A targeted survey of the nearshore fish community was conducted in Clamshell Lake on June 25-27, 2018 by Fisheries Lake IBI program staff. Sampling stations 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 10 stations with three sites sampled from the boat. A 50-foot seine was used to sample seven stations and three sampling stations had conditions that prevented the use of seines. Nearshore sampling captured 19 native species of fish including six species that are intolerant of habitat disturbance (Banded Killifish, Blackchin Shiner, Blacknose Shiner, Iowa Darter, Rock Bass, and Smallmouth Bass) as well as one tolerant species (Green Sunfish).
\n
\nData from this targeted nearshore survey is combined with data from standard gill and trap netting surveys to calculate a Fish-based Index of Biological Integrity (FIBI) that describes the overall health of the lake. 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. 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. The FIBI score for Clamshell Lake based on this survey is exceptionally high, well above the impairment threshold for aquatic life use determined for similar lakes. Data from this survey will contribute biological information about the health of the fish community to the Pine River Watershed assessment process in coordination with MN Pollution Control Agency.
\n
\n
A targeted survey of nearshore fish species in Clamshell Lake was conducted on July 26-27, 2022, by DNR 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 eight sampling stations, but two station were sampled from the boat due to site conditions. Similarly, a 50-foot seine was used to sample five stations, a 15-foot seine was used at one station, and site conditions prevented the use of seines at four stations. Nearshore sampling captured 20 species of fish including seven species that are intolerant of disturbance (i.e., Banded Killifish, Blackchin Shiner, Blacknose Shiner, Iowa Darter, Northern Sunfish, Rock Bass, and Smallmouth Bass) and two that are tolerant of disturbance (i.e., Fathead Minnow and Green Sunfish).
\n
\nThe nearshore data will be combined with trap net and gill net data from a survey planned in 2024 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, Blacknose Shiner, and Banded Killifish), while other species are tolerant of degraded conditions (e.g., Fathead Minnow and Green Sunfish). 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 indicate that the fish community in Clamshell Lake is healthy. Data from this survey will contribute biological information about the health of the fish community to the Pine River Watershed assessment process in coordination with MN Pollution Control Agency.
\n
\nA temperature-dissolved oxygen profile was collected in the deepest basin on Clamshell Lake on July 26th, 2022, to evaluate the amount of cold, oxygenated water (i.e., oxythermal habitat) available to Lake Whitefish and Cisco, also known as Tullibee. Based on the profile, the top of the thermocline (i.e., the location in the water column with the sharpest transition from warm to cold water) occurred at approximately 16 feet. Dissolved oxygen decreased to below 3.0 mg/L at 19.4 feet, which was just below the thermocline, at the time of sampling. The temperature at which dissolved oxygen decreased to below 3.0 mg/L (i.e., TDO3, a single variable to characterize oxythermal habitat) was 14.6°C (58.3°F).
\n
\nTDO3 values near 17.2°C for Lake Whitefish or 21.5°C for Cisco indicate that oxythermal conditions are marginal for both species. Dissolved oxygen concentrations below the thermocline indicate that oxythermal habitat was adequate for Lake Whitefish and Cisco at limited depths at the time of sampling during the summer of 2022. However, low dissolved oxygen concentrations (less than 3 mg/L) at some depths below the thermocline and warm surface temperatures would likely limit available Lake Whitefish or Cisco habitat within the water column to an extent. Data collected in 1993-2002 indicate marginal oxythermal habitat in some years, with the least favorable conditions recorded in 1993. When adequate oxythermal habitat is available, Lake Whitefish or Cisco are not squeezed into unfavorable, warmer water conditions and therefore do not experience higher levels of stress.
\n
Clamshell Lake is a 189 acre basin and is part of the 14,000 acre Whitefish chain of lakes in northern Crow Wing County. Development of the shoreline is very heavy, with 89 homes/cabins on 4.4 miles of shoreline as of the 1995 survey.In 2000, northern pike were found in high numbers compared to similar lake types. Walleyes, white suckers, bluegills, pumpkinseeds, rock bass, largemouth bass and yellow bullheads were found in average numbers. Black crappies, brown bullheads and tullibees were found in low numbers.
","surveyType":"Standard Survey"},{"surveySubType":"Re-Survey","fishCatchSummaries":[{"gearCount":6,"quartileCount":"0.3-1.6","totalCatch":1,"CPUE":"0.17","gear":"Standard trap nets","species":"BLB","totalWeight":336,"averageWeight":"0.74","quartileWeight":"0.3-0.6"},{"averageWeight":"0.80","species":"BRB","totalWeight":725,"gearCount":6,"totalCatch":2,"gear":"Standard trap nets","quartileCount":"0.6-2.6","CPUE":"0.33","quartileWeight":"0.5-0.9"},{"quartileWeight":"0.1-0.2","averageWeight":"0.11","totalCatch":3,"CPUE":"0.50","quartileCount":"0.3-1.2","gear":"Standard trap nets","gearCount":6,"totalWeight":154,"species":"YEP"},{"quartileWeight":"0.3-0.5","averageWeight":"0.58","species":"YEB","totalWeight":523,"quartileCount":"2.1-15.8","totalCatch":2,"CPUE":"0.50","gear":"Standard gill nets","gearCount":4},{"CPUE":"1.00","totalCatch":4,"quartileCount":"N/A","gear":"Survey seining","gearCount":4,"totalWeight":18,"species":"RKB","averageWeight":"0.01","quartileWeight":"N/A"},{"averageWeight":"2.19","totalWeight":46749,"species":"NOP","gearCount":4,"gear":"Standard gill nets","totalCatch":47,"quartileCount":"3.5-8.9","CPUE":"11.75","quartileWeight":"1.6-3.0"},{"averageWeight":"0.00","species":"BKF","totalWeight":0,"gear":"Survey seining","totalCatch":8,"quartileCount":"N/A","CPUE":"2.00","gearCount":4,"quartileWeight":"N/A"},{"quartileWeight":"0.2-0.5","averageWeight":"0.82","gearCount":4,"quartileCount":"0.5-1.7","totalCatch":4,"gear":"Standard gill nets","CPUE":"1.00","totalWeight":1484,"species":"RKB"},{"averageWeight":"0.44","totalWeight":11286,"species":"YEB","totalCatch":56,"gear":"Standard trap nets","quartileCount":"2.7-13.5","CPUE":"9.33","gearCount":6,"quartileWeight":"0.4-0.6"},{"averageWeight":"0.65","totalWeight":2049,"species":"NOP","quartileCount":"N/A","totalCatch":7,"CPUE":"1.17","gear":"Standard trap nets","gearCount":6,"quartileWeight":"N/A"},{"averageWeight":"0.48","totalCatch":1,"quartileCount":"N/A","gear":"Standard gill nets","CPUE":"0.25","gearCount":4,"totalWeight":219,"species":"HSF","quartileWeight":"N/A"},{"quartileWeight":"N/A","averageWeight":"0.02","quartileCount":"N/A","totalCatch":24,"gear":"Survey seining","CPUE":"6.00","gearCount":4,"totalWeight":257,"species":"LMB"},{"quartileWeight":"N/A","species":"LKW","totalWeight":6670,"totalCatch":6,"quartileCount":"N/A","gear":"Standard gill nets","CPUE":"1.50","gearCount":4,"averageWeight":"2.45"},{"quartileWeight":"N/A","totalCatch":293,"gear":"Survey seining","quartileCount":"N/A","CPUE":"73.25","gearCount":4,"totalWeight":742,"species":"BLG","averageWeight":"0.01"},{"quartileWeight":"0.2-0.5","averageWeight":"0.22","gearCount":6,"CPUE":"1.00","totalCatch":6,"quartileCount":"0.4-1.7","gear":"Standard trap nets","species":"RKB","totalWeight":608},{"averageWeight":"0.00","totalCatch":10,"quartileCount":"N/A","gear":"Survey seining","CPUE":"2.50","gearCount":4,"totalWeight":20,"species":"PMK","quartileWeight":"N/A"},{"quartileWeight":"1.7-3.6","CPUE":"0.75","totalCatch":3,"quartileCount":"0.5-2.3","gear":"Standard gill nets","gearCount":4,"species":"WAE","totalWeight":5671,"averageWeight":"4.17"},{"averageWeight":"0.21","totalCatch":27,"CPUE":"4.50","quartileCount":"N/A","gear":"Standard trap nets","gearCount":6,"species":"HSF","totalWeight":2521,"quartileWeight":"N/A"},{"quartileWeight":"0.5-1.3","totalWeight":630,"species":"LMB","gearCount":4,"CPUE":"0.25","totalCatch":1,"quartileCount":"0.4-1.6","gear":"Standard gill nets","averageWeight":"1.39"},{"quartileWeight":"N/A","totalWeight":184,"species":"BLG","gearCount":4,"quartileCount":"N/A","totalCatch":2,"gear":"Standard gill nets","CPUE":"0.50","averageWeight":"0.20"},{"species":"YEP","totalWeight":241,"gearCount":4,"totalCatch":58,"quartileCount":"N/A","gear":"Survey seining","CPUE":"14.50","averageWeight":"0.01","quartileWeight":"N/A"},{"quartileWeight":"0.5-1.4","species":"TLC","totalWeight":5269,"totalCatch":18,"quartileCount":"2.3-10.0","CPUE":"4.50","gear":"Standard gill nets","gearCount":4,"averageWeight":"0.65"},{"quartileCount":"0.3-1.7","totalCatch":2,"gear":"Standard gill nets","CPUE":"0.50","gearCount":4,"totalWeight":2073,"species":"WTS","averageWeight":"2.29","quartileWeight":"1.7-2.7"},{"averageWeight":"0.72","species":"BLB","totalWeight":1958,"quartileCount":"0.4-3.1","totalCatch":6,"gear":"Standard gill nets","CPUE":"1.50","gearCount":4,"quartileWeight":"0.3-0.7"},{"averageWeight":"0.09","gearCount":4,"totalCatch":2,"quartileCount":"1.0-10.3","CPUE":"0.50","gear":"Standard gill nets","species":"YEP","totalWeight":80,"quartileWeight":"0.1-0.2"},{"quartileWeight":"0.4-1.0","averageWeight":"0.90","species":"BRB","totalWeight":818,"gearCount":4,"totalCatch":2,"gear":"Standard gill nets","quartileCount":"0.4-2.5","CPUE":"0.50"},{"totalWeight":108,"species":"LMB","gearCount":6,"quartileCount":"0.3-1.4","totalCatch":1,"CPUE":"0.17","gear":"Standard trap nets","averageWeight":"0.24","quartileWeight":"0.2-0.8"},{"quartileWeight":"0.1-0.2","averageWeight":"0.14","gearCount":6,"totalCatch":162,"gear":"Standard trap nets","quartileCount":"9.5-57.3","CPUE":"27.00","totalWeight":10237,"species":"BLG"},{"averageWeight":"0.14","gearCount":6,"totalCatch":31,"CPUE":"5.17","quartileCount":"1.5-6.8","gear":"Standard trap nets","species":"PMK","totalWeight":1927,"quartileWeight":"0.1-0.3"},{"totalWeight":0,"species":"BNS","totalCatch":1,"quartileCount":"N/A","CPUE":"0.25","gear":"Survey seining","gearCount":4,"averageWeight":"0.00","quartileWeight":"N/A"},{"quartileWeight":"2.4-4.3","averageWeight":"4.26","totalWeight":1933,"species":"BOF","gearCount":6,"quartileCount":"0.5-1.2","totalCatch":1,"gear":"Standard trap nets","CPUE":"0.17"}],"headerInfo":{"wb_id":"18035600","wb_alt_name":"","survey_type":"Re-Survey","id_date":"1995-06-26","wb_name":"Clamshell","county":"Crow Wing","wb_type":"Lake","survey_id":"114314"},"surveyID":"114314","lengths":{"BLB":{"maximum_length":12,"minimum_length":9,"fishCount":[[10,2],[11,2],[12,1],[9,2]]},"BOF":{"fishCount":[[23,1]],"minimum_length":23,"maximum_length":23},"YEP":{"fishCount":[[3,22],[4,3],[5,4],[6,2]],"minimum_length":3,"maximum_length":6},"YEB":{"fishCount":[[10,7],[11,4],[12,2],[6,3],[7,7],[8,15],[9,20]],"minimum_length":6,"maximum_length":12},"LKW":{"maximum_length":20,"fishCount":[[18,3],[19,2],[20,1]],"minimum_length":18},"PMK":{"maximum_length":6,"minimum_length":3,"fishCount":[[3,1],[4,11],[5,13],[6,7]]},"WTS":{"maximum_length":17,"fishCount":[[17,2]],"minimum_length":17},"BLG":{"minimum_length":1,"fishCount":[[1,35],[2,5],[3,18],[4,33],[5,76],[6,46],[7,13]],"maximum_length":7},"NOP":{"fishCount":[[11,1],[12,1],[13,5],[14,7],[15,5],[16,2],[17,5],[18,4],[19,3],[20,3],[21,3],[23,3],[24,1],[25,5],[26,1],[28,1],[29,2],[33,1],[36,1]],"minimum_length":11,"maximum_length":36},"BRB":{"maximum_length":12,"fishCount":[[11,2],[12,2]],"minimum_length":11},"WAE":{"minimum_length":21,"fishCount":[[21,1],[22,1],[23,1]],"maximum_length":23},"TLC":{"maximum_length":15,"minimum_length":6,"fishCount":[[10,4],[12,1],[13,1],[14,2],[15,4],[6,1],[7,3],[8,1],[9,1]]},"RKB":{"maximum_length":10,"fishCount":[[1,3],[10,3],[3,1],[5,1],[6,3],[7,2],[9,1]],"minimum_length":1},"HSF":{"maximum_length":8,"minimum_length":4,"fishCount":[[4,4],[5,9],[6,9],[7,4],[8,2]]},"LMB":{"minimum_length":2,"fishCount":[[2,19],[13,1],[5,3],[6,2],[7,1]],"maximum_length":13}},"surveyDate":"1995-06-26","narrative":"Clamshell Lake is a 189 acre basin and a part of the 14,000 acre Whitefish chain of lakes in northern Crow Wing County. Development is very heavy, with 89 homes/cabins on 4.4 miles of shoreline.In 1995, northern pike were found in \"high\" numbers compared to similar type lakes. Tullibees, walleyes white suckers, bluegills, pumpkinseeds, rock bass and yellow bullheads were found in \"average\" numbers. Largemouth bass, black bullheads, bowfin (dogfish) and brown bullheads were found in \"low\" numbers.
","surveyType":"Standard Survey"},{"narrative":"A temperature-dissolved oxygen profile was collected in the deepest basin on Clamshell Lake on August 15th, 2023 to evaluate the amount of cold, oxygenated water (i.e., oxythermal habitat) available to Lake Whitefish and Cisco, also known as Tullibee. Based on the profile, the top of the thermocline (i.e., the location in the water column with the sharpest transition from warm to cold water) occurred at approximately 14 feet. Dissolved oxygen decreased to below 3.0 mg/L at 22 feet, which was below the thermocline, at the time of sampling. The temperature at which dissolved oxygen decreased to below 3.0 mg/L (i.e., TDO3, a single variable to characterize oxythermal habitat) was 12.6°C (54.7°F).
\n
\nTDO3 values cooler than 17.2°C for Lake Whitefish or 21.5°C for Cisco indicate that oxythermal conditions are favorable for these species. Dissolved oxygen concentrations below the thermocline indicate that suitable oxythermal habitat for these species was available across a range of depths at the time of sampling. Data collected in 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, and 2022 also indicated suitable oxythermal habitat. When adequate oxythermal habitat is available, Lake Whitefish or Cisco are not squeezed into unfavorable, warmer water conditions and therefore do not experience higher levels of stress.
Temperature and dissolved oxygen profiles were collected in the deepest basin in Clamshell Lake on August 14, 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 are also present). 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 to below 17.2 degrees C (63.0 degrees F) at 21.2 feet and the dissolved oxygen concentration decreased to 3.0 mg/L at 19.8 feet at the time of sampling. The water column did not contain a layer of water with sufficient temperature and dissolved oxygen 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 18.5 degrees C (number degrees F). TDO3 values warmer than 17.2 degrees C (63.0 degrees F) indicate that oxythermal conditions were unsuitable for Lake Whitefish at the time of this survey.
\n
\nData collected by the Minnesota Department of Natural Resources in 2011-2023 during the late summer thermal stress period, indicate suitable oxythermal habitat in most years surveyed, with the least favorable conditions recorded in 2024. When inadequate oxythermal habitat is available, Lake Whitefish are squeezed into unfavorable, warmer water conditions and experience higher levels of stress.
\n
Clamshell Lake is a 189 acre lake, and is part of the Whitefish Chain located in northern Crow Wing County. There is an Army Corps of Engineers boat access on the north shore of the lake. Access is also possible through a channel from Bertha Lake. Development is heavy with 103 homes and two resorts on 6.5 miles of shoreline. The maximum depth is 44 feet, with 75% of the lake 15 feet or less. Water clarity is good with a secchi depth of 16 ft.
\n
\nNorthern pike are abundant with a gillnet catch of 13.3/ net. They tend to run on the small side with an average length of 19 inches and weight of 1.6 lbs. Some larger northern pike were captured with 14% over 24 inches. The largest was 34 inches. Walleyes are not stocked directly into Clamshell, but are stocked annually as fry and every other year as fingerlings into the Whitefish Chain. Only 4 walleyes were caught in this survey, all of them over 20 inches in length.
\n
\nLargemouth bass in the Whitefish Chain, including Clamshell, were sampled by a spring electrofishing survey. Largemouth bass were quite numerous with a catch rate of 112.5/hr. More information can be found in the Whitefish Lake survey.
\n
\nBluegill catches were above average, but the average size was only 5.9 inches. Growth was good with 19% over 7 inches. Black crappie over 8 inches account for 55% of the catch, but they are not very numerous. Yellow perch, an important prey species for walleye and northern, were caught in about average numbers. Size was too small to be targeted by anglers.
\n
\nOther fish species present included bowfin, brown bullhead, hybrid sunfish, lake whitefish, pumpkinseed sunfish, rock bass, tullibee (cisco), white sucker, yellow bullhead, and greater redhorse. Species sampled during IBI backpack electrofishing, and seining included Iowa darter, Johnny darter, banded killifish, blackchin shiner, blacknose dace, bluntnose minnow, central mudminnow, golden shiner, and green sunfish.
\n
Clamshell Lake is a 189 acre lake, and is part of the Whitefish Chain located in northern Crow Wing County. There is an Army Corps of Engineers boat access on the north shore of the lake. Access is also possible through a channel from Bertha Lake. The maximum depth is 44 feet, with 75% of the lake 15' or less. Water clarity is good with a secchi depth of 15 ft.
\n
\nNorthern pike were sampled in high numbers in gill nets when compared to similar lakes at 12.7/net. Average size was 20.8\", with 29% measuring least 24\" in length. Northern pike up to 40.6\" were sampled. Catch and release of these larger fish will help keep a balanced northern pike population. Lakes in this part of the state have a new northern pike regulation enacted in 2018: possession limit of 10 with not more than 2 over 26\". All from 22\"-26\" must be immediately released. Please refer to the current Minnesota Fishing Regulations for additional information.
\n
\nLargemouth bass were sampled in high numbers in gill nets at 1.8/net. Mean length was 13.4\". Largemouth bass electrofishing was done in Clamshell, along with various stations across the Whitefish Chain of Lakes, resulting in a combined catch rate of 68.8/hr run-time. Mean length was 13.5\". Five smallmouth bass were also netted while electrofishing. All but one were over 17\".
\n
\nWalleyes are not stocked into Clamshell, but are stocked annually as fry and every other year as fingerlings into the Whitefish Chain. Walleyes can move through the chain and into Clamshell. The gill net catch of 0.5/net was low compared to similar lakes. Average length was 17.0\".
\n
\nBluegills were sampled in average numbers at 34.6/trap net. Average length was 6.1\" with 25% measuring at least 7.0\" in length. Black crappies were sampled in low numbers in gill nets at 0.7/net. Average size was small at 4.8\". Trap nets sampled crappies in average numbers at 1.6/net. Average length was 6.1\". For both gear types combined 22% measured at least 8.0\" in length.
\n
\nClamshell Lake is designated as AIS (aquatic invasive species) infested waters because of zebra mussels. Lake users are required to inspect and remove any aquatic plants and animals from their watercraft and trailers as well as pull the plug and drain all water from the watercraft, including bilges, livewells and baitwells.
\n
Clamshell Lake is 211 acres and is a part of the 14,000-acre Whitefish chain of lakes in northern Crow Wing County. The maximum depth is 44 feet and 75% of the lake is 15 feet deep or less. On the north shore of the lake there is a U.S. Army Corps of Engineer access.
\n
\nNorthern Pike were sampled in high numbers at 10.7 per gill net with an average length of 20.7\". Out of 64 Northern Pike sampled, 18% were 26\" or greater with the largest fish measuring 29.9\".
\n
\nWalleye were not sampled, which is typical for Clamshell.
\n
\nBluegill were sampled at a rate of 37.8 per trap net with an average length of 5.5\". The largest fish was 8.9\" and 12% measured 7\" or greater. Only one Black Crappie was caught in the trap nets and was 8.4\". Low numbers of Black Crappies are normal for the lake. A 5-fish bag for both Black Crappie and Bluegill were implemented on the Whitefish Chain of Lakes in 2021.
\n
\nLargemouth Bass numbers for the Whitefish Chain, which includes Clamshell were 44.9 per hour of run-time during night electrofishing. Average length was 13.1\" with a max size of 19.2\".
\n
\nClamshell is designated as AIS (aquatic invasive species) infested waters because of zebra mussels. Lake users are required to inspect and remove any aquatic plants and animals from their watercraft and trailers as well as pull the plug and drain all water from the watercraft, including bilges, livewells and baitwells.
\n
Black bullhead, black crappie, yellow perch and walleye catches were below 1st quartile indicating low populations. Yellow bullhead, pumpkinseed and bluegill catch rates were above 3rd quartile showing above average numbers. Growth rates appeared average for all species aged.
","surveyType":"Standard Survey","lengths":{},"surveyID":"114228","surveySubType":"Re-Survey","fishCatchSummaries":[{"gearCount":6,"totalCatch":1,"gear":"Standard trap nets","quartileCount":"0.3-1.6","CPUE":"0.17","totalWeight":0.5,"species":"BLB","averageWeight":"0.50","quartileWeight":"0.3-0.6"},{"averageWeight":"0.48","totalCatch":6,"quartileCount":"0.6-2.6","CPUE":"1.00","gear":"Standard trap nets","gearCount":6,"species":"BRB","totalWeight":2.9,"quartileWeight":"0.5-0.9"},{"averageWeight":"0.10","gearCount":6,"totalCatch":2,"gear":"Standard trap nets","quartileCount":"0.3-1.2","CPUE":"0.33","totalWeight":0.2,"species":"YEP","quartileWeight":"0.1-0.2"},{"averageWeight":"0.19","gearCount":4,"CPUE":"4.50","totalCatch":18,"quartileCount":"2.1-15.8","gear":"Standard gill nets","totalWeight":3.4,"species":"YEB","quartileWeight":"0.3-0.5"},{"species":"NOP","totalWeight":45.9,"totalCatch":23,"gear":"Standard gill nets","quartileCount":"3.5-8.9","CPUE":"5.75","gearCount":4,"averageWeight":"2.00","quartileWeight":"1.6-3.0"},{"species":"RKB","totalWeight":2.75,"gearCount":4,"gear":"Standard gill nets","totalCatch":3,"quartileCount":"0.5-1.7","CPUE":"0.75","averageWeight":"0.92","quartileWeight":"0.2-0.5"},{"quartileWeight":"0.4-0.6","averageWeight":"0.44","gearCount":6,"totalCatch":81,"gear":"Standard trap nets","quartileCount":"2.7-13.5","CPUE":"13.50","species":"YEB","totalWeight":35.8},{"averageWeight":"0.70","quartileCount":"N/A","totalCatch":3,"gear":"Standard trap nets","CPUE":"0.50","gearCount":6,"species":"NOP","totalWeight":2.1,"quartileWeight":"N/A"},{"species":"RKB","totalWeight":3.1,"gearCount":6,"totalCatch":6,"CPUE":"1.00","quartileCount":"0.4-1.7","gear":"Standard trap nets","averageWeight":"0.52","quartileWeight":"0.2-0.5"},{"averageWeight":"0.50","species":"WAE","totalWeight":1,"totalCatch":2,"quartileCount":"0.5-2.3","gear":"Standard gill nets","CPUE":"0.50","gearCount":4,"quartileWeight":"1.7-3.6"},{"quartileWeight":"N/A","averageWeight":"0.40","gear":"Standard trap nets","totalCatch":2,"quartileCount":"N/A","CPUE":"0.33","gearCount":6,"totalWeight":0.8,"species":"HSF"},{"totalWeight":3.6,"species":"BLG","gearCount":4,"CPUE":"11.75","totalCatch":47,"quartileCount":"N/A","gear":"Standard gill nets","averageWeight":"0.08","quartileWeight":"N/A"},{"quartileWeight":"0.5-1.4","species":"TLC","totalWeight":38.2,"gearCount":4,"totalCatch":22,"gear":"Standard gill nets","quartileCount":"2.3-10.0","CPUE":"5.50","averageWeight":"1.74"},{"averageWeight":"3.00","totalCatch":3,"quartileCount":"0.3-1.7","gear":"Standard gill nets","CPUE":"0.75","gearCount":4,"species":"WTS","totalWeight":9,"quartileWeight":"1.7-2.7"},{"quartileWeight":"0.2-0.4","species":"BLC","totalWeight":1.6,"quartileCount":"1.0-3.9","totalCatch":10,"CPUE":"2.50","gear":"Standard gill nets","gearCount":4,"averageWeight":"0.16"},{"averageWeight":"0.60","gear":"Standard gill nets","totalCatch":1,"quartileCount":"0.4-3.1","CPUE":"0.25","gearCount":4,"species":"BLB","totalWeight":0.6,"quartileWeight":"0.3-0.7"},{"quartileWeight":"0.1-0.2","averageWeight":"0.10","species":"YEP","totalWeight":0.2,"totalCatch":2,"quartileCount":"1.0-10.3","CPUE":"0.50","gear":"Standard gill nets","gearCount":4},{"averageWeight":"0.17","totalWeight":12.3,"species":"PMK","gearCount":6,"quartileCount":"1.5-6.8","totalCatch":74,"gear":"Standard trap nets","CPUE":"12.33","quartileWeight":"0.1-0.3"},{"quartileWeight":"0.1-0.2","totalCatch":481,"gear":"Standard trap nets","quartileCount":"9.5-57.3","CPUE":"80.17","gearCount":6,"totalWeight":61.8,"species":"BLG","averageWeight":"0.13"},{"averageWeight":"4.70","species":"BOF","totalWeight":23.5,"gearCount":6,"totalCatch":5,"gear":"Standard trap nets","quartileCount":"0.5-1.2","CPUE":"0.83","quartileWeight":"2.4-4.3"},{"averageWeight":"2.00","totalWeight":4,"species":"WTS","quartileCount":"0.3-0.9","totalCatch":2,"CPUE":"0.33","gear":"Standard trap nets","gearCount":6,"quartileWeight":"2.0-3.9"},{"quartileWeight":"0.2-0.5","averageWeight":"0.23","totalCatch":3,"quartileCount":"0.8-4.0","gear":"Standard trap nets","CPUE":"0.50","gearCount":6,"totalWeight":0.7,"species":"BLC"}],"headerInfo":{"wb_id":"18035600","wb_alt_name":"","id_date":"1990-06-25","survey_type":"Re-Survey","wb_name":"Clamshell","county":"Crow Wing","wb_type":"Lake","survey_id":"114228"},"surveyDate":"1990-06-25"},{"surveyDate":"2005-06-13","surveyID":"114598","lengths":{"YEP":{"maximum_length":7,"fishCount":[[5,19],[6,2],[7,1]],"minimum_length":5},"YEB":{"fishCount":[[10,8],[11,1],[5,1],[7,1],[8,17],[9,24]],"minimum_length":5,"maximum_length":11},"PMK":{"fishCount":[[3,4],[4,5],[5,15],[6,16]],"minimum_length":3,"maximum_length":6},"WTS":{"maximum_length":21,"fishCount":[[16,1],[17,2],[18,1],[21,1]],"minimum_length":16},"BOF":{"fishCount":[[19,2],[21,4],[22,1],[23,4],[24,2],[25,2],[26,6],[27,1],[28,2]],"minimum_length":19,"maximum_length":28},"HSF":{"minimum_length":5,"fishCount":[[5,4],[6,11],[7,12]],"maximum_length":7},"LMB":{"minimum_length":7,"fishCount":[[13,1],[7,1],[8,2]],"maximum_length":13},"GRR":{"fishCount":[[23,1]],"minimum_length":23,"maximum_length":23},"BLG":{"maximum_length":8,"minimum_length":3,"fishCount":[[3,18],[4,26],[5,81],[6,69],[7,19],[8,1]]},"BRB":{"maximum_length":11,"minimum_length":9,"fishCount":[[11,3],[9,1]]},"NOP":{"minimum_length":12,"fishCount":[[12,2],[14,3],[15,3],[16,5],[17,6],[18,4],[19,2],[20,1],[21,2],[22,4],[23,3],[24,5],[25,2],[26,3],[27,2],[28,1],[31,2],[32,1]],"maximum_length":32},"BLC":{"minimum_length":4,"fishCount":[[4,1],[7,3],[8,1]],"maximum_length":8},"RKB":{"maximum_length":9,"minimum_length":7,"fishCount":[[7,2],[8,2],[9,2]]},"TLC":{"maximum_length":19,"fishCount":[[14,2],[15,1],[16,2],[17,1],[18,3],[19,3]],"minimum_length":14}},"headerInfo":{"survey_type":"Population Assessment","id_date":"2005-06-13","county":"Crow Wing","wb_name":"Clamshell","wb_id":"18035600","wb_alt_name":"","survey_id":"114598","wb_type":"Lake"},"fishCatchSummaries":[{"totalWeight":1089,"species":"BRB","quartileCount":"0.6-2.6","totalCatch":3,"gear":"Standard trap nets","CPUE":"0.33","gearCount":9,"averageWeight":"0.80","quartileWeight":"0.5-0.9"},{"quartileWeight":"0.3-0.5","species":"YEB","totalWeight":3098,"CPUE":"2.83","totalCatch":17,"quartileCount":"2.1-15.8","gear":"Standard gill nets","gearCount":6,"averageWeight":"0.40"},{"totalWeight":46575,"species":"NOP","totalCatch":46,"CPUE":"7.67","quartileCount":"3.5-8.9","gear":"Standard gill nets","gearCount":6,"averageWeight":"2.23","quartileWeight":"1.6-3.0"},{"quartileWeight":"0.2-0.5","gearCount":6,"gear":"Standard gill nets","totalCatch":1,"quartileCount":"0.5-1.7","CPUE":"0.17","totalWeight":300,"species":"RKB","averageWeight":"0.66"},{"averageWeight":"0.44","gearCount":9,"totalCatch":35,"gear":"Standard trap nets","quartileCount":"2.7-13.5","CPUE":"3.89","totalWeight":7049,"species":"YEB","quartileWeight":"0.4-0.6"},{"quartileWeight":"N/A","averageWeight":"2.25","totalWeight":5092,"species":"NOP","CPUE":"0.56","totalCatch":5,"quartileCount":"N/A","gear":"Standard trap nets","gearCount":9},{"quartileWeight":"N/A","totalWeight":2700,"species":"GRR","totalCatch":1,"gear":"Standard trap nets","quartileCount":"N/A","CPUE":"0.11","gearCount":9,"averageWeight":"5.95"},{"quartileWeight":"0.2-0.5","gear":"Standard trap nets","totalCatch":5,"quartileCount":"0.4-1.7","CPUE":"0.56","gearCount":9,"species":"RKB","totalWeight":1086,"averageWeight":"0.48"},{"quartileWeight":"N/A","averageWeight":"0.29","totalWeight":3597,"species":"HSF","gearCount":9,"totalCatch":27,"CPUE":"3.00","quartileCount":"N/A","gear":"Standard trap nets"},{"quartileWeight":"N/A","species":"BLG","totalWeight":202,"totalCatch":4,"quartileCount":"N/A","CPUE":"0.67","gear":"Standard gill nets","gearCount":6,"averageWeight":"0.11"},{"averageWeight":"0.03","totalCatch":1,"quartileCount":"N/A","gear":"Standard gill nets","CPUE":"0.17","gearCount":6,"species":"PMK","totalWeight":14,"quartileWeight":"N/A"},{"averageWeight":"2.69","totalCatch":1,"quartileCount":"0.3-1.0","CPUE":"0.17","gear":"Standard gill nets","gearCount":6,"totalWeight":1222,"species":"BOF","quartileWeight":"3.3-4.9"},{"averageWeight":"2.03","totalWeight":11052,"species":"TLC","gear":"Standard gill nets","totalCatch":12,"quartileCount":"2.3-10.0","CPUE":"2.00","gearCount":6,"quartileWeight":"0.5-1.4"},{"averageWeight":"2.30","totalCatch":4,"CPUE":"0.67","quartileCount":"0.3-1.7","gear":"Standard gill nets","gearCount":6,"species":"WTS","totalWeight":4172,"quartileWeight":"1.7-2.7"},{"averageWeight":"0.16","gearCount":6,"quartileCount":"1.0-3.9","totalCatch":2,"gear":"Standard gill nets","CPUE":"0.33","species":"BLC","totalWeight":143,"quartileWeight":"0.2-0.4"},{"averageWeight":"0.08","gear":"Standard gill nets","totalCatch":22,"quartileCount":"1.0-10.3","CPUE":"3.67","gearCount":6,"species":"YEP","totalWeight":814,"quartileWeight":"0.1-0.2"},{"quartileWeight":"0.4-1.0","averageWeight":"0.52","totalWeight":234,"species":"BRB","CPUE":"0.17","totalCatch":1,"quartileCount":"0.4-2.5","gear":"Standard gill nets","gearCount":6},{"quartileWeight":"0.2-0.8","averageWeight":"0.50","totalCatch":4,"gear":"Standard trap nets","quartileCount":"0.3-1.4","CPUE":"0.44","gearCount":9,"totalWeight":911,"species":"LMB"},{"quartileWeight":"0.1-0.3","gearCount":9,"totalCatch":39,"gear":"Standard trap nets","quartileCount":"1.5-6.8","CPUE":"4.33","species":"PMK","totalWeight":2822,"averageWeight":"0.16"},{"quartileWeight":"0.1-0.2","averageWeight":"0.13","gearCount":9,"totalCatch":210,"quartileCount":"9.5-57.3","CPUE":"23.33","gear":"Standard trap nets","species":"BLG","totalWeight":12715},{"averageWeight":"5.15","totalWeight":53706,"species":"BOF","gearCount":9,"totalCatch":23,"CPUE":"2.56","quartileCount":"0.5-1.2","gear":"Standard trap nets","quartileWeight":"2.4-4.3"},{"quartileWeight":"2.0-3.9","species":"WTS","totalWeight":1600,"gearCount":9,"totalCatch":1,"CPUE":"0.11","quartileCount":"0.3-0.9","gear":"Standard trap nets","averageWeight":"3.53"},{"gearCount":9,"totalCatch":3,"quartileCount":"0.8-4.0","CPUE":"0.33","gear":"Standard trap nets","species":"BLC","totalWeight":346,"averageWeight":"0.25","quartileWeight":"0.2-0.5"}],"surveySubType":"Population Assessment","surveyType":"Standard Survey","narrative":"Clamshell is a 189 acre lake and part of the Whitefish chain of lakes located in northern Crow Wing County. There is an access on the north side of the lake. Clamshell has a maximum depth of 44 feet and 75% of the lake is 15 feet deep or less. Development is heavy on the lake, with 89 homes being counted during the 1995 survey along 4.4 miles of shoreline.Walleyes are not stocked directly into Clamshell, but fry and fingerlings are stocked into connected Whitefish Lake. No walleyes were captured during the 2005 netting.The northern pike catch rate was average (14.3/gill net). Average size was 21.0\" and 2.2 lbs., with 33% of the fish being 24\" or larger.The black crappie catch rate was low in both gill nets (0.3/gill net) and trap nets (0.3/trap net). Only 20% of the fish were 8\" or larger.The bluegill catch rate was average (23.3/trap net). Average length was 5.8\" and only 10% were 7\" or larger.Other fish species captured included bowfin, brown bullhead, greater redhorse, hybrid sunfish, largemouth bass, pumpkinseed, rock bass, tullibee (cisco), white sucker, and yellow bullhead.
"}],"shoreLengthMiles":6.49,"county":"Crow Wing","waterClarity":[["08/15/2023","15.58"],["06/13/2011","16"],["08/25/2011","21"],["06/12/2018","15"],["08/14/2024","11.5"],["06/10/2024","16"]],"lakeName":"Clamshell","averageWaterClarity":"15.8","littoralAcres":154.88},"timestamp":1793556730}