TPWD 1956 F-5-R-3 #254: Inventory of Species Present in Oak Creek Reservoir at Blackwell, Texas

--- Page 1 --- JOB COMPLETION REPORT ATE OF TEXAS Project No. F5R3_ Name Fisheries Investigations and Surveys of the Waters of Region 3-B. Job. No. Bay Title _ Inventory of Species Present in Oak Creek Reservoir at Blackwell, Texas. Period Covered: June 22, 1953 - May 1, 1956 ABSTRACT 1. Eighty-four gill net collections and fifty-seven seining collections were made during inventory, reservoir conditions were noted, water analysis taken periodically, and stomach analysis and parasitism examination made of 389 individuals. 2. Excepting algae and pondweeds, there is no aquatic vegetation in the lake; and the reservoir was in a state of continuous readjustment during inventory. 3. Twenty-seven species of seven families were identified from the 5,542 indivi- duals captured in seining and netting. The distribution of these fauna seemed uniform over the lake; however exact duplication of netting and seining collection work was imposs- ible because of fluctuation in the lake level, and because much of the innundated area was covered with dense concentrations of mesquite. 4. White crappie were probably the most important game species present in the ~-servoir; however evidence indicated relatively high percentages for channel catfish and cgemouth bass, and white bass and flathead catfish were probably increasing. The lake is very popular with fishermen. 5. Stomach analysis from 51.92% of the fish examined indicated that natural controls may have been exerted upon the yellow bullhead population by channel catfish and flathead catfish and that yellow bullheads could have exerted a similar control on several species of sunfishes. 6. River carpsuckers and carp have not yet increased to any apparent significance where their numbers are of detriment to the game species. OBJECTIVES To determine the species present, their relative abundance and to determine the principal ecological factors influencing their distribution. PROCEDURE Eighty-four gill net collections were made at twelve netting locations in Oak Creek Reservoir. Experimental nylon gill nets, measuring 125 feet long by 8 feet in depth and made up in five, 25 feet sections were used. Mesh size for these nets increased progressively in each following section at one-half inch intervals, beginning with one- inch mesh and terminating with a three-inch mesh section. Fifty-seven seining collections were made at fourteen seining locations in the ervoir. In nearly all collections, both 26 feet < inch mesh bag seines and 15 feet + inch mesh common sense seines were used. To estimate relative abundance a count was made --- Page 2 --- 2. of all individuals taken in two hauls with a 26 feet + inch mesh bag seine for each collec- tion. In addition to that work other seining collections were made to determine seasonal distribution of species and to secure samples of fry after the spring spawning of fishes. For this latter work, four feet common sense seines with + inch mesh and 1/16 inch mesh were used. Water analysis for dissolved carbon dioxide and oxygen content was taken period- ically and surface temperature, pH, and climatic conditions were recorded for each netting and seining collection. Turbidity was taken for six collections. Samples from netting collections were weighed, measured and sexed in the field. A sample of each species was examined for stomach content, and organs requiring laboratory study were preserved in 10% formalin. FINDINGS Oak Creek Reservoir is located approximately three miles southeast of Blackwell, Texas. The impoundment creating the reservour is about six miles east of the confluence of Bushy and Oak Creeks. The dam is 3,800 feet long, earth fill construction, and was completed in 1952, by Campbell Construction Company of Dallas, for the municipalities of Sweetwater, Bronte, and Blackwell. The impounded water is conserved for the municipal and industrial consumption of those cities. When at emergency spillway level, the lake will have 1,500 surface acres and will store about 52,900 acre feet of water. At that elevation the reservoir would have about twenty miles of shoreline. The contributing watershed of 222 square miles is primarily San Angelo sandstone formation and topsoils are usually Frio clays, black lime sands and sandy loams. Climate for the watershed is semi-arid, having an average rainfall of 24.35 inches. Reliable information pertaining to the average annual discharge of Oak Creek was not available. However, there is no permanent stream flow above the reservoir and run-off is extremely variable. Vegetative cover for the area is predominantly mesquite-grassland association and the area is employed for farming and ranching. The area about the reservoir is a producing oil field, and when the reservoir is at spillway elevation; four of these wells are within the inundated area and are located on islands constructed to place them above maximum lake elevations. One reported pol- lution from this source was reported, but insufficient evidence was obtained to establish positive proof. Before the reservoir impounded any significant portion of water the old stream bed containing an estimated 275 acre feet of water was treated in an attempt to erradicate the fish populations. This work proved to be unsuccessful as will be discussed under a later category. The City of Sweetwater has initiated a charge for fishing at the lake. These fees are fifty cents per day for a family or twenty-five cents per day for an individual. A charge of five dollars per year is made for each family or individual desiring a year's permit. RESERVOIR CONDITIONS Aquatic Vegetation: Excepting algae and a few concentrations of pond weeds (Potomo eton natans) there is no aquatic vegetaion in the lake. Willows (Salix niger) and Pecan (Hicoria sp.) are numerous near the mouth of Bushy Creek. The remaining shore vegetation is mesquite (Proso~ pos julifloria). --- Page 3 --- Temperatures and Fluctuations: Oak Creek Reservoir Year Month El. AF. Air Temp. Water Temp. ges July 76.3 7,130 1.953 August 76.2 7,060 1953 September 13,000 1953 October 82.2 11,700 1953 November 83.1 12,520 82 69 1953 December 82.5 11,970 67 62 1954 January 82.0 11,520 1954 February 81.7 11,250 Ke) hg 1954 March 81.1 10,730 68 64 1954 April 80.6 10,310 70 66 1954 May 85.7 15,120 69 72 1954 June 88.7 18, 730 1954 July 88.6 18,600 1954 August 87.4 17,070 89 86 1954 September 86.3 15,770 83 80 1954 October 85.4 14, 800 1954 November 84.8 14,180 68 val 1954 December 85.2 14,590 1955 January 84.8 14,180 kg 52 35 February 84. 13, 780 2/95 March 85.2 14,590 60 59 1955 April 84.8 14,180 1955 May 84. 13,780 @ Te 1955 June 89.1 19,270 1955 July 88.8 18, 870 81 79 1955 August 89.0 19,130 Although not shown in the above data Oak Creek Reservoir impounded it's first run-off in 1952. This quanity was estimated to be about 1,500 acre feet. From that cap- acity the volume increased to a maximum of 19,130 acre feet in August 1955. The lake had receded slightly from this maximum when work was completed; however the data on this fluctuation was unavailable. Water Analysis: Oak Creek Reservoir Year Month Turbidity Air Temp.(F) Water Temp.(F) pH Diss Diss Alk. Oo COs 1953 November 82 69 8.2 10.00. 0.0 1953 December 67 62 8.4 11.50 0.0 ‘February Ke) ke) 8.2 11.50 0.0 ay54 March 18 68 64 8.3 13.50 2.0 1954 April 70 66 8.4 11.30 5.00 1954 May 18 69 72 8.4 11.30 3.00 92 1954 August 89 86 8.6 9.50 9.00 1954 September 18 83 80 8.3 10.00 6.00 70 --- Page 4 --- 4, 1954 November 68 71 8.3 12.50 0.00 1955 January ke) 52 8.2 13.30 0.00 1955 March 60 59 8.2 14.20 7-50 66 1955 May 12 72 72 8.4 12.00 0.00 1955 July 81 79 8.4 9.50 2.00 1955 September | 81 80 8.4 10.50 3.00 1955 October 80 76 8.1 11.00 0.00 48 1955 December 72 yal 8.2 12.50 1.0 1956 February 57 54 8.2 10.50 0.00 1956 April 18 64 62 8.2 13.50 2.00 neem As shown above the reservoir was murky at times and its: water contained less total alkalinity than other reservoirs in this area. Where an error was obvious in tech- nique or the standardization of reagents questioned; data is omitted. FISH POPULATIONS As previously stated the water retained in the stream bed within the reservoir area, about 275 acre feet volume, was treated with 5% rotenone at an estimated rate of 3 pounds per acre foot; to eradicate existing fish populations prior to the impoundment of run-off. Restocking was from the State Hatchery at San Angelo and included the release of an estimated 25,000 largemouth bass fry, and unknown numbers of sunfishes and golden shiners. As shown in the tables for netting the first year's work resulted in extremely meager samples (.0029 fish per feet net set), and the reservoir was regarded as being in a constant state of readjustment during the remainder of inventory. Species Distribution: As shown in the checklist 5,542 individuals representing twenty-seven species and seven families were taken during inventory. Seining was the primary basis of distribution; however since the basin was not cleared of dense mesquite all work at this reservoir was difficult. Two seining beaches were cleared where seining collections could be obtained on a regular basis. The remaining sampling was done where areas were located free of obstructions and depending upon reservoir fluctuations. The species collected are as follows: Common Name Family Name Scientific Name ———_—_ eee Longnose gar Lepisosteidae Lepisosteus osseus Gizzard shad Clupeidae Dorosoma cepedianun Gray redhorse sucker Catostomidde | Moxostoma congestum River carpsucker Catostomidae Carpiodes carpio Smallmouth buffalo Catostomidae Ictiobus bubalus Carp Cyprinidae Cyprinus carpio Golden shiner Cyprinidae Notemigonus crysoleucas Spottail shiner Cyprinidae Notropis venustus Redhorse shiner Cyprinidae Notropis lutrensis Plains minnow Cyprinidae Hybognathus placita Parrot minnow Cyprinidae Pimephales vigilax Channel catfish Cyprinidae Ictalurus punctatus Yellow bullhead Cyprinidae Ictalurus natalis Flathead catfish Cyprinidae Pylodictus olivaris --- Page 5 --- 5. BOTTOM TYPES AND INNUNDATED VEGETATION IN OAK CREEK RESERVOIR Symbols 8.—- sand c - clay fg - fine gravel cg ~ coarse gravel ——— x - innundated areas of mesquite S s s <x 8 c c S x S Cc s x s c Cc s c s c cg sc 8 c s c c c x x x Oo s c xx x Cc c xx c Cc c c c cg sc EXLXR = s Cc Sessssae C X XOKKXK xxx s xxx x c s xxXxXxX X s x x s s c x fg x c x c Cc g c x x c Cc C XX é fg "4 xxx ~ Highway 70 Y xXxC X Co i x 5 c xxx x xX xX c xXx ~ Pecan Creek Cc - ~ Oak Creek --- Page 6 --- ‘suotyetndod tepun passnostp re1el[ ezaym ydeoxa seatoads fue £q uopqgnqyiistp otgztoeds fue go SUOTYBOTPUT SYTUTJEp OU 210M arTaqy, perenne sueTuuNIs SsnqyouTpoTdy septusetog mip Teyeayserg STieTnuue STxoUOg sept yoesyuag etddero 84.TyM suTteueks sTuodey Sep tyoesyue) ystguns ueern ST}OTevau StuodeT deplyoerzueg ystguns ree8uo7y snjtine STuodey SepTyoesyuag ystguns ATTaqmoTTey ST[TTuMYy stwodey ep FyoeslyUeD ystguns poy odse8uerg snITyooioem stmodery seplyowsrzued TITZenta snydojoroTH sTuodey depTyoesj}Uen ystjuns 1eepey snyejyound stwodeT SepTyoeijyueg ystguns poyz0dg snso[ns snjjysrqouseeyp Sep tyoerjuey sseq Yjnowrem Septowpes snioydorompm Seplyoesryusg sseq Yynoweszreq sdoskiyo snoooy sep luBrzeg sseq a1 TUM sTuTjge etsnquey septurpadrg UsSTjoyTnbsow uoumoy --- Page 7 --- OAK CREEK RESERVOIR Symbols: S = = Seining Station N = - Netting Station * x=- = O11 Well _— Pecan Creek --- Page 8 --- Seining Collections: It was impossible to maintain exact seining stations because of reservoir fluc- tuations; however an attempt was made to repeat sampling as near to a designated area as was possible.. Only nineteen species were captured during the initial year, four species were added during the second segment and checklist was increased by four species during the last year's work. Technique was modified somewhat by improved nylon seines. The included data does not include or take into account unsuccessful seining attempts. The approximate location of seining stations are shown on the preceding map. --- Page 9 --- 9. Seining Collections From Oak Creek Reservoir June 22, 1953 through June 30, 195). eee Species June July August September November December February March April May June Total Percent enn Mosquitofish 21 43 112 38 17 ) ) 0 12 116 100 459 26.40 Redhorse shiner 138 121 38 0) el 6) 18 31 el 39 25 452 26.00 Spottail shiner 10) 0) 8 el 5 9 31 (0) al 6) 20 115 6.60 Parrot Minnow 0) 0 fe) @) 0 © 6 h 0 11 12 33 1.90 Largemouth bass 2 8 7 3 ) ) 4 21 16 14 #12 87 5.00 White crappie 2 3 0) 6 6] @) 6) 6 2 3 11 33 1.90 Green sunfish 4 ) 6 12 11 10 9 12 4 18 8 ob 5.40 Longear sunfish 4 fe) 0 5 fe) 3 4 8 6 9 8 56 3.20 Bluegill 10 28 el 22 13 8 i 2 5 al 14 151 8.70 Redear sunfish ie) 0) O 2 6) h 0) 4 0 12 9 31 1.80 Yellowbelly sunfish O @) 0 0 0 1 0 2 8) 0) 0 3 -LO Spotted sunfish 1 6) 0) 25 0 0) (6) 7 6) ll 13 37 2.10 Orangespotted sunfish ) ) ) ) 5 8) 0 ) O fe) 2 7 40 _ eee Total 182 203 192 114 81 35 79 97 87 254 234 1558 100.0 ror eee --- Page 10 --- 10. Seining Collections from Oak Creek Reservoir July 1, 1954 through May 1, 1955. _ Species July August October November December February March April May Total Percent enn nN A eke einen Mosquitofish 13 21 ) 0 0 ah 12 10 2 104 7.05 Redhorse minnow 68 102 yh 30 22 110 6 73 58 513 34.80 Spottail shiner fe) ) 13 O 6 O 21 1h 8 62 4.21 Parrot minnow ) 11 7 ) 23 8 Xi. 16 22 o7 6.58 Plains minnow ) 21 8 4 11 5 6 13 8 76 5.15 Golden shiner ) ) fe) ye 16 T 21 28 31 #107 7-25 Gizzard shad y 4 6 0 0) 20 0 3L «(16 81 5.49 River carpsucker 0 fe) ) 2 y ) 1 1 6 14 095 Longnose gar ) 0) ) 0 2 @) 0 6 h 12 atid, Largemouth bass 2 4 2 1 9 ) fe) 4 = 16 38 2.57 White bass ) 0 ) ) 2 ) 4 13 2 21 1.42 Bluegill 21 13 6 13 y 2 6 12 18 95 6.45 Green sunfish h 16 9 2 @) ) 21 8 11 7 4,82 Redear sunfish ©) ©) 10 0 2 .2 ©) 8 2 2h 1.63 Longear sunfish ) @) fe) 13 2 ¢) ¢) 6 12 33 2.24 Yellowbelly sunfish 38 26 19 11 ©) 4 0 8 2 108 7-33 Warmouth bass ©) 2 2 fe) 0 in 3 ci 6 18 1.22 Total 150 220 126 80 103 186 112 252 «4 2h5 147k 100.00 --- Page 11 --- ll. Seining Collections from Oak Creek Reservoir, et enh annie Species June September October February April Total Total Total Total Percent 1953-54 1954-55 1955-56 1953-56 —_—_—_—_e_— A Ee nnn nnn Mosquitofish 3 2 5 0 ) 459 104 10 573 14.40 Redhorse shiner aL 6 21 12 he 452 513 64. 1029 25.80 Spottail shiner @) 0 ©) 0 @) 115 62 ) 177 443 Parrot minnow 8 5 9 8 12 33 97 ke 172 4.30 Largemouth bass 1 he 2 1 1 87 38 9 134 3-35 White crappie 16 al al 18 20 33 @) 96 129 3.22 Green. sunfish 21 @) 3 fe) @) oh val ak. 189 4.73 Longear sunfish fe) ¢) 2 0) 1 56 33 3 95 2.37 Bluegill 10 h 8 17 14 151 95 53 299 748 Redear sunfish O 0 y ye 2 31 oh 10 65 1.62 Yellowbelly sunfish 0 0) O 6) O 3 108 0 Lil 2.77 Spotted sunfish 0) 0) 0) ] O 37 0) 0) 37 Oh Orangespotted sunfish 8 ©) 3 7 6 @) ak 31 .79 White bass 12 6 6 7 12 ) 21 43 64 1.60 Warmouth bass O ) @) fe) ) @) 18 ) 18 AS Plains minnow 21 56 20 20 23 0) 76 140 216 5.40 Golden shiner 21 48 1Lhg 100 120 O 107 438 545 13.64 Gizzard shad 0 0 0 0 0 0 81 0 81 2.02 River carpsucker 2 0 h 1 ) ) 14 7 21 52 Longnose gar 0) O 6) 0) O 0) 12 0 12 a 35 Ly 152 257 195 21) 1558 L474. 963 3995 100.01 Note: Work during the third year was modified as amended for that period. Included data is from collections where actual counts were made. --- Page 12 --- 12. Netting Collections: As in seining exact duplication of netting was impossible except in a few instances. Only the netting stations pertinent in other discussions are shown on the preceding) map. As the included charts are regarded as the best available expres- sion of a total interrelationship; populations for the most important species and the apparent influencesupon each species are discussed separately; where evidence of such influence was obtained. --- Page 13 --- 13. Netting Collections from Oak Creek Reservoir August 1953 through June 1954. Species August September November December January February March April May June Total . be oo, Gizzard shad No. O ) @) 12.000. 3 12. 2a. 18 8 75 % 0 ©) ) 13.7 12.0 30.8 50.0 4.6 72.0 22.3 25.00 River carpsucker No. 4 2 1 19 11 4 5 4 ) 12 62 % 50.0 50.0 9.1 21.6 4.0 10.3 11.0 18.2 ) 33.3 20.30 Carp No. O @) 0 1 ) ) ) @) e) 0 1 % ©) @) re) 1.1 @) 0 0 0) ®) @) 30 Longnose gar No. 6) @) 6) 6) 6) te) 6) 6) 0 L 1 % ) ) ) 0 0 ) ©) ) ) 2.7 - 30 Drum No. 0O 0 0 4 © 0 0) 0 ) ¢) 4 % 9) 0 fe) 4.6 0 ©) 0) re) ) 0 1.30 Yellow bullheads No. 0 ) 4 ah 3 7 8 3 @) 7 56 % ) ) 36.3 27.3 12.0 18.0 19.1 13.7 ) 19.5 18.70 Channel catfish No. ie) 6) 1 a 6) 3 3 9 6) 2 19 % fe) ) 9.1 ae 6) 7-7 7-2 41.0 0 5.6 6.40 Largemouth bass No. 4 1 5 17 4 5 3 4 2 1 46 % 50.0 25.0 45.4 19.4 16.0 12.9 7.2 18.2 8.0 2.7 15.30 White crappie No. O ) ¢) y ¢) 2 ) 0 ) 5 11 % ) 0 0 4.6 0 5.10 O ) 0 13.9 3.60 Sunfishes No. O 1 ) 6 4 6 2 1 5 0 25 % 0 25.0 0 6.8 16.0 15.4 4.8 4.6 20.0 0) 8.40 Total 22 25 36 ©3000 --- Page 14 --- yb Netting Collections from Oak Creek Reservoir May 1, 1954 through May 31, 1955. Species July Aug. Sept. October November December January February March April May Total Percent Gizzard shad No. O 12 0 0 fe) 0 8 12 21 «416 114 183 16.28 q, 0 30.77 O ) @) @) 40.00 23.52 37-5 14.81 20.21 River carpsucker 5 h 1 4 85 2 3 1 9 a1 43 178 15.84 26.2 10.25 1.60 7.01 TOs'f 4.65 15.0 1.96 16.08 19.44 7.61 Longnose gar 0) ie) 0) e) O e) ) 0 ie) 2 ii 13 1.15 0) 0 0 @) 0 @) 0 0 0 1.85 1.95 Gray redhorse 0 8) 6) 6) 6) 6) ) 0 6) 6) 2 sucker 0 0 ) ©) 0 n°) 0 0 0 0 3.54 2 why. Drum ) O ) 0 ) fe) @) 2 1 @) 8 11 0 0 0) 0 ) ) ) 3.93 1.78 0 1.41 -97 Yellow bullheads 2 4 2 6 9 8 3 13 6 28 116 197 17.54 11.01 10.25 3.36 _.10.52 8.30 18.60 15.01 25.49 10.71 25.58 20.56 Flatheads 0 0 0 ) 6) 0 0 0 ) 0 2 2 .19 @) 0 O ) ) fe) 0 ) 0 © 3.54 Channel catfish 3 2 2 5 1 2 1 0) 0 3 126 1h5 12.91 15.65 5.12 3.39 8.77 -92 4.65 5.00 0 0 2.77 22. 3h Largemouth bass 0 fe) 1 @) 1 3 1 ) 30 3 h 16 1.43 0 ) 1.69 0) 92 6.97 5.00 0 5.35 2.77 .71 White bass ) 8 @) fe) ) 1 ) 8 fe) ) fe) ) 20.51 0 fe) © 2.32 0 15.68 0 ) 0 at asc White crappie ) 0 2° ) 0 i 0 1 11 4 21 43 3.83 @) @) 3.3 @) fe) 2.32 @) 1.96 19.64 6.48 3.72 Sunfishes 9 9 51 he 12 26 y 1h 5 28 117 31 28.21 47.20 23.7 86.45 73.68 ple ee a 6.46 20.00 27-45 8.92 25.52 20.74 ‘ eee Total Number 19 39 «459 57 108 4.3 20 51 56 108 564 1,124 100.00 --- Page 15 --- Le Netting Collections from Oak Creek Reservoir. neem Species June July September October December February April Total Total Total Total Percent 1953-54 1954-55 1955-56 1953-56 Gizzard shad No. 16 5 0 0 ) 0 0 15 183 21 279 14.68 % Yh yy 6.57 ©) 0 © 0 0 River carpsuckers No. 6 8 5 0 3 5 12 62 178 39 279 14.68 % 16.66 10.53 27.78 fe) 8.58 oS 12.5 Longnose gar No. 0 0) 0) 0) @) 6) 0 1 13 0) 14 73 % ) @) 0 @) fe) ) 0 Freshwater drum No. O ) 0) 0 ) ) 0 y 11 0 15 78 % O 0 ©) 0 0 0 Yellow bullhead No. 6 20 2 y 1 57 ) 56 207 90 353 18.57 % 16.66 26.3 21.1 11.1 2.85 51.36 ) Channel catfish No. 2 14 2 1 ye 2 3 19 145 28 192 10.10 % 5.55 18.42 11.1 2.7 11.42 1.8 3.13 Largemouth bass No. 2 1 @) ) re) 4 ) 6 16 7 69 3.63 % 5.55 1.31 0 0 @) 3.61 0 White crappie No. O 1 O 17 22 39 Si. 11 103 130 ay 12.84 % 0 1532 ¢) 47.23 62.8 35.13 53.12 Carp No. O fe) 0 0 ) 0 0 1 ) fe) 1 205 % 0 0 ) 0 ) ©) 0 Sunfishes No. 4 23 9 13 3 1 2 25 317 55 397 20.89 (combined) % lil.l 30-2 59.0 36.12 8.58 ae) 2.09 Flathead catfish No. 0 0 0 1 1 0) @) 0 2 2 h JL % 0 0 0) 2.77 2.86 fe) 0 White bass No. O ©) ) 0 0 ) 12 7 ) 12 29 1.52 % @) ©) 6) 6) 6) fo) 12.5 Golden shiner No. O h 0 fe) 1 3 16 fe) 0 ek oh 1.26 vA ) 5.26 re) ) 2.86 2.7 16.66 Se eer rere gen niente ics i cata 36 76 18 36 35 11 96 317 1175 408 1900 100.00 The above data by month is for the final year of inventory. Actual catches by month for the preceding twenty-four months is included in completion reports for F5RL and F5R2. a nnemnneeeeeneeeeereeee --- Page 16 --- 16. Netting Collections from Oak Creek Reservoir. Comparative Data on Fish Populations for Principal Species —_————_—_—_—_-——— Species No. captured Weight Comparison Numerical Comparison (% by Weight) (% by Number) 1953-54 1954-55 1955-56 _ Average 1953-54 1954-55 1955-56 _ Average Dorosoma cepedianum 279 23.20 16.28 16.25 1857 25.00 8.01 5.14 12.71 Carpiodes carpio 279 52.70 15.04 29.50 33.68 20.30 36.18 9.55 22.01 Ameiurus natalis 353 4 uO 17.54 14.29 12.08 18.50 14.29 22.05 18.28 Lepisosteus osseus 14 2.70 1.15 ) 1.28 230 6.41 ) 2.23 Ictalurus punctatus 192 1.50 12.91 10.33 8.2h 6.40 10.53 6.86 7.93 Micropterus salmoides 69 2.20 1.43 3.02 2.21 15.30 3.02 1.70 6.67 Pomoxis annularis ehh 5.20 3.83 21.47 10.16 3.60 2.82 31.37 12.59 Sunfishes 397 5.10 28.21 4.92 12.74 8.40 13.72 13.48 11.86 ennui atin eee --- Page 17 --- L7. Netting Collection from Oak Creek Reservoir Comparative Physical Condition of Principal Species. 1953-1954 1954-1955 Total Average No. "K" Range Avg. K No. "K" Range Avg. K No. "K" Range Avg. K No. Catch "Kk" Dorosoma cepedianum 25 1.66-2.10 1.71 2h 1.51-2.45 1.84 12 1.75-1.84 1.82 279 21.86 1.79 Carpiodes carpio 25 1.97-2.29 2.03 20 2.00-2.59 2.49 12 2.28-2.43 2.29 279 20.43 2.27 Cyprinus carpio 1 2.he 2.42 1100.00 2.42. Lepisosteus osseus 1 on 4 OL 5 2.52 2.52 14 he.g5 2-17 Ameiurus natalis 26 1.39-2.32 2.24 16 2.24-2.59 2.0 20 2.47-2.72 2.64 353 17.56 2.43 Ictalurus punctatus 19 2.07-2.89 2.33 8 1.86-2.42 2,34 1h 1.82-1.86 1.84 192 21.35 2.17 Apolodinotus grunniens 4 =6©2.11-2.17 2.13 8 2.38-2.55 2.42 15 80.00 1.52 Micropterus salmoides 46 2.32+2.70 2.60 8 2.33+2.47 2.36 he 2,33-3.25 2.84 69 84.09 2.60 Pomoxis annularis 11 3.05-3.60 3.12 20 2.42-2.68 2.54 2h 2,32-3.25 2.96 ahh. 22.54 2.87 Sunfishes 25 3.10-3.60 3.18 12 3.92-4.25 3.98 12 3.66-4.64 4.60 397 12.34 3.92 --- Page 18 --- 18. LOCALITIES HAVING HIGH PERCENTAGES OF GAME FISH IN OAK CREEK RESERVOIR ‘Largemouth Bass White Crappie All Largemouth Bass were taken in the Greatest numbers of White Crappie indicated localities were taken as indicated Channel Catfish --- Page 19 --- 19. STOMACH ANALYSIS AND FOOD HABITS The following data is included as taken from specimens netted in the field, and ‘S on a volumetric displacement basis. It is considered probable that for some species che small number of stomachs obtained is insufficient to indicate the food habits of the population. Stomach Analysis for Principal Species White Bass Number Stomachs Fish Examined Shad Others 7 29 98% Insects 2% Largemouth Bass Number Stomachs Fish Examined Shad *Fish Remains Sunfish Insects Crustaceans 12 34 11% 14 13% 1% 1% White Crappie Number Stomachs Fish Examined Shad Insects 30 62 78h 2% Channel Catfish Number Stomachs Fish Examined Shad Yellow Bullheads Fish Remains Algae 23 56 12% 29% 4O% 19% Yellow Bullheads amber Stomachs Fish Examined Shad Sunfish Fish Remains Algae Insects Other 121 204, 13% % 31% 11% 3% % Silt and unidentifiable material in- cluding fluid 33% Flathead Catfish Number Stomachs Fish Examined Yellow Bullheads Channel Catfish 4 y 88% 12% * The greatest quantity of this portion of largemouth bass diet was believed to be the two common shiners. As shown in the above data 389 individuals of six species were opened and ex- amined for stomach content, sexual development, and parasitism. Of that number 202 stomachs (51.92%) contained food. In addition to the above data a number of stomach contents were observed when fishermen cleaned fish at the lake. FISH POPULATION TENDENCIES AND INFLUENCES Largemouth bass. There was a gradual decline in the number of largemouth bass captured by netting during the inventory period. However because these fish are not easily entrapped by gill nets and because of the increase in reservoir area which made several locations (where these fish were captured at the beginning of work) no longer suitable for netting; this apparent decline may be the result of sampling. All individuals captured were in excellent condition, and the lake continues to maintain a favorable rep- sation for this species. Spawning was apparently successful in all three seasons, and probably occurred from mid-April to the last week in May. --- Page 20 --- 20. Channel Catfish. These fish were in the process of becoming established during the last two year's work, were in excellent condition, and apparently increasing each year. There was probably some competition between this species and yellow bullheads and this latter species offered a significant portion of the food found in channel catfish. Spawn- ing was apparently successful in the first two years; however no evidence was obtained of successful activity in the third segment. Yellow bullheads. The number of this species increased tremendously in the second segment and receded with almost equal suddenness during the last year's work. The reason for this fluctuation may be explainable in the increase in the channel catfish and flat- head catfish populations. Yellow bullheads were the most important food item for flatheads and were possibly the most important food for channel catfish. The spawning activity of these fish was not observed nor was there sufficient evidence regarding their other requirements. The increase of bullheads occurred at approximately the same time as the increase and decline of several species of the sunfishes. Since sunfish were a significant portion of bullhead's food; the latter species may have helped serve as a natural control of sunfishes. Flathead Catfish. During inventory, 18 flathead catfish were transported to Oak Creek Reservoir from Lake Nasworthy. Prior to that time no récord was obtained of any catches of this species from the reservoir, nor did they occur in netting collections. During the last segment several flatheads were known to have been taken by sportsmen; more individuals were captured than in the total for the other two segments. Although the number of stomachs examined is too small to furnish reliable data on the food habits for this species; it is believed that yellow bullheads may be a preferred food, and that flatheads may have a tendency to provide a natural control for this species. Sunfishes. As indicated in seining collections bluegill were the dominant species for this reservoir during inventory. There was also an apparently cyclic sub-dominance fluctuation among other species that resulted with green sunfish having a sub-dominance during the first segment and relinquished this position to spotted sunfish during the se- cond twelve-month period. During the final year's work orangespotted sunfish were evolving to a sub-dominant position. Longear sunfish (regarded as the most probable dominant species under native conditions) maintained a static population. From March 1954 through April 1955 sunfish were taken of sufficient size to furnish pan fish; however during the last 13 months of inventory not one individual was collected or known to have been taken of sufficient size to furnish sport or food. For this reason the sunfishes of Oak Creek are regarded as primarily forage species. It is believed that these species may spawn at almost any time during the year. White Bass. This species was of questionable significance @uring the period of work. However population increases were noted in the last segment's work. No spawning activity was observed; however this activity is believed to occur from February to April. White Crappie. This species is believed to furnish most of the game fish harvest from the reservoir, and is probably the most desired fish by sportsmen. The reservoir has an excellent reputation as a fishing spot for this species. Probable spawning period March - May. River Carpsuckers. At inventory completion the numbers of these fish indicate that their development as a population is considerably slower than evidence from cther work done in this area would lead one to expect. Carpsuckers are not yet regarded as a manage- ment problem; however there is little doubt that in the future these fish will gain domin- ance of the fish populations as is indicated by all other work for this region. Virtually all individuals examined were in advanced stages of sexual development, and since there is apparently no utility for the species they may be regarded as a potential management problem. --- Page 21 --- 21. Cyprinids and Other Forage Species. The obvious trend of the redhorse shiner to gain dominance over spottail shiners, who held criginal dominance in the stream condition, is illustrated in the Seining Collection Data. The decline in mosquito- fish and increases in golden shiners and plains minnows are attributed to the increase of the reservoir volume. The small percentages for gizzard shad are considered to be a result of the difficulty involved in seining rather than to any lack of numbers for that population. Only one carp was taken in all collections, and gray redhorse suckers were found only in the stream pools above the reservoir. Longnose gar and drum were taken in- frequently and were of unknown significance. RECOMMENDATIONS From the evidence obtained during inventory it was concluded that Oak Creek Reservoir was producing desirable quantities and yields of game fish, and that no corrective action is required at this time; however all available methods of persuasion should be extended to encourage free access to this reservoir for sportsmen. Prepared by Lawrence S. Campbell Approved by weil” Project Leader Ch¥ef Aquatic Biviogist Date April 4, 1957