L _— _— ‘ "A .4 UP]? 421} I Michigan "State ~ University This is to certify that the thesis entitled Limnological Investigations of Eagle Lake, Michigan presented by Robert John Ceru has been accepted towards fulfillment of the requirements for Masters Fisheries and Wildlife degree in 550'" £21934, Major professo .' Date December 22, 1977 0-7639 . ——_—M——uu—_._" _‘__.-—._.—«— «.-.. .___ . ...... .... .. _ LIMNOLOGICAL OBSERVATIONS OF EAGLE LAKE, MICHIGAN BY Robert John Ceru A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Fisheries and Wildlife 1977 ABSTRACT LIMNOLOGICAL OBSERVATIONS OF EAGLE LAKE, MICHIGAN BY Robert John Ceru Limnological and biological parameters of Eagle Lake, Michigan were investigated between May-October, 1975, and March-November, 1976 in order to document present lake conditions. Results indicate mesotrophic conditions with thermal stratification and hypolimnetic oxygen depletion during the summer. Mean values were 4.5 meters for Secchi disk, 0.056 mg/liter for total phosphorus, and 0.45 mg/ liter for total Kjeldahl nitrogen. Thirty-six phytoplankton genera were identified and their abundance and succession discussed. Mean summer Chlorophyll¢1 concentration was 3.53/ug/liter during 1976. The rate of growth for blue- gills compared favorably with the tentative state average. ACKNOWLEDGEMENTS The advice, guidance and support received from E. W. Roelofs, my major professor, during my graduate studies and in writing this thesisirsgratefully acknowledged and appre- ciated. Sincere appreciation is expressed to N. R. Kevern for his many thoughtful suggestions and assistance in initiating the research and for his critical review of the thesis. Appreciation is extended to T. W. Porter for provoking an attitude of accuracy and for his critical review of the thesis. Special thanks is given to Mr. William Stout, President of the Eagle Lake Association for collecting Chlorophyll a and bacteria samples, and generously providing gas and the use of his house anytime during the study. His patience, support and encouragement stimulated enthusiasm throughout the study. I thank my fellow students, particularly Robin Bentz, for helping collect these data. Special gratitude is expressed to my brothers and sisters in the Work of Christ Community for their inspira- tion, understanding and encouragement. Particular thanks goes to Miss Dee Wilkie for typing the thesis and Mr. Richard Schaefer for doing all of the graphics. ii This research was supported by a grant from the Eagle Lake Association and partially by the Michigan State University Agricultural Experiment Station. iii TABLE OF CONTENTS LIST OF TABLES . . . . . . . . . . . . . . . . . . . . . V LIST OF FIGURES . . . . . . . . . . . . . . . . . . . .vii INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . 1 DESCRIPTION OF STUDY AREA . . . . . . . . . . . . . . . 1 METHODS . . . . . . . . . . . . . . . . . . . . . . . . 2 PHYSICAL PARAMETERS . . . . . . . . . . . . . . . . . . 7 Morphometry . . . . . . . . . . . . . . . . . . . Secchi disk transparenc . . . . . . . . . . . . . Water temperature . . . . . . . . . . . . . . . . . l2 \O\l CHEMICAL PARAMETERS . . . . . . . . . . . . . . . . . . 15 Dissolved oxygen . . . . . . . . . . . . . . . . . 15 Alkalinity, hardness and pH . . . . . . . . . . . . l7 Nitrogen : . . . . . . . . . .'. . . . . . . . . . 21 Phosphorus . . . . . . . . . . . . . . . . . . . . 21 Chlorides . . . . . . . . . . . . . . . . . . . . . 27 BIOLOGICAL PARAMETERS . . . . . . . . . . . . . . . . . 28 Phytoplankton . . . . . . . . . . . . . . . . . . . 28 Chlorophyllcz . . . . . . . . . . . . . . . . . . . 33 Aquatic insects . . . . . . . . . . . . . . . . . . 3S Coliform bacteria . . . . . . . . . . . . . . . . . 35 Aquatic plants . . . . . . . . . . . . . . . . . . 36 Fish . . . . . . . . . . . . . . . . . . . . . . . 36 SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . 47 LITERATURE CITED . . . . . . . . . . . . . . . . . . . . 49 APPENDIX . . . . . . . . . . . . . . . . . . . . . . . . 55 iv Table 10. Al. A2. LIST OF TABLES Morphometric measurements of Eagle Lake, Michigan . . . . . . . . . . . . ... . . . . . . Areas and volumes of water at various levels for Eagle Lake, Michigan ... . . . . . . . . . . Bottom temperatures (0C) for stations 2, 5 and 6 during 1976 in Eagle Lake, Michigan . . . . . Total phosphorus in surface waters of various lakes . . . . . . . . . . . . . . . . . . . List of phytoplankton genera identified from _Eagle Lake, Michigan between July and October, 1975. Genera are listed in order of decreasing relative abundance . . . . . . . . . . . . . Relative abundance of aquatic insects collected from Eagle Lake, Michigan on June 25, 1975 . List of aquatic plants collected from Eagle Lake, Michigan in August, 1975 . . . . . List of fish collected from Eagle Lake, Michigan during 1975 and 1976 . . . . Year class, ages, number, mean total length at capture, mean calculated total length, mean length at each annulus and mean growth incre— ment for bluegills from Eagle Lake, Michigan . A comparison of average total lengths of blue- gills at each annulus between Eagle Lake, Michigan and other lakes . . . . . . . . . . . . . . Sampling schedule by date (month/day) for various parameters in Eagle Lake, Michigan during 1975 . . . . . . . . . . . . . . Sampling schedule by date (month/day) for various parameters in Eagle Lake, Michigan during 1976 . . Page 14 27 29 35 37 38 40 43 56 57 A3. A4. A5. A6. A7. A8. A9. A10. A11. A12. Summary of water temperature.values (0C) for Eagle Lake recorded during 1976 at Station 2 Summary of water temperature values (0C) for Eagle Lake recorded during 1976 at Station 5 Summary of water temperature values (0C) for Eagle Lake recorded during 1976 at Station 6 Summary of dissolved oxygen concentrations (mg/1) for Eagle Lake during 1975 and 1976 . . . Summary of dissolved oxygen concentrations (mg/1) for Eagle Lake during 1975 and 1976 . . . . Summary of pH values for Eagle Lake recorded during 1975 and 1976 . . . . . . . . . . . . . . . Summary of total alkalinity concentrations (mg/l CaCO3) for Eagle Lake recorded during 1975 and 1976 . . . . . . . . . . . . . . . . . . Summary of hardness concentrations (mg/1 CaCO3) for Eagle Lake recorded during 1975 and 1976 . Summary of total Kjeldahl nitrogen concentra- tions (mg/l) for Eagle Lake recorded during 1975 and 1976 . . . . . . . Summary of total phosphorus concentrations (mg/l) for Eagle Lake recorded during 1975 and 1976 . . . . . . . . . . . . . . . . . vi 58 59 6O 61 62 63 64 65 . 66 67 Figure 1. 10. 11. 12. 13. LIST OF FIGURES Locations of sampling stations for Eagle Lake, Michigan . . . . . . . . . . . . . . . . Hydrographic map of Eagle Lake, Michigan Percent volume hypsograph curve for Eagle Lake, Michigan. Center of gravity, Zg, indicated at depth where 50% of volume lies above and below . . . . . . . . . . . Secchi disk transparency for Eagle Lake, May- October, 1975; March—November, 1976 Temperature profiles for Eagle Lake, Michigan, 1975 and 1976 . . . . . . . . . . . . Dissolved oxygen profiles for Eagle Lake, Michigan . . . . . . . . . . . Depth distribution of total alkalinity in Eagle Lake, Michigan . . . . . . . . . . . . Depth distribution of hardness in Eagle Lake, Michigan . . . . . . . . . . . . . . . . . . Depth distribution of total Kjeldahl nitrogen in Eagle Lake, Michigan during 1975 . . Depth distribution of total Kjeldahl nitrogen in Eagle Lake, Michigan during 1976 . . . . Depth distribution of total phosphorus in Eagle Lake, Michigan during 1975 . . . Depth distribution of total phosphorus in Eagle Lake, Michigan during 1976 . . . . Distribution of major groups of phytoplankton in Eagle Lake, Michigan and the dominant genus based on numerical averages of samples collected at the surface . . vii Page 10 11 13 16 19 20 22 23 25- 26 3O 14. 15. 16. 17. l8. 19. Distribution of major groups of phytoplankton in Eagle Lake, Michigan and the dominant genus based on numerical averages of samples collected at 10 feet below the surface .-. . Chlorophyll a concentrations for Eagle Lake, Michigan during the summer, 1976 . . . . . . . Total length-scale radius relationship for 209 bluegills from Eagle Lake, Michigan . . . Growth in length of bluegills collected from Eagle Lake, Michigan . . . . . . . . . . . . . Length-weight relationship of 184 bluegills from Eagle Lake, Michigan . . . . . . . . . . Condition coefficients for bluegill collected from Eagle Lake, Michigan during 1975 and 1976 . . . . . . . . . . . . . . . . . . . . viii 31 34 39 42 44 46 INTRODUCTION Most previous water quality control work has been con- centrated in problem areas, with resulting lack of good background water quality determinations in many areas (Michigan DNR, 1970). Once background measurements are determined, they provide a useful basis from which future water quality trends can be evaluated. The purpose of this study was to obtain such back- ground information on physical, chemical and biological parameters in Eagle Lake. This study will provide the res- idents of the lake with some technical data that will be a useful indication of the present water quality and provide a basis for future development and management of the lake. DESCRIPTION OF STUDY AREA Eagle Lake is located near Bloomingdale in the drainage basin of the Kalamazoo River (Tls., 1N. Rl4W., Sections 3, 34, and 35, Van Buren and Allegan Counties). It is a medium size (surface area of 91 hectares), relatively deep lake (mean and maximum depths of 6.7 and 19.0 meters respec- tively), with a small inlet on the southeastern shore. It has a watershed of 193 hectares (Marsh and Borton, 1974), which consists of deep to moderately deep, well to somewhat poorly drained, nearly level to gently sloping, very coarse textured soils. Most of the northeast and south shoreline is bordered by wooded areas while the north end consists of a swamp dominated by cattails. The remainder of the shoreline is gently sloping and bordered by year- round homes. Eight permanent sampling stations were established in order to standardize the sampling program (Figure 1). Stations 2, 3, 5 and 6 were all open water stations with no aquatic macrophyte colonization and a depth ranging from 16 to 19 meters. Stations 1, 4 and 8 were situated in near—shore areas ranging in depth from 1 to 1.5 meters. Mud bottoms of these latter stations were flat with abun- dant macrophyte growth. Station 7 had a depth of 9 meters - with a sloping bottom and sparse macrophyte growth. METHODS A hydrographic map of Eagle Lake was obtained from the Michigan United Conservation Clubs. Areas were measured using a compensating polar planimeter and map measurer. The methods used in calculating the various morphometric parameters are those given by Welch (1948) and Cole (1975). Samples for chemical analysis were obtained from spring until fall in 1975 and 1976 (Appendix Tables Al and A2). Samples from stations 1, 4 and 8 were taken just below the surface. Samples from stations 2, 5 and 6 were .cmmflcoflz .mxmq mammm How mQOHDMDM mafiamfimm mo mCOHumooq .H wusmflm taken at the surface, epilimnion-thermocline interface and bottom. Water samples for Chlorophy11<1 determinations were collected bimonthly from station 2 between May and September, 1976. Secchi disk visibility was measured approximately every two weeks between May and October in 1975 and March and November in 1976. Phytoplankton samples were collected every two weeks between July and October, 1975 at stations 2, 3, 6 and 7 at the surface and 10 feet. Data for coliform bacteria were obtained from records of the Allegan County Health Department for the summers of 1974 and 1975. Samples for water chemistry were collected with a 1—1iter Kemmerer bottle. Dissolved oxygen, pH, alkalinity, hardness, and chloride analyses were performed in the field. Dissolved oxygen was titriometrically analyzed by the azide modification of the Winkler iodometric method - (APHA, 1971). A Beckman portable pH meter was used to de- termine water pH. Alkalinity (phenolphthalein and methyl orange) was analyzed by the acid titration method (APHA, 1971). Hardness was measured by the EDTA titration method (Kevern, 1973). Mercuric nitrate titration was used to determine chloride concentrations (APHA, 1971). Nitrogen and phosphorus samples were taken to the Water Quality Laboratory of the Institute of Water Research at Michigan State University for analysis. Total phosphorus and total Kjeldahl nitrogen were determined on a Technicon Auto— analyzer with the block digester technique. Phytoplankton samples were obtained with a l—liter Kemmerer bottle. When brought to the surface, 0.5 liter was transferred to a plastic bottle and a 1% solution of Lugol's killing and preserving liquid was added. Samples were brought to the laboratory and allowed to settle. Each smaple was reduced to 50 m1 and centrifuged at 1400 RPM for 30 minutes. The concentrated phytoplankton was then transferred to a slide for identification and counting. Keys of Prescott (1951, 1970) and Smith (1950) were used in identifying algae to the generic level. Samples for Chlorophyllct were obtained weekly from May through September, 1976 at station 2. Secchi disk vis— ibility was measured prior to sampling for Chlorophyll an A water sample was taken at twice the depth of the Secchi disk measurement and preserved immediately with 3—4 drOps of a supersaturated solution of magnesium carbonate. Each sample was-mailed to the Department of Natural Resources Laboratory in Lansing, Michigan where it was analyzed according to Standard Methods (APHA, 1971). Aquatic insects were collected with a standard Eckman dredge (15.2 cm X 15.2 cm) on June 25, 1975 at 2, 4 and 8-meter depths along a transect from shore to station 2. Duplicate samples were collected and washed in a 30-mesh screen. The residue containing organisms was placed in a 1—liter bottle and preserved in an 80% alcohol solution and taken to the laboratory. Organisms were removed by careful picking and identified to the family level with the aid of Pennak (1953). Aquatic plants were collected in late August, 1975. Plants were sampled by hand along many transects from shore to deep water. Plants were brought to the laboratory and identified with the aid of Fasset (1957). SurfaCe samples for coliform bacteria were collected randomly along the shoreline and analyzed according to standard methods (APHA, 1971). Bluegill sunfish (Lepomis Macrochirus) were collected during the summers of 1975 and 1976 with 2 experimental gill nets, 6 by 200 feet with four sections of different mesh sizes (ranging from 1 to 4 inches, stretched measure); 2 cast nets of single mesh size (0.5 and 1.0 inches) and 10 feet in diameter; and angling. The scale method as described by Lagler (1956) and Regier (1962) was employed in determining age and growth characteristics. Length measurements (standard and total) were made to the nearest millimeter. Weights were measured to the nearest gram for fish heavier than 30 grams and to the nearest 0.1 gram for fish under 30 grams. Scale samples were collected by removing approximately 10-15 scales from the left side of the fish just below the lateral line and at the midpoint of the spiny dorsal fin. Scales were dried in envelopes and plastic impressions were made with a roller press similar to the one described by Smith (1954). Scale impressions were enlarged and examined' on a Bausch and Lomb microprojector. From magnified impressions, measurements were made of the distance of each annulus and the anterior edge of the scale from the focus. The measurements were recorded on scale cards along the anterior radius. Calculated data for the lengths at the time of each annulus formation were ob- tained on a nomograph as described by Hile (1941). PHYSICAL PARAMETERS Morphometry A hydrographic map of Eagle Lake is shown in Figure 2. The lake has a surface area of 91 hectares and a maximum depth of 19.0 meters (Table 1). Shore development is 1.7. Table 1. Morphometric measurements for Eagle Lake, Michigan Item Value Maximum Depth 19.0 meters Mean Depth 6.7 meters Area 909,361 square meters Total Shore Length 5,596 meters Shore Development 1.7 Volume 6,119,183 cubic meters Volume Development 1.1 Areas and volumes of water at various levels are pre- Sented in Table 2. Although the lake has four deep basins, cmmflsoflz .mxcq mammm mo mmE cenmmumoupxm .m musmflm V III mm.--n.l:m§b..¢..z O _ _ meiosuaawee 58.2 of: 39:. II II lull. l.l|l ~\ . d4. ,_ . o y _W k. .... ...: uz‘l-Halal-i; .. G at... ... . 3lilié-l-6lin o o . . ....17 v o ...—r: l . ”8.52:3 v 0. 3.13.1... \_..~.._ a O 3.62:; i (“3.3 s . g. .65 35:50 ... .30: 46.50 I JJJO T "Elam o- o :0“ REE 353::u <52. :6; . n.oo.nu,o.&EED ..u n voo.fi...o.._6_ 7|... 913‘“ ... 3:32: acorn. £3075 U. . 9:; ...02M (\II AKDOFZQUd UZ. :33 I . 323.0 . . . 9 3.0.0 ........ ... 95FOESZOE UL. . Beanifi FL «:30 w L to... E .1 0 IO» :5 ozwomu ?; .. c . O .J . \O \- III ,III.’ . ..h. . .I-J' 5.3 II... IHWWWMvIa not... 9H! CL. .00. 3.3.3.03..- ! It: . » 3:223 :23. z: o 13344 83.34 4 sg‘xn acts—230a o!- >u>una 442.0(1) as a: «a: midi. wJOonm mwfla mEsHo> mo wom muons spawn um Umumoflpcfl .mN wafl>mum mo Hmucmu .cmmHQOHS .mxmq mammm How m>uso cucumOmm>£ mfisao> ucmoumm 385E REMQ 9. I Nx 0‘ Q 0 . 3 N . q q a . . a J . q _ 4 Al. . . . Q -9 SN ifl 18 f9 00 -S 18 18 19w L3 .m musmflm 2yw7z24auwznea1 11 .H®QE@>OZI£OHMZ umhma .HOQODOOImmz .mxmq mammm MOM xocoummmcmuu xmflp H «WSZQEV wit. .mhaa soomm .w musmflm 562 Run Kuhn .3st 3.3. uses ass (5% 163$. _ _ _ _ _ _ _ _ ._ . 9 l m / I xx mks I .w w mt: .. OW L 12 highest in the Spring and then decreased to the lowest readings in October and November. Although water transpar- ency patterns were similar during both years, values ranged from 3.7 to 8.1 meters in 1975, and 2.9 to 7.7 meters in 1976. Mean monthly differences between the two years ranged from as high as 3.8 meters in May to as low as 0.3 meters in October. In general, decreasing values for water transparency corresponded with increasing values for Chlorophyll a, during 1976 and are thus related to phytoplankton produc- tion. Hrbacek et a1. (1961) and Hutchinson (1957) found similar patterns. Wind velocity seemed to be much higher in 1976 than in 1975. This may be a partial explanation for the lower readings in 1976. Tressler and Domogalla (1931) state that the action of the waves produced by high winds in summer will stir up and distribute decomposition products and debris throughout the water mass. Water Temperature Maximum surface temperatures recorded were 25 C in late July, 1975 and 24.9 C in early August, 1976. Maximum hypo- limnetic temperatures were 16.6 C in early September, 1975 and 17.7 C in June, 1976 (Appendix Tables A3, A4, A5). Thermal stratification was already in progress (Figure 5) when this study was begun on May 28, 1975. The upper limit of the thermocline was at 3.7 meters and the lower limit at 6.0 meters. On September 3, 1975, the thermocline 47444734; IO- /5‘ ad 4 fiflVaamms l ’f’ ’f’ 214' IO‘ DEPTA/ (We J If APRIL 27, I976 9 I4 19 24 I 4 1 1 /0'1 [5‘ m. Figure 5. WEEK /3, me 13 WTURE ( 'c) 4 ‘f T’ @ a4 l0- [5'- 2" mews 4 7 ‘9 7'3f 5'. ,0. ,5: 2* MM£'%/%% 4 9 1w H 24 J 1 l l 4 z”cx%xez‘mkne 4 ‘? ’f’ ’7 25" I 5. ,0. 154 2" may Zg,/976 4 7 ’3’ ’f’ 2.4 5. /0-1 ,5. 2'" M60557 5, H76 ‘* 7 ’1’ ’7 if 5. m~ 451 1 2m zwwmaaugnm Temperature profiles for Eagle Lake, Michigan, 1975 and 1976. 14 occupied the stratum of water between 6.4 and 10.0 meters. When the study resumed on March 26, 1976, the lake was not homothermous, having a 2.1 C temperature difference from surface to 16 meters. On June 8, 1976 the thermocline occurred between 5 and 8 meters. By October 9, 1976 its upper limit had reached 10 meters and its lower limit 12 meters. On November 6, 1976 the lake exhibited a homother- mous condition. Eagle Lake appears to be a dimictic lake with mixing periods during early March and November. Thermocline depth ranged from 2 to 5 meters on days when data were collected. It is worthwhile to note that each sampling station exhibited different thermal conditions during thermal strat— ification near the bottom of the basin (Table 3). On March 26 and November 6, 1976, temperatures varied 0.1 to 0.5 C at a depth of 15 meters. However, between April 29 and October 9, 1976, bottom temperatures varied 1.4 to 3.8 C. Welch (1935), working on Douglas Lake, Michigan, also found that during thermal stratification the deep layers of dif- ferent depressions developed different thermal properties. Table 3. Bottom temperatures (0C) for stations 2, 5 and 6 during 1976 in Eagle Lake, Michigan bkmch April Jume .mrnet Ehpflafier Cbtflxr Ikweflxn' Station 26 29 9 5 13 9 6 2 5.5 8.8 9.9 10.0 9.9 9.8 6.9 5 5.5 9.1 10.9 10.8 10.7 10.5 7.0 6 5.0 7.7 8.0 7.0 8.0 . 7.9 7.0 15 CHEMICAL PARAMETERS Dissolved Oxygen Dissolved oxygen content of Eagle Lake varied through- out the study period. Average surface values for May 28, 1975 and September 3, 1975 were 7.9 and 7.7 mg/liter re- spectively (Appendix Tables A6, A7). On May 28, 1975, a positive heterograde curve as described by Aberg and Rodhe (1942) was noted (Figure 6). Hypolimnetic oxygen depletion had already begun to appear. Bottom values for stations 2 and 5 averaged 4.6 mg/liter. By September 3, 1975, little or no oxygen remained in the hypolimnion. Sampling resumed on March 26, 1976. Oxygen values showed little difference from surface to bottom. By June 9, a positive heterograde curve was recorded with an average metalimnion value of 11.4 mg/liter. This metalim- metic maximum decreased gradually until a typical clino- grade curve existed from August to October. By November 6, fall turnover had occurred and uniform oxygen values were recorded. Oxygen content in the hypolimnion decreased rapidly in 1976 after June 9. Average bottom oxygen values for stations 2 and 5 were 3.4 mg/liter, while station 6 had 0.6 mg/liter at the bottom. By September 13, there was no oxygen recorded from 14 meters to the bottom at all stations. Early loss of dissolved oxygen may be due to plant and animal respiration, bacterial respiration in decomposition 16 Dissolved Oxygen ( mg / l) 0 f T O T 4? 0 T ? 5~ 5- 5= [01 /0-* lo-i /$< as as MAY 22, I775 MS .5, H75 may 24, H76 * . a; ,1. o 4.: I? o 5 m ’3 5‘ 5- 5~ E . .8 ’ ‘ 5 /0-1 /0- 10 fl: 4— a. 8 15- 15- 15 E l M 271 /‘7% JUNE 7, /776 Am 5, /776 0 f ’f’ o f ’3 o f ’E. 5— 5- 5— 101 /04 IO 4 154 15- I54 seemaaemvamfit crflzERWZflfls A©W$¢E?6n%% Figure 6. Dissolved oxygen profiles for Eagle Lake, Michigan. 17 of sedimenting organic matter (Wetzel, 1975), and chemical oxidation (Gjessing and Gjerdahl, 1970). A pattern of oxygen distribution in different basins existed that was similar to the one reported for temperature. During ther- mal stratification the deeper portions of station 6 showed much lower oxygen concentrations than the other two deep water stations. According to Wetzel (1975), uniform hori- zontal distribution of the oxygen profile in the hypolimnion is assisted by vertical turbulence, horizontal transloca- tions, and density currents that move along the basin sediments. Because station 6 is located in the deepest and steep- est sloping basin in Eagle Lake, oxygen rich waters may not. be circulating as well as in the other sections of the lake. Winds are normally out of the southwest and the hills to the southwest of station 6 may prevent the wind from com- pletely circulating the water. Alkalinity, Hardness, and pH Eagle Lake waters were mostly alkaline, with pH values ranging from 7:0 to 8.4 in 1975 and from 6.6 to 8.4 in 1976 (Appendix Table A8). During stratification, pH decreased from surface to bottom. Greatest variation occurred in June and September, 1976, with differences of 1.2 and 1.3 pH units, respectively, from surface to bottom. In the early Spring during both years pH values in- creased in the metalimnion. Hutchinson (1957) and Cole 18 (1975) attribute this to the removal of CO during photosyn- 2 thesis by phytoplankton. Tucker (1957) reported that the 'five lakes he studied in Michigan all demonstrated decreas- ing pH values with depth during thermal stratification. Wetzel (1975) states that a combination of decompositional processes results in a decrease in pH of the hypolimnetic waters. Mean alkalinity Values (as CaCO3) were 140 mg/liter in 1975 and 138 mg/liter in 1976 (Figure 7, Appendix Table A9). TAverage values increased from spring to late summer during 1975. During spring overturn, 1976, alkalinity values were almost uniform with depth. However, between June and September, 1976, alkalinity values in the epilimnion and metalimnion decreased while alkalinity values in the hypo- limnion increased. Golterman (1975) attributes increasing alkalinity values in the hypolimnion to biogenic or abio— genic declarification of the epilmnion. During photosyn- thesis, algae utilize CO which results in the precipitation 2 of calcium carbonate (Wetzel, 1975). The sinking carbonate is redissolved in the hypolimnion by the carbonic acid formed from hydration of the C0 of decay (Cole, 1975).. 2 Mean hardness values (as CaCO3) were 151 mg/liter in 1975 and 149 mg/liter in 1976 (Figure 8, Appendix Table A10). Average hardness only varied l to 2 mg/liter between spring and late summer during both years. According to Kevern (1973), Eagle Lake may be classified as a moderate to hardwater lake. 19 7:27:41. ALKALIN/TV 6719/! c2603) 1% 130 Mb 150 160 I 0‘ 1 1 I\1 L 1 1 1 1 1 1 1 1 1 1 1 1 l 1 24 \ —MY28 4‘ \\ —--- SE’TEJVBEYB " - \ g ‘d \\ \. " \ \ § .. \ \ E ,2. \ \. H \ \ «r \ \ M75 729744 ALMA/wry (mg/l (.1603) I24 60 I40 150 160 1 O l 1 1 L 1 ml 1 1 1 1 1 1 1 1 1 1 L 1_ l 2 j l‘ \ —‘-MAch 24 . . K\ “—“chWE'? a 4- I --—--55°rm /3 .2 1 \ - . \ g 8 d \ ll \. - \.\ \ § IO " '\\ . X ’z - \\\ 14- \. . \ \. I6 \ \.\ [”6 Figure 7. Depth distribution of total alkalinity in Eagle Lake, Michigan. 20 mam-:55 {/5// (3603) [1) ”lo /50 /60 I70 1 1 1 1 1 1 1 1 1 1 1 1 DE’T/l (trackers) 5‘ st HARD/V555 (”y// (.9503) an mo um mo ID 0 I 1 1 1 1 \ 1 1 \ l .1 1 1 I I 1 1 1 1 4 : . \.\ -———— JUNE 7 q _ l \ ————— .5997st 13 e - \ \ a I \ \ \ \ _ \ a .. \\. \ \. [Z ‘ \ \ \. H ‘ \ \ \ x [6 4 c 0 .1 ml 1476 Figure 8. Depth distribution of hardness in Eagle Lake, Michigan. 21 Nitrogen Nitrogen concentrations (all reported as N) in the surface water ranged from 0.11 to 1.79 mg/liter during the two years (Figures 9 and 10, Appendierable All). Average nitrogen concentrations in surface waters varied during 1975 but showed little difference in 1976. Values ranged from 0.89 mg/liter on May 28, 1975 to 0.21 mg/liter on September 3, 1975. During spring overturn in 1976, nitro- gen concentrations showed little difference with depth. With the exception of May 28, 1975, nitrogen values in- creased with depth during thermal stratification. It should be noted that nitrogen concentrations increased from 0.27 to 1.64 mg/liter in the bottom waters from March to Septem— ber, 1976. Mean nitrogen concentration in surface waters was 0.45 mg/liter for both years. Mean nitrogen concentra- tion in bottom waters was 0.89 mg/liter for both years. According to a lake productivity table developed by Wetzel (1975), Eagle Lake is meso-eutrophic based on mean nitrogen concentration in surface waters. Sources of or- ganic nitrogen may be from littoral macrophytes (Wetzel and Manny, 1972), decomposition of aquatic vascular vegetation (Nichols and Keeney, 1973) and allochthonous inputs (Manny, 1972). Phosphorus Total phosphorus concentrations (all reported as P) in the surface water ranged from 0.003 to 0.23 mg/liter during 22 .mhma mcflusp cmmflnoez .mxmq mammm CH coaches: Hamcamflm Hmpou mo :oflusnfluumfle cameo .m musmflm «Q are Eggs. $305k SEQ. . 9 m. kmfiSMtkmnulll .// mm .3... III // .... // / // / N\ / // // g. H / . // n M/ //. . 7 _ J, _ .. w _ r /\ _ . s _ r _ N _ . J a u q q 4 d J a d u u u 4 q d 1 — — q _ m _ q q q u i - c a d _ 14 — ql - _ _ — — o 3 .3 a: «1‘ we I 9‘ u 0. n o n v m N. 23 mCHHSU cmmHEOHE .mxmq mammm cfl smmouuflc acmpawmx Hmuou wo cofiusnflmumflp cumwo .mhma /. ll. / /. /. /. / /. / /././o // /. / Q EMEE ....l... J / VUmSR§.:IIII. ./ ON \GESQ _ / b ................................. _ eeeeee ./. . o\ m\ *4 n\ «a ‘4 or v o. s o n. e. n 1 Q C W) H2430 1 Q l 3~ .oa musmflm 1 9 J. 1‘ l N \ \3 I N STOKE? 41fl§ulll :w melel 1 ..$\ '8 .. w . a IQ J T? C ‘N 1“ . _ A - a . 1 d . 1. q . 0 :0“ n. MN 0 31,6 mag; «ER. 26 .mmma mQHH5© cmmflnoflz .wxmq mammm as msuonmmosm prou How coflusnfluwmflp spawn .NH ouomflm mxwmfi§$fifimm?!lli w.m2§\.llll mwthE£IIIII /. / I /. /. / IE /. / l /. /. / IN\ E /. / I M /. /./ / :9 H /a% I Q //./. r W: // -.. 9 / 1 r\ / J ; __ 1. H.....14...............aa..4__.4~__._. :0 Mn n MN u m\ \ mq 0 Q\ Mae nowgwwokk 3Q. 27 Table 4. Total phosphorus in surface waters of various lakes. Mean Range Region (mg/l) (mg/l) Northeastern Wisconsin Lakes (479) (Juday and Birge, 1931) .023 .008 - .140 Spring Lake, Michigan (Bentz, 1977) .031 .006 - .056 Minnesota Lakes (45) (Moyle, 1947) .047 .005 - .200 Ontario Lakes (8) (Rigler, 1964) - .005 - .018 Michigan Lakes (5) (Tucker, 1957) - .007 - .014 Eagle Lake, Michigan .056 .003 — .230 Increasing total phosphorus concentrations with depth during thermal stratification was also reported by Tucker (1957), Reid (1961), and Wetzel (1975). This may be attributed to horizontal water movements that carry phos- phorus from the mud-water interface into the free water during near anaerobic conditions (Mortimer, 1971) and the continual sedimentation of sestonic phosphorus (Steiner, 1938 and Hutchinson, 1941). Chlorides Chlorides in Eagle Lake surface waters averaged 8.9 mg/liter in 1975 and 9.9 mg/liter in 1976. During both years values ranged from 8.1 to 10.0 mg/liter. Moyle (1949) 28 reported that chlorides occur in Minnesota waters in concen- trations usually between 0.0 and 10.0 mg/liter. According to Livingston (1963), average concentratiOn of chloride in natural fresh waters is 8.3 mg/liter. Values above 50 mg/ liter probably represent some contamination from human wastes (Kevern, 1973). It is safe to assume little contam- ination in Eagle Lake by domestic waste. // B I OLOGICAL PARAMETERS Phytoplankton A list of phytoplankton genera identified from Eagle Lake is given in Table 5. Throughout the summer, decreases in abundance of several green algae were accompanied by an increase in abundance of a number of blue-green algae. The only exception to this occurred on August 20, 1975. Algae in the Cryptophyta, Pyrrophyta, and Chrysophyceae decreased while Bacillariophyceae algae increased markedly. The algae which decreased at the same time as the populations of Sphaerocystis spp. and Oocystis spp. were Schroederia spp., Cryptomonas spp., and Chroococcus spp. Those algae which increased in number simultaneously with the above decreases included Aphanizomenon spp., Anabaena spp., Lygnbya spp., and Asterionella spp. The dominant genera in the Chloro- phyta, Bacillariophyceae, and Cyanophyta were Sphaerocystis spp. and Oocystis spp., Cyclotella spp., and Aphanizomenon spp., respectively. Figures 13 and 14 show the dominants Table 5. List of phytoplankton genera identified from Eagle Lake, Michigan between July and October, 1975. Genera are listed in order of decreasing relative abundance. Cyanophyta Aphanizomenon spp. Aphanothece spp. Anabaena spp. Lyngbya spp. Chroococcus spp. Aphanocapsa spp. Microcystis spp. Merismopedia spp. Coelosphaerium spp. Gleotrichia spp. Chrysophyta: Chrysophyceae Synura spp. Dinobryon spp. Cryptophyta Cryptomonas spp. Pyrrophyta. Ceratium spp. Euglenophyta Trachelomonas spp. ChrySOphyta: Bacillariophyceae Cyclotella spp. Fragilaria spp. Synedra spp. Cocconeis spp. // Asterionella spp. Melosira spp. Cymbella spp. Navicula spp. Pinnularia spp. Rhopalodia spp. Chlorophyta Sphaerocystis spp. Oocystis spp. Cosmarium spp. Elakotothrix spp. Schroederia spp. Pediastrum spp. Volvox spp. Gleocystis spp. Staurastrum spp. Mougeotia spp. Closterium spp. LA) O a k t f 5 3?” 3) Wu g 3 § k E‘{ a ‘ 2 m a f 2 § 3 § 2 0 0 gg m :3 a Q 0 Qt ‘\ k0 b Rh. IQ N B . a 3E g2 \ $ 3* f; a 8 8% a .8 E E E. 23 5 20 4 18 Z lé J UL 5" 4 UGUST SEPT EMBER OCTOBER T/ME ;.;.;. CyANOPHS/TA PVRROPI-IVTA IIIIII 0%WGORHH2%E manual EMCMLMWORHWEME‘ ,4: GRHPRZRHVTA [ZZZZZJ CHLQQDPHVZA Distribution of the major groups of phytoplank— ton in Eagle Lake and the dominant genus based on numerical averages of samples collected at the surface. Figure 13. 31 p fir? CRVPTOMONASW . . CRVPTOMOXJA’; SPHAEROCV'SfisaFP CYCLOTELLA APHANIZOMEVOstp afiflmwvcgsrkg47 006 VST/S app CVCLOTELLA s” AFWMNWflZWENDN CVCLOTELLA AP/IANIZOMQVON‘” APHAN/ZOMENOA/W 6 BERGEN TA 615 20 7 23 5 20 4 l8 2 I6 JULY AUGUST SEPTEMBER OCTOBER T/ME CVMIOPHVTA — PVRROP/IS’TA — CHRVSOPI-IVCEAE - = BdC/LLAR/OP/IVCEAE -- CRVPTOPI-IVTA 1:1 Cl/LOROPH‘HTA Figure 14. Distribution of the major groups of phytoplank- ton in Eagle Lake and the dominant genus based on numerical averages of samples collected at 10 feet below the surface. 32 and percent relative abundance for groups at the surface and ten feet. It should be noted that the following genera only occurred sporadically during the study period: Meris- mopedia spp., Coelosphaerium spp., Gleotrichia spp., Cymbella spp., Navicula spp., Pinnularia spp., Rhopalodia spp., Trachelomonas spp., Volvox spp., Gleocystis spp., Staurastrum spp., Mougeotia spp., and Closterium spp. Only limited vertical stratification of phytoplankton was observed during the study period. During July and August, Cryptomonus spp. was more abundant at 10 feet than at the surface. During July, blue-green algae were concen- trated at the surface. However, on August 5, the opposite was observed. A greater abundance of’blue-green algae was noted at 10 feet than at the surface. Throughout the re- mainder of the study period, no real differences in abun- dance was observed for blue-green algae at either depth. Most of the phytoplankton was found more or less evenly dispersed at both water depths. A review of phytoplankton records from other lake studies (BozniakanuiKennedy, 1968; Kratz, 1941; Riley, 1940; Birge and Juday, 1922; and Hutchinson, 1967) shows the sud— den dominance of Cyclotella spp. in late August to be atypical. Dinobryon spp. appeared in the lake throughout the study period, but with a low relative abundance. In many lakes Dinobryon spp. abundance has been correlated with a 33 low phosphate concentration and oligotrophic conditions (Pearsall, 1932; Hutchinson, 1944; Rodhe, 1948; and Lund, 1965). In a recent study, Lehman (1976) reports that the population dynamics of Dinobryon spp. is substantially dependent on the physico-chemical environment. Although the presence and dominance of Aphanizomenon spp. in the late summer may indicate eutrophy (Teiling, 1955), the presence of Dinobryon spp. and the minimum appearance of Melosira spp. and Microcystis spp. would in- dicate oligotrOphic-mesotrophic conditions (Teiling, 1955 and Bozniak and Kennedy, 1968). A similar dominance of Aphanizomenon spp. during the summer was reported by Kratz (1941), and attributed to temperature. When Nygaard's (1949) compound index was applied to the lake, it indicated eutrophic conditions. However, in a phytoplankton study of twelve Adirondack lakes, Reynolds and Mercer (1974) showed that phytoplankton indexes were not always consistent with other parameters used to indi- cate trophic status. Chlorophylla. Values for Chlorophyll a ranged from 2.2 to 5.8/ug/ liter during the summer of 1976. The mean chlorophyll a concentration was 3.5/ug/liter. Values tended to fluctuate throughout the summer with peak concentrations on May 30 and August 15 (Figure 15). Eagle Lake would be classified as mesotrophic, 34 '§ 0‘ I I N 1 (mommy/.1. a. CdA/CEW 774v {/13 //) J J I l 1 MA V JUNE JUL? A0605?“ mg!” 774“? (humfifis) Figure 15. Chlorophyll a concentrations for Eagle Lake, Michigan during the summer, 1976. 35 utilizing only Chlorophyllci data (Wetzel, 1975; Michigan Self-Help Survey, 1977; Dobson, et a1., 1974; and Sakamoto, 1966). Secchi disk data presented earlier support this conclusion. Aquatic Insects A list of aquatic insects collected and identified from Eagle Lake on June 25, 1975 is found in Table 6. At this time of the year aquatic insects in the order Diptera dominated in numbers of individuals. Table 6. Relative abundance of aquatic insects collected from Eagle Lake, Michigan on June 25, 1975. Rehfifivellmndmme Order Family Genus meiers mefiers megers Diptera Chinmxnfidae D D D Chajxnfidae N O O Cenmxpamxfidae O N O Emmmenxxera IQimmerfltma Hemgfxua N O N Cohaxxera Dytiscidae R N N D==IXmunant R==f€¢€ O = Occasional N = NOt Present Coliform Bacteria Results from the summers of 1974 and 1975 for coliform data show that during both years total coliform counts 36 ranged from 100-300 per 100 m1 M.P.N. According to the Allegan County Health Department, coliform counts for Eagle Lake are normal for inland lakes and streams free of sewage pollution. Aquatic Plants The aquatic macrophyte growth was fairly abundant in most of the shallow areas in Eagle Lake. Table 7 gives the list of aquatic macrophytes collected from Eagle Lake in August, 1975. Patches of the bulrush (Scirpus validus) and the spike rush (Eleocharis spp.) were scattered over the sandy shallow areas. Water lilies (Nymphaea tuberosa and Nuphar spp.) were abundant along the northern and southern shore- lines. An abundant patch of cattails (Typha spp.) and Chara (Chara spp.) grew along the north shoreline. Many species of the pondweed (Potamogeton spp.) and wild cherry (Vallisneria americana) grew with Chara along the western shoreline. Although aquatic macrophyte growth was fairly abundant, it does not appear to be at a nuisance level. Fish Fish collected from Eagle Lake are listed in Table 8. Age and growth determinations were made for bluegills only due to the large numbers of individuals collected. 37 Table 7. List of aquatic plants collected from Eagle Lake, Michigan in August, 1975. Chara spp. Eleocharis spp. Typha spp. Sparganium spp. Elodea canadensis 'T/ Vallisneria americana Potamogeton praelongus Potamogeton Richardsonii Potamogeton Robbinsii Potamogeton amplifolius Potamogeton natans Potamogeton pictinatus Potamogeton vaginatus Brasenia Schreberi Nymphaea tuberosa Scirpus validus Megalondonta beckii Pontederia cordata Peltandra Virginica Najas flexilis 38 Table 8. List of fish collected from Eagle Lake, Michigan - during 1975 and 1976. Scientific Name Common Name Lepisosteus oculatus (Winchell) Spotted Gar Esox lucius Linnaeus Northern Pike Micropterus salmoides (Lacepede) Largemouth Bass Pomoxis nigromaculatus (Lesueur) Black Crappie Chaenobryttus gulosus (Cuvier) Warmouth Lepomis cyanellus Rafinesque Green Sunfish Lepomis macrochirus Rafinesque Bluegill Lepomis gibbosus (Linnaeus) Pumpkinseed Perca flavescens (Mitchell) Yellow Perch The total length-scale radius relationship was deter- mined from 209 bluegills in order to estimate the length of a fish at the time of previous annuli formation. This re- lationship is best described by the regression equation: TL = 16.08 + 1.24 (SR), where TL is total length in millimeters and SR is scale radius X 27 in millimeters (Figure 16). The mean calculated total length at ages one through six were found to be 49.5, 84.6, 122.2, 158.3, 181.2, and 186.0 millimeters (Table 9). Age group 4 (1972 year class) appears to have the best growth at each annulus. Age groups 1 and 2 (1975 and 1974 year class) show evidence of being 39’ , .cmmfinoflz .mxmq mammm Eonm mHHHmmDHQ mom Mom mflnmcoflumamu msflcmu mamomlnumcma Hmuoe .ma mwzmflm «R x 3.5 005.2 .350 OQN 09 ON. 8 0r 0 P p . _ F p p _ . _ ION. C WW) lug/v37 7910.2. 40 m.v m.mm H.mm v.5m H.mm m.mv pcmamuocH . ... guzouo c002 o.mmH N.Hma m.me N.NNH m.vm m.mv AEEV moasscm comm pm cumcmq Hmuou Apmucmflmav com: o.oma o.wma o.mva o.mHH o.m> o.Hm o.mom a ohma o.NmH v.vma m.oma >.mm m.mm m.mom ha Huma n.0wH m.mmH m.mm h.@m h.mma mm whoa m.mHH m.mm N.om H.mva em mnma m.mm m.he H.maa me N vmma >.vv H.m> em H mhma v.om mm o onma o m w m N H AEEV unsummo mHmEom mm¢ mmmHO moms pm um spasma CH AEEV numcmq coymasonO com: Hopou cmwz Honssz .cwmflnoflz .mxmq mammm Eowm maaflm nodan Mom unmamuosfl auBoum some can msHsccm zoom um numsma Hmuou some .npmcmH Hmuou pmumasoamo some .mnsummo um npmcwa HMPOD some .Hmnfis: .mmmm .mmmao Hmmm .m manna 41 slower in growth at each annulus. .A comparison of growth in length for Eagle Lake blue- gills and the State average for Michigan is shown in Figure 17. The growth rate of bluegills (mean length at capture) compares favorably with the tentative average growth rate for the State. However, growth in length, utilizing mean calculated length for Eagle Lake bluegills, compares less favorably with the tentative State average during the first few years of growth. Bennet (1970) and Grice (1959) report that a large source of available food per individual fish is a primary controlling factor in the production of fish above average size. It is also possible that the low concentrations of dissolved oxygen during thermal stratification may slow growth rates during the early years (Stewart, et a1., 1967). Table 10 shows that the growth rate for Eagle Lake bluegills is about average or higher than growth rates for _bluegills from other areas. Although growth rates are not extremely high, it is safe to say that Eagle Lake bluegills are not stunted. The standard length-weight relationshipwas determined by constructing a scatter diagram utilizing the standard length in millimeters and weight in grams for 184 bluegills (Figure 18). The mathematical relationship between length and weight may be expressed in logarithmic form as Log W = log a + n log L TOTAL LEA/C TH (mm) Figure 17. 42 1.. l I l 0')- 6‘ 2 .3 4 AGE? GvkfiMD Qu— MEAN CALCULATED LENGTH -— -- Maw LEVGTH AT CAPTURE —-—-— Tmrxva 572175 (M/C‘l-l/éA/V AVERAGE (PEESONAL (MHz/ma mu ) Growth in length of bluegills collected from Eagle Lake, Michigan. "J/ 43 \\ .mmaav pocaaoq ANvav umxoflm Ammev mamas Ammmav upmxusm Amamav Hamm cam azoum Annmav Nucom Amvmav mummwamm< paw ocflnumo Ahwma I—INMQ‘LOKOP o.©mH m.HmH m.mmH N.NwH m.¢m m.m¢ GmmflSOHZ .mxmq mamwm .m mam mmH wed mva baa Hm mmmum>< meum mHOCflHHH .h ovm NAN mmH «PH wNH om ow Ommum>¢ OPMPm mcmHUCH .@ Ham maa ems mma ama mm as mmmum>< mumum muommacas .m m.oam N.mom m.hma H.mwa H.NMH v.mm w.mm mmme>¢ mfiwum NHSOmMHZ .w o.mmH o.wma o.moa o.©h o.¢m 0.5m cmmH£Ofl2 ~mxmq HOPmHm UHHSE .m MBA hma hma NHH on mm cmmHQOHE .Oxmq msflhmm .N m.amm H.wNN h.mom @.N©H 5.00H m.mm h.mv cmmHSOHE .mxmq ammo .H h o m. w m N H coflpmooq pcm mxmq mean no Hams cmmzumn msHDQCM 50mm um maaflmosafl mo mcumcma amuOD mmmnm>m mo somHHmmEoo a .mmme Hmnpo Ucm.cmmH30Hz .mxmq mammm .oa manna 44 .cmmH50H2 .mxmq mammm Eoww mHHHmmDHQ ema mo mflcmcowumamu usmflwzlzpmsmq «E st E05.» Qmwuzfim Qfl DE 06 0? Ll — - P _ _ o 1 40 W3 30.». + $3.1 n 2 m3 rON~ rose .mH musmflm C W315) 1119/3/14 45 where weight in grams slope of the line y-intercept standard length W n Log a L The length-weight relationship was found to be best de- scribed by the equation Log W = -4.649 + 3.087 Log SL. The coefficient of condition, K, a measurement of relative plumpness, was calculated from 184 bluegills. K is calculated from the equation =wx105 SL L3 K where = standard length in millimeters = weight in grams L W The condition value for each age group of bluegills from Eagle Lake is shown in Figure 19. Mean condition value was 3.32. The condition value increased with age until after the 4th year where it decreased slightly. According to Minnesota standards, average condition value for bluegills ranges from 3.3 — 4.0 (Carlander, 1944). Beckman (1944), after studying over 500 lakes located in all parts of Michigan, reports mean condition values ranging from 3.26 - 3.96 for bluegills of similar size to those found in Eagle Lake. 46 3.6 F 3.5 — 3.4-I '- 3.2 - 3c 1 I l 0 I 2 3 ME (years) It uP Figure 19. Condition coefficients for bluegill collected from Eagle Lake, Michigan during 1975 and 1976. 47 SUMMARY Limnological and biological parameters of Eagle Lake, Michigan were studied between May - October, 1975, and March - November, 1976 in order to document present lake conditions. A Physical-chemical measurements indicated that the lake registered between oligotrophy and eutrophy on the tropic spectrum. Thermal stratification and hypolim- netic oxygen depletion occurred at all deep water stations during the summer of both years. Secchi disk transparency was fairly high in 1975 and moderate during 1976. Mean total phosphorus and total Kjeldahl nitrogen concentrations for the two years were 0.056 mg/liter and 0.45 mg/liter, respectively. Chloride data indicated little contamination from domestic waste. Thirty-six phytoplankton genera were identified from samples during 1975. Green algae dominated during July but then declined steadily in abundance. Diatoms began increasing in late June and dominated during late August. Blue-green algae remained fairly low in abundance during July and August. However, during September and October blue-greens dominated the phyto- plankton population. Chlorophyll a values ranged from 2.2 to 5.8/4g/1iter during the summer of 1976. Five families of aquatic insects were collected on 48 June 25, 1975. Dipterans were the most numerous at the 2, 4 and 8-meter depths. Total coliform bacteria counts from 1974 and 1975 were in the normal range for inland lakes free of sewage pollution. Fourteen genera and sixteen species of aquatic macro- phytes and macroalgae were identified. Aquatic macrophyte growth did not appear to be at a nuisance level. 3 Age and growth determinations were made for 209 blue- gills collected between 1975 and 1976. The rate of growth for bluegills compared favorably with the tentative State average and with bluegills in other lakes of the Midwest for which data are available. Coefficient of condition values were average for the species. LITERATURE CITED LITERATURE CITED Aberg, B. and W. Rodhe, 1942. Uber die Milieufakteren in eingen sudschwedischen Seen. In Wetzel, 1975. American Public Health Association, 1971. Standard methods for the examination of water and wastewater, 13th ed. Washington, D. C. 874 pp. Beckman, W. C., 1948. The length-weight relationship, factors for conversions between standard and total lengths, and coefficients of condition for seven Michigan fishes. Trans. Amer. Fish. Soc., 75:237-256. Bennett, G. W., 1970. 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Michigan inland lakes and their watersheds: An Atlas. Michigan Department of Natural Resources. 166 pp. ‘ Michigan Department of Natural Resources, 1977. Inland Lake Self-Help Program. Annual Report. 31 pp. Moyle, J. B., 1949. Some indices of lake productivity. Trans. Amer. Fish. Soc., 76:322-334. Neumann, J., 1959. Maximum depth and average depth of lakes. J. Fish. Res. Bd. Can., 16:923-927. Nichols, D. S. and D. R. Keeny, 1973. Nitrogen and phos- phorus release from decaying water milfoil. Hydrobiologia, 42:509-525. 7., Nygaard, G., 1949. Hydrobiological studies of some Danish ponds and lakes. II. The quotient hypothesis and some new or little known phytoplankton organisms. In Brook, 1965. Planktonic algae as indicators of lake types, with special reference to the Desmidiaceae. Limnol. and Oceanogr. 10(2). 403- 411. ' Pennak, R. W., 1953. Fresh-water invertebrates of the United States. Ronald Press Co., New York. 769 pp. Prescott, G. W., 1951. Algae of the western Great Lakes area. 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Monogr., 10(2):279-306. Sakamoto, M., 1966. Primary production by photoplankton community in some Japanese lakes and its dependence on lake depth. Arch. Hydrobiol., 62:1-28. Schindler, D. W., F. A. J. Armstrong, S. K. Holmgren, and G. J. Brunskill, 1971. Eutrophication of Lake 227, Exper- imental Lakes Area, northwestern Ontario, by addition of phosphate and nitrate. J. Fish. Res. Bd. Can., 28:1763-1782. . Shannon, E. E. and P. L. Brezonik, 1972. Limnological char- acteristics of north and central Florida lakes. Limnol. and Oceanogr., 17(1):97-110. Smith, G. M., 1950. The fresh-water algae of the United States. McGraw-Hill Book Co., Inc., New York. 719 pp. Smith, S. H., 1954. Method of producing plastic impressions of fish scales without using heat. Prog. Fish. Cult., 16(2):75-78, 2 figs. Stewart, N. E., D. L. Shumway, and P. Doudoroff, 1967. In- fluence of oxygen concentration on the growth of juve- nile largemouth bass. J. Fish. Res. Bd. Can., 24(3): 475-494. . Teiling, E., 1955. Some mesotrophic phytoplankton indica- tors. Proc. Int. Assoc. Limnol., 12L212-215. Tressler, W. L. and B. P. Domogalla, 1931. Limnological studies of Lake Wingra. Trans. Wisc. Acad., Arts and Lett., 26:331-351. Tucker, A., 1957. The relation of phytoplankton periodicity to the nature of the physico-chemical environment with special reference to phosphorus. Amer. Mid. Nat., 57:300-333. Welch, P. S., 1935. Limnological methods. Blakiston Co., Philadelphia. 381 pp. , 1952. Limnology: 2nd ed. McGraw-Hill Book Co., New York. 538 pp. Wetzel, R. G., 1975. Limnology. W. B. Saunders Co., Philadelphia. 743 pp. Wetzel, R. G. and B. A. Manny, 1972. Secretion of dissolved organic carbon and nitrogen by aquatic macrophytes. Verh. Int. Ver. Limnol., 18:162-170. APPENDIX 56 I x x N . x GH\OH N\oa ma\a «\a m\a om\m G\m mm\s mm\s s\s mm\m mm\m ><><><><><><><><><><><>< x x X X mDBHRWQSH Adana ammshaz Hamcamfls Hanna mmcfluoHSO mmmcpumm COQEAV cm>aommflo 583854 mm Hanna ousumumgama xmflo opmo Hsoomm .mxmq mammm :H mumumamumm msoflum> How .mhma mafiusc cmmflnoflz Awmc\£usoav mump an maocmnom msHHQEmm .H< manna 57 X X X X X X XXXXXXXXXXXXXXXXXXXXXXXX G\HH a\oa aa\a maxa NH\m m\a am\m mm\m m\m m\m H\w mm\s aa\s Ha\s om\m waxm a\m s\m Hm\m mm\m ma\m m\m amxa Gm\m mmflfififigu mnhghfiogm stHfizz fiance Hamoamflm Afiupa mflflfihwm Nuacaamxa<_ mm sauna ggfigo cm>aommfio wflfihHWEme swan .uaawm mama .mxmq oammm sfl mumpoEmumm msoflum> How Awmo\£usoav mumc we oascwcom mcHHmEmm .ohma meansp ammASOAE .md OHQMB 58 m.a m.a Ga m.a a.a o.oH a.a m.m ma a.o H.0H o.oa m.oa .m.oa m.m m.m «a a.w k.oa m.oa o.HH o.HH o.a m.m ma m.o H.HH G.HH G.HH m.HH ~.a m.m NH a.o o.ma m.HH o.mH m.HH H.0H o.o Ha o.s m.ma ¢.NH m.ma o.~a s.oa o.G ca 0.» m.ma m.ma a.ma m.NH a.oa H.G a 0.5 m.ma o.sH o.mH o.ma o.aa H.G m o.s m.mH H.0m o.ma o.va o.HH N.G k o.s m.ma H.Hm o.v~ ~.ma H.HH N.o o o.s m.mH H.HN m.am o.ma N.HH m.o m o.s m.ma H.Hm m.vm o.om m.HH m.w a o.s m.ma H.HN m.a~ o.mm m.HH a.o m H.s m.ma N.Hm m.am m.mm s.HH a.m m H.k m.mH N.HN m.a~ H.4N H.NH m.© a H.s G.ma N.HN s.am N.s~ m.ma a.o o .>oz m .uoo ma .pmom m .ms¢ m masw mN Hflwmm mN scum: REV whoa Cumoo mean .N ceaumum #8 ohmd mcflusp cwcnoomu mxmq mammm Mom Aoov mozam> mhsumummfimu uwumz mo mumfifism .m< magma 59 o.> N.OH H.oH m.OH m.m oH o.n m.0H >.oH m.OH m.OH o.m m.m mH o.b o.HH m.OH o.HH o.HH H.m w.m wH o.n N.HH m.OH N.HH N.HH n.m n.m mH o.> >.HH v.HH m.HH m.HH o.OH m.m NH 0.5 N.NH w.HH m.HH m.HH m.OH m.m HH 0.» m.MH N.NH w.NH o.NH o.HH m.m OH o.n v.mH N.mH o.vH m.NH N.HH o.o m o.h >.mH o.>H N.mH N.MH m.HH o.o m o.h_ m.mH N.ON o.ON N.vH m.HH o.m h o.> m.mH o.HN o.mN H.mH m.HH o.o o 0.5 m.mH o.HN m.vN n.5H w.HH H.@ m o.> m.mH N.HN m.vN o.ON m.HH H.o v o.> m.mH N.HN m.VN o.NN o.NH N.@ m 0.5 m.mH N.HN o.mN N.mN m.NH m.o N 0.5 m.mH N.HN o.mN >.mN o.mH m.o H 0.5 m.mH m.HN o.mN m.mN m.mH o.> o G .>oz a .uoo ma .uaom m .62¢ a mass am Hanna Gm noun: Asv ohmH :umoo WB waspmquEop Hmpmz mo XMMEESm .w4 oHnme 60 '— m.h m.> H.> mH o.h m.h m.n. m.n N.m m.v SH o.> m.> m.n m.> m.h m.v oH o.> m.> o.m o.> o.m v.h o.m mH o.h N.m N.m o.m m.w n.h H.m wH 0.5 m.m m.m m.m m.m o.m N.m mH o.h m.m m.m m.m m.m v.m v.m NH 0.x ~.oa o.oH m.OH a.oa _G.m a.m HH 0.» N.HH m.0H N.HH o.HH o.m o.o OH H.s m.¢H v.NH m.NH >.HH m.m o.m m H.> m.mH .m.mH o.mH o.mH o.HH H.@ m H.h m.mH o.ON m.mH N.HH N.HH H.m h H.n o.mH m.ON m.NN m.mH v.HH N.@ m H.h h.mH o.HN N.HN m.bH N.HH m,o m H.h >.mH N.HN m.¢N m.om N.HH w.o v H.» m.mH N.HN o.mN N.HN o.NH m.o m N.> m.mH N.HN o.mN o.mN. H.NH m.o N N.> m.mH v.HN o.mN o.MN m.NH 0.5 H N.h m.mH m.HN o.mN o.mN m.NH H.n o m .>oz a .300 mH .ummm m .ms< a mass am Hanna Gm roams rev oan npmmo maven .w COmepm um ohmH mcHH5© cmpuoomu mxmq mHmmm How Aoov mwsHm> cuspmummfiou nouns mo Xumfissm .m¢ mHnme 61 0.0 0.0 H.@ oH m.m mH 0.0 0.0 H.m o.OH H.o vH N.OH ¢.o o.o N.o H.m ¢.0H v.v NH m.H m.o m.o v.m N.OH OH m.QH N.m o.m ¢.o m.m v.HH m H.m N.m w.m m.m w.HH v.v o N.QH m.m o.m h.m H.0H N.HH v m.m m.m m.m o.OH o.NH N H.QH N.m m.m >.m o.oH o.NH H.m N.w o m I 0.0 0.0 N.o m.o wH I m . OH mH I o.o o.o N.o m.m n.n v.0H H.o m.v VH I m.o o.o N.o ¢.¢ >.m o.OH NH I m.m m.o «.0 m.m o.m aroH OH I H.m m.v m.o m.h m.m H.HH m I m.m m.m m.m v.HH H.0H N.HH H.v o I N.m m.m o.m h.oH H.oH ¢.HH m.m v I N.m m.m 5.x o.m N.OH v.HH N I m.m m.w h.m w.m m.OH ¢.HH m.m m.h o N .62 a .60 2 .Emm m .msm a 0:2. mm Hausa SN roam: m .udwm mm was as :3me ohmH mhmH HDQRH medo .ohmH paw mhmH mCHH:© mxmq memm MOM AH\mEv mCOHpmuucmocoo somaxo cmDHOmme wo XHMEEDm .mm mHnma 62 0.0 0.0 0.0 v.v o.o m.H NH H.0H H.HH 5H H.0H o.o 0.0 0.0 m.o m.m H.HH mH N.0H 0.0 0.0 H.o o.o v.m m.HH vH m.OH o.o o.o m.o >.H e.> >.HH NH m.m o.H v.0 ¢.o m.N N.m N.HH 0H m.OH H.m H.v m.o N.m n.m o.NH m H.0H e.m >.n m.o m.HH m.OH H.NH o.m o m.oH m.m H.w m.w b.0H m.OH N.NH m.m v m.OH m.m e.m H.m n.m v.oH H.NH N m.oH ©.m m.m I m.m m.0H o.NH 0.5 n.> o m G .62 a .60 Q .pmmm m .95 a 82. am 3.35 mm :08: m .068 mm .62 c5 coflBm obmH mhmH aflafio manna mcHHsp mxmq mHmmm How AH\mEV msoHumupcoocoo commxo pm>H0mmmme0pmwmwwmw .n< mHQme 63 v.0 N.h o.h N.> H.m Eouuom m.> v.m m.> m.m v.m sumeIsz m.n v.m 5.5 I N.m H.m oomwusm o o.w m.> m.h N.> m.n EouHom 5.5 w.m m.n m.h H.m nummoIcHz m.n m.m v.5 v.m N.m womwmom m w.o H.> . s.n o.b m.m Eoupom m.n m.m >.> m.h o.> cummoIsz m.s N.m 0.5 m.> v.5 mommusm N mH umnsmummm a mass mm nouns m umnsmummm mm was shame acaumum whmH . mhmH .wbmH cam mhmH mcHHsp omcuoows mxmq mHmmm How mmsHm> :Q mo XHmEEDm .m< mHnme 64 HoH hVH omH moH oeH Eouuom mNH mMH hNH mmH wNH nummoIcHz vNH NNH va NmH mmH ovumusm o HhH mvH mmH voH owH Eouuom mNH va mmH ovH omH nummochz mNH me mmH HmH omH mommnom m voH mmH mmH voH va Eouuom mNH SMH va HvH @NH summoIcHz mNH NNH mmH I NNH oommusm N NH Honewummm m meow 0N comm: m Hmnfimumwm wN wmz nwmmo coHumum mhmH mhmH .mhmH can mhmH mcHusc. popuoomu mqu mHmmm MOM Am COMO H\mEv mcoHumuucmosoo XDHCHmeHm Hmuou mo humfissm .m< mHQme 65 va va mvH NmH mvH Bowvom mmH mvH mmH omH OVH cummoIcHz ovH OVH mvH NmH NmH ecumusm o OBH NmH an mmH me Eopuom 44H maa mva _aaa mma spamonaz NVH wvH mvH omH NmH mommusm m mmH mmH mvH NmH va Eouuom va ovH wvH mvH NvH CpmmoIcHE owH mvH HmH ovH va momwusm N ma umnsmpmmm a mass Gm roams m Hansouamm mm so: shame aoHpMpm whmH man memo m .Gsaa can mnaa mcauac pocuoomu mxmq mHmmm How A COMO H\mEv mcoHumuusmosoo mmmcpumc mo XHMEESm .OH¢ mHQme 66 Nm.o om.o mH.o mN.o mv.o mommusm w Nm.o Nm.o ON.o HH.o mv.H oommusm v Nm.o No.0 ON.o NN.o NN.H mommusm H em.H Hm.o ov.o No.H wm.o Eouuom H¢.o mm.o wm.o ON.o mm.H nummoIsz mm.o vm.o 0N.o NN.o no.0 mommusm m m>.H mm.o ON.o nm.o Nm.o Eouuom mm.o Hm.o mN.o NN.o mm.H nummoIsz om.o Nm.o hH.o HN.o m>.o wUMHHDm m mm.H mN.H oN.o No.0 mn.H Eoupom mm.o Nm.o 5N.o mN.o om.o summochz mN.o mv.o 5N.o mN.o. mh.o mUMHHsm N mH HmnEmummm m mean mN comm: m HmQEmumom mN mm: Lemma coHpmum mbmH mhmH mama .oan can man mCHusc cmcuoomu mxmq mHmmm How AH\mEV mcoHumuucmocoo cmmouuH: HampHmmM HMHOD mo XHMEEDm .HHd mHnme 67 smo.o soo.o moo.o Ho.o so.o souuom m «No.0 mvo.o ooo.o oo.o mo.o. chamoIoHs a omo.o mmo.o mHo.o Ho.o mo.o mumwuam H omm.o ooH.o HHo.o mm.o mm.o souuom wmo.o mmo.o 0Ho.o Ho.o mH.o spamoIcHs Nmo.o swo.c moo.o Ho.o mm.o mommusm m omm.o mmo.o moo.o Go.o 4H.o souuom smo.o mao.o aoo.o mo.o mH.o nummoucas omo.o smo.o «00.0 Ho.o om.o wommusm m osm.o omH.o HHo.o sm.o HH.o souuom mmo.o smo.o moo.o Ho.o mo.o summoIcHz Hmo.o mmo.o moo.o Ho.o Hm.o momwusm N mH Honsmummm a wash mm seems m umnsmumwm mm was gamma coHumum oan msmH mean .msaa cam msaa mcausw popuoomu mxmq mHmmm MOM AH\mEv mcoHumuucmosoo masonmmosm Hmu0p mo wumfiasm .NH¢ mHnma MICHIGAN STATE UNIV. 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