalWeight":0.6,"averageWeight":"0.60","quartileWeight":"0.6-1.0","totalCatch":1,"CPUE":"0.05","species":"BLB","gearCount":20},{"averageWeight":"1.31","totalCatch":86,"quartileWeight":"1.5-2.3","CPUE":"4.30","gearCount":20,"species":"WTS","gear":"Standard gill nets","totalWeight":113,"quartileCount":"1.0-3.5"},{"gear":"Standard gill nets","quartileCount":"4.0-9.6","totalWeight":302.6,"quartileWeight":"1.1-1.9","totalCatch":275,"averageWeight":"1.10","CPUE":"13.75","species":"WAE","gearCount":20},{"species":"PMK","gearCount":20,"CPUE":"1.00","averageWeight":"0.05","totalCatch":20,"quartileWeight":"N/A","totalWeight":1,"quartileCount":"N/A","gear":"Standard gill nets"},{"averageWeight":"2.93","quartileWeight":"1.5-2.7","totalCatch":3,"CPUE":"0.15","species":"SHR","gearCount":20,"gear":"Standard gill nets","totalWeight":8.8,"quartileCount":"0.1-0.5"},{"totalWeight":2.7,"quartileCount":"0.6-6.4","gear":"Standard gill nets","CPUE":"0.15","quartileWeight":"0.6-0.9","totalCatch":3,"averageWeight":"0.90","gearCount":20,"species":"YEB"},{"gear":"Standard gill nets","quartileCount":"0.1-0.9","totalWeight":17.1,"averageWeight":"1.90","totalCatch":9,"quartileWeight":"1.0-3.0","CPUE":"0.45","species":"LKW","gearCount":20},{"totalCatch":910,"quartileWeight":"0.1-0.2","averageWeight":"0.18","CPUE":"45.50","species":"YEP","gearCount":20,"gear":"Standard gill nets","quartileCount":"7.1-33.9","totalWeight":161},{"averageWeight":"0.48","quartileWeight":"0.3-0.5","totalCatch":45,"CPUE":"2.25","species":"RKB","gearCount":20,"gear":"Standard gill nets","totalWeight":21.5,"quartileCount":"1.0-6.6"}],"surveySubType":"Population Assessment","lengths":{},"narrative":"The walleye population appears to be abundant with consistent recruitment. The northern pike population appears to be stable with abundance fluctuating around a mean of 2-3/lift. Mean size of northern pike increased during the early 1980's but has appeared to stabilize in recent years. Abundances of other species appears to be within ranges previously observed.
"},{"surveyType":"Standard Survey","surveyID":"100731","surveyDate":"1998-09-15","headerInfo":{"survey_type":"Population Assessment","wb_alt_name":"","survey_id":"100731","wb_name":"Cass","id_date":"1998-09-15","wb_type":"Lake","wb_id":"04003000","county":"Beltrami"},"narrative":"The walleye gill net catch rate continues to be high (third highest documented expressed as catch per unit effort) and is the highest ever documented as pounds per lift. The walleye fishery is being carried by several strong year classes, and the sample was comprised of a healthy distribution of sizes from 7 to 28 inches. Angler walleye catch and harvest rates should remain stable and will likely be influenced by variables other than abundance. Sixty-seven percent of the perch sample was comprised of fish between 5.0 and 6.9 inches. These fish should recruit to the fishery starting in the summer of 2001 likely increasing the harvest rates for perch. Until that time, however, perch harvest rates should change little. Northern pike abundance and size range appear to have changed little thus angler catch and harvest rates should change little. Numbers of other fish sampled in fall assessment netting show little change with the possible exception of lake whitefish which may be increasing.
","surveySubType":"Population Assessment","lengths":{},"fishCatchSummaries":[{"totalWeight":231,"quartileCount":"0.5-5.2","gear":"Standard gill nets","CPUE":"22.35","averageWeight":"0.52","totalCatch":447,"quartileWeight":"0.4-1.0","gearCount":20,"species":"TLC"},{"gear":"Standard gill nets","totalWeight":5.1,"quartileCount":"0.1-0.2","gearCount":20,"species":"BUB","quartileWeight":"1.1-2.7","totalCatch":3,"averageWeight":"1.70","CPUE":"0.15"},{"totalWeight":173,"quartileCount":"3.0-7.9","gear":"Standard gill nets","species":"NOP","gearCount":20,"CPUE":"2.55","quartileWeight":"1.7-2.8","totalCatch":51,"averageWeight":"3.39"},{"gear":"Standard gill nets","quartileCount":"1.0-3.5","totalWeight":113.9,"species":"WTS","gearCount":20,"averageWeight":"1.65","quartileWeight":"1.5-2.3","totalCatch":69,"CPUE":"3.45"},{"totalCatch":1,"quartileWeight":"3.1-5.3","averageWeight":"37.40","CPUE":"0.05","species":"MUE","gearCount":20,"gear":"Standard gill nets","quartileCount":"0.1-0.3","totalWeight":37.4},{"gear":"Standard gill nets","quartileCount":"4.0-9.6","totalWeight":424.7,"species":"WAE","gearCount":20,"averageWeight":"1.21","quartileWeight":"1.1-1.9","totalCatch":351,"CPUE":"17.55"},{"quartileCount":"N/A","totalWeight":0.4,"gear":"Standard gill nets","gearCount":20,"species":"PMK","CPUE":"0.15","quartileWeight":"N/A","totalCatch":3,"averageWeight":"0.13"},{"CPUE":"0.15","quartileWeight":"1.5-2.7","totalCatch":3,"averageWeight":"3.33","gearCount":20,"species":"SHR","quartileCount":"0.1-0.5","totalWeight":10,"gear":"Standard gill nets"},{"CPUE":"0.15","averageWeight":"0.83","quartileWeight":"0.6-0.9","totalCatch":3,"species":"YEB","gearCount":20,"totalWeight":2.5,"quartileCount":"0.6-6.4","gear":"Standard gill nets"},{"totalWeight":30.5,"quartileCount":"0.1-0.9","gear":"Standard gill nets","species":"LKW","gearCount":20,"CPUE":"0.75","totalCatch":15,"quartileWeight":"1.0-3.0","averageWeight":"2.03"},{"gearCount":20,"species":"BLG","CPUE":"0.05","averageWeight":"0.70","quartileWeight":"N/A","totalCatch":1,"quartileCount":"N/A","totalWeight":0.7,"gear":"Standard gill nets"},{"species":"YEP","gearCount":20,"CPUE":"38.15","quartileWeight":"0.1-0.2","totalCatch":763,"averageWeight":"0.15","quartileCount":"7.1-33.9","totalWeight":112,"gear":"Standard gill nets"},{"gearCount":20,"species":"RKB","quartileWeight":"0.3-0.5","totalCatch":25,"averageWeight":"0.33","CPUE":"1.25","gear":"Standard gill nets","totalWeight":8.2,"quartileCount":"1.0-6.6"}]},{"narrative":"Background
\nCass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. The U.S. Forest Service modified the dam during winter 2015-2016 to a fixed-crest rock-arch structure with a gated bypass channel that will increase outlet capacity during high water events.
\n
\nThe Leech Lake Band of Chippewa Indians operates a commercial fishery for Lake Whitefish and Cisco on the Cass Lake chain. A limited subsistence fishery for game species is also allowed for Band members.
\n
\nA U.S. Environmental Protection Agency (EPA) Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The EPA has placed a consumption advisory on Lake Whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species.
\nThere are currently no special fishing regulations in effect on Cass Lake. All species are managed under statewide regulations.
\n
\n
\nPresent Fish Population Status
\nThe Walleye population of Cass Lake is healthy and is comprised of good numbers of fish distributed among numerous size and age classes. The 2016 gill net catch rate was 16.6 fish per net, slightly greater than the long-term median catch rate (13.1 fish/net). Approximately half of the catch was between 12 and 15 inches. There are a number of strong year classes in the population ranging from age 3 to age 8 and these fish should provide good numbers of eater-sized fish for this year as well as the next several seasons. The catch rate for age-0 Walleye (approximately 6 inches) during fall electrofishing was below average, but given the strength of adjacent year classes and good numbers of fish approaching optimal harvest size, the future of the Cass Lake Walleye fishery remains bright.
\n
\nThe gill net catch rate for Yellow Perch (31 per net) was below the long-term median (47 per net). The number of fish over 8 inches in the sample was much improved over 2015 (2016 = 22%; 2015 = 11%) and the largest fish exceeded 12 inches in length. Anglers continue to find pockets of keeper-sized perch and, albeit with a little bit of sorting, catches of nice-sized fish are still possible.
\n
\nThe 2016 Northern Pike catch rate of 3.7 fish per net was greater than the long-term median of 3.1 fish per gill net. Better than usual reproduction the past several years has resulted in an abundance of small fish (< 24 inches). However, Cass Lake remains a place to catch good numbers of medium-sized fish (22 to 30 inches) in the population and these fish represented 33% of the sample during spring trap netting efforts.
\n
Cass Lake supports a native Muskellunge population that is entirely self-sustaining. Muskellunge assessments are conducted periodically (every five or six years) using large-frame trap nets and boat electrofishing. Recently, these have been two-year assessments with year one efforts focused on capturing and tagging fish using trap nets and collecting fish to examine for tags in year two with boat electrofishing. This allows a population estimate to be calculated using mark-recapture techniques. Sampling efforts focus on Allen's Bay and along the western shore of the lake where most of the spawning habitat is located. There are expansive flats in the main basin of the lake that may have suitable spawning habitat but these areas cannot be sampled due to gear limitations. As a result, we regard the population estimate presented here as reflecting the number of fish using the aforementioned areas to spawn rather than a true lakewide population estimate. Fish are captured during the spawning period and thus the sample is comprised nearly entirely of sexually mature fish. In Cass Lake, that means fish in excess of about 33 inches.
\n
\nElectrofishing efforts in 2017 captured 77 adult Muskellunge (60 males, 18 females). The average size of male fish was 40 inches while the average length of female fish was 45 inches. Fish ranged in length from 33.3 to 50.8 inches with five fish exceeding 48 inches and two fish over 50 inches. The population estimate of adult Muskellunge 642 fish, which is similar to the 2011 population estimate of 616 adult fish.
\n
\nMuskellunge generally reach sexual maturity at five to six years old. We saw a good number of age-6 fish in the sample, which represent new additions to the mature population. Average size of these fish was just under 40 inches and similar for each sex. Although female fish reach larger sizes than males, their growth patterns remain similar until they reach sexual maturity.
\n
\nFive of the 49 fish that were tagged in 2016 were recaptured in 2017. All recaptured fish were males and all had grown less than one inch during the past year. In addition, five fish that were originally tagged during the 2011 - 2012 assessment were recaptured in 2017. These fish were already adults when tagged and their growth during the five to six years since being tagged was approximately one-half inch per year. Given the ages assigned to these fish when originally captured, the oldest fish were 16 years old.
\n
\n
Background
\nCass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. The U.S. Forest Service modified the dam during winter 2015-2016 to a fixed-crest rock-arch structure with a gated bypass channel that will increase outlet capacity during high water events.
\n
\nThe Leech Lake Band of Chippewa Indians operates a commercial fishery for Lake Whitefish and Cisco on the Cass Lake chain. A limited subsistence fishery for game species is also allowed for Band members.
\n
\nA U.S. Environmental Protection Agency (EPA) Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The EPA has placed a consumption advisory on Lake Whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species.
\n
\nThere are currently no special fishing regulations in effect on Cass Lake. All species are managed under statewide regulations.
\n
\nPresent Fish Population Status
\nThe Walleye population of Cass Lake is healthy and is comprised of good numbers of fish distributed among numerous size and age classes. The 2017 gill net catch rate was 10.8 fish per net, slightly less than the long-term median catch rate (13.1 fish/net). Approximately half of the catch was between 14 and 17 inches. Most fish were ages 1 to 9 and the oldest fish in the assessment was age 15. The record-strong 2013 year class, which averages about 16 inches, comprised over half of the total sample. These fish are ideal size for the frying pan and should provide anglers with good harvest opportunities. The clearer-than-usual water in 2017 was likely due to the well-established zebra mussel population and this trend is expected to continue. As a result, much of the Walleye fishing pressure is focused around low light periods or when there is a chop on the water as the clear water tends to keep fish deeper during the day. The catch rate for age-0 Walleye (approximately 6 inches) during fall electrofishing was well below average, though good numbers of age-1 fish were seen during this sampling and in the gill nets.
\n
\nThe gill net catch rate for Yellow Perch (29 per net) was well below the long-term median (47 per net). However, the number of fish over 8 inches in the 2017 catch (23%) was similar to 2016 (22%) and improved over the recent low levels (e.g., 2015 = 11%). The largest fish exceeded 12 inches in length and anglers continue to find pockets of nice-sized fish.
\n
\nThe 2017 Northern Pike catch rate of 3.6 fish per net was greater than the long-term median of 3.1 fish per gill net. Better than usual reproduction a few years ago has resulted in an abundance of medium-sized fish (22 to 30 inches) with nearly half the gill net catch in this size range. In addition, approximately 10% of the catch was larger than 30 inches with the largest fish at 35 inches. Remember, Cass Lake lies in the North Central Zone for Northern Pike so the daily bag limit is 10 fish per day with a 22- to 26-inch protected slot limit (no harvest of fish in this size range) and no more than two fish can be over 26 inches. See the 2017 Minnesota Fishing Regulation booklet for more information.
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\nA two-year Muskellunge assessment was completed in 2017. Choose to view the 2017 Targeted Survey for more information.
\n
The walleye population of Cass Lake is robust and comprised of fish from numerous modest and strong year classes. Analysis of the fall 2000 gill net sample indicates that fish from 12 year classes were sampled. The oldest was a male from the 1982 year class. About 30% of the walleye sample was comprised of fish less than 12 inches (nearly all were age 1). Forty-four percent of the sample was comprised of walleye greater than 15.9 inches. Walleye gill net catch rate was 18.1 fish per lift. This was the second highest catch rate ever documented on this lake, and the highest since 1990. This continues an unbroken string of double digit catch rates first established in the fall of 1989.Analysis indicates that six year classes of yellow perch were sampled. The oldest was from the 1990 year class. No perch from the 1991 though 1993 year classes were sampled. Approximately 3% of the sample was comprised of perch 10 inches or larger. Nearly 84% of the sampled perch were less than 8 inches in length.Analysis indicates that seven year classes of northern pike were sampled, the oldest of which were from the 1993 year class. Approximately 56% of the sample was comprised of northern pike less than 23.0 inches, while 16% of the sampled northern pike were 28.0 inches or larger.Catch information for other fish species was similar to the long-term average. Some species were sampled in such low number that no useful trend could be discerned.
","surveySubType":"Population Assessment","lengths":{},"fishCatchSummaries":[{"gearCount":20,"species":"TLC","CPUE":"21.90","averageWeight":"0.50","quartileWeight":"0.4-1.0","totalCatch":438,"quartileCount":"0.5-5.2","totalWeight":220,"gear":"Standard gill nets"},{"gear":"Standard gill nets","totalWeight":2,"quartileCount":"0.1-0.2","averageWeight":"2.00","totalCatch":1,"quartileWeight":"1.1-2.7","CPUE":"0.05","gearCount":20,"species":"BUB"},{"totalCatch":3,"quartileWeight":"0.7-1.2","averageWeight":"0.90","CPUE":"0.15","species":"BRB","gearCount":20,"gear":"Standard gill nets","quartileCount":"0.3-1.6","totalWeight":2.7},{"species":"BLC","gearCount":20,"CPUE":"0.10","quartileWeight":"0.2-0.5","totalCatch":2,"averageWeight":"0.45","quartileCount":"0.2-1.1","totalWeight":0.9,"gear":"Standard gill nets"},{"species":"NOP","gearCount":20,"averageWeight":"3.25","quartileWeight":"1.7-2.8","totalCatch":70,"CPUE":"3.50","gear":"Standard gill 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nets","gearCount":20,"species":"MUE","CPUE":"0.10","totalCatch":2,"quartileWeight":"3.1-5.3","averageWeight":"4.80"},{"quartileWeight":"1.1-1.9","totalCatch":319,"averageWeight":"1.28","CPUE":"15.95","gearCount":20,"species":"WAE","gear":"Standard gill nets","totalWeight":406.9,"quartileCount":"4.0-9.6"},{"gearCount":20,"species":"PMK","averageWeight":"0.09","totalCatch":20,"quartileWeight":"N/A","CPUE":"1.00","gear":"Standard gill nets","quartileCount":"N/A","totalWeight":1.8},{"gearCount":20,"species":"SHR","averageWeight":"0.73","quartileWeight":"1.5-2.7","totalCatch":3,"CPUE":"0.15","gear":"Standard gill nets","quartileCount":"0.1-0.5","totalWeight":2.2},{"averageWeight":"0.90","quartileWeight":"0.6-0.9","totalCatch":11,"CPUE":"0.55","gearCount":20,"species":"YEB","gear":"Standard gill nets","quartileCount":"0.6-6.4","totalWeight":9.9},{"gearCount":20,"species":"LKW","CPUE":"0.30","averageWeight":"2.58","totalCatch":6,"quartileWeight":"1.0-3.0","totalWeight":15.5,"quartileCount":"0.1-0.9","gear":"Standard gill nets"},{"quartileCount":"N/A","totalWeight":0.3,"gear":"Standard gill nets","CPUE":"0.10","quartileWeight":"N/A","totalCatch":2,"averageWeight":"0.15","species":"BLG","gearCount":20},{"quartileCount":"7.1-33.9","totalWeight":161.4,"gear":"Standard gill nets","species":"YEP","gearCount":20,"CPUE":"54.45","averageWeight":"0.15","quartileWeight":"0.1-0.2","totalCatch":1089},{"species":"LMB","gearCount":20,"totalCatch":5,"quartileWeight":"0.6-1.0","averageWeight":"0.80","CPUE":"0.25","gear":"Standard gill nets","quartileCount":"0.3-1.2","totalWeight":4},{"species":"RKB","gearCount":20,"CPUE":"4.10","quartileWeight":"0.3-0.5","totalCatch":82,"averageWeight":"0.43","totalWeight":35.5,"quartileCount":"1.0-6.6","gear":"Standard gill nets"}],"surveySubType":"Population Assessment","lengths":{},"narrative":"The walleye population of Cass Lake is healthy and comprised of many individuals distributed among numerous modest and strong year classes. Preliminary analyses of the fall 2001 gill net sample indicate that fish from 12 year classes were sampled, the oldest a male from the 1986 year class (age 15+). Approximately 52% of the walleye sample consisted of fish from the strong 1999 year class. Size of these age-2+ fish ranged from 10-14 inches total length, with a mode near 12 inches. Approximately 35% of all walleye sampled were 16 inches or larger. Walleye gill net catch-per-effort was 16.0 fish per net lift, which is above the long-term median. This continues an unbroken string of double-digit catch rates first established in the fall of 1989. During the 1990's, average weight of individual fish also increased, further enhancing the quality of this population.Mean catch rates for yellow perch were right at the long-term median for both numbers and weight per gill net lift. Approximately 18% of the sample consisted of perch 8 inches or larger, and about 3% were 10 inches or larger. There is some indication that quality of this population has decreased over the past 30 years, as evidenced by a gradual decline in average fish size. Nevertheless, Cass Lake continues to provide excellent perch angling opportunities.Northern pike catch rates were at all-time highs for both numbers and weight per gill net lift. Approximately 79% of the sample was comprised of northern pike less than 26.0 inches, while 13% were 28.0 inches or larger. This population appears to be balanced, with an abundance of new recruits as well as good numbers of quality-sized fish.Catch rates for all other fish species were similar to long-term averages, highly variable, or so low that no useful trends could be discerned.
","headerInfo":{"survey_id":"100844","wb_alt_name":"","survey_type":"Population Assessment","wb_name":"Cass","county":"Beltrami","wb_type":"Lake","wb_id":"04003000","id_date":"2001-09-17"},"surveyID":"100844","surveyDate":"2001-09-17","surveyType":"Standard Survey"},{"narrative":"DATA FROM THE EARLY 1970'S SHOW HIGH ANNUAL MORTALITY OF WALLEYE AND ANGLING IS SUSPECTED AS THE CAUSE OF MOST OF THE MORTALITY. THE DAM UPSTREAM ON THE MISSISSIPPI RIVER BELOW STUMP LAKE LACKS AN OPERATING PLAN AND SHORT-TERM WATER LEVEL FLUCTUATIONS MAY BE AS MUCH AS 16 COMPLEX OF LAKES. THESE FLUCTUATIONS, AS WELL AS EFFLUENT DISCHARGE FROM THE BEMIDJI SEWAGE PLANT, MAY EFFECT WALLEYE REPRODUCTION. THERE IS A CON- SUMPTION ADVISORY FOR NORTHERN PIKE AND WALLEYE FROM CASS LAKE AND A DIOXIN CLEAN-UP SITE ADJA- CENT TO THE CHANNEL BETWEEN PIKE BAY AND CASS LAKE. THE NUMBER OF WALLEYE PER GILLNET LIFT IN 1988 WAS THE MEDIAN REPORTED SINCE 1948. MEAN WEIGHT OF FISH WAS ABOUT 1.1 PDS. LENGTH FREQUENCIES OF WALLEYE SHOWED CONSISTENT RECRUITMENT WITH FISH RANGING FROM 8.0-25.0 INCHES. CATCH INDICES FOR YELLOW PERCH, NORTHERN PIKE, AND CISCO WERE SIMILAR TO THE LONG TERM AVERAGE (1948-1988).
","fishCatchSummaries":[{"gear":"Standard gill nets","totalWeight":178.2,"quartileCount":"0.5-5.2","averageWeight":"0.70","quartileWeight":"0.4-1.0","totalCatch":254,"CPUE":"12.70","species":"TLC","gearCount":20},{"species":"BUB","gearCount":20,"CPUE":"0.10","averageWeight":"2.30","quartileWeight":"1.1-2.7","totalCatch":2,"totalWeight":4.6,"quartileCount":"0.1-0.2","gear":"Standard gill nets"},{"totalWeight":1.4,"quartileCount":"0.3-1.6","gear":"Standard gill nets","species":"BRB","gearCount":20,"CPUE":"0.05","averageWeight":"1.40","quartileWeight":"0.7-1.2","totalCatch":1},{"CPUE":"1.50","quartileWeight":"1.7-2.8","totalCatch":30,"averageWeight":"4.03","species":"NOP","gearCount":20,"quartileCount":"3.0-7.9","totalWeight":120.9,"gear":"Standard gill nets"},{"quartileWeight":"0.6-1.0","totalCatch":3,"averageWeight":"0.93","CPUE":"0.15","gearCount":20,"species":"BLB","gear":"Standard gill nets","quartileCount":"0.5-4.1","totalWeight":2.8},{"quartileCount":"1.0-3.5","totalWeight":100.6,"gear":"Standard gill nets","species":"WTS","gearCount":20,"CPUE":"3.30","totalCatch":66,"quartileWeight":"1.5-2.3","averageWeight":"1.52"},{"gear":"Standard gill nets","quartileCount":"0.1-0.3","totalWeight":9,"averageWeight":"9.00","totalCatch":1,"quartileWeight":"3.1-5.3","CPUE":"0.05","gearCount":20,"species":"MUE"},{"totalWeight":134.1,"quartileCount":"4.0-9.6","gear":"Standard gill nets","CPUE":"6.30","averageWeight":"1.06","quartileWeight":"1.1-1.9","totalCatch":126,"gearCount":20,"species":"WAE"},{"species":"PMK","gearCount":20,"CPUE":"0.40","quartileWeight":"N/A","totalCatch":8,"averageWeight":"0.05","totalWeight":0.4,"quartileCount":"N/A","gear":"Standard gill nets"},{"quartileCount":"0.1-0.5","totalWeight":1.1,"gear":"Standard gill nets","gearCount":20,"species":"SHR","CPUE":"0.05","averageWeight":"1.10","quartileWeight":"1.5-2.7","totalCatch":1},{"quartileCount":"0.6-6.4","totalWeight":3.8,"gear":"Standard gill nets","CPUE":"0.20","totalCatch":4,"quartileWeight":"0.6-0.9","averageWeight":"0.95","species":"YEB","gearCount":20},{"CPUE":"0.20","averageWeight":"1.88","quartileWeight":"1.0-3.0","totalCatch":4,"species":"LKW","gearCount":20,"totalWeight":7.5,"quartileCount":"0.1-0.9","gear":"Standard gill nets"},{"CPUE":"0.05","averageWeight":"0.10","totalCatch":1,"quartileWeight":"N/A","species":"BLG","gearCount":20,"totalWeight":0.1,"quartileCount":"N/A","gear":"Standard gill nets"},{"quartileCount":"7.1-33.9","totalWeight":112.3,"gear":"Standard gill nets","CPUE":"33.20","averageWeight":"0.17","totalCatch":664,"quartileWeight":"0.1-0.2","gearCount":20,"species":"YEP"},{"totalWeight":0.6,"quartileCount":"0.3-1.2","gear":"Standard gill nets","gearCount":20,"species":"LMB","CPUE":"0.35","quartileWeight":"0.6-1.0","totalCatch":7,"averageWeight":"0.09"},{"gear":"Standard gill nets","quartileCount":"1.0-6.6","totalWeight":6.4,"species":"RKB","gearCount":20,"quartileWeight":"0.3-0.5","totalCatch":16,"averageWeight":"0.40","CPUE":"0.80"}],"lengths":{},"surveySubType":"Population Assessment","surveyType":"Standard Survey","surveyDate":"1988-06-01","surveyID":"100643","headerInfo":{"id_date":"1988-06-01","wb_id":"04003000","wb_type":"Lake","county":"Beltrami","wb_name":"Cass","survey_type":"Population Assessment","wb_alt_name":"","survey_id":"100643"}},{"narrative":"NUMBERS OF WALLEYE PER GILLNET LIFT IN 1987 WAS SLIGHTLY LOWER THAN IN ANY YEAR PREVIOUS, HOWEVER, POUNDS PER GILLNET LIFT IN 1987 WAS WITHIN RANGE OF PREVIOUS SAMPLES. CATCH INDICES FOR YELLOW PERCH, NORTHERN PIKE, AND TULLIBEE WERE SIMILAR TO THE LONG TERM AVERAGE (1948-1987). LENGTH- FREQUENCIES OF WALLEYE SHOWED CONSISTENT RECRUIT- MENT WITH FISH RANGING FROM 8.0-25.0 INCHES.
","lengths":{},"surveySubType":"Population Assessment","fishCatchSummaries":[{"quartileWeight":"0.4-1.0","totalCatch":224,"averageWeight":"0.78","CPUE":"11.20","gearCount":20,"species":"TLC","gear":"Standard gill nets","totalWeight":174,"quartileCount":"0.5-5.2"},{"gear":"Standard gill nets","totalWeight":190.9,"quartileCount":"3.0-7.9","gearCount":20,"species":"NOP","quartileWeight":"1.7-2.8","totalCatch":48,"averageWeight":"3.98","CPUE":"2.40"},{"CPUE":"0.05","quartileWeight":"0.6-1.0","totalCatch":1,"averageWeight":"0.60","gearCount":20,"species":"BLB","quartileCount":"0.5-4.1","totalWeight":0.6,"gear":"Standard gill nets"},{"totalWeight":85.5,"quartileCount":"1.0-3.5","gear":"Standard gill nets","gearCount":20,"species":"WTS","CPUE":"2.15","averageWeight":"1.99","totalCatch":43,"quartileWeight":"1.5-2.3"},{"species":"WAE","gearCount":20,"CPUE":"3.45","totalCatch":69,"quartileWeight":"1.1-1.9","averageWeight":"1.34","quartileCount":"4.0-9.6","totalWeight":92.7,"gear":"Standard gill 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nets"}],"headerInfo":{"county":"Beltrami","id_date":"1987-07-01","wb_id":"04003000","wb_type":"Lake","wb_name":"Cass","survey_id":"100342","survey_type":"Population Assessment","wb_alt_name":""},"surveyType":"Standard Survey","surveyID":"100342","surveyDate":"1987-07-01"},{"surveyID":"2510717756125000","surveyDate":"2007-07-01","surveyType":"Standard Survey","headerInfo":{"wb_name":"Cass","county":"Beltrami","wb_type":"Lake","wb_id":"04003000","id_date":"2007-07-01","survey_id":"2510717756125000","wb_alt_name":"","survey_type":"Large Lake Survey"},"fishCatchSummaries":[{"quartileCount":"N/A","totalWeight":360,"gear":"Survey seining","CPUE":"172.17","averageWeight":"0.00","totalCatch":3099,"quartileWeight":"N/A","species":"WTS","gearCount":18},{"gearCount":20,"species":"BLG","CPUE":"0.45","averageWeight":"0.35","quartileWeight":"N/A","totalCatch":9,"totalWeight":1432,"quartileCount":"N/A","gear":"Standard gill nets"},{"quartileCount":"0.1-0.9","totalWeight":1478,"gear":"Standard gill 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trawling","quartileCount":"N/A","totalWeight":22},{"CPUE":"42.55","quartileWeight":"N/A","totalCatch":851,"averageWeight":"0.00","species":"BNM","gearCount":20,"totalWeight":15,"quartileCount":"N/A","gear":"Standard trawling"},{"species":"BKF","gearCount":18,"averageWeight":"0.00","totalCatch":25,"quartileWeight":"N/A","CPUE":"1.39","gear":"Survey seining","quartileCount":"N/A","totalWeight":0},{"gear":"Standard gill nets","totalWeight":57590,"quartileCount":"7.1-33.9","gearCount":20,"species":"YEP","totalCatch":778,"quartileWeight":"0.1-0.2","averageWeight":"0.16","CPUE":"38.90"},{"gear":"Standard gill nets","quartileCount":"1.0-6.6","totalWeight":12731,"gearCount":20,"species":"RKB","quartileWeight":"0.3-0.5","totalCatch":76,"averageWeight":"0.37","CPUE":"3.80"},{"quartileCount":"N/A","totalWeight":0,"gear":"Standard trawling","CPUE":"0.15","averageWeight":"0.00","totalCatch":3,"quartileWeight":"N/A","species":"BKF","gearCount":20},{"quartileCount":"3.0-7.9","totalWeight":92339,"gear":"Standard gill nets","gearCount":20,"species":"NOP","CPUE":"2.90","averageWeight":"3.51","totalCatch":58,"quartileWeight":"1.7-2.8"},{"CPUE":"61.83","averageWeight":"0.00","quartileWeight":"N/A","totalCatch":1113,"gearCount":18,"species":"LGP","totalWeight":1296,"quartileCount":"N/A","gear":"Survey seining"},{"gearCount":20,"species":"LGP","quartileWeight":"N/A","totalCatch":39,"averageWeight":"0.00","CPUE":"1.95","gear":"Standard trawling","quartileCount":"N/A","totalWeight":0},{"gearCount":18,"species":"JND","totalCatch":760,"quartileWeight":"N/A","averageWeight":"0.00","CPUE":"42.22","gear":"Survey seining","quartileCount":"N/A","totalWeight":420},{"totalWeight":1,"quartileCount":"N/A","gear":"Standard trawling","CPUE":"1.55","averageWeight":"0.00","totalCatch":31,"quartileWeight":"N/A","gearCount":20,"species":"JND"},{"gear":"Standard gill nets","totalWeight":5340,"quartileCount":"0.6-6.4","quartileWeight":"0.6-0.9","totalCatch":9,"averageWeight":"1.31","CPUE":"0.45","species":"YEB","gearCount":20},{"gear":"Survey seining","totalWeight":0,"quartileCount":"N/A","averageWeight":"0.00","quartileWeight":"N/A","totalCatch":1,"CPUE":"0.06","gearCount":18,"species":"RKB"},{"totalWeight":617,"quartileCount":"N/A","gear":"Survey seining","CPUE":"439.33","averageWeight":"0.00","totalCatch":7908,"quartileWeight":"N/A","gearCount":18,"species":"YEP"},{"totalWeight":2,"quartileCount":"N/A","gear":"Survey seining","CPUE":"104.83","averageWeight":"0.00","quartileWeight":"N/A","totalCatch":1887,"species":"BMS","gearCount":18},{"gear":"Standard trawling","totalWeight":0,"quartileCount":"N/A","totalCatch":199,"quartileWeight":"N/A","averageWeight":"0.00","CPUE":"9.95","species":"RKB","gearCount":20},{"species":"YEP","gearCount":20,"totalCatch":19460,"quartileWeight":"N/A","averageWeight":"0.00","CPUE":"973.00","gear":"Standard trawling","quartileCount":"N/A","totalWeight":1080},{"totalWeight":16,"quartileCount":"N/A","gear":"Survey seining","CPUE":"11.33","averageWeight":"0.00","totalCatch":204,"quartileWeight":"N/A","species":"LMB","gearCount":18},{"gearCount":20,"species":"NOP","averageWeight":"0.00","totalCatch":1,"quartileWeight":"N/A","CPUE":"0.05","gear":"Standard trawling","totalWeight":0,"quartileCount":"N/A"},{"averageWeight":"0.00","totalCatch":10,"quartileWeight":"N/A","CPUE":"0.50","species":"TPM","gearCount":20,"gear":"Standard trawling","quartileCount":"N/A","totalWeight":0},{"gear":"Survey seining","quartileCount":"N/A","totalWeight":0,"species":"BST","gearCount":18,"quartileWeight":"N/A","totalCatch":2,"averageWeight":"0.00","CPUE":"0.11"},{"species":"CSH","gearCount":18,"CPUE":"16.22","averageWeight":"0.00","totalCatch":292,"quartileWeight":"N/A","totalWeight":0,"quartileCount":"N/A","gear":"Survey seining"},{"gearCount":20,"species":"LMB","CPUE":"2.60","averageWeight":"0.00","totalCatch":52,"quartileWeight":"N/A","quartileCount":"N/A","totalWeight":8,"gear":"Standard trawling"},{"quartileCount":"N/A","totalWeight":2,"gear":"Standard trawling","CPUE":"0.50","averageWeight":"0.00","quartileWeight":"N/A","totalCatch":10,"gearCount":20,"species":"BST"},{"averageWeight":"0.00","quartileWeight":"N/A","totalCatch":152,"CPUE":"8.44","gearCount":18,"species":"SPO","gear":"Survey seining","quartileCount":"N/A","totalWeight":0},{"gear":"Standard gill nets","quartileCount":"1.0-3.5","totalWeight":28378,"averageWeight":"1.60","quartileWeight":"1.5-2.3","totalCatch":39,"CPUE":"1.95","species":"WTS","gearCount":20},{"gearCount":20,"species":"SPO","CPUE":"2.45","totalCatch":49,"quartileWeight":"N/A","averageWeight":"0.00","totalWeight":0,"quartileCount":"N/A","gear":"Standard trawling"},{"quartileCount":"0.5-5.2","totalWeight":98710,"gear":"Standard gill nets","gearCount":20,"species":"TLC","CPUE":"13.05","totalCatch":261,"quartileWeight":"0.4-1.0","averageWeight":"0.83"}],"lengths":{"SUN":{"fishCount":[[0,501],[1,319]],"minimum_length":1,"maximum_length":1},"PMK":{"fishCount":[[3,1],[4,3]],"maximum_length":4,"minimum_length":3},"BLG":{"minimum_length":3,"maximum_length":9,"fishCount":[[3,1],[4,2],[7,1],[8,4],[9,1]]},"LKW":{"maximum_length":18,"minimum_length":11,"fishCount":[[11,1],[18,1]]},"SHR":{"minimum_length":12,"maximum_length":12,"fishCount":[[12,1]]},"LMB":{"maximum_length":3,"minimum_length":1,"fishCount":[[1,147],[2,105],[3,4]]},"BLC":{"minimum_length":1,"maximum_length":10,"fishCount":[[1,28],[10,1],[8,1]]},"RKB":{"fishCount":[[10,3],[3,4],[4,6],[5,9],[6,8],[7,19],[8,17],[9,10]],"minimum_length":3,"maximum_length":10},"BRB":{"fishCount":[[11,1],[13,1]],"minimum_length":11,"maximum_length":13},"NOP":{"fishCount":[[18,2],[19,5],[20,6],[21,4],[22,5],[23,11],[24,2],[25,4],[26,2],[27,3],[28,3],[29,3],[30,4],[31,1],[32,3]],"minimum_length":18,"maximum_length":32},"TLC":{"maximum_length":16,"minimum_length":8,"fishCount":[[10,4],[11,82],[12,83],[13,43],[14,28],[15,15],[16,4],[8,2]]},"YEP":{"minimum_length":1,"maximum_length":12,"fishCount":[[10,20],[11,6],[12,1],[4,1],[5,270],[6,203],[7,128],[8,83],[9,66],[1,24519],[2,144]]},"WTS":{"fishCount":[[12,3],[13,3],[14,8],[15,1],[16,5],[17,6],[18,5],[19,2],[6,1],[8,3],[9,2]],"minimum_length":6,"maximum_length":19},"WAE":{"fishCount":[[2,2],[3,6],[5,1],[6,2],[7,5],[10,26],[11,12],[12,24],[13,22],[14,25],[15,13],[16,17],[17,11],[18,15],[19,8],[20,5],[21,6],[22,3],[23,1],[28,1],[8,1],[9,12]],"maximum_length":28,"minimum_length":2},"YEB":{"maximum_length":13,"minimum_length":9,"fishCount":[[11,1],[12,1],[13,6],[9,1]]}},"surveySubType":"Large Lake Survey","narrative":"Special Problems and Conditions Affecting Fish or Fishing
\n
\nCass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. A Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The U. S. Environmental Protection Agency has placed a consumption advisory on lake whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species. The Leech Lake Band of Chippewa Indians operates a commercial fishery for lake whitefish and cisco on the Cass Lake chain. The only special fishing regulation currently in effect is a ban on winter spearing for Cass Lake proper (excluding the remainder of the chain of lakes).
\n
\nPresent Fish Population Status
\n
\nThe walleye population of Cass Lake is healthy and is comprised of good numbers of fish distributed among numerous year classes. The 2007 gill net catch rate of 10.5 fish/net is slightly below the long-term median catch rate (13.3 fish/net). Historic data indicate that overall walleye biomass was slightly higher during the 1990\u0019s than in recent years. The recruitment of several recent strong year classes \u0013 most notably the 2002 year class \u0013 appears to be carrying the population. Approximately 63% of the sample consisted of fish less than age-5, and most of those were from the 2005 and 2006 year classes.
\n
\nAnalyses of the fall 2007 gill net sample indicate that walleye from 9 year classes were sampled, the oldest a female from the 1991 year class (age-16). Only 3% of the walleye sample consisted of fish from the strong 1999 year class, and only 5% were from the strong 2001 year class. Fish from the strong 2002 year class were more abundant, and made up 23% of the gill net catch. Thirty-two percent of all walleye sampled were 16 inches or larger.
\n
\nMean catch rates for yellow perch were below long-term medians for both number and weight per gill net lift. Approximately 24% of the sample consisted of perch 8 inches or larger, and 3% were 10 inches or larger. Average size of yellow perch declined from 2006, likely due to an abundance of age-2 fish newly recruited to the gill nets. There is some evidence that quality of this population has decreased over the past 30 years, as indicated by an overall gradual decline in average fish size.
\n
\nThe 2007 northern pike catch rate of 2.9 fish per net was about the same as the long-term median of 2.8 fish/net, and the catch rate in terms of weight (10.2 lbs/net) was slightly above the long-term median (9.5 lbs/net). Approximately 67% of the sample was comprised of northern pike less than 26.0 inches, while 26% were 28.0 inches or larger.
\n
\nCatch rates for all other fish species were similar to long-term averages, highly variable, or so low that no useful trends could be discerned.
\n
Background
\nCass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. The U.S. Forest Service is currently in the process of a major modification of the outlet to convert from a gated dam to a fixed crest rock structure that will increase outlet capacity during high water events.
\n
\nThe Leech Lake Band of Chippewa Indians operates a commercial fishery for lake whitefish and cisco on the Cass Lake chain. A limited subsistence fishery for game species is also allowed for Band members.
\n
\nA U.S. Environmental Protection Agency (EPA) Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The EPA has placed a consumption advisory on lake whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species.
\nThere are currently no special fishing regulations in effect on Cass Lake. All species are managed under statewide regulations.
\n
\nSummer 2015 will be the second year of our two-year creel survey. If you encounter a DNR creel clerk, please take just a few minutes to answer a few questions about your fishing success. Getting accurate information is vital to managing fish populations in the lake. Questions will range from when you started fishing, to what species you were targeting, and how many you kept/released. The clerk may also ask to measure your catch to provide information on the size of harvested fish which helps up understand which year classes are supporting the fishery, how many pounds of fish are being harvested, angler preferences, etc. Your cooperation would be much appreciated.
\n
\n
\nPresent Fish Population Status
\nThe walleye population of Cass Lake is healthy and is comprised of good numbers of fish distributed among numerous size and age classes. The 2014 gill net catch rate was 11.2 fish per net, slightly below the long-term median catch rate (13.1 fish/net). Fish representing ages 0 to 12 were all represented except no 10-year-old fish were caught. Approximately two-thirds of the walleye sample consisted of age-1 fish (8 to 10 inches) and age-3 fish (13 to 15 inches) inches. The strong 2008 and 2011 year classes averaged 18.2 and 14.4 inches in length, respectively. These fish should provide good numbers of eater-sized fish. The catch rate for age-0 walleye (approximately 6 inches) during fall electrofishing was the typical, and coupled with the abundance of age-1 fish seen in the gill nets, the future of the Cass Lake walleye fishery is bright.
\n
\nThe gill net catch rate for yellow perch (34 per net) was below the long-term median (47 per net). There was a moderate number of fish over 8 inches in the sample (19%) with some fish approaching 12 inches in length. There is some evidence that quality of this population has decreased over the past 30 years, as indicated by an overall gradual decline in average fish size. However, the current size structure should provide ample angling opportunities and with a little bit of sorting, catches of nice-sized fish are still possible.
\n
\nThe 2014 northern pike catch rate of 4.8 fish per net was the highest ever observed and greater than the long-term median of 2.9 fish per gill net. This increased abundance is better-than-usual reproduction the past several years and with that comes an abundance of small fish (< 24 inches). However, there are still good numbers of quality-sized fish (26 to 32 inches) in the population and these fish represented 40% of the gill net sample.
\n
WAE CATCH/EFFORT NEARLY DOUBLED COMPARED TO 1989 AND CONTINUES AN INCREASING TRENDS THAT BEGAN IN 1988. THIRTY-SEVEN PERCENT OF THE WAE WERE <12 INCHES INCLUDING 9 YOUNG-OF-THE-YEAR. SEVERAL STRONG YEAR CLASSES SHOULD RECRUIT TO THE FISHERY IN THE NEXT FEW YEARS. CATCH/EFFORT FOR THE OTHER SPECIES WAS SIMILAR TO PREVIOUS YEARS. NATURAL REPRODUCTION OF MUE WAS AGAIN DOCUMENTED WITH YOY COLLECTED AT FOUR SITES.
"},{"fishCatchSummaries":[{"gear":"Standard gill nets","quartileCount":"0.5-5.2","totalWeight":86,"averageWeight":"0.61","quartileWeight":"0.4-1.0","totalCatch":140,"CPUE":"7.00","species":"TLC","gearCount":20},{"gearCount":20,"species":"BUB","averageWeight":"2.15","quartileWeight":"1.1-2.7","totalCatch":2,"CPUE":"0.10","gear":"Standard gill nets","quartileCount":"0.1-0.2","totalWeight":4.3},{"quartileWeight":"0.7-1.2","totalCatch":3,"averageWeight":"1.40","CPUE":"0.15","species":"BRB","gearCount":20,"gear":"Standard gill nets","quartileCount":"0.3-1.6","totalWeight":4.2},{"totalCatch":4,"quartileWeight":"0.2-0.5","averageWeight":"0.62","CPUE":"0.20","gearCount":20,"species":"BLC","gear":"Standard gill nets","totalWeight":2.5,"quartileCount":"0.2-1.1"},{"gear":"Standard gill nets","quartileCount":"3.0-7.9","totalWeight":154.3,"species":"NOP","gearCount":20,"quartileWeight":"1.7-2.8","totalCatch":51,"averageWeight":"3.03","CPUE":"2.55"},{"gear":"Standard gill nets","totalWeight":0.1,"quartileCount":"0.5-4.1","gearCount":20,"species":"BLB","averageWeight":"0.10","totalCatch":1,"quartileWeight":"0.6-1.0","CPUE":"0.05"},{"CPUE":"3.85","quartileWeight":"1.5-2.3","totalCatch":77,"averageWeight":"1.63","species":"WTS","gearCount":20,"totalWeight":125.7,"quartileCount":"1.0-3.5","gear":"Standard gill nets"},{"gear":"Standard gill nets","quartileCount":"4.0-9.6","totalWeight":280.8,"averageWeight":"0.96","quartileWeight":"1.1-1.9","totalCatch":291,"CPUE":"14.55","species":"WAE","gearCount":20},{"totalWeight":14.9,"quartileCount":"N/A","gear":"Standard gill nets","gearCount":20,"species":"PMK","CPUE":"3.65","quartileWeight":"N/A","totalCatch":73,"averageWeight":"0.20"},{"totalWeight":2.4,"quartileCount":"0.1-0.5","gear":"Standard gill nets","gearCount":20,"species":"SHR","CPUE":"0.05","averageWeight":"2.40","quartileWeight":"1.5-2.7","totalCatch":1},{"gear":"Standard gill nets","totalWeight":20.3,"quartileCount":"0.6-6.4","gearCount":20,"species":"YEB","averageWeight":"0.85","totalCatch":24,"quartileWeight":"0.6-0.9","CPUE":"1.20"},{"quartileWeight":"1.0-3.0","totalCatch":1,"averageWeight":"3.90","CPUE":"0.05","species":"LKW","gearCount":20,"gear":"Standard gill nets","quartileCount":"0.1-0.9","totalWeight":3.9},{"species":"YEP","gearCount":20,"CPUE":"56.80","averageWeight":"0.17","quartileWeight":"0.1-0.2","totalCatch":1136,"quartileCount":"7.1-33.9","totalWeight":187.9,"gear":"Standard gill nets"},{"quartileCount":"0.3-1.2","totalWeight":2.5,"gear":"Standard gill nets","gearCount":20,"species":"LMB","CPUE":"0.40","quartileWeight":"0.6-1.0","totalCatch":8,"averageWeight":"0.31"},{"quartileCount":"1.0-6.6","totalWeight":69.4,"gear":"Standard gill nets","species":"RKB","gearCount":20,"CPUE":"8.00","averageWeight":"0.43","quartileWeight":"0.3-0.5","totalCatch":160}],"lengths":{},"surveySubType":"Population Assessment","narrative":"THE GILLNET CATCH REFLECTED THE PRESENCE OF MANY YOUNG WALLEYES. THE WALLEYE CATCH WAS THE SECOND HIGHEST ON RECORD EXCEEDED ONLY BY 1990. A WIDE VARIETY OF SIZES WERE COLLECTED INDICATING THE PRESENCE OF MANY YEAR CLASSES. CATCHES OF THE OTHER SPECIES WERE WITHIN THE RANGES PREVIOUSLY OBSERVED WITH THE EXCEPTIONS OF YELLOW BULLHEAD AND CENTRARCHIDS. IT IS UNKNOWN WHY THE HIGH NUMBERS OF YELLOW BULLHEADS, ROCK BASS, PUMPKIN- SEEDS, AND BLACK CRAPPIE WERE COLLECTED.
","surveyDate":"1991-05-11","surveyID":"100434","surveyType":"Standard Survey","headerInfo":{"wb_name":"Cass","wb_type":"Lake","wb_id":"04003000","id_date":"1991-05-11","county":"Beltrami","wb_alt_name":"","survey_type":"Population Assessment","survey_id":"100434"}},{"narrative":"Background
\nCass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. The U.S. Forest Service modified the dam during winter 2015-2016 to a fixed-crest rock-arch structure with a gated bypass channel that will increase outlet capacity during high water events and aid in lowering water levels during winter to increase water storage capacity for the spring season.
\n
\nThe Leech Lake Band of Chippewa Indians operates a commercial fishery for Lake Whitefish and Cisco on the Cass Lake chain. A limited subsistence fishery for game species is also allowed for Band members.
\n
\nA U.S. Environmental Protection Agency (EPA) Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The EPA has placed a consumption advisory on Lake Whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species.
\n
\nThere are currently no special fishing regulations in effect on Cass Lake. All species are managed under statewide regulations.
\n
\nPresent Fish Population Status
\nThe Walleye population of Cass Lake is healthy and is comprised of good numbers of fish distributed among numerous size and age classes. The 2019 gill net catch rate was 15.7 fish per net, slightly greater than the long-term median catch rate (13.1 fish/net), and among the highest catch rates observed over the past 15 years. Nearly half of the catch was between 14 and 20 inches. Captured fish ranged from ages 0 to 11 with most fish ages 1 to 6. The record-strong 2013 year class, which averages about 18.5\" inches, comprised approximately 20% of the total sample. These fish are ideal size for harvest and there are also good numbers of fish from slightly younger year classes that will provide fish for the frying pan. One-year-old fish (approximately 10 inches) were the most abundant year class in the gill net catch, which suggests the future of Walleye in Cass Lake is bright. The clearer-than-usual water is due to the well-established zebra mussel population and this trend is expected to continue. As a result, much of the Walleye fishing pressure should be focused around low light periods or when there is a chop on the water as the clear water tends to keep fish deeper during the day. The catch rate for age-0 Walleye (approximately 6 inches) during fall electrofishing was quite low, but this is a common occurrence the year after a strong year class (like we saw in 2018).
\n
\nThe gill net catch rate for Yellow Perch (69 per net) was well above the long-term median (47 per net). Growth rates have increased remarkably which has increased the number of keeper-sized fish in the population compared to recent years. The catch rate for fish over 9 inches in 2019 (10.8 fish/net) was the second-highest observed since the Large Lake Program began in 1983. The largest fish exceeded 12 inches in length and anglers continue put together some impressive catches.
\n
\nThe 2019 Northern Pike catch rate of 2.7 fish per net was less than the long-term median of 3.2 fish per gill net. This decline in gill net catch rate is encouraging as modest densities of Northern Pike tend to result in faster growth rates and larger fish. Remember, Cass Lake lies in the North Central Zone for Northern Pike so the daily bag limit is 10 fish per day with a 22- to 26-inch protected slot limit (no harvest of fish in this size range) and no more than two fish can be over 26 inches. See the 2020 Minnesota Fishing Regulation booklet for more information. About one-third of Northern Pike in the 2019 gill net assessment were within the protected slot limit, and 47% of fish were larger than 26 inches and thus available for harvest.
\n
The walleye population of Cass Lake is healthy and is comprised of good numbers of fish distributed among numerous year classes. The 2006 gill net catch rate of 13.7 fish/net is very similar to the long-term median catch rate (13.3 fish/net). Historic data indicate that overall walleye biomass was slightly higher during the 1990s than in recent years. However, the recruitment of several recent strong year classes - especially the 2002 year class - appears to be replenishing the population. Mean size of individual walleye declined slightly from 2005, reflecting an abundance of young fish. Fifty percent of the sample consisted of fish less than age-4+, and most of those were from the 2003 and 2005 year classes.
\n
\nAnalyses of the fall 2006 gill net sample indicate that walleye from 14 year classes were sampled, the oldest a female from the 1989 year class (age-17). Only 3% of the walleye sample consisted of fish from the strong 1999 year class. Fish from the strong 2001 and 2002 year classes were abundant, and made up a combined 44% of the gill net catch. Twenty-nine percent of all walleye sampled were 16 inches or larger.
\n
\nMean catch rates for yellow perch were below long-term medians for both number and weight per gill net lift. Approximately 34% of the sample consisted of perch 8 inches or larger, and 8% were 10 inches or larger. Average size of yellow perch improved in 2006; however, there is some evidence that quality of this population has decreased over the past 30 years, as indicated by a gradual decline in average fish size.
\n
\nThe 2006 northern pike catch rate of 1.8 fish per net was below the long-term median of 2.7 fish/net, and the catch rate in terms of weight (6.8 lbs/net) was slightly below the long-term median (9.2 lbs/net). Approximately 60% of the sample was comprised of northern pike less than 26.0 inches, while 17% were 28.0 inches or larger.
\n
\nCatch rates for all other fish species were similar to long-term averages, highly variable, or so low that no useful trends could be discerned.
\n
Cass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. The Leech Lake Band of Chippewa Indians operates a commercial fishery for lake whitefish and cisco on the Cass Lake chain. A limited subsistence fishery for game species is also allowed for Band members. The only MN-DNR special fishing regulations currently in effect are a 48-inch minimum length limit for muskellunge and a ban on winter spearing for Cass Lake proper (excluding the remainder of the chain of lakes). A U.S. Environmental Protection Agency (EPA) Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The EPA has placed a consumption advisory on lake whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species.
\n
\nPresent Fish Population Status
\nThe walleye population of Cass Lake is healthy and is comprised of good numbers of fish distributed among numerous size and age classes. The 2008 gill net catch rate was 9.7 fish per net, and slightly below the long-term median catch rate (13 fish/net). Historic data indicate that overall walleye biomass was slightly higher during the 1990\u0019s than in recent years.
\nTwelve consecutive year classes of walleye were sampled in 2008 with the oldest fish representing the 1996 year class (age 12). The strong 2001 and 2002 year classes have provided good numbers of fish from 20 to 22 inches. Fourteen percent of the gill net catch was greater than 20 inches in length. The 2006 year class is shaping up to be the strongest year class since 2002. This year class averaged 12.5 inches in length during fall gill netting. Approximately 70% of the sample consisted of fish less than age-3 with a similar percentage of fish less than 15 inches. These fish should provide good fishing opportunities for the next several years as they grow to a desirable size.
\nThe gill net catch rate for yellow perch (49 per net) was similar to the long-term median (48 per net). Approximately 20% of the sample consisted of perch 8 inches or larger, and 4% were 10 inches or larger. The length distribution of yellow perch in 2008 was nearly identical to the long-term median distribution with fish up to 12 inches. There is some evidence that quality of this population has decreased over the past 30 years, as indicated by an overall gradual decline in average fish size.
\nThe 2007 northern pike catch rate of 3.5 fish per net was slightly greater than the long-term median of 2.9 fish per gill net. The size structure of the pike population is good with approximately 30% of the sample was composed of northern pike greater than 26 inches with 13% greater than 30 inches.
\nMuskellunge are not sampled effectively with gill nets and few are seen during annual gill net assessments. The 2008 creel survey showed the muskellunge catch rate to be the highest on record (0.04 fish/angler hour). The average length of a released fish was 37 inches with the largest fish recorded during the survey measuring 47 inches.
Cass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. The Leech Lake Band of Chippewa Indians operates a commercial fishery for lake whitefish and cisco on the Cass Lake chain. A limited subsistence fishery for game species is also allowed for Band members. The only MN-DNR special fishing regulation currently in effect is a ban on winter spearing for Cass Lake proper (excluding the remainder of the chain of lakes). A U.S. Environmental Protection Agency (EPA) Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The EPA has placed a consumption advisory on lake whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species.
\n
\nPresent Fish Population Status
\nThe walleye population of Cass Lake is healthy and is comprised of good numbers of fish distributed among numerous size and age classes. The 2011 gill net catch rate was 13.3 fish per net, and slightly above the long-term median catch rate (12.9 fish/net). Fish representing each year class from 2001 to 2011 were sampled (ages 0 to 10). Approximately 61% of the walleye sample consisted of fish between 12 and 17 inches. These fish should provide good fishing opportunities for the next few years. The strong 2008 year class averaged 13.5 inches in length during the fall assessment and should provide good numbers of eater-sized fish beginning in 2012. Sampling for young-of-the-year walleye using bottom trawls and electrofishing suggest that the 2011 year class will be well above average strength which, coupled with a strong 2008 year class, means the future is bright for the Cass Lake walleye fishery.
\nThe gill net catch rate for yellow perch (47 per net) was similar to the long-term median (48 per net). Nineteen percent of the sample consisted of perch 8 inches or larger, and 7% were 10 inches or larger. There is some evidence that quality of this population has decreased over the past 30 years, as indicated by an overall gradual decline in average fish size. However, the current size structure should provide ample angling opportunities and with a little bit of sorting, catches of nice-sized fish are still possible.
\nThe 2011 northern pike catch rate of 3.8 fish per net was slightly greater than the long-term median of 2.9 fish per gill net. The size structure of the pike population is good with approximately 18% of the sample greater than 26 inches and 9% greater than 30 inches. A spring trap netting assessment in 2011 captured nearly 1,200 northern pike. The largest fish approached 42 inches and the average length was 22 inches. Twenty-three percent of female northern pike were greater than 28 inches but no male pike achieved this length. It is rare for a male northern pike in Cass Lake to reach 28 inches.
\nA two-year muskellunge assessment was initiated in 2011 and 112 fish were captured during the first season. Fish ranged in length from 33.3 to 53.7 inches with an average length of 43.4 inches. Eighteen muskellunge were greater than 48 inches in length.
\n
A targeted survey of nearshore fish species in Cass Lake, which is located wholly within the Leech Lake Reservation, was conducted over several days, including July 29, August 1, and August 12-13, 2024, by Index of Biological Integrity (IBI) Program staff. Sampling sites were evenly spaced around the lake, and each was sampled by backpack electrofishing and seining with a 50-foot or 15-foot seine, where possible. Backpack electrofishing was completed at all 24 sampling stations. Similarly, a 50-foot seine was used to sample 16 stations, and a 15-foot seine was used to sample six stations. Two stations were not seined due to dense aquatic vegetation or depth. Nearshore sampling captured 24 species of fish including seven species that are intolerant of disturbance (i.e., Banded Killifish, Blacknose Shiner, Iowa Darter, Logperch, Longnose Dace, Mimic Shiner, and Rock Bass) and two species that are tolerant of disturbance (i.e., Fathead Minnow and Black Bullhead).
\n
\nA concurrent summer trap net survey was also conducted by IBI Program Staff. Fifteen trap nets were set along the shoreline and in shallow offshore locations that encompassed multiple habitat types. Trap net sampling captured 16 species of fish, including three that are intolerant of disturbance (i.e., Greater Redhorse, Muskellunge, and Rock Bass) and one that is tolerant of disturbance (i.e., Black Bullhead). Yellow Perch comprised a majority of the trap net catch by number and Bowfin comprised a majority by biomass.
\n
\nThe nearshore and trap net data were combined with gill net data from a September 2024 survey to describe the fish community and provide a Fish-based IBI (FIBI) score. The FIBI uses fish community data to measure a lake's health, and the types of fish species present can help identify any stressors that may be negatively affecting the lake environment. In Minnesota lakes, certain fish species cannot survive without clean water and a healthy habitat (e.g., Blackchin Shiner, Iowa Darter, and Rock Bass), while other species are tolerant of degraded conditions (e.g., Black Bullhead and Fathead Minnow). The FIBI score, composed of several fish community diversity and composition metrics, indicates the overall health of a lake by comparing it to what is expected for a healthy lake. For additional information on the FIBI, search for \"lake index of biological integrity\" on the mndnr.gov website.
\n
\nResults from this survey provide evidence that the warm and coolwater fish community in Cass Lake is healthy as indicated by an FIBI score that exceeds the Minnesota DNR FIBI exceptional use threshold determined for similar lakes.
\n
\nTemperature and dissolved oxygen measurements were also collected from the deepest basin in Cass Lake on July 30th, 2024, to evaluate the quantity and quality of cold, oxygenated water (i.e., oxythermal habitat) available to Lake Whitefish, the most sensitive coldwater species present in this lake (Cisco, also known as 'Tullibee', are also present). During the summer, Lake Whitefish require a layer of oxythermal habitat that contains water temperatures below 17.2 degrees C (63.0 degrees F) and dissolved oxygen concentrations above 3.0 mg/L. Based on the profile from the deepest basin, the water temperature decreased below 17.2 degrees C (63.0 degrees F) at 58.7 feet and the dissolved oxygen concentration decreased to 3.0 mg/L at 87.9 feet at the time of sampling. The thickness of this layer of water in the water column was 29.2 feet, indicating that oxythermal habitat was present for Lake Whitefish.
\n
\nFurther, the temperature at which dissolved oxygen decreased to 3.0 mg/L (i.e., TDO3, a single variable to characterize oxythermal habitat) was 10.7 degrees C (51.3 degrees F). TDO3 values cooler than 17.2 degrees C (63.0 degrees F) indicate that oxythermal conditions were suitable for Lake Whitefish at the time of the survey.
\n
\nThis is the first Minnesota DNR temperature and dissolved oxygen survey completed on Cass Lake during the late summer period of maximum oxythermal stress. When inadequate oxythermal habitat is available, Lake Whitefish are squeezed into unfavorable, warmer water conditions and experience higher levels of stress.
\n
\nYou can help protect the fish community in Cass Lake by reducing runoff and maintaining natural shorelines.
\n
Special Problems and Conditions Affecting Fish or FishingCass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. A Superfund cleanup site exists on Pike Bay on the south side of Cass Lake. The U. S. Environmental Protection Agency recently placed a consumption advisory on lake whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species. The Leech Lake Band of Chippewa Indians operates a commercial fishery for lake whitefish and cisco on the Cass Lake chain. The only special angling regulation currently in effect is a ban on winter northern pike spearing for Cass Lake proper (excluding the remainder of the chain of lakes).Present Fish Population StatusThe walleye population of Cass Lake remains healthy and is comprised of good numbers of fish distributed among many different year classes. However, the 2003 gill net catch rate of 10.5 fish/net is currently below the long-term median catch rate of 13.3 fish/net. The historic data also indicate that overall walleye biomass was slightly higher during the 1990's than in 2002 and 2003. It appears that the slight reduction in overall population size may be due to the presence of two weaker-than-average year classes that currently make up the adult segment of the population.Analyses of the fall 2003 gill net sample indicate that walleye from 13 year classes were sampled, the oldest a male from the 1990 year class (age 13+). Approximately 25% of the walleye sample consisted of fish from the strong 1999 year class. Size of these age-4+ fish ranged from 14 to 19 inches total length, with an average length of 16.2 inches. Juvenile fish from the 2001 and 2002 year classes also appear to be abundant, and made up a combined 51% of the gill net catch. Still, approximately 28% of all walleye sampled were 16 inches or larger. During the past decade, average weight of individual walleye has increased, further enhancing the quality of this population.Mean catch rates for yellow perch were below the long-term median for both numbers and weight per gill net lift; however, historic data indicate that this population fluctuates cyclically. Approximately 21% of the sample consisted of perch 8 inches or larger, and about 3% were 10 inches or larger. There is some indication that quality of this population has decreased over the past 30 years, as evidenced by a gradual decline in average fish size. Nevertheless, Cass Lake continues to provide excellent perch angling opportunities.The 2003 northern pike catch rate of 3.1 fish per net was very near the long-term median of 2.9 fish/net, although the catch rate in terms of weight (8.8 lbs/net) was slightly below the long-term median (9.7 lbs/net). Increased rates of recruitment in recent years - possibly due to higher than average water levels during the late 1990's - appear to have increased the number of small to medium-sized northern pike in Cass Lake. Approximately 82% of the sample was comprised of northern pike less than 26.0 inches, while only 8% were 28.0 inches or larger.Catch rates for all other fish species were similar to long-term averages, highly variable, or so low that no useful trends could be discerned.
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\nCass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. The U.S. Forest Service modified the dam during winter 2015-2016 to a fixed-crest rock-arch structure with a gated bypass channel that will increase outlet capacity during high water events and aid in lowering water levels during winter to increase water storage capacity for the spring season.
\n
\nThe Leech Lake Band of Chippewa Indians operates a commercial fishery for Lake Whitefish and Cisco on the Cass Lake chain. A limited subsistence fishery for game species is also allowed for Band members.
\n
\nA U.S. Environmental Protection Agency (EPA) Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The EPA has placed a consumption advisory on Lake Whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species.
\n
\nThere are currently no special fishing regulations in effect on Cass Lake. All species are managed under statewide regulations.
\n
\n
\nPresent Fish Population Status
\nThe Walleye population of Cass Lake is healthy and is comprised of good numbers of fish distributed among numerous size and age classes. The 2018 gill net catch rate was 16.2 fish per net, slightly greater than the long-term median catch rate (13.1 fish/net), and among the highest catch rates observed over the past 15 years. Approximately half of the catch was between 14 and 18 inches. Captured fish ranged from ages 0 to 17 with most fish ages 2 to 5. The record-strong 2013 year class, which averages about 17 inches, comprised over one-third of the total sample. These fish are ideal size for harvest and there are also good numbers of fish from slightly younger year classes that will also provide fish for the frying pan. The clearer-than-usual water is due to the well-established zebra mussel population and this trend is expected to continue. As a result, much of the Walleye fishing pressure should be focused around low light periods or when there is a chop on the water as the clear water tends to keep fish deeper during the day. The catch rate for age-0 Walleye (approximately 6 inches) during fall electrofishing was above average which suggests that the 2018 year class will provide good fishing in a few years.
\n
\nThe gill net catch rate for Yellow Perch (44 per net) was near the long-term median (47 per net). Growth rates have increased remarkably which has increased the number of keeper-sized fish in the population compared to recent years. The catch rate for fish over 9 inches in 2018 (9.5 fish/net) was the second-highest observed since the Large Lake Program began in 1983. The largest fish exceeded 12 inches in length and anglers last fall and winter put together some impressive catches.
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\nThe 2018 Northern Pike catch rate of 2.0 fish per net was less than the long-term median of 3.2 fish per gill net. This decline in gill net catch rate is encouraging as modest densities of Northern Pike tend to result in faster growth rates and larger fish. Remember, Cass Lake lies in the North Central Zone for Northern Pike so the daily bag limit is 10 fish per day with a 22- to 26-inch protected slot limit (no harvest of fish in this size range) and no more than two fish can be over 26 inches. See the 2018 Minnesota Fishing Regulation booklet for more information. Sixty-five percent of Northern Pike in the 2018 gill net assessment were within the protected slot limit (so measure carefully), but 30% of fish were larger than 26 inches and thus available for harvest.
\n
THE 1986 GILLNET INDICES ARE LOWER THAN THOSE OBSERVED IN 1983,1984 AND 1985 FOR WALLEYE, NORTH- ERN PIKE, AND YELLOW PERCH. THE ABUNDANCE OF WALL- EYE 7-11 SEINING BUT WERE NOT OBSERVED IN THE FALL INDEX NETTING. THE AVERAGE WEIGHT FROM THE 1986 SUMMER CREEL WAS 1.1 FOR WALLEYE, 2.43 FOR NORTHERN PIKE AND 0.34 FOR YELLOW PERCH.
"},{"fishCatchSummaries":[{"averageWeight":"0.73","quartileWeight":"0.4-1.0","totalCatch":143,"CPUE":"7.15","gearCount":20,"species":"TLC","gear":"Standard gill nets","totalWeight":104.6,"quartileCount":"0.5-5.2"},{"gearCount":20,"species":"BUB","CPUE":"0.05","averageWeight":"1.80","quartileWeight":"1.1-2.7","totalCatch":1,"totalWeight":1.8,"quartileCount":"0.1-0.2","gear":"Standard gill nets"},{"quartileCount":"0.3-1.6","totalWeight":2.4,"gear":"Standard gill nets","CPUE":"0.10","totalCatch":2,"quartileWeight":"0.7-1.2","averageWeight":"1.20","gearCount":20,"species":"BRB"},{"gear":"Standard gill nets","totalWeight":249.3,"quartileCount":"3.0-7.9","species":"NOP","gearCount":20,"totalCatch":70,"quartileWeight":"1.7-2.8","averageWeight":"3.56","CPUE":"3.50"},{"totalCatch":3,"quartileWeight":"0.6-1.0","averageWeight":"1.27","CPUE":"0.15","species":"BLB","gearCount":20,"gear":"Standard gill nets","quartileCount":"0.5-4.1","totalWeight":3.8},{"gear":"Standard gill nets","quartileCount":"1.0-3.5","totalWeight":116.2,"totalCatch":67,"quartileWeight":"1.5-2.3","averageWeight":"1.73","CPUE":"3.35","gearCount":20,"species":"WTS"},{"gear":"Standard gill nets","totalWeight":6,"quartileCount":"0.1-0.3","gearCount":20,"species":"MUE","totalCatch":1,"quartileWeight":"3.1-5.3","averageWeight":"6.00","CPUE":"0.05"},{"gearCount":20,"species":"WAE","CPUE":"10.60","averageWeight":"0.85","totalCatch":212,"quartileWeight":"1.1-1.9","quartileCount":"4.0-9.6","totalWeight":179.7,"gear":"Standard gill nets"},{"quartileWeight":"N/A","totalCatch":24,"averageWeight":"0.12","CPUE":"1.20","species":"PMK","gearCount":20,"gear":"Standard gill nets","quartileCount":"N/A","totalWeight":2.9},{"averageWeight":"2.49","quartileWeight":"1.5-2.7","totalCatch":7,"CPUE":"0.35","species":"SHR","gearCount":20,"gear":"Standard gill nets","totalWeight":17.4,"quartileCount":"0.1-0.5"},{"totalWeight":2,"quartileCount":"0.6-6.4","gear":"Standard gill nets","gearCount":20,"species":"YEB","CPUE":"0.10","totalCatch":2,"quartileWeight":"0.6-0.9","averageWeight":"1.00"},{"CPUE":"0.05","quartileWeight":"N/A","totalCatch":1,"averageWeight":"4.00","species":"TME","gearCount":20,"quartileCount":"N/A","totalWeight":4,"gear":"Standard gill nets"},{"averageWeight":"2.20","quartileWeight":"1.0-3.0","totalCatch":4,"CPUE":"0.20","species":"LKW","gearCount":20,"gear":"Standard gill nets","quartileCount":"0.1-0.9","totalWeight":8.8},{"gearCount":20,"species":"YEP","totalCatch":1144,"quartileWeight":"0.1-0.2","averageWeight":"0.17","CPUE":"57.20","gear":"Standard gill nets","totalWeight":189.9,"quartileCount":"7.1-33.9"},{"gear":"Standard gill nets","quartileCount":"1.0-6.6","totalWeight":28.9,"species":"RKB","gearCount":20,"averageWeight":"0.42","quartileWeight":"0.3-0.5","totalCatch":68,"CPUE":"3.40"}],"lengths":{},"surveySubType":"Population Assessment","narrative":"THE NUMBER OF WALLEYE PER GILLNET LIFT IN 1989 WAS THE HIGHEST REPORTED IN 12 YEARS OF SAMPLING DATES BACK TO 1948. MEAN WEIGHT OF FISH WAS ABOUT 0.8 POUNDS. LENGTH FREQUENCIES OF WALLEYE SHOWED 54% OF THE GILLNET CATCH 12.9 IN. WITH FISH RANGING FROM 7.0-25.0 INCHES. CATCH INDICES FOR YELLOW PERCH, NORTHERN PIKE AND CISCO WERE SIMILAR TO THE LONG TERM AVERAGE (1948-1988).
","headerInfo":{"survey_id":"100391","wb_alt_name":"","survey_type":"Population Assessment","wb_name":"Cass","county":"Beltrami","wb_id":"04003000","wb_type":"Lake","id_date":"1989-10-31"},"surveyDate":"1989-10-31","surveyID":"100391","surveyType":"Standard Survey"},{"narrative":"Cass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. The Leech Lake Band of Chippewa Indians operates a commercial fishery for lake whitefish and cisco on the Cass Lake chain. A limited subsistence fishery for game species is also allowed for Band members. A U.S. Environmental Protection Agency (EPA) Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The EPA has placed a consumption advisory on lake whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species. There are currently no special fishing regulations in effect on Cass Lake. All species are managed under statewide regulations.
\n
\nPresent Fish Population Status
\nThe walleye population of Cass Lake is healthy and is comprised of good numbers of fish distributed among numerous size and age classes. The 2013 gill net catch rate was 11.0 fish per net, slightly below the long-term median catch rate (13.2 fish/net). Fish representing ages 0 to 10 were all represented as well as one 17-year-old fish. Approximately 70% of the walleye sample consisted of fish between 12 and 17 inches, most of which are two- to five-year-old fish. The strong 2008 and 2011 year classes averaged 16.4 and 12.6 inches in length, respectively. These fish should provide good numbers of eater-sized fish for the next few years. The catch rate for age-0 walleye during fall electrofishing was the highest ever observed which suggests that the 2013 year class will also be strong and that the future of the Cass Lake walleye fishery is bright.
\n
\nThe gill net catch rate for yellow perch (48 per net) was similar to the long-term median (47 per net). Although catch rates increased by 30% compared to 2012, this increase was largely due to increased catch of smaller fish. However, there were still a moderate number of fish over 8 inches in the sample (20%) with some fish approaching 12 inches in length. There is some evidence that quality of this population has decreased over the past 30 years, as indicated by an overall gradual decline in average fish size. However, the current size structure should provide ample angling opportunities and with a little bit of sorting, catches of nice-sized fish are possible.
\n
\nThe 2013 northern pike catch rate of 4.4 fish per net was greater than the long-term median of 2.9 fish per gill net. The size structure of the pike population is good with approximately 16% of female fish greater than 28 inches and 7% greater than 30 inches. It is rare for a male northern pike in Cass Lake to reach 28 inches.
\n
\nOver the next two years, anglers may encounter a DNR creel clerk that may want to ask a few questions about their fishing trip. If you do encounter our clerk please take just a few minutes to answer these questions. Getting accurate information is vital to managing fish populations in the lake. Questions will range from when you started fishing, to what species you were targeting, and how many you kept/released. The clerk may also ask to measure your catch to provide information on the size of harvested fish which helps up understand which year classes are supporting the fishery, how many pounds of fish are being harvested, angler preferences, etc. Your cooperation would be much appreciated.
\n
Cass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. The U.S. Forest Service modified the dam during winter 2015-2016 to a fixed-crest rock-arch structure with a gated bypass channel that will increase outlet capacity during high water events.
\nThe Leech Lake Band of Chippewa Indians operates a commercial fishery for Lake Whitefish and Cisco on the Cass Lake chain. A limited subsistence fishery for game species is also allowed for Band members.
\nA U.S. Environmental Protection Agency (EPA) Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The EPA has placed a consumption advisory on lake whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species.
\nThere are currently no special fishing regulations in effect on Cass Lake. All species are managed under statewide regulations.
\nPresent Fish Population Status
\nThe Walleye population of Cass Lake is healthy and is comprised of good numbers of fish distributed among numerous size and age classes. The 2015 gill net catch rate was 14.5 fish per net, slightly greater than the long-term median catch rate (13.1 fish/net). Approximately two-thirds of the Walleye sample consisted of age-2 fish (10 to 12 inches) and age-4 fish (15 to 17 inches) inches. There are a number of strong year classes in the population ranging from age 2 to age 7 and these fish should provide good numbers of eater-sized fish for this year as well as the next several seasons. The catch rate for age-0 Walleye (approximately 6 inches) during fall electrofishing was above average, and when coupled with the strong catch in the gill nets, the future of the Cass Lake Walleye fishery appears bright.
\nThe gill net catch rate for Yellow Perch (34 per net) was below the long-term median (47 per net). The number of fish over 8 inches in the sample was modest (11%) although some fish approached 12 inches in length. Anglers continue to find pockets of keeper-sized perch despite the current size structure, albeit with a little bit of sorting, and catches of nice-sized fish are still possible.
\nThe 2015 Northern Pike catch rate of 5.0 fish per net was the highest ever observed and greater than the long-term median of 3.0 fish per gill net. This increased abundance is the result of better-than-usual reproduction the past several years and with that comes an abundance of small fish (< 24 inches). However, there are still good numbers of quality-sized fish (> 26 inches) in the population and these fish represented 21% of the gill net sample.
\n
Cass Lake supports a native Muskellunge population that is entirely self-sustaining. Maximum size of angler-caught Muskellunge has improved during the last few creel survey cycles with fish up to 50 inches in length reported to the creel clerk. In recent creel surveys, anglers have released nearly all Muskellunge caught, including those greater than minimum length limits.
\n
\nMuskellunge sampling efforts in spring 2016 consisted of trap netting during the spawning period. This effort represents year one of a two-year mark-recapture abundance estimate of the adult population. A total of 49 adult Muskellunge was caught (24 females and 25 males). Captured fish ranged from 35.4 to 50.0 inches with three fish over 48 inches and one fish over 50 inches. All fish over 45 inches were females. Fish ranged from ages 5 to 13 with approximately 60% of the catch between ages 6 and 9.
\nA more detailed analysis of the Cass Lake Muskellunge population will be available after the completion of the second year of this two-year study.
\n
Background
\n
\nCass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. The U.S. Forest Service modified the dam during winter 2015-2016 to a fixed-crest rock-arch structure with a gated bypass channel that will increase outlet capacity during high water events and aid in lowering water levels during winter to increase water storage capacity for the spring season.
\n
\nThe Leech Lake Band of Chippewa Indians operates a commercial fishery for Lake Whitefish and Cisco on the Cass Lake chain. A limited subsistence fishery for game species is also allowed for Band members.
\n
\nA U.S. Environmental Protection Agency (EPA) Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The EPA has placed a consumption advisory on Lake Whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species.
\n
\nAll species in Cass Lake are managed under statewide regulations, except sunfish, for which a chain-wide five fish daily bag limit was implemented on March 1, 2021. The possession limit for sunfish remains at 20 fish.
\n
\n
\nPresent Fish Population Status
\n
\nThe Walleye population of Cass Lake is healthy and is comprised of good numbers of fish distributed among numerous size and age classes. The 2020 gill net catch rate was 14.0 fish per net, slightly greater than the long-term median catch rate (13.2 fish/net), and among the highest catch rates observed over the past 15 years. Captured fish ranged from ages 0 to 11 with most fish ages 1 to 7. One-third of the population was between 12 and 14 inches, most of which belong to the strong 2018 year class. These fish will provide good catch rates and fish for the frying pan for the next several years. The record-strong 2013 year class is still prominent in the population and providing anglers with quality-sized fish that average about 21 inches. The clearer-than-usual water is due to the well-established zebra mussel population and this trend is expected to continue. As a result, much of the Walleye fishing pressure should be focused around low light periods or when there is a chop on the water as the clear water tends to keep fish deeper during the day. The catch rate for age-0 Walleye (approximately 6 inches) during fall electrofishing was modest, but Cass Lake has a history of producing strong year classes every two or three years and this trend is expected to continue. The modest year classes between the strong ones help provide anglers with a wide size range of fish which helps reduce fishing mortality on the stronger age groups.
\n
\nThe gill net catch rate for Yellow Perch (33 per net) was below the long-term median (45 per net). Growth rates have increased remarkably which has increased the number of keeper-sized fish in the population compared to recent years. The catch rate for fish over 9 inches in 2020 (7.1 fish/net) was among the highest observed since the Large Lake Program began in 1983. The portion of the gill net catch over 8 inches (41%) was the highest ever observed. The largest fish exceeded 12 inches in length and anglers continue put together some impressive catches.
\n
\nThe 2020 Northern Pike catch rate of 2.3 fish per gill net was less than the long-term median of 3.2 fish per net. The observed decline in gill net catch rates for Northern Pike over the past few years is encouraging as modest densities tend to result in faster growth rates and larger fish. Remember, Cass Lake lies in the North-Central Zone for Northern Pike so the daily bag limit is 10 fish per day with a 22- to 26-inch protected slot limit (no harvest of fish in this size range) and no more than two fish can be over 26 inches. See the 2021 Minnesota Fishing Regulation booklet for more information. About one-third of Northern Pike in the 2020 gill net assessment were below the protected slot limit, one-third within the size restriction, and one-third of fish were larger than 26 inches. This will provide good harvest opportunities of fish both above and below the protected slot limit.
\n
Special Problems and Conditions Affecting Fish or FishingCass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. A Superfund cleanup site exists on Pike Bay on the south side of Cass Lake. The U. S. Environmental Protection Agency has placed a consumption advisory on lake whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species. The Leech Lake Band of Chippewa Indians operates a commercial fishery for lake whitefish and cisco on the Cass Lake chain. The only special angling regulation currently in effect is a ban on winter northern pike spearing for Cass Lake proper (excluding the remainder of the chain of lakes).Present Fish Population StatusThe walleye population of Cass Lake is healthy and is comprised of good numbers of fish distributed among numerous year classes. The 2004 gill net catch rate of 12.4 fish/net is very close to the long-term median catch rate of 12.9 fish/net. However, historic data indicate that overall walleye biomass was slightly higher during the 1990's than in recent years. It appears that the recent reduction in overall population size may be due to the presence of several weaker-than-average year classes that currently make up the adult segment of the population. Average size of individual walleye in the gill net sample was low, indicating a shift in the age distribution towards younger fish.Analyses of the fall 2004 gill net sample indicate that walleye from 10 year classes were sampled, the oldest a female from the 1994 year class (age 10+). Surprisingly, only 6% of the walleye sample consisted of fish from the strong 1999 year class. Younger fish from the strong 2001 and 2002 year classes were abundant, and made up a combined 67% of the gill net catch. Only 10% of all walleye sampled were 16 inches or larger.Mean catch rates for yellow perch were below long-term medians for both number and weight per gill net lift; however, historic data indicate that this population fluctuates cyclically. Only 10% of the sample consisted of perch 8 inches or larger, and about 2% were 10 inches or larger. Similar to the walleye population, a low average weight indicates a shift in the age distribution towards younger fish. There is some evidence that quality of this population has decreased over the past 30 years, as indicated by a gradual decline in average fish size.The 2004 northern pike catch rate of 2.4 fish per net was very near the long-term median of 2.9 fish/net, and the catch rate in terms of weight (8.5 lbs/net) was slightly below the long-term median (9.6 lbs/net). Approximately 70% of the sample was comprised of northern pike less than 26.0 inches, while 21% were 28.0 inches or larger. A slight improvement in northern pike size structure may be due to good recruitment that occurred during the late 1990's.Catch rates for all other fish species were similar to long-term averages, highly variable, or so low that no useful trends could be discerned.
","fishCatchSummaries":[{"totalWeight":64918,"quartileCount":"0.5-5.2","gear":"Standard gill nets","CPUE":"8.20","quartileWeight":"0.4-1.0","totalCatch":164,"averageWeight":"0.87","species":"TLC","gearCount":20},{"quartileCount":"0.3-1.6","totalWeight":236,"gear":"Standard gill nets","CPUE":"0.05","quartileWeight":"0.7-1.2","totalCatch":1,"averageWeight":"0.52","gearCount":20,"species":"BRB"},{"gearCount":20,"species":"NOP","totalCatch":47,"quartileWeight":"1.7-2.8","averageWeight":"3.62","CPUE":"2.35","gear":"Standard gill nets","totalWeight":77186,"quartileCount":"3.0-7.9"},{"totalWeight":51623,"quartileCount":"1.0-3.5","gear":"Standard gill nets","CPUE":"3.25","averageWeight":"1.75","totalCatch":65,"quartileWeight":"1.5-2.3","gearCount":20,"species":"WTS"},{"CPUE":"12.35","totalCatch":247,"quartileWeight":"1.1-1.9","averageWeight":"0.80","species":"WAE","gearCount":20,"totalWeight":89866,"quartileCount":"4.0-9.6","gear":"Standard gill nets"},{"gear":"Standard gill nets","quartileCount":"N/A","totalWeight":92,"gearCount":20,"species":"PMK","quartileWeight":"N/A","totalCatch":1,"averageWeight":"0.20","CPUE":"0.05"},{"totalWeight":1072,"quartileCount":"0.1-0.5","gear":"Standard gill nets","CPUE":"0.05","totalCatch":1,"quartileWeight":"1.5-2.7","averageWeight":"2.36","gearCount":20,"species":"SHR"},{"CPUE":"0.70","averageWeight":"0.88","totalCatch":14,"quartileWeight":"0.6-0.9","species":"YEB","gearCount":20,"totalWeight":5612,"quartileCount":"0.6-6.4","gear":"Standard gill nets"},{"quartileCount":"0.1-0.9","totalWeight":4356,"gear":"Standard gill nets","CPUE":"0.15","averageWeight":"3.20","quartileWeight":"1.0-3.0","totalCatch":3,"gearCount":20,"species":"LKW"},{"gearCount":20,"species":"BLG","CPUE":"0.25","quartileWeight":"N/A","totalCatch":5,"averageWeight":"0.12","quartileCount":"N/A","totalWeight":270,"gear":"Standard gill nets"},{"gear":"Standard gill nets","quartileCount":"7.1-33.9","totalWeight":54246,"quartileWeight":"0.1-0.2","totalCatch":885,"averageWeight":"0.14","CPUE":"44.25","gearCount":20,"species":"YEP"},{"averageWeight":"0.46","quartileWeight":"0.3-0.5","totalCatch":121,"CPUE":"6.05","species":"RKB","gearCount":20,"gear":"Standard gill nets","quartileCount":"1.0-6.6","totalWeight":25478}],"surveySubType":"Population Assessment","lengths":{"SHR":{"minimum_length":17,"maximum_length":17,"fishCount":[[17,1]]},"BLG":{"fishCount":[[3,1],[4,2],[5,1],[7,1]],"maximum_length":7,"minimum_length":3},"PMK":{"fishCount":[[6,1]],"maximum_length":6,"minimum_length":6},"LKW":{"minimum_length":19,"maximum_length":20,"fishCount":[[19,2],[20,1]]},"WTS":{"maximum_length":18,"minimum_length":7,"fishCount":[[10,3],[11,1],[12,7],[13,5],[14,4],[15,2],[16,12],[17,16],[18,9],[7,2],[8,3],[9,1]]},"WAE":{"maximum_length":24,"minimum_length":7,"fishCount":[[10,15],[11,53],[12,42],[13,42],[14,39],[15,14],[16,5],[17,4],[18,4],[19,3],[20,2],[21,1],[23,1],[24,3],[7,1],[8,7],[9,11]]},"YEB":{"minimum_length":9,"maximum_length":12,"fishCount":[[10,4],[11,3],[12,4],[9,3]]},"TLC":{"maximum_length":15,"minimum_length":8,"fishCount":[[10,7],[11,22],[12,20],[13,56],[14,24],[15,9],[8,15],[9,11]]},"YEP":{"fishCount":[[10,8],[11,6],[4,7],[5,319],[6,313],[7,164],[8,41],[9,27]],"maximum_length":11,"minimum_length":4},"BRB":{"minimum_length":9,"maximum_length":9,"fishCount":[[9,1]]},"NOP":{"minimum_length":18,"maximum_length":32,"fishCount":[[18,1],[19,1],[20,3],[21,6],[22,7],[23,7],[24,2],[25,7],[26,2],[27,1],[28,3],[30,2],[31,1],[32,4]]},"RKB":{"fishCount":[[10,12],[3,1],[4,7],[5,10],[6,17],[7,23],[8,24],[9,27]],"minimum_length":3,"maximum_length":10}},"surveyType":"Standard Survey","surveyID":"100936","surveyDate":"2004-09-21","headerInfo":{"survey_type":"Population Assessment","wb_alt_name":"","survey_id":"100936","wb_name":"Cass","id_date":"2004-09-21","wb_type":"Lake","wb_id":"04003000","county":"Beltrami"}},{"narrative":"THE GILLNET CATCH OF WAE WAS THE SECOND HIGHEST RECORD AND WAS OVER 3 TIMES THE CLASS 22 MEDIAN. A WIDE RANGE OF SIZES WAS COLLECTED INDICATING MANY YEAR CLASSES ARE PRESENT. FEW, IF ANY, YOY WAE WERE COLLECTED IN CONTRAST TO 1991. THE CATCH OF YEP WAS THE HIGHEST RECORDED IN 15 YEARS OF NETTING AND WAS ALMOST 6 TIMES THE CLASS 22 MEDIAN. CATCHES OF PMK AND RKB WERE ALSO HIGHER THAN IN MOST PREVIOUS YEARS AND ABOVE THE CLASS 22 MEDIANS. CATCHES OF OTHER WERE SIMILAR TO NUMBERS COLLECTED IN PREVIOUS YEARS FROM CASS LAKE. A 40+ INCH NOP WAS COLLECTED-THE SECOND TIME THIS HAS OCCURRED IN THREE YEARS.
","lengths":{},"surveySubType":"Population Assessment","fishCatchSummaries":[{"gear":"Standard gill nets","quartileCount":"0.5-5.2","totalWeight":122.2,"averageWeight":"0.75","quartileWeight":"0.4-1.0","totalCatch":164,"CPUE":"8.20","gearCount":20,"species":"TLC"},{"species":"BUB","gearCount":20,"totalCatch":2,"quartileWeight":"1.1-2.7","averageWeight":"2.80","CPUE":"0.10","gear":"Standard gill nets","totalWeight":5.6,"quartileCount":"0.1-0.2"},{"quartileCount":"0.3-1.6","totalWeight":2.7,"gear":"Standard gill nets","gearCount":20,"species":"BRB","CPUE":"0.10","averageWeight":"1.35","totalCatch":2,"quartileWeight":"0.7-1.2"},{"quartileWeight":"0.2-0.5","totalCatch":1,"averageWeight":"0.40","CPUE":"0.05","gearCount":20,"species":"BLC","gear":"Standard gill nets","quartileCount":"0.2-1.1","totalWeight":0.4},{"quartileCount":"3.0-7.9","totalWeight":233.2,"gear":"Standard gill nets","gearCount":20,"species":"NOP","CPUE":"2.85","averageWeight":"4.09","totalCatch":57,"quartileWeight":"1.7-2.8"},{"CPUE":"0.05","averageWeight":"0.80","totalCatch":1,"quartileWeight":"0.6-1.0","gearCount":20,"species":"BLB","quartileCount":"0.5-4.1","totalWeight":0.8,"gear":"Standard gill nets"},{"CPUE":"3.90","averageWeight":"2.24","totalCatch":78,"quartileWeight":"1.5-2.3","species":"WTS","gearCount":20,"totalWeight":174.5,"quartileCount":"1.0-3.5","gear":"Standard gill nets"},{"gear":"Standard gill nets","quartileCount":"0.1-0.3","totalWeight":11.4,"species":"MUE","gearCount":20,"quartileWeight":"3.1-5.3","totalCatch":2,"averageWeight":"5.70","CPUE":"0.10"},{"gear":"Standard gill nets","quartileCount":"4.0-9.6","totalWeight":393.8,"averageWeight":"1.11","quartileWeight":"1.1-1.9","totalCatch":354,"CPUE":"17.70","gearCount":20,"species":"WAE"},{"gear":"Standard gill nets","totalWeight":4.1,"quartileCount":"N/A","gearCount":20,"species":"PMK","averageWeight":"0.15","totalCatch":28,"quartileWeight":"N/A","CPUE":"1.40"},{"averageWeight":"2.54","quartileWeight":"1.5-2.7","totalCatch":10,"CPUE":"0.50","species":"SHR","gearCount":20,"gear":"Standard gill nets","quartileCount":"0.1-0.5","totalWeight":25.4},{"gear":"Standard gill nets","quartileCount":"0.6-6.4","totalWeight":9.8,"species":"YEB","gearCount":20,"quartileWeight":"0.6-0.9","totalCatch":10,"averageWeight":"0.98","CPUE":"0.50"},{"gear":"Standard gill nets","totalWeight":4,"quartileCount":"0.1-0.9","species":"LKW","gearCount":20,"quartileWeight":"1.0-3.0","totalCatch":1,"averageWeight":"4.00","CPUE":"0.05"},{"gear":"Standard gill nets","totalWeight":0.6,"quartileCount":"N/A","species":"BLG","gearCount":20,"quartileWeight":"N/A","totalCatch":3,"averageWeight":"0.20","CPUE":"0.15"},{"gearCount":20,"species":"YEP","CPUE":"88.60","quartileWeight":"0.1-0.2","totalCatch":1772,"averageWeight":"0.15","totalWeight":270,"quartileCount":"7.1-33.9","gear":"Standard gill nets"},{"gearCount":20,"species":"LMB","quartileWeight":"0.6-1.0","totalCatch":2,"averageWeight":"0.25","CPUE":"0.10","gear":"Standard gill nets","quartileCount":"0.3-1.2","totalWeight":0.5},{"gearCount":20,"species":"RKB","CPUE":"7.10","quartileWeight":"0.3-0.5","totalCatch":142,"averageWeight":"0.39","quartileCount":"1.0-6.6","totalWeight":55.2,"gear":"Standard gill nets"}],"headerInfo":{"county":"Beltrami","wb_id":"04003000","wb_type":"Lake","id_date":"1992-05-22","wb_name":"Cass","survey_id":"100435","wb_alt_name":"","survey_type":"Population Assessment"},"surveyType":"Standard Survey","surveyDate":"1992-05-22","surveyID":"100435"},{"surveyType":"Standard Survey","surveyDate":"2022-07-01","surveyID":"16652225946701000","headerInfo":{"survey_type":"Large Lake Survey","wb_alt_name":"","survey_id":"16652225946701000","wb_name":"Cass","id_date":"2022-07-01","wb_id":"04003000","wb_type":"Lake","county":"Beltrami"},"narrative":"Cass Lake is nearly 16,000 acres and is the largest lake in the Cass Lake chain, which altogether includes over 25,000 acres of connected waters. The lake has a mix of expansive, shallow flats and deeper water with lots of underwater structure. Walleye, Yellow Perch, and Muskellunge are the most sought-after species.
\n
\nThe Walleye population of Cass Lake is healthy and is comprised of good numbers of fish distributed among numerous size and age classes. The 2022 gill net catch rate was 11.2 fish per net, slightly less than the long-term median catch rate (13.1 fish/net). Captured fish ranged from ages 0 to 21 with most fish ages 1 to 9. Nearly half of the catch was between 14 and 17 inches, most of which belong to the strong 2018 year class. These fish will provide good catch rates and fish for the frying pan for the next several years. The record-strong 2013 year class is still prominent in the population and providing anglers with quality-sized fish in the mid-20-inch range. There are also some younger fish in the population that will be too small to keep (10 to 12 inches) that will provide some additional action and provide harvest opportunity in the coming years.
\n
\nThe clearer-than-usual water is due to the well-established zebra mussel population and this trend is expected to continue. As a result, Walleye anglers should focus their effort around low light periods or when there is a chop on the water as the clear water tends to keep fish deeper during the day. The catch rate for age-0 Walleye (approximately 6 inches) during fall electrofishing was poor. Cass Lake has a history of producing strong year classes every two or three years and this trend is expected to continue. The modest year classes between the strong ones help provide anglers with a wide size range of fish and reduces fishing mortality on the stronger ones.
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\nThe gill net catch rate for Yellow Perch (49 per net) was similar to the long-term median (45 per net). Growth rates have increased remarkably which has increased the number of keeper-sized fish in the population compared to recent years. The catch rate for fish over 9 inches in 2022 (15.1 fish/net) was the record high catch since annual monitoring began in 1983. The portion of the gill net catch over 8 inches (49%) was also the highest ever observed. The largest fish exceeded 12 inches in length and anglers continue put together some impressive catches.
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\nThe Northern Pike catch rate of 2.6 fish per net was slightly below the long-term median of 3.2 fish per gill net. Average to below average gill net catch rates for Northern Pike over the past few years is encouraging as modest densities tend to result in faster growth rates and larger fish. Remember, Cass Lake lies in the North Central Zone for Northern Pike so the daily bag limit is 10 fish per day with a 22- to 26-inch protected slot limit and no more than two fish can be over 26 inches. About one-quarter of Northern Pike in the gill net assessment were below the protected
\nslot limit, one-half within the size restriction, and one-quarter of fish were larger than 26 inches. This gives anglers a nice opportunity to put together a meal of pike comprised of fish both above and below the protected slot limit.
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\nAll species in Cass Lake are managed under statewide regulations, except sunfish, for which a chain-wide five fish daily bag limit was implemented on March 1, 2021. The possession limit for sunfish remains at 20 fish.
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\nCass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. The U.S. Forest Service modified the dam during winter 2015-2016 to a fixed-crest rock-arch structure with a gated bypass channel that will increase outlet capacity during high water events and aid in lowering water levels during winter to increase water storage capacity for the spring season.
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\nThe Leech Lake Band of Chippewa Indians operates a commercial fishery for Lake Whitefish and Cisco on the Cass Lake chain. A limited subsistence fishery for game species is also allowed for Band members.
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\nA U.S. Environmental Protection Agency (EPA) Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The EPA has placed a consumption advisory on Lake Whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species.
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Cass Lake is a nearly 16,000 acre lake and is the largest lake in the Cass Lake chain, which altogether includes over 25,000 acres of connected waters. The lake has a mix of expansive, shallow flats and deeper water with lots of underwater structure. Walleye, Yellow Perch, and Muskellunge are the most sought-after species.
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\nThe Walleye population of Cass Lake is comprised of good numbers of fish distributed among numerous size and age classes. The 2024 gill net catch rate was 8.0 fish per net, less than the long-term median catch rate (13.1 fish/net). Captured fish ranged from ages 1 to 11 with most fish ages 3 to 6. Nearly 75% of the catch was between 14 and 20 inches. Most fish on the smaller end of that range belong to the 2021 year class and the larger fish belong to the strong 2018 year class. These fish will provide the bulk of the angler catch for the next few years. The record-strong 2013 year class is still present in the population and providing anglers with quality-sized fish in the mid to upper 20-inch range.
\n
\nThe clearer-than-usual water is due to the well-established zebra mussel population and this trend is expected to continue. As a result, Walleye anglers should focus their effort around low light periods or when there is a chop on the water as the clear water tends to keep fish deeper during the day. The catch rate for age-0 Walleye (approximately 6 inches) during fall electrofishing was poor. Cass Lake has a history of producing strong year classes every two or three years and this trend is expected to continue. The modest year classes between the strong ones help provide anglers with a wide size range of fish and reduces fishing mortality on the stronger ones.
\n
\nThe gill net catch rate for Yellow Perch (51 per net) was similar to the long-term median (45 per net). Growth rates have increased remarkably which has increased the number of keeper-sized fish in the population compared to recent years. The catch rate for fish over 9 inches in 2023 (14.2 fish/net) is among the highest since annual monitoring began in 1983. The largest fish are around 13 inches in length and anglers continue put together some impressive catches.
\n
\nThe Northern Pike catch rate of 3.6 fish per net was similar to the long-term median of 3.0 fish per gill net. Average to below average gill net catch rates for Northern Pike over the past few years is encouraging as modest densities tend to result in faster growth rates and larger fish. Remember, Cass Lake lies in the North Central Zone for Northern Pike so the angling daily bag limit is 10 fish per day with a 22- to 26-inch protected slot limit and no more than two fish can be over 26 inches. About one-third of Northern Pike in the gill net assessment were below the protected slot limit, one-third within the size restriction, and one-third of fish were larger than 26 inches. This gives anglers a nice opportunity to put together a meal of pike comprised of fish both above and below the protected slot limit.
\n
\nAll species in Cass Lake are managed under statewide regulations, except sunfish, for which a chain-wide five fish daily bag limit was implemented on March 1, 2021. The possession limit for sunfish remains at 20 fish.
\n
\nCass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. The U.S. Forest Service modified the dam during winter 2015-2016 to a fixed-crest rock-arch structure with a gated bypass channel that will increase outlet capacity during high water events and aid in lowering water levels during winter to increase water storage capacity for the spring season.
\n
\nThe Leech Lake Band of Chippewa Indians operates a commercial fishery for Lake Whitefish and Cisco on the Cass Lake chain. A limited subsistence fishery for game species is also allowed for Band members.
\n
\nA U.S. Environmental Protection Agency (EPA) Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The EPA has placed a consumption advisory on Lake Whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species.
\n
Cass Lake is a nearly 16,000 acre lake and is the largest lake in the Cass Lake chain, which altogether includes over 25,000 acres of connected waters. The lake has a mix of expansive, shallow flats and deeper water with lots of underwater structure. Walleye, Yellow Perch, and Muskellunge are the most sought-after species.
\n
\nWhile the Walleye population of Cass Lake is down a bit, there are fish distributed among numerous size and age classes. The 2025 gill net catch rate was 7.8 fish per net, less than the long-term median catch rate (12.9 fish/net). Captured fish ranged from ages 1 to 15 with most fish ages 4 to 7. Nearly half of the catch was between 17 and 20 inches. Most fish on the smaller end of that range belong to the 2021 year class and the larger fish belong to the strong 2018 year class. These fish will continue to provide the bulk of the angler catch for the next few years. The record-strong 2013 year class is still present in the population and providing anglers with quality-sized fish in the mid to upper 20-inch range.
\n
\nThe clearer-than-usual water is due to the well-established zebra mussel population and this trend is expected to continue. As a result, Walleye anglers should focus their effort around low light periods or when there is a chop on the water as the clear water tends to keep fish deeper during the day. The catch rate for age-0 Walleye (approximately 6 inches) during fall electrofishing was poor. Cass Lake has a history of producing strong year classes every two or three years and while we haven't seen on since 2021, the abundance of mature females is well above average and we are experimenting with a new stocking strategy to improve fry survival. The modest year classes between the strong ones help provide anglers with a wide size range of fish and reduces fishing mortality on the stronger ones.
\n
\nThe gill net catch rate for Yellow Perch (47 per net) was similar to the long-term median (46 per net). Growth rates have increased remarkably which has increased the number of keeper-sized fish in the population. The catch rate for fish over 9 inches in 2025 (16.5 fish/net) is the highest since annual monitoring began in 1983. The largest fish are around 13 inches in length and anglers continue to put together some impressive catches.
\n
\nThe Northern Pike catch rate of 2.6 fish per net was similar to the long-term median of 3.0 fish per gill net. Average to below average gill net catch rates for Northern Pike over the past few years is encouraging as modest densities tend to result in faster growth rates and larger fish. Remember, Cass Lake lies in the North Central Zone for Northern Pike so the daily bag limit is 10 fish per day with a 22- to 26-inch protected slot limit and no more than two fish can be over 26 inches. About one-third of Northern Pike in the gill net assessment were below the protected slot limit, one-third within the size restriction, and one-third of fish were larger than 26 inches. This gives anglers a nice opportunity to put together a meal of pike comprised of fish both above and below the protected slot limit.
\n
\nAll species in Cass Lake are managed under statewide regulations, except sunfish, for which a chain-wide five fish daily bag limit was implemented on March 1, 2021. The possession limit for sunfish remains at 20 fish.
\n
\nCass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. The U.S. Forest Service modified the dam during winter 2015-2016 to a fixed-crest rock-arch structure with a gated bypass channel that will increase outlet capacity during high water events and aid in lowering water levels during winter to increase water storage capacity for the spring season.
\n
\nThe Leech Lake Band of Chippewa Indians operates a commercial fishery for Lake Whitefish and Cisco on the Cass Lake chain. A limited subsistence fishery for game species is also allowed for Band members.
\n
\nA U.S. Environmental Protection Agency (EPA) Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The EPA has placed a consumption advisory on Lake Whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species.
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