Post by sam on Jun 26, 2010 22:51:14 GMT -5
Upper Tippecanoe River, Indiana river fishing
Written by IDNR
Thursday, 29 April 2010
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Current Status of Fish Populations and Fishingin the Upper Tippecanoe River Lake Area
INDIANA DIVISION OF FISH & WLDLIFE
PREPARED BY Jed Pearson, fisheries biologist
Rod Edgell, assistant fisheries biologistNathan Thomas, assistant fisheries biologistNortheast Regional OfficeIndiana Division of Fish and Wildlife1353 South Governors DriveColumbia City, Indiana 467252009
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EXECUTIVE SUMMARYVarious surveys were conducted at six natural lakes in the Tippecanoe River watershedduring 2009 to obtain current information on the status offish populations and fishing,determine which lakes met fish management objectives established by the UpperTippecanoe River Lake Association (UTRLA), and identify which lakes might benefitfrom new fish management actions.Spring electrofishing catch rates of 8-inch and larger largemouth bass ranged from117/hour at Crooked to 305/hour at Big and averaged 215/hour. All but Crookedexceeded the UTRLA management objective of 80 to 140/hour. Although bass numberswere high, their size structure was dominated by small individuals. Only Crookedcontained an adequate proportion (>25%) of legal-size bass (>14-in). No lake containedthe objective proportion (>8%) for 18-inch and larger bass.Bluegill electrofishing catch rates fell within the management objective of 140 to400/hour at each lake except Goose, ranging from 193/hour at Loon to 539/hour at Gooseand averaging 238/hour. All lakes except Crane contained an adequate proportion (>15%)of 7-inch and larger bluegills, ranging from 12% at Crane to 34% at Old. All lakes metthe objective (>4%) for 8-inch and larger bluegills except Loon.Bluegills ranked first numerically in each lake but varied from 47% of the catch at Big to80% at Loon and averaged 59%. Percentages at all lakes except Loon were within theobjective range of 40 to 60%. Largemouth bass ranked second numerically in each lakeexcept Goose, but the relative species composition of largemouth bass in Crooked andLoon (8%) fell below the management objective of 10 to 25% and above the objective atBig (28%).Anglers fished a combined total of 36,055 hours at the six lakes and removed 17,003 fishThe overall effort per acre per day (0.48) was close to the management objective (>0.50)and exceeded the objective at Crane (0.60), Goose (0.72), and Old (0.58) but was belowthe objective at Big (0.32), Crooked (0.39), and Loon (0.31). Fishing preferences variedamong lakes and in most cases met the management objectives. Bluegill preference wasabove the objective (>40%) at each lake except Loon. Bass preference exceeded theobjective (>30%) at Big, Crooked, Goose, and Loon. Angler preference for muskies atLoon (6%) also exceeded the management objective (>5%).Bluegill fishing failed to meet several objectives. The harvest of 13,395 bluegills wasbelow the objective of 45,600 bluegills (0.5/ac/d) and the harvest rate (0.7/hr) was 30%below the objective. Based on interviews of boat anglers who targeted bluegills, theharvest rate (0.6/hr) was 40% below expectations. Specific bluegill harvest rates by boatanglers were highest at Crane (0.8/hr), Crooked and Goose (0.7/hr), but lowest at Old(0.6/hr), Loon (0.5/hr), and Big (0.4/hr). Although angler catch rates of bluegills werelow and bluegill sizes were adequate at all lakes except Loon.
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Anglers removed a total of 338 largemouth bass. Seventy-five bass were taken fromCrooked Lake and represented 11% of the estimated number of legal-size bass present inthe spring. Bass up to 18 inches were taken from Crooked and Goose. At Loon, 22% ofthe harvested bass were 18-inch and larger, making it the only lake to reach themanagement objective (>10%) for that size category.Angler satisfaction with fishing quality differed by species, by lake, and betweenresidents and lake visitors. Overall, 40% of bluegill anglers described fishing as "good",less than the management objective of 50%. Bass anglers who rated fishing as goodaccounted for 54%, slightly above the 50% objective. Few bluegill anglers who fishedfrom boats rated fishing good at Big, Crane, and Crooked. Over half rated fishing "good"at Goose, Loon, and Old. Large percentages of bass anglers considered fishing good atGoose, Loon, and Old. Those who rated fishing poor ranged up to 67% at Crane.Muskie fishing quality at Loon was described as good. The estimated catch rate (harvestplus release) was one muskie per 21 hours of muskie fishing and exceeded the objectiveof one muskie per 30 hours of fishing.Water clarity was greatest at Crooked on June 15 (19 ft) and lowest at Crane (<3 ft) onJuly 9. Clarity decreased from June to July at all lakes except Old. Where measurementswere continued, clarity was 6 feet at Big, 10 feet at Crooked, and less than 3 feet at Loon.Ample oxygen (>5 ppm) was present in June only in the top 6 feet in Crane and Old, 8feet in Big and Goose, 10 feet in Loon, and down to 26 feet and again below 38 feet inCrooked. By July, ample oxygen was present to 6 feet in Crane, 10 feet in Goose andOld, 12 feet in Big and Loon, and 30 feet in Crooked.Submersed aquatic plants covered 53% of the littoral zone in Crane to 97% in Crookedand averaged 79%. Coontail was the dominant species, but varied from 30% coverage inLoon to 87% in Old and averaged 57%. Coverage of floating-leaf emergent plant beds(lilies) ranged from 3 acres in Old to 32 acres in Crooked. Emergent beds covered theleast amount of surface area as a fraction of the whole lake in Loon (4%). Mean coverageof emergent beds was 10% of the total lake area.Overall, the UTRLA lakes met a greater number of bluegill objectives than largemouthbass objectives. Therefore, fish management initiatives should first be directed towardlargemouth bass. Big and Crane could serve as candidate sites for testing alternative bassmanagement strategies to improve balance. Because angler opinions of bluegill fishingdid not match up with population parameters or fishery characteristics, efforts should alsobe directed at promoting available bluegill fishing opportunities to increase fishing effort,fishing success, and perceptions of fishing quality.Although Loon met all four bass fishing objectives, as well as three muskie fishingobjectives, it has the least-satisfactory bluegill fishery. More research is needed to betterunderstand how various environmental and biological features influence bluegill fishingat Loon and to identify management actions that will improve bluegill fishing.
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CONTENTSPageList of Tables 5List of Figures 7Background 8Management Objectives 9Project Area 10Sampling Methods and Analyses 11Results 13Largemouth bass sampling 13Bluegill sampling 14Fish community surveys 15Angler creel surveys 16Habitat assessments 20Discussion 22Recommendations 29References 28Appendices 54
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LIST OF TABLESTable Page1. Electrofishing catch per hour of various size groups of largemouth bass during springsampling and electrofishing catch per hour of age-1 and older largemouth bass duringJune surveys at six UTRLA lakes in 2009 312. Proportions (percentages) of various size groups of largemouth bass captured byelectrofishing during spring sampling at six UTRLA in 2009 323. Electrofishing catch per hour of various size groups of bluegills at six UTRLA lakes in2009 334. Proportions (percentages) of various size groups of bluegills captured by electrofishingat six UTRLA lakes in 2009 345. Number offish collected during fish population surveys at six UTRLA lakes during2009 356. Percentage offish collected during fish population surveys at six UTRLA lakes during2009 367. Estimated number of fishing hours by boat and shore anglers on weekends andweekdays and fishing hours per acre at six UTRLA lakes in 2009. MeanB represents theaverage number of boat anglers per count per day and MeanS represents the averagenumber of shore anglers per count per day 378. Various fish species and combinations of species sought by anglers at six UTRLAlakes in 2009. Numbers represent interviewed angler-parties with each response 38
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9. Combined preferences for various fish species sought by anglers at six UTRLA lakesin 2009. Values represent the number and percentage of responses that each species wasmentioned by interviewed angler-parties 3910. Estimated number offish removed and the number of bass caught and released byanglers at six UTRLA lakes in 2009 4011. Angler harvest rates of bluegill and angler catch rates of bass (harvest and releases) atsix UTRLA lakes in 2009 4112. Length distributions of bluegills and largemouth bass harvested by anglers at sixUTRLA lakes in 2009 4213. Number and percentages of responses of boat anglers who fished for bluegills andlargemouth bass who rated fishing as "good, fair, or poor" at six UTRLA in 2009 4314. Water clarity (secchi depth) on various occasions at six UTRLA lakes in 2009... .4415. Water temperatures (F) at various depths within six UTRLA lakes on two occasionsin 2009. Shaded areas represent the top of the thermocline 4516. Dissolved oxygen concentrations (ppm) at various depths within six UTRLA lakes ontwo occasions in 2009. Dark shaded areas represent depths with ample oxygen (>5 ppm).Light shaded areas represent depths with low oxygen levels (<5 and >3 ppm). Nonshaded area represent depths where insufficient oxygen is present for fish (<3 ppm).. ..4617. Submersed aquatic plant community parameters, species frequency of occurrence atsample sites, and species dominance at six UTRLA lakes in 2009 4718. Coverage and extent of floating-leaf emergent plant beds at six UTRLA lakes in2009 48
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LIST OF FIGURESFigure Page1. The UTRLA lakes 492. The UTRLA watershed (shaded area) 503. Water clarity in the UTRLA lakes 514. Back-calculated growth rates of largemouth bass and bluegills at six UTRLA lakes,based on scale samples taken in 2009 525. Summary offish population and fishing quality parameters at the UTRLA lakes in2009. Values in light gray cells (green in color) met the management objectives, values inwhite cells (yellow in color) exceeded management objectives, and values in dark graycells ( red in color) were below management objectives 53
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BACKGROUNDIn 2008 the Upper Tippecanoe River Lake Association (UTRLA) in partnership withthe Division of Fish and Wildlife (DFW) completed a diagnostic plan for seven lakeslocated within the upper reaches of the Tippecanoe River Watershed (Williams Creek2008). The process was coordinated through Indiana's Lake and River EnhancementProgram (LARE) and the Tippecanoe Watershed Foundation (TWF) for the purpose ofimproving water quality. Within this context, however, is a goal to develop sustainablefish populations that support the recreational needs of lake users.To measure success toward achieving the goal, an UTRLA fish committee wasformed and held a series of discussions to establish quantifiable fish managementobjectives that describe the desired number and size of selected sport fish within the lakesand those caught by anglers (UTRLA Fish Management Plan 2010-2019). Once sportfish management objectives were set, various surveys were conducted during 2009 toobtain current information on the status offish populations and fishing in the UTRLAlakes, determine which lakes met the objectives, and identify which lakes might benefitfrom new management actions. When conducted according to standard samplingprocedures, fishery surveys can help document common problems that affect fishresources on a broad scale that may then be addressed through common approaches.Likewise, standardized sampling (i.e. using similar gear and similar effort at a similartime) can also be used to generate comparable data from various waters to quantify site-specific problems and generate public support for management initiatives where the datademonstrate a greater need.Results of these surveys at the UTRLA lakes are presented in this report and arebeing used to describe where and when specific management actions should beconducted. Although past information on file for each lake is also included in theappendices, the main emphasis of this report is to assess whether the current status ofeach lake is achieving the fish management objectives. Additional information on habitatfeatures, including clarity, temperature/oxygen profile, and aquatic plants, was alsoobtained and is discussed briefly in relation to their possible impacts on fish.
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MANAGEMENT OBJECTIVESEighteen measurable objectives with 26 benchmarks were established by the UTRLAcommittee as criteria for long-term fish population balance and satisfactory fishingopportunities. The objectives were primarily based on established averages for variousfish population parameters at Indiana natural lakes, with the exception that committeemembers wanted a greater proportion of 18-inch and larger bass. Although current habitatconditions vary among the lakes, expectations were that each lake, if properly managed,should contain suitable habitat that is capable of sustaining a typical fish community witha typical level of fishing:/. Provide a relative species composition ofbluegills at 40 to 60%.2. Provide a relative species composition oflargemouth bass at 10 to 25%.3. Provide a relative species composition ofcrappies or yellow perch at 5 to 10%.4. Provide an electrofishing catch rate of 3-inch and larger bluegills at 160 to 400/hour.5. Provide a relative size distribution of 7-inch and larger bluegills >15%.6. Provide a relative size distribution of 8-inch and larger bluegills >4%.7. Provide a summer electrofishing catch rate of*ge-1 and older bass or a spring catchrate of 8-inch and larger bass at 80 to 140/hour.8. Provide a relative size distribution of 14-inch and larger bass >25%.9. Provide a relative size distribution of 18-inch and larger bass >8%.10. Provide an average summer fishing effort >0.5/hour/acre/day.11. Provide an angler preference for bluegillfishing >40% and bass fishing >30%.12. Provide a harvest rate of bluegill >0.5/acre/day and 1/hour of targeted bluegill fishing.13. Provide a catch size distribution of 7-inch and larger bluegills >50% and >20%for 8-inch and larger bluegills.14. Provide a catch rate of bass >l/hour of targeted bass fishing.15. Provide a catch size distribution > 10% for 18-inch and larger bass.16. Provide >50% of bluegill and bass anglers with a "good" satisfaction level.17. Provide a cisco population in Crooked Lake that sustains a gill net catch rate >2/lift andannual harvest of 500 ciscoes.18. Provide a muskie population in Loon Lake that sustains a spring trap net catch >4/lift ofadults (>30 in), an angler interest of>5%, an angler catch rate ofl/30-hours of targetedmuskie fishing, and a muskie angler satisfaction level ("fair and good") >50%.
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PROJECT AREAThe UTRLA Project Area is located in northeastern Indiana midway between FortWayne and South Bend in the southwest corner of Noble County and northwest corner ofWhitley County (Figure 1). State Road 109 bisects the eastern part of the watershed. Thearea encompasses 13,714 acres with an average slope of 3.5% and contains agriculturalland (64%), forest (15%), water (11%), residential land (8%), and grassland (2%).Although 12 named natural lakes are located within the watershed, the primary onesinclude Big (228 ac), Crane (28 ac), Crooked (206 ac), Goose (84 ac), Loon (222 ac),New (50 ac), and Old (32 ac). Each one except New Lake has a state-owned publicaccess site. Because of limited access, New Lake was not included in the samplingproject. Dollar, Green, Haroff, and Winters lakes were also not included in the projectbecause of their small size (<10 ac) and restricted access. Little Crooked Lake, a basinconnected to the east end of Crooked Lake, was included with Crooked Lake sampling.The UTRLA lakes are connected by a series of small ditches created years ago toimprove drainage (Figure 2). Crane and Crooked lakes drain through separate ditches intoBig, while Goose and Old lakes drain through separate ditches into Loon. New Lakeempties into Old. The outlets of Big and Loon merge north of Loon and drain to SmalleyLake, eventually to Webster, James, and Tippecanoe lakes and then into the TippecanoeRiver and ultimately the Wabash River. The Loon sub-watershed above the lake outletcovers 7,122 acres and the Big sub-watershed outlet covers 5,733 acres. Hydraulicretention time varies from 79 and 124 days at Crane and Old, 289 and 355 days at Loonand Big to 2.2, 4.6 and 9.2 years at Goose, New, and Crooked, respectively.Water quality and habitat conditions vary within the UTRLA lakes and have beendocumented, along with their watershed characteristics, in the UTRLA management plan(Williams Creek 2008). Based on sampling in 2006, mean secchi disk transparency (ft) inJuly and August was 3.3 at Big and 3.9 at Loon, 4.0 at Goose, 9.7 at Old, and 15 atCrooked. Crane Lake's clarity is also typically poor (Figure 3). Chlorophyll-a (ppb)ranged from 2 at Crooked, 8 at Old, 17 at Big, 25 at Crane, 45 at Goose, and 58 at Loon.Substrates are dominated by sand and marl in Crooked, sand and muck in Big and Loon,and muck in Crane, Goose and Old. Residential shoreline development is more prevalentat Big and Loon, less prevalent at Crooked, Goose and Old, while Crane is undeveloped.10
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SAMPLING METHODS AND ANALYSESFish population and angler data at the UTRLA lakes was obtained in 2009 throughseveral types of standardized surveys used in Indiana. Targeted sampling for largemouthbass was conducted in late April and May, bluegill sampling was conducted in late Mayand June, fish community surveys were conducted in June, and angler creel surveys wereconducted from mid-May through August. Procedures generally followed DFWguidelines for targeted sampling, general surveys, and creel surveys.Spring bass sampling, using pulsed DC electrofishing (504V) and a two-person crewto retrieve stunned bass, was conducted twice for up to two hours at random sites eachnight at Big and Loon or for one shoreline lap each night at Crane, Goose, and Old.Sampling was separated by bi-weekly intervals. Each bass was measured (total length)and released after scale samples were taken for age and growth analyses. At Crooked,bass electrofishing was conducted on three occasions at weekly intervals using mark-recapture techniques (right ventral fin-clip) to estimate the number of 8-inch and largerbass. Two crews were used to cover the entire shoreline each night. Bass were groupedinto four length categories at each lake (7.8- to 11.7-in, 11.8- to 13.7-in, 13.8- to 17.8-in,>17.8-in). The categories were then rounded to the nearest inch for data discussion. Meannightly catch/hour was calculated for each of the four length categories. Size structureindices were also calculated. Back-calculated growth rates of bass were also determinedfrom scales using a 0.8-inch body-length to scale-length intercept.Targeted electrofishing for bluegills was conducted on one night in late May usingprocedures similar to bass sampling but for only two 15-minute stations per lake. On asecond night in June, bluegills were electrofished along with all species. Similar stationswere sampled on both occasions, but effort was increased to 45 minutes at Goose and 60minutes at Big, Loon, and Crooked on the second night to conform to standard fishpopulation survey guidelines. Bluegills were also grouped into four length categories(2.8- to 5.7-in, 5.8- to 6.7-in, 6.8- to 7.7-in, >7.8-in). These categories were also roundedto the nearest inch for data discussion. As with bass, mean nightly catch/hour and sizestructure indices were calculated for bluegills and scales were taken for age and growthdeterminations using the same 0.8-inch intercept.11
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During the fish community assessments, various numbers of gill nets and trap netswere set in proportion to lake size. Four gill net lifts were made at Crane and Old, six atGoose, and eight at Big, Crooked and Loon. Two trap net lifts were made at Old, three atGoose, and four at Big, Crane, Crooked, and Loon. The nets were checked and moveddaily within each lake. All netted fish were measured and released when possible.Angler surveys were conducted from May 11 through August 31, 2009 using twocreel clerks with each covering three lakes. Boat and shore anglers were counted eighttimes at hourly intervals on each survey day except at Big and Crooked, either during anearly (7 am -2 pm) or late (3 pm -10 pm) period on six to eight weekend days and 15 to18 weekdays. Counts were made during six 1.5-hour intervals at Big and Crooked due tolake shape and boat speed limits. Each clerk spent the entire survey day at only one lake.The amount of sampling effort per lake was less than standard creel surveys inIndiana (due to the number of lakes involved), so total fishing effort was calculated ateach lake over the entire survey period stratified for weekends and weekdays bymultiplying the average daily count per strata times 16 hours/day times 34 weekend daysor 80 weekdays. Angler catch was determined by interviewing anglers during the surveyday. Total catch of each species was estimated by expanding the observed catch times thefraction of total effort attributed to interviewed anglers. Harvested fish were measured toassess size structure. During interviews, a spokesperson for the party was asked if theywere a resident at the lake, which species they fished for, whether they released any legal(>14-in) or sub-legal (<14-in) bass, and how they rated fishing quality ("good, fair, orpoor"). Harvest rates and fishing quality perceptions were compiled from anglers whotargeted each species, either singly or in combination with other species. Catch rates (i.e.harvest plus release) were also calculated for bass and muskies.Various habitat assessments were conducted at each lake using current surveyguidelines. Clarity (secchi) and temperature/oxygen profiles (2- and 5-ft intervals) weremeasured on the first day of each fish survey in June and again at all lakes on July 9.Three additional secchi readings were taken in July at Big, Crooked, and Loon.Submersed plants were sampled at various littoral sites from July 27-30 using a standarddouble-headed rake. Emergent beds were mapped with GPS and range-finder equipmentduring August and characterized by their species composition along visual transects.12
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RESULTSLargemouth bass samplingSpring electrofishing catch rates of 8-inch and larger bass ranged from 117/hour atCrooked to 305/hour at Big and averaged 215/hour (Table 1). All lakes but Crookedexceeded the management objective of 80 to 140/hour established by the UTRLAcommittee. Catch rates of 8- to 12-inch bass ranged from 49/hour at Crooked to 213/hourat Big and averaged 139/hour, while catch rates of 12- to 14-inch bass ranged from25/hour at Old to 86/hour at Big and averaged 58/hour. Although Big had the greatestnumber of sub-legal bass (<14-in), it provided the lowest catch rate of 14- to 18-inch bass(5/hr). Crooked had the lowest overall catch rate but the highest catch rate of 14- to 18-inch bass (26/hr). The average catch rate of 14- to 18-inch bass was 15/hour. Goose Lakenot only had a high catch rate of 14- to 18-inch bass (22/hr) but also the highest catch rateof 18-inch and larger bass (7/hr). In contrast, Big and Loon each produced catch rates ofless than 2/hour for 18-inch and larger bass. The average catch rate of 18-inch and largerbass was 3/hour. Although spring electrofishing indicated 8-inch and larger bass areabundant in the UTRLA lakes, catch rates of age-1 and older bass during the Junesurveys were close to or within the management objectives of 80 to 140/hour at Crooked(79/hr), Loon (86/hr), and Old (126/hr). Catch rates of age-1 and older bass remainedabove the objective at Big (314/hr), Crane (168/hr), and Goose (203/hr).Bass numbers were high and overall bass populations in the UTRLA lakes aredominated by sub-legal fish. The percentage of 14-inch and larger bass in the springsamples averaged only 11% and ranged from 2% at Big to 25% at Crooked (Table 2).The UTRLA management objective is 25% or more. Likewise, no lake reached theobjective of 8% or more for 18-inch and larger bass. Goose had the largest percentage of18-inch and larger bass (4%) but the other lakes had 2% or less. The average percentageof 18-inch and larger was only 2%.Based on the mark-recapture sampling at Crooked Lake, it contained 2,888 (SE=301)8-inch and larger bass (14/ac). Of these, 1,201 were 8- to 12-inch (42%), 977 were 12- to14-inch (34%), 656 were 14- to 18-inch (23%), and 54 were 18-inch and bigger (2%). Atthe completion of sampling, 820 marked bass were placed in the population (28%). Asimilar percentage of marked bass (21%) were captured in the June sample.13
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Bass growth rates in the UTRLA lakes were typical of rates in other northern Indianalakes but varied among the lakes (Figure 4). Bass lengths, based on back-calculations ofsize at their current age, averaged 4.1, 7.1, 9.5, 11.5, 13.4, and 15.1 inches at age-1through age-6, respectively. By age-6, however, bass were much larger in Crooked (15.3in) and Loon (15.9 in) than they were in Big (13.9 in), Crane (14.3 in), Goose (14.0 in),and Old (14.1 in). Although less incremental growth occurred during the fourth year ateach lake, bass continued to grow during their fifth and sixth years. Loon and Old had thelargest sixth-year increments.BluegUl samplingWith the exception of Goose (539/hr), electrofishing catch rates of 3-inch and largerbluegills were similar among the lakes and fell within the management objective of 140to 400/hour, ranging from 193/hour at Loon to 297/hour at Big (Table 3). IncludingGoose, the overall mean catch rate was 288/hour. Catch rates of 3- to 6-inch bluegillsvaried from 95/hour at Loon to 332/hour at Goose and averaged 178/hour. Catch rates of6- to 7-inch bluegills varied from 30/hour at Crooked to 101/hour at Goose and averaged51/hour. Goose had the highest catch rate of 7-inch and larger bluegills (56/hr) and Cranehad the lowest (14/hr). The average among all six lakes was 35/hour. Catch rates of 8-inch and larger bluegills were more variable than catch rates of other size groups, rangingfrom 0/hour at Loon to 50/hour at Goose and averaging 24/hour.Proportions of various bluegill size groups also differed among lakes (Table 4). Loon(49%) and Old (48%) had the lowest percentages of 3- to 6-inch bluegills, whilepercentages at the other lakes varied from 62% at Goose to 73% at Crooked. Loon alsohad the largest percentage of 6- to 7-inch bluegills (29%) and 7- to 8-inch bluegills (22%)but had the lowest percent of 8-inch and larger bluegills (0%). All lakes except Crane(12%) exceeded the combined management objective of 15% for 7-inch and largerbluegills and all lakes except Loon exceeded the management objective of 4% for 8-inchand larger bluegills. Old had the second greatest percentage of 7- to 8-inch bluegills(16%) and the greatest percentage of 8-inch and larger bluegills (18%).Bluegill growth rates were also typical of bluegills in other northern Indiana naturallakes. Overall, bluegills in the UTRLA lakes averaged 1.4, 2.8, 4.6, 6.4, 7.4, and 8.214
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inches at age-1 through age-6, respectively. Bluegills were larger in Big, Crane, Goose,and Old than they did in Crooked and Loon (Figure 4). Although first-year incrementswere similar, differences became apparent in the second year with larger increments atCrane and Old and smaller increments at Crooked and Loon. By age-4 bluegills werelarger than 6 inches in each lake except Crooked and Loon. For example, age-4 bluegillsin Goose were 2.1 inches larger than age-4 bluegills in Crooked and 1.6 inches largerthan age-4 bluegills at Loon. Growth slowed considerably during the fifth year at Goosebut increased in the sixth year. No age-6 bluegills were collected at Loon.Fish community samplingThe fish community surveys provided a combined catch of 5,409 fish representing 28species (Table 5). Catches varied from 437 fish at Old and 450 at Crane to over 1,000fish at Big, Crooked, and Loon and was 1,316 fish at Goose. The number of speciesvaried from 13 at Crane and Goose to 19 at Big and averaged 16. With the exception ofLoon (0.35), native species diversity indices ranged from 0.61 at Crane to 0.69 at Big.Sport fish accounted for 94% of the total catch by number, 90% to 98% at each lake,while non-game fish accounted for 6%.Although relative species compositions were similar among lakes, there were a fewnotable differences (Table 6). Bluegills ranked first numerically in each lake but variedfrom 47% of the catch at Big to 80% at Loon and averaged 59%. Percentages at all lakesexcept Loon were within the range of 40 to 60% established as the UTRLA managementobjective. Largemouth bass ranked second numerically in each lake except Goose whereredear sunfish were more abundant. Nevertheless, the relative species composition oflargemouth bass in Crooked and Loon (8%) fell below the management objective of 10 to25%, but was within the objective range at Crane (19%), Goose (12%), and Old (14%),and above the objective at Big (28%). Several other species comprised 5% or more of thecatch at individual lakes, including redear sunfish in all lakes, spotted gar at Big, yellowperch at Crooked, and black crappie and yellow perch at Goose. Goose was the only laketo meet the management objective of 5 to 10% for black crappies and/or yellow perch,while Crooked was the only lake to meet the objective of 5 to 10% for perch.15
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Of 28 species caught in the surveys, three were considered non-endemic. Carp werefound at Big, Goose, Loon and Old with the highest catches at Big (6) and Old (7). Twonorthern pike were caught in Loon and one white bass was caught in Big. Twenty-threeciscoes, a species considered native to Crooked, were caught in five gill nets in deepwaterhabitat (4.6/lift). Other catches included a logperch in Big, as well as bluntnose minnows,redfin pickerel, longnose gar, and rock bass in Crooked and a spotted sucker in Old.White suckers were found only in Big and Crane. No gizzard shad were collected at anylake even though shad are present in other parts of the Tippecanoe watershed.Four species previously found in UTRLA lakes were not observed in the 2009surveys, including black bullhead, black-chin shiner, channel catfish, and tadpolemadtom. Although a few muskies were observed during spring electrofishing, none werecaught, despite stocking 1,200 per year in Loon since 1978. Other species previouslystocked and captured on occasion in past surveys but not caught in 2009 were rainbowtrout and smallmouth bass. Seven species (bluegills, largemouth bass, pumpkinseeds,redear sunfish, warmouth, yellow bullhead, and yellow perch) were present in all sixlakes. Hybrid sunfish were collected at Old Lake.Angler creel surveysAnglers fished a combined total of 36,055 hours at the six UTRLA lakes, of which89% were logged by boat anglers and 11% by shore anglers (Table 7). Weekend anglersaccounted for 44% of the total effort and weekday anglers accounted for 56%. Amongboat anglers, their effort accounted for 43% of the pressure on weekends and 57% onweekdays. Total fishing effort varied per lake in large part due to lake size, ranging from1,909 hours at Crane to 9,071 hours at Crooked. Angler effort on an acreage basis waslowest at Loon (35 hr/ac), Big (37 hr/ac), and Crooked (44 hr/ac), moderate at Old (66hr/ac) and Crane (68 hr/ac), and highest at Goose (82/ac). Likewise, boat angler effortwas lowest at Big (30 hr/ac), Loon (31 hr/ac) and Crooked (40 hr/ac), moderate at Old(59 hr/ac) and Crane (68 hr/ac), and highest at Goose (76 hr/ac). The overall effort peracre per day (0.48) was close to the management objective (>0.50) and exceeded theobjective at Crane (0.60), Goose (0.72), and Old (0.58) but was below the objective atBig (0.32), Crooked (0.39), and Loon (0.31).16
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Anglers fished for a variety of species (Table 8). Of 636 interviewed angler-parties,44% fished solely for bluegills and 32% for bass. Those who fished for both represented8%. Crappie anglers (4%) and crappie anglers who also fished for bluegills (4%) rankedthird. Those who expressed no preference accounted for 3%, while muskie anglersaccounted for 1%. Very few anglers fished for perch singly (<1%) or in combination withother species. One party fished for carp and another for gar, while sunfish werementioned by four parties (<1%). Based on the number of times a species was mentioned,anglers fished mainly for bluegills (50%) and bass (36%), followed by crappies (8%),muskies (1%), perch (1%), sunfish (<1%) and miscellaneous species (3%).Fishing preferences, based on the number of times a species was mentioned byinterviewed anglers, varied considerably among lakes and in most cases met themanagement objectives (Table 9). Bluegill preference met the 40% objective at each lakeexcept Loon (36%) and was highest at Old (68%). Bluegill preference at the other lakesranged from 49-54%. Bass preference met the 30% objective at Big, Crooked, and Gooseand was highest at Loon (51%), but below the objective at Crane (21%) and slightlybelow at Old (29%). Angler preference for muskies at Loon (6%) also met themanagement objective (>5%).Anglers removed a total of 17,003 fish from the six lakes, including 13,395 bluegills,1,469 redear sunfish, 1,023 crappies, 671 perch, 338 bass, 77 other sunfish, 18 catfishfrom Goose Lake, and 11 muskies from Loon Lake (Table 10). Anglers took the mostbluegills out of Crooked Lake (4,229), followed by Goose (3,650), Big (1,791), Loon(1,599), Crane (1,204) and Old (921). Big Lake provided the most crappies (579) withGoose second (273). Goose (743) and Crooked (491) provided the most redear sunfish.Crooked (362) and Loon (242) gave up the most perch. Of the 338 total bass taken byanglers, 116 came from Goose, 94 from Loon, 75 from Crooked, 43 from Big, and 11from Crane. The 75 bass taken from Crooked represented 11% of the estimated numberof 14-inch and larger bass present in the spring (75/710). No bass were reportedlyremoved from Old Lake.Bluegill fishing failed to meet several UTRLA management objectives (Table 11).The total harvest of 13,395 bluegills (0.15/ac/d) was below the objective of 45,600(0.50/ac/d). Crane (0.38/ac/d) and Goose (0.38/ac/d) came closest to the objective. Old17
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(0.25/ac/d), Crooked (0.18/ac/d), Big (0.07/ac/d), and Loon (0.06/ac/d) were well below.The overall bluegill harvest rate, i.e. harvest/(total effort x preference), was 0.7/hour andwas 30% below the objective (1.0/hr). The harvest rate exceeded the objective at Crane(1.2/hr), met the objective at Goose (1.0/hr), and was slightly under the objective atCrooked (0.9/hr). Harvest rates were low at Old (0.6/hr), Loon (0.6/hr), and Big (0.4/hr).Based solely on interviews of boat anglers who specifically targeted bluegills, the overallharvest rate of 0.6/hour was 40% below expectations. Specific bluegill harvest rates byinterviewed boat anglers were higher at Crane (0.8/hr), Crooked and Goose (0.7/hr), butlower at Old (0.6/hr), Loon (0.5/hr), and Big (0.4/hr).Although few bass were taken by anglers, many were caught and released (Tables 10and 11). Anglers released 15,677 bass, 89% of which were smaller than the size limit(<14 in) and 11% were larger than the limit. Big (5,352) and Loon (5,315) accounted for68% of the released bass, followed by Crooked (2,350), Goose (1,712), Old (669), andCrane (279). Per acre, bass catches were similar at Crane and Crooked (10-12/ac) buttwice as great at the other lakes (20-24/ac). The overall bass catch per acre per day was0.18, while the total catch of 16,015 bass provided a catch rate of 1.2/hour and was abovethe management objective of 1.0/hour. Boat anglers who specifically targeted bass caughtthem at a rate of 1.0/hour. The rate was highest at Big (1.4/hr) and Loon (1.0/hr),followed by Goose (0.9/hr), Old (0.8/hr), Crooked (0.7/hr), and lowest at Crane (0.4/hr).Although catch rates of bluegills were low, bluegill sizes met the objectives at alllakes except Loon (Table 12). The proportion of 7-inch and larger bluegills (CSD7) was38% at Loon and below the objective (>50%), compared to 77% at Big and Old, 81% atCrooked, 87% at Goose, and 89% at Crane. The proportion of 8-inch and larger bluegills(CSD8) also met the objective (>20%) at Crooked (48%), Crane (44%), Goose (39%),and Old (30%), slightly below the objective at Big (18%), but well below the objective atLoon (3%). Crooked provided the most 8-inch and larger bluegills (2,023), followed byGoose (1,409), Crane (535), Big (323), Old (279), and Loon (39). The largest bluegillswere 9.5 inches long and caught at Crane, Goose, and Old. In contrast, the size ofharvested bass did not meet the UTRLA objective (Table 12). Harvested bass were lessthan 15 inches at Big and only 14 inches at Crane. Loon was the only lake where 18-inchand larger bass (22%) met the objective (>10%).18
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Angler satisfaction with fishing quality differed by species, by lake, and between lakeresidents and lake visitors (Table 13). Overall, 39% of bluegill anglers who fished fromboats described fishing as "good". This percentage was less than the managementobjective of 50%. Another 32% described fishing as "fair" and 29% described fishing as"poor". Bass anglers who fished from boats who rated fishing as good accounted for53%, slightly above the 50% objective, while 28% rating fishing as fair and 18% ratingfishing as poor. Although fewer residents fished than visitors, resident bluegill anglershad a more positive perception of fishing quality (40% good, 36% fair) compared tovisitors (39% good, 30% fair). Resident bass anglers also had a more positive perceptionof fishing quality (58% good) than visiting anglers (51% good).Additional differences were noted between residents and visitors. No lake residentanglers described bluegill fishing as good at Big or Crooked, compared to 60% or more atGoose, Loon, and Old. A larger percentage of visiting anglers rated fishing as good at Big(18%) and Crooked (32%), but Crane had the lowest percentage (14%). More than half ofthe visiting bluegill anglers at Goose, Loon, and Old, however, rated fishing good.Likewise, larger percentages of bass anglers who fished from boats considered fishinggood at Goose (72%), Loon (75%), and Old (64%) than Big (21%), Crane (22%), orCrooked (31%). Those who rated bass fishing poor ranged from 3% at Loon and 4% atGoose to 67% at Crane. No lake resident bass anglers at Big or Old rated fishing good,but 28% of visiting bass anglers at Big and 88% at Old rated fishing good. Few lakeresidents also considered bass fishing good at Crooked (11%), as did visiting anglers(36%). Most lake residents rated bass fishing as good at Goose (77%) and Loon (85%),as did visitors (55% and 73%, respectively).Muskie fishing quality at Loon was described as good. Of seven interviewed muskieangler-parties, four considered fishing good and three considered fishing fair, therebyexceeding the combined management objective of 50%. The estimate of 11 muskiestaken from the lake was based on observation of a single 37-inch observed fish. The partythat took the fish also released another muskie the same day (July 8). No other anglersreported releasing any muskies. Muskie anglers fished 466 hours (6% of 7,770 hrs).Therefore, the estimated catch rate (harvest plus release) was one muskie per 21 hours ofmuskie fishing and exceeded the objective of one muskie per 30 hours of fishing.19
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Habitat assessmentsWater clarity varied within and among the lakes (Table 14). Clarity was greatest atCrooked on June 15 (18.5 ft) and lowest (2.5 ft) at Crane on July 9 and Loon on July 24and July 30. Clarity decreased from the first measurement in June to the secondmeasurement on July 9 at all lakes except Old. At Big, Crooked, and Loon wheremeasurements were continued through July, clarity subsequently declined, decreasing to5.3, 9.5, and 2.5 feet, respectively. Clarity decreased 75% at Loon through the monitoringperiod and about 50% at Big and Crooked.Although surface temperatures varied during each survey in June due to differentsampling dates (Table 15), they were similar by July 9 and ranged from 73 to 75°F.Temperatures 5 feet below the surface on July 9 differed by only Io (73 to 74°F).Thermoclines were established by June but at various depths and moved downward byearly July in Big (12 ft), Crooked (16 ft), Goose and Loon (10 ft), and Old (6 ft), butremained the same in Crane (6 ft). Thermocline thickness was generally 8 to 10 feet.Dissolved oxygen profiles also differed at each lake (Table 16). Ample amounts ofoxygen for fish (>5 ppm) were present in June only in the top 6 feet at Crane and Old, 8feet in Big and Goose, 10 feet in Loon, and down to 26 feet and again below 38 feetdown to 94 feet in Crooked. By July, ample oxygen was present to 6 feet in Crane, 10feet in Goose and Old, 12 feet in Big and Loon, and 30 feet in Crooked. Oxygen amountswere also inadequate for fish (<3 ppm) below these depths in Crane, Big, Goose andLoon, but not until 14 feet in Old and 86 feet in Crooked.Submersed aquatic plant communities were also different in each lake (Table 17).Coverage within the littoral zones varied from 53% in Crane to 97% in Crooked. Meancoverage was 79%. The number of species ranged from four at Crane to 14 at Crookedand averaged nine. Native species diversity was lowest at Crane (0.23) and Old (0.24)and highest at Loon (0.83) and Crooked (0.87). Crane Lake also had the lowest numberof species per site and lowest number of native species per site.Coontail was the most dominant species and was the only species found in all sixlakes. It varied from 30% coverage in Loon to 87% in Old and averaged 57%. Coontaildominance, i.e. a measure of its coverage and density, was nearly five times greater inOld (52%) than Loon (11%). Coontail dominance was also low at Crane (14%) and20
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moderate in Big (25%), Crooked (22%), and Goose (33%). Dominance of other majornative plants, those that were 10% or more, included eel grass in Big and Loon alongwith chara and northern water milfoil in Crooked. Filamentous algae was present in alllakes, varying from 2% of the sites in Crooked to 30% in Big and Crane, 35% in Loon,70% in Goose, and 80% in Old.Two non-native plant species were found in the UTRLA lakes. Eurasian water milfoilwas found in each lake except Big, although a state-funded herbicide program has been inplace to reduce its abundance. Its coverage was greater in Goose (63%) and Crane (43%),but less than 20% in Crooked, Loon and Old. Curly-leaf pondweed was found in fourlakes and varied from 2% at Crooked to 10% at Crane. It was not detected in Big orLoon, although curly-leaf pondweed usually goes into scenescense by early-July.Floating-leaf emergent plant bed coverage (primarily water lily and spatterdock)varied within the UTRLA lakes (Table 18). Total bed coverage ranged from 3.2 acres inOld to 31.6 acres in Crooked. Emergent beds covered the least amount of surface area asa fraction of the whole lake in Loon (4%), Big (7%), and Old (10%), while greatest inCrooked (15%), Goose (16%), and Crane (17%). As a measure of edge cover for fish, thedistances along the lakeward edge of emergent beds ranged from 3,768 feet at Old to18,067 feet at Crooked and totaled 92,136 feet. Emergent beds covered more of theshoreline at Crooked and Goose (81%), less at Crane (75%) and Old (69%), and the leastamount at Big (49%) and Loon (32%).21
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DISCUSSIONStandardized sampling conducted in 2009 provided a tool to compare the currentstatus offish populations and fishing within the UTRLA lakes and assess whethermanagement objectives are being met. Overall, the lakes met a greater number of bluegillobjectives than largemouth bass objectives (Figure 5). Of the 24 bluegill populationobjectives (4 objectives at 6 lakes), 83% were met. In contrast, only 21% of the basspopulation objectives were met. Likewise, 53% of the bluegill fishing objectives and 28%of the bass fishing objectives were met. Based on these results, a new fish managementinitiative at the UTRLA lakes should first be directed toward improving largemouth basssize structure and fishing opportunities where needed.Bass populations in the UTRLA lakes are generally characterized by high densities ofsub-legal fish, a condition more common now at other northern Indiana lakes followingimposition of a 14-inch minimum size limit in 1998 and greater voluntary release of legalbass by anglers (Pearson 2008). Compared to other northern Indiana lakes, electrofishingcatch rates of 8-inch and larger bass were above the normal range at each lake exceptCrooked, while proportions of 14-inch and larger bass were low. The proportions of 18-inch and larger bass were also below the northern Indiana average of 4% at all lakesexcept Goose. High catch rates of sub-legal bass and low proportions of legal bass aremore pronounced at Big and Crane.High numbers and high proportions of sub-legal bass can develop where recruitmentand survival of young bass is excessive, resulting in slow growth. Low numbers and lowproportions of legal bass can also develop where fishing mortality or natural mortality ofold bass is high. Because few bass were taken by anglers at the UTRLA lakes, includingonly 11% at Crooked, the current scarcity of 14-inch and larger bass is probably not dueto fishing mortality. Instead, growth of age-6 and older bass may not be sufficient toproduce bigger bass, especially at Big and Crane. As a result, any new regulationdesigned to reduce exploitation of 14-inch and larger bass would not address an over-abundance of smaller bass. Likewise, any new regulation designed to reduce bass lessthan 14 inches may have little effect on size structure if anglers are reluctant or unable toremove sufficient numbers. If sufficient numbers are removed, fishing mortality of 14-inch and larger bass might also increase and negate any improvement in size structure.22
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What may be needed, therefore, is a management approach that can ensure sufficientremoval of bass less than 14 inches while providing more protection of bass larger than14 inches. As a result, Big and Crane could serve as candidate sites for testing alternativeregulations to improve bass population balance. How changes in bass regulations mightaffect bluegill abundance and size in these lakes could also be examined.Even with new bass regulations, UTRLA lakes may not be capable of producingproportions of 18-inch and larger bass to achieve the objective (8%) for a variety ofreasons (e.g. habitat, productivity, forage). Only seven lakes in northern Indiana, basedon standardized sampling since the early 1980s, are known to have developedpopulations where proportions of 18-inches and larger bass were 8% or higher but nonewere sustained (DFW largemouth bass dataset). Ironically, these populations developedunder a variety of size limits, including no limit (Beaver Dam, Sacarider), 12-inch (Hartz,Robinson), 14-inch (Barrel&l/2, Lake-of-the-Woods), and 18-inch limits (Barrel&l/2,Shock). In addition, all produced electrofishing catch rates of 8-inch and larger bass lessthan 80/hour. A more reasonable objective at the UTRLA lakes, in light of the high catchrates, may be 4%. For example, 24 northern Indiana lakes on 52 sampling occasions haveproduced bass populations where proportions of 18-inch and larger bass reached 4%.Goose currently meets that standard, while Crane did in 1981 and Old did in 1991.Although the 8% objective may be unrealistic, achieving 4% or higher would bepreferable over the current low proportions <2%. Achieving 4% or more, however, mayrequire a trade-off in over bass numbers. Lakes where 18-inch and larger bass make up4% or more of the population have typically had electrofishing catch rates of 8-inch andlarger bass below the UTRLA objective (73/hr) and densities averaging 17.5/acre.Because Loon met all four bass fishing objectives, there is little evidence to suggeststocking muskies adversely affects bass fishing. Overall fishing effort at Loon was nearlyidentical to fishing effort at Big and not much lower than Crooked, yet angler interest asmeasured in preference for bass fishing was about 50% greater at Loon than Big orCrooked. Greater interest in bass fishing may be due to better bass size structure. Loonwas the only lake where anglers took 18-inch and larger bass and had the most satisfiedbass anglers (75%). However, Loon met the fewest number of bluegill objectives and hasapparently not benefited from additional prédation on bluegills by muskies.23
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While Loon could benefit from additional bluegill management, there is little need forany new bluegill initiatives at Big, Crooked, and Old lakes, given the adequate numberand size of bluegills already present. Likewise, there is little need for additional bluegillmanagement at Crane or Goose. The proportion of 7-inch and larger bluegills in Cranewas slightly below the objective, but an adequate percentage of 8-inch and largerbluegills was present. Goose contains also ample numbers of 7-inch and larger bluegills,so there is little reason to suspect it may contain too many small bluegills.Angler opinions of bluegill fishing quality at the UTRLA lakes did not match up withbluegill population parameters or fishery characteristics. Although all populationobjectives were met at Big and Crooked, and most bluegill fishery objectives were met atCrane, angler satisfaction with bluegill fishing quality was low at these three lakes. Incontrast, anglers at Goose and Old had a more favorable opinion of bluegill fishingquality even though population and fishery parameters were similar to Big, Crane, andCrooked. Even at Loon, where bluegill population parameters were the least desirable,bluegill anglers had a good opinion of fishing. Electrofishing and trap nets generallyprovide reliable data on the status of bluegill populations, so the discrepancy betweenfishery characteristics and angler opinions may reflect bias in assessing quality based oninterviewing anglers during creel surveys. In doing so, anglers who have a negativeperception of quality are less likely to fish and less likely to be encountered. Anglers whofish where they think fishing is poor may have low expectations or derive satisfactionfrom factors other than catch. Likewise, anglers dissatisfied with fishing where goodfisheries exist may have unreasonably high expectations or poor personal experience.Nevertheless, effort should be directed at promoting available bluegill fishingopportunities to increase effort and improve angler perceptions of quality.Why Loon, compared to other UTRLA lakes, met the fewest bluegill objectives is notknown. However, angler dissatisfaction with bluegill fishing, despite the positiveresponses reflected in the 2009 survey, has persisted since the 1970s when Loon residentscomplained of small bluegill size and asked that pike be stocked to increase prédation onbluegills. In 2004, 47% of bluegill anglers considered fishing poor at Loon and only 11%considered it good (Pearson 2005). Although muskies were stocked in lieu of pike, theyhave not improved bluegill population characteristics or fishing success. Instead, the24
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relative species composition on bluegills increased from 55% in 1988 to 61% in 2000,77% in 2004, and 80% in 2009. Until 2009, proportions of 7-inch and larger bluegillsnever exceeded 5% and were less than 2% twice. Electrofishing catches of 3-inch andlarger bluegills were also consistently high, ranging from 808/hour in 1988 to 451/hour in2000 and 1,999/hour in 2004. These previous surveys, however, were conducted in July.In contrast, the June 2009 proportion of 7-inch and larger bluegills was much higher(22%) and the catch rate of 3-inch and larger bluegills (193/hr) was much lower. Becausethe changes in 2009 may simply reflect sampling variability, additional sampling in Julycould help verify whether the increase in size and decrease in numbers observed in Junerepresented a real shift in the population.As the percentage of bluegills increased at Loon, the percentage of perch decreasedfrom 11% in 1988 to 4% in 2000, 2% in 2004, and 1% in 2009. More importantly, theactual number of perch captured during the surveys decreased from 134 in 1988 to 82 in2000, 53 in 2004, and only 11 in 2009. Lake chubsuckers, similar in shape and size toperch, also declined. Both may be more vulnerable to muskie prédation because of theirshape. Meanwhile, the number of black crappies and redear sunfish, two species similarin shape to bluegills, increased from 1988 to 2004 before decreasing in 2009, althoughtwo other sunfish species, pumpkinseeds and warmouth, did not. How these changes mayor may not be related to muskie stockings is not known, but perch are a preferred preyitem for muskies in Wisconsin (Bozek and Burri 1999). Perch, as well as chubsuckers,also declined at Lake Webster downstream of Loon after muskies were stocked but percheventually returned to previous levels (Pearson 2005). At Webster, however, gizzard shadare also present. They provide additional muskie forage which, unlike at Loon and othersunfish-dominated lakes, could temper prédation on perch. White suckers, anotherspecies typically eaten by muskies (Bozek and Burri 1999), are also absent from Loon.Once perch declined at Loon, muskies should have fed on bluegills, thus reducingbluegill density and improving growth. That apparently did not happen, as has beenreported elsewhere (Graff 1986, Wahl and Stein 1988). Instead, bluegills and crappiesincreased. Perch declined and bluegills increased after pike were stocked in a Minnesotalake (Anderson and Schupp 1986). In contrast, after removing large pike from a Nebraskalake, more large perch and bluegills were present (Jolley et. al 2008). Although perch25
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prey on small bluegills, especially in winter (Fullhart et. al. 2002), and can influencebluegill size (Anderson and Schupp 1986, Reed and Parsons 1996, Tomcko and Pierce2005), large bluegills were not abundant in Loon when more perch were present.Whether perch ever played a significant role in limiting bluegill density is not known.Therefore, to more fully understand the impacts of muskie stockings within fishcommunities, it may be in the long-term interest of managers and anglers to evaluate howLoon Lake's fish community responds if muskie stockings are stopped. Anglers wouldstill have ample muskie fishing opportunities in lakes downstream in the watershed,including Webster, Tippecanoe, and Barbee chain.Bluegill size at Loon has also remained apparently independent of changes that mayhave occurred in the bass population following imposition of a 12-inch size limit in 1990and 14-inch limit in 1998. Bass electrofishing catch rates during summer surveysdeclined at Loon over the last decade from a mean of 144/hour in 1988 and 52/hour in2004 and 65/hour in 2009 (see Appendix 5). Catch rates in spring, however, increasedfrom 113/hour in 2004 to 192/hour in 2009. Most of the increase was among 8- to 12-inch bass. Given the uncertainty over the actual long-term trend in bass abundance andsize, it is not possible to adequately assess their impacts on bluegill numbers and size.No single factor likely explains why Loon does not produce better bluegill fishing.From a habitat perspective, its turbidity ranks second to Crane, although Loon has thehighest chlorophyll-a value. Not unlike the other UTRLA lakes except Crooked, Looncontains sufficient oxygen for fish only in the top 10 to 12 feet during summerstratification. Loon has the largest watershed (7,140 ac) and presumably more sedimentand nutrient inputs, but it ranks third in the ratio of watershed size to lake size (32:1) andthird in retention time. It also has the largest percentage of residential shorelinedevelopment with numerous sand and gravel beaches that may provide more spawningareas and contains several native plant species with plant coverage is typical (75%),although coontail coverage is the lowest. Emergent beds also cover the least amount ofsurface area compared to other UTRLA lakes, so it is not likely that vegetation providestoo much cover for bluegills to escape predators. Whether these factors influence bluegillpopulation characteristics at Loon and at other natural lakes is not known.26
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Until more is known how habitat features affect bluegill, it is not possible to identifystrategies to address habitat limitations at Loon. This is not to say, however, that generalhabitat improvements are unwarranted. Efforts to reduce nutrient and sediment inputsthrough wetland restoration, best-management farming practices, along with efforts toprevent in-lake recycling of nutrients, can be expected to improve water clarity over time.As water clarity improves, oxygen concentrations could increase in deeper water andprovide additional fish habitat. Control of non-native aquatic plants and other aquaticvegetation restoration actions could expand coverage of native submersed and emergentplants. Steps to limit future shoreline development and alterations, as well as potentialadverse impacts from boating or other human activities, could help protect nearshorehabitat. These various habitat strategies, while not necessarily directed at individualspecies, can be expected to benefit most sport fish populations and anglers as well asenhance lake quality and maintain their economic value.More research is needed to better understand why Loon, similar in size and depth toBig and Crooked, has such different environmental an