TPWD 1956 F-5-R-3 #242: Inventory of Species in San Angelo Reservoir: Job Completion Report, Project F-5-R-3

--- Page 1 --- JOB COMPLETION REPORT FILE ny State of TEXAS Project No. F-5-R-3 Name; Fisheries Investigations and Surveys of the Waters of Region 3-B. Job No. B-3 Title: Inventory of Species in San Angelo Reservoir Period Covered: May 1, 1955 - May 1, 1956 ABSTRACT 1. To obtain data on the fishery populations and some of the influencing ecological conditions seventy-nine gill net collections and thirty-six seining col- lections were taken from San Angelo Reservoir. Water analyses for dissolved carbon dioxide and oxygen content were taken periodically and more detailed chemical ana- lysis data was obtained from the State Board of Water Engineers. Other recorded data included water temperature (surface and at established depths) pH, and climatic conditions at the time of each sampling of the fishery populations. A sample num- ber of fish for each principal species were examined and condition (K) was computed. Food habits were determined from stomach contents. Other data relevant to the study included observation for a spawning activity and a study of the lake's productivity. 2. San Angelo Reservoir impounded most of its storage during the first year of inventory. The lake level fluctuated slightly until September 1954. From that time a continued decline of about .5 feet per month has occurred. 3. About 8,811 individuals of thirty species and ten families were cap- tured by seining or in gill net collections. Two species were believed to be intro- duced by bait dealers or fishermen. 4. White bass indicated a trend toward domination over similar game species. Largemouth bass declined significantly, and channel catfish and white crappie had advanced to a position of being the most important game species at the end of inventory. 5. Gizzard shad were the most important forage species. 6. River carpsucker were apparently well established as the dominant species in the reservoir and that tendency may be increasing. Since there is no knonw utilization of this species it is concluded that these fish constitute the primary management problem for the reservoir. 7. During inventory the most severe drought ever recorded for this area occurred. At no time during the first four years following the closing of the flood control conduits has the reservoir reached the average annual minimum pool. Maximum storage during the period was about the area allocated for siltation. --- Page 2 --- 8. It is believed that the anticipated annual fluctuations of the water level as expected under the adopted plan for reservoir management will prove suf- ficiently detrimental to prohibit the successful propagation of largemouth bass. OBJECTIVES To determine the species present and their relative abundance as well as to determine the ecological factors influencing their distribution. PROCEDURE During inventory seventy-nine gill net collections were made at 23 net- ting stations in San Angelo Reservoir. Experimental nylon gill nets measuring 125 feet long by 8 feet in depth and made up in five, 25 foot 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. Thirty-six seining collections were made at fourteen localities along the lake shore. In nearly all collections both 26 foot i" mesh bag seines and 15 foot _" mesh common sense seines were used. To estimate relative abundance a count was made of all individuals taken in two hauls with a 26 foot 4" mesh bag seine for each collection. In additional seining where relative abundance data was not taken, a four foot common sense seine with a 1/16" mesh was used. To collect fry after the spring spawning by fishes, a 4 foot by 8 foot straight nylon seine with 1/32" mesh was used. Water analysis for dissolved carbon dioxide and oxygen content was taken periodically and surface temperature, pH and the climatic conditions were recorded for each netting and seining collection. Significant turbidity was recorded on five occasions. To make a detailed study of the largemouth black bass population, 2,237 individuals of that species were tagged and released at eight localities in the reservoir. In net collections, most fish were identified, counted, weighed, measured and sexed in the field. A sample number of each species were examined for stomach content and a scale sample taken. On occasions it was necessary to preserve an individual, its stomach or some other organ for more detailed examination in the laboratory. When this was required, the specimen was preserved in 10% formalin. COOPERATING AGENCIES United States Corp of Engineers United States Geological Survey State Board of Water Engineers Fish and Wildlife Service, River Basin Studies FINDINGS Description - San Angelo Reservoir is adjacent to much of the north and western residential additions of the city of San Angelo in Tom Green County, Texas. --- Page 3 --- The impoundment, 40,855 feet long, of compacted impervious earth fill and reinforced concrete construction, was completed in 1951-52 by the U. S. Corps of Engineers for flood control and storage of water for municipal, industrial, and irrigation uses. The dam bisects the North Concho River 6.6 miles above the confluence with the South Concho River and at that point is 128 feet above the river bed. Two concrete conduits are located at this point to provide the regulation of flood releases and in making reservoir withdrawals. These conduits are 18 feet in diameter, 489 feet long, pass through the base of the dam and have a maximum discharge potential of 25,100 second=feet. The reservoir is primarily for flood control and has a maximum design of 691,400 acre feet capacity; however the top of the flood control pool would contain about 391,500 acre feet and would have a maximum area of 12,696 surface acres. Con- servation pool is designated at 1908 feet above mean sea level, and at that level the reservoir would contain 114,300 acre feet and will have 5,441 surface acres. “Dead Storage", that portion of the reservoir allocated for siltation, is below elevation 1886.0 and has 33,900 acre feet capacity and an area of about 2,468 surface acres. The average annual minimum pool is estimated to be 65,613 acre feet volume and will extend to 3,437 surface acres. Average annual maximum pool is estimated to be 97,949 acre feet and 4,790 surface acres. Under the adopted management plan of operation the reservoir would be at conservation pool 3.5 percent of the time and no water would be retained above that elevation. All storage above "Dead Storage" and below conservation pool level, a total capacity of 80,000 acre feet, was pur- chased by the city of San Angelo for municipal and industrial consumption. Water levels are estimated to be above the average annual maximum pool elevation about 29 percent of the time and above the average annual minimum pool elevation about 7h percent of the time. Average annual fluctuation would be 8.0 feet, and maximum annual range in pool fluctuation would be about 28 feet. Maximum rate of recession will be about 5.5 feet per day, and would be the result of flood releases. Probable month of maximum stage will be September and probable month of low stage will be January . The 1,511 square miles of contributing watershed above the dam are within the southern portion of the Osage Plains, and are characterized by strata of Choza, San Angelo, and Blaine formations of the Permian Age. Sedimentary beds of the Trinity and Fredericksburg groups of the Cretaceous Age outcrop adjacent to the reservoir area. Soils are predominately Abilene clay loams and the flood plain is composed of alluvial sandy loams, clay silts, and deposits of gravel. The most important soils in the contributing area are characterized as dark chocolate-brown silty clay loams, calcareous, and high in organic matter. Native vegetation of the area is mixed short prairie grasses; however with abuse of the ranges a disclimax savannah of grasses and brush, primarily of mesquite, has resulted. Complete cli- matic records for fifty-two years indicate that average annual temperature is 64.9 degrees F., average minimum temperature in January is 32.1 degrees and average maximum temperature in August is 96.6 degrees. Average frost free period is 233 days (March 22 - November 10). Average precipitation for fifty-five years is 21.69 inches with a maximum of 42.12 in 1882; and with minimums of 8.29 inches in 1917 and 7.41 inches in 1956. The North Concho River and its tributaries originate primarily in southern Howard county, and in central and northern Glasscock county. The stream flows southeasterly to its confluence. The upper watershed is intermittent except for --- Page 4 --- Year L953 EL. 1954 El. 1955 El. 1956 two spring areas, and where low water impoundments provide for small storages of run-off. Maximum recorded discharges for the river was 62,900 second-feet, and aver- age discharge over a 26.5 year period was 50.6 second-feet. Extreme low flow has been recorded for the past 19 years. Zero flow occurred about nine percent of the time, and the longest recorded continuous period of no flow, prior to inventory, was 86 days in 1931. Longest period of an apparent and significant continuous flow noted during this survey was six days. Additional information pretaining to this stream is available in completion reports for Jobs A-1, A-2, B-1 and B-2. Capacities and Fluctuations - The following data pertaining to capa- cities and fluctuatuions in lake level during inventory are taken from records of the U. S. Corp of Engineers and air temperatures as recorded in the table are taken from that source. Fluctuation data and air temperatures were taken at the control tower in the dam, and were usually taken between 8 A.M. and 9 A.M. Water tempera- tures were taken by commission personnel and were recorded in partat Parr's Boat Docks on the south shore of the lake, and on other occasions at Green's Concession on the north shore. Water temperatures were usually recorded between 8 A.M. and 10 A.M. Capacities and Fluctuations of San Angelo Reservoir Jan. Feb March April May June July Aug. Sept. Oct. Nov. Dec. 1800 46.46 46.70 46.48 51.57 51.0 70.7 69.09 71.58 83.46 83.30 84.82 8h.31 51 137 104 871 734 12391 10824 13346 32956 32509 35992 34801 1800 84.31 83.85 83.65 83.24 82.75 87.0 91.00 92.95 91.98 90.39 89.71 89. 33860 33181 32287 31409 41350 52279 57074 54155 52656 50527 48607 473 1800 88.84 88.61 84.40 87.84 86.96 86.85 85.92 85.86 85.60 85.09 84.51 84.00 46206 45582 35010 43529 41247 4o967 38639 38492 37857 36631 35265 34088 1800 83.65 83.48 83.20 82.70 33181 32966 32287 31192 Symbols; EL. - feet above mean sea level AF - acre feet As shown above significant increases in the capacity of the reservoir occur- red six times during the thirty-six month inventory period. However, there was a general recession in reservoir level of about one-half foot per month from July 1954 to April 1956, and a corresponding decrease in capacity of about 1000 acre feet per month. Surface area reduced about 600 surface acres or about 16 percent. ‘The most severe drought in the recorded history of this area has occurred since 1950 and this condition: had not changed at the time this report was prepared. At no time since January 1953 when dam construction was complete and the flood gates closed, has the reservoir reached the average annual minimum pool; nor has the expected minimum annual average discharge of the North Concho River occurred. The significance of these findings and their influence on the existing fish populations are discussed later in this report. --- Page 5 --- Temperatures at San Angelo Reservoir a Year 1953 1953 1953 1953 1953 1953 1953 1953 1953 1953 1953 1953 1954 1954 1954 1954 1954 1954 1954 1954 1954 1954 1954 1954 1955 1955 1955 1955 1955 1955 1955 1955 1955 1955 1955 1955 1956 1956 1956 1956 Month January February March April May June July August September October November December January February March April May June July August September October November December January February March April May June July August September October November December January February March April Temperature of Surface Water (F) Min. Avg. 43 Max. 51 60 68 69 81 83 78 19 68 60 64. 78 52 62 Air Temperature (F) Avg. Min. 17 16 28 38 Tal 66 58 61 53 ih 31 11 19 27 26 33 ho Max. 83 78 84 90 106 106 ee 6 ° VWI UI --- Page 6 --- Water Analysis - San Angelo Reservoir Year Month Turbidity Air Temp. (F) Water Temp. (F) pH Diss. Diss. Oo CO. 1953 November 23 80 70 8.4 11.00 0.0 1953 December ~ 67 60 8.2 13.50 0.0 1954 January - 58 5h 8.2 13.50 0.0 1954 February - 4o hg 8.2 14.00 0.0 1954 March - 58 54. 8.4 8.00 0.0 1954 April - 60 62 8.4 8.00 0.0 1954 May - 64 70 8.4 10.00 0.0 1954 June 12 76 60 8.6 7.00 5.0 1954 July 18 8h 83 8.4 "7.00 2.0 1954 August - 87 85 8.4 7.00 2.0 1954. September - 80 Th 8.4 10.00 0.0 1954 October - 75 68 8.2 13.00 0.0 1954 November - 69 58 8.2 14.00 0.0 1954. December - ~ - 8.2 11.00 0.0 1955 January - 55 49 8.2 15.00 0.0 1955 February - 60 ke 8.3 10.00 0.0 1955 March - 63 62 8.2 11.00 0.0 1955 April 16 72 70 8.4 9.50 5.0 1955 May 18 T2 69 8.4 10.00 3.0 1955 June - 86 79 8.4 12.00 0.0 1955 July - 8h. 83 8.2 11.00 4.0 1955 August - 84 79 8.3 13.00 2.0 1955 September - 79 77 8.2 13.00 2.0 1955 October - 67 Th 8.3 10.00 0.0 1955 November ~ 80 64 8.2 16.00 0.0 1956 January - 80 58 8.3 14.00 0.0 1956 March - 69 63 8.4 11.00 0.0 Detailed data on several other important aspects of water quality is not available for the reservoir; however records of the State Board of Water Engineers and the United States Geological Survey provide some information pertaining to water quality of the North Concho River. It is considered probable that reservoir water is less alkaline and may also have less chloride content. Total chlorides obtained in water analysis were from 180 to 300 p.p.m., and hardness was from 333 to 353. As shown, no dissolved oxygen deficiencies were recorded and carbon dioxide content was not excessive. Bottom Characteristics - Prior to inundation 2,940 acres below elevation 1908 and located between the dam and the limits of the recreational areas were cleared of most of the woody vegetation. Most of this clearing was done on the right bank of the river. On the north shore, above elevation 1886.0, most of the inundatable --- Page 7 --- Te area was covered with mesquite and other brush species. Bottom types vary from alluvium beach sand and terrace deposits near the inundated river bank to loams of the previously described types. An area of about 300 acres adjacent to and par- alleling the dam (where excavations were made for building materials during con- struction) is exposed caliche, and within that area a number of alkali deposits are located on the north shore near Jones Point. Aquatic Vegetation - Excepting algae and minute pelagic forms; there is no important emergent or floating aquatic vegetation in San Angelo Reservoir. Bul- rushes occur in the river bed above the lake where gravel or silt deposits permit. Willows and pecan are the only important woody types on the shores. On the folowing map twenty-one fish attractors that were constructed prior to inventory are design- ated. These structures are of second growth mesquite and are secured to the bottom with cables and stones. FISH POPULATIONS Species Distribution - Seining and netting collections resulted in the cap- ture of thirty species of ten families during the thirty-six month inventory period. Species and families recorded are; Checklist of Species Common Name Family Name Scientific Name Longnose gar Lepisosteidae Lepisosteus osseus Gizzard shad Clupeidae Dorosoma cepedianum Smallmouth buffalo Catostomidae Ictiobus bubalus Ww Carpiodes carpio Moxostoma congestum River carpsucker Gray redhorse sucker " Carp Cyprinidae Cyprinus carpio Golden shiner a Notemigonus crysoleucas Goldfish* " Carassius auratus Banded Tetra* " Redhorse shiner Proserpine shiner Astyanax fasciatus Notropis lutrensis Notropis proserpinus Spottail shiner Plains minnow Parrot minnow Stoneroller Channel catfish Ameiuridae Ictalurus punctatus Yellow bullhead " Ictalurus natalis Flathead catfish " Pylodictus olivaris Mosquitofish Poeciliidae Gambusia affinis White bass Serranidae Roccus chrysops Largemouth bass Centrarchidae Micropterus salmoides Warmouth bass " Chaenobryttus gulosus Green sunfish : Lepomis cyanellus Spotted sunfish " Lepomis punctatus Redear sunfish " Lepomis microlophus Yellowbelly sunfish " Lepomis auritus Longear sunfish " Lepomis megalotis White crappie " Pomoxis annularis Logperch Percidae Percina caprodes Freshwater drum Sciaenidae Aplodinotus grunniens * ~ Species introduced as bait during inventory period. Notropis venustus Hybognathus placita Pimephales vigilax Campostoma, anomalum --- Page 8 --- IOYVORIVAY -— X ULOAUASHY OTHONV NVS NI SUHOLOVULLVY HSIA dO NOLLVOOT 8 --- Page 9 --- Of the above species logperch, warmouth bass, banded tetra, and proserpine minnows were taken in the river near the mouth only, and were not taken in seining collections from the unprotected| areas of the reservoir. Seining stations were difficult to locate and maintain, particularly on the north shore of the lake. Seining Collections: It was impossible to maintain exact seining stations because of reservoir fluctuations;; however an attempt was made to repeat sampling as near to a designated locality as was possible. Technique was modified somewhat by improved nylon seines during the last two year's work; however the following charts include only data obtained by sampling with bag seines. Most distribution information was obtained in seining collections where population estimates were not attempted, and the following should be regarded as of importance only when considering the most important species present and their interrelationship. --- Page 10 --- MUSTH Buradg 3tTg BUTSSOI5 189ey MOT GAMSAUd ANVD - gUTOg seuor qUTOg UOTYeATESg — - peoy youry oTesuy ueg Fo £47) uotTsspouog Aywnog - uoT#eIg SUTION - N uoT#eIg SUTUTES - § eytnbsey 4PeyVpunutT — y stoquisg Aenysty uepay uroAuasad OTHDNV NVS “OT --- Page 11 --- ll. Seining Collections from San Angelo Reservoir, 1953 - 1954. Species June July August September October March April May June Total Percent SSS Mosquitofish 101 37 ky 112 14 21 32 180 116) 654 25.8 Redhorse shiner 64 16 121 38 111 ) 140 117 «OO 607 23.8 Spottail shiner 31 0) 10 ) ) @) 12 Oo 4 57 aed Golden shiner fe) @) @) ) @) 6) ) 8 14 22 8 Parrot minnow @) fe) ) ) ) ) re) 25 2 27 1.0 Largemouth bass KL 8 ) ) 12 6 13. «O88 2 90 3.4 River carpsucker 0) 0) e) 6) 6) (0) 6) 7 3 10 3 Gizzard shad 100 121 O 12 121 116 y 21 fe) 4.95 19.0 White crappie 6 6 2 fe) @) 25 2 ) @) Tal 1.5 Green sunfish 14 21 4 ek 5 28 13 «#12 12 133 5.2 Western Longear 8 8 h 11 5 5 10.0— 8 (6) 59 2.3 Bluegill 21 11 6 61 28 16 61 31 12 2h7 9.9 Redear sunfish @) 2 ) 2 fe) 2 4 9 4 23 9 Yellowbelly sunfish 9) @) ) 1 0) 1 0 y ) 6 .2 Spotted sunfish fe) y ) ) @) ) 7 Ai. 31 63 2.4 Orangespotted sunfish ) ) 0 ) 5 @) 3 7 6 ean 8 Total 386 «234 8188 261 301 220 301 458 206 2555 99.5 eee --- Page 12 --- Seining Collections from San Angelo Reservoir, 1954 - 1955. Species July August September October November December January March April Total % by Number Mosquitofish 36 100 48 12 8 ) 0 36 25 265 15.22 Redhorse shiner 14h0 =. 90 45 147 12 al 25 12 Xe) 532 30.53 Spottail shiner 12 ) 20 12 0 10 9 0 0 63 3.62 Parrot minnow 8 10 9 al 13 ¢) ) 25 9 95 5.45 Gizzard shad 20 10 30 8 8 14 8 ) 17 115 6.60 River carpsucker 4 ) 4 0 2 9) 9 @) ©) 19 1.09 Largemouth bass 8 4 10 21 ) 2 3 2 12 62 3.56 White bass 9) 9) ) 12 3 2 @) 12 4 33 1.89 White crappie 8 3 14 20 h 2 h ) 2 57 3.27 Channel catfish 1 ) @) 1 @) fe) fe) ) 2 4 223 Green sunfish 27 12 20 30 12 fe) 12 21 11 rs) 8.32 Bluegill 35 14 31 30 18 1h 11 38 28 219 12.57 Redear sunfish 2 2 h 10 ¢) ) 5 5 6 34 1.95 Western longear 12 6 4 4 @) fe) 3 21 2 52 2.98 sunfish Orangespotted sunfish 0 re) 2 fe) (6) 6) 3 fe) 2 7 ite) Yellowbelly sunfish 0 ) 1 6 0 e) 2 20 11 hO 2.30 Total 313 251 2he 334 80 65 94 192 «#4171 1742 100.00 --- Page 13 --- Le Seining Collections from San Angelo Reservoir, 1955 - 1956. ae Species June August October February Total Percent (1953-1956 Total) (1953-1956 Percent) eee Mosquitofish 8 21 20 14 63 8.86 982 19.59 Redhorse shiner ak 36 36 60 156 21.94 1295 25.87 Spottail shiner 0 O ) 0 ) 0.00 120 2.37 Golden shiner 21 1h 21 23 19 11.11 101 2.07 Parrot minnow 20 16 16 25 TT 10.82 199 3.96 Largemouth bass 6 6 10 10 32 451 184 3.67 River carpsucker y 8 6 y 22 3.09 51 1.01 Gizzard shad 6 ) fe) @) 6 85 616 12.30 White crappie 11 11 6 12 Xe) 5.62 138 2.78 Green sunfish 13 5 10 1 29 4.09 307 6.18 Western longear sunfish @) @) @) ) @) 0.00 111 2.28 Bluegill sunfish 14 11 21 28 7h 10.40 540 10.77 Redear sunfish 10 14 31 8 63 8.87 120 2.37 Yellowbelly sunfish © 6 1 2 9 1.24 55 1.09 Spotted sunfish 1 0 2 ) 3 43 66 1.28 Orangespotted sunfish 1 5 5 6 17 2.39 WS .88 White bass 13 5 5 7 30 4.25 63 1.25 Channel catfish 3 5 ) 3 11 1.55 15 .28 eee Total 155 163 190 203 711 100.00 5,008 100.00 --- Page 14 --- 14. Netting Collections: As in seining work exact duplication of netting was impossible except in a few instances. Only the netting stations pertinent in other discussion are shown on the included map. As the charts are regarded as the best available expression of a total interrelationship; populations for the most important species and the apparent ecolog- ical influences upon each species are discussed separately where evidence of such influence was obtained. --- Page 15 --- 15. Netting Collections from San Angelo Reservoir, 1953 - 1954. _ eee Species June July August September October November December January February March May June Total Percentage eee Gizzard shad ) 5 17 21 ) 21 17 67 43 1. (14 31 2h7 14.30 River carpsucker 0 0) 39 5 1 11 111 212 43 17 8 58 505 29.00 Carp ) 2 0 @) ) ) ) ) 8 9 2 9 30 «LT Smallmouth buffalo ©) ©) 0 ©) @) ) © ) 1 0 0 Oo ul .O7 Longnose gar ) ) ) ) ) @) ) ¢) 1 2 1 o 4 .26 Gray redhorse sucker 0 0 ) ©) ) 0 7 5 1 1 ©) 2 16 Oh Freshwater drum 0 ©) 0 @) 0 ) ) ) ©) 0 re) 7 F 4e White bass 0 ) 0) ©) 0) fe) ) 1 0 0 1 0 2 «15 Yellow bullhead @) 0) @) ) ) 0 h ©) ) ) 3 0 7 42 Flathead catfish ) ©) 0 ) 0) 1 (e) ) ) 1 1 1 4 .26 Channel catfish ©) 2 63 2 2 31 7 97 20 28 28 33-313 17.90 Largemouth bass 31 12 14 11 61 28 he 72 17 1k ok 321 18.50 -White crappie y 1 11 2 9 28 38 64 KL whl 19 252 14.60 Sunfishes 0 ) 2 ©) ) 7 fe) y 10 2 9 5 39 30 LLL LL LL LCC LCL LET CLT LATICO ntTtateiennetaananegensaasttsteAatseminetettiitanenententniestinntnanitssnemaetamnemeant Total 35 22 146 Tal 73 127 227 522 185 99 102 1691748 100.00 LC LLL CL COLL CLC EL CAS Cent ECT tcetenttni enna nnn sinensis hhehanthenaaeseni hn tssdnininbenemenisinenemnnsantsin --- Page 16 --- 16. Netting Collections from San Angelo Reservoir, 1954 - 1955. Species July August September October November December January February March April Total Percentage Gizzard shad 14 ) 21 ho ak 37 35 kg 99 33-352 25.99 River carpsuckers 31 13 1h 34 70 87 119 68 17 56 «499 36.89 Carp ) 0 0 ) ) 0 3 fe) 1 0 h 30 Gray redhorse suckers 0 fe) ) ) ) @) 3 1 fe) ) Ty 30 Freshwater drum ) ) 8 0 6 4 5 3 8 2 36 2.66 Yellow bullhead 0 0 ) 9) 0 ©) 1 ¢) ) 0 1 07 Largemouth bass 21 5 6 h ) 2 2 12 0 2 54 3.69 White bass ) ) 9 @) ) 2 9) he 3 9) 18 1.33 White Crappie 30 21 fe) 21 15 12 6 20 a O 126 9.30 Longnose gar ) ) ) 3) ) @) 9) 1 1 8) 2 147 Channel catfish y 12 18 13 ) 11 2 36 15 19 130 6.90 Sunfishes ) 60 19 12 1 fe) 2 21 1 1 128 9.50 Total 100 111 95 12h 106 167 176 196 166 113 1354 100.00 --- Page 17 --- LT Netting Collections from San Angelo Reservoir. eee Species May June October February March Total Total Total Total Percentage . 1953-54 1954-55 1955-56 1953-56 Gizzard shad 33 22 hg 99 66 2h7 352 269 826 21.71 River carpsucker 56 119 68 17 56 505 4.99 316 1324 34.81 Carp ) 3 ) 1 6 30 y 10 yy 1.15 Smallmouth buffalo ) fe) @) 0) 1 1 fe) 1 2 .05 Longnose gar fe) @) 1 2 ) 4 2 3 9 2 Gray redhorse sucker 0O 3 1 fe) 0 16 y y eh .63 Freshwater drum 2 5 3 8 3 4 36 21 62 1.64 White bass @) 6 h 3 8 2 18 21 4 1.08 Yellow bullhead 6) L 0) (@) 6) 7 el 1 9 023 Flathead catfish ) fe) ) ) @) 4 9) ) 4 10 Channel catfish 19 2 36 15 h 313 130 76 500 13.14 Largemouth bass 2 2 12 @) ) 321 54 16 389 10.22 White crappie ) 6 20 2 1 252 126 29 OT 10.71 Sunfishes i @) 2 2 2 39 128 7 162 4.29 ee a a ae ee ee ne eee Total 113 «169 196 149 146 1748 1354 773 3803 100.00 nent --- Page 18 --- go" t 62° 0S°6 Ga" Zk’ 0S° 69° 90° Zot soystyung €S°TT TL°OT 0€'°6 LS° HT oT’ Lh 0S°2 19°9 OT’ TT LOW etdder. 347M 19° H e°ot 69°€ 0S°gT ZQ°e 00°€ gS°9 49°Z 6gE sseq YyNowses1eT Se" BO°T €€°T ST° TEE 00°€ €6°9 To" Th sseq 39 TUM ZT° OT’ 00°0 93° €o° 00°0 00°0 60° + ystsyso peeyyeTd 9$°ST HT°ET 06°9 26° LT HE'S SL°8 09°9 19° 00S ystyzeo [eumeyp +2" €2° 10° ay’ 9f° 00°0 LL° €o° 6 peeyTINg MOTTOEZ LS°T 49°T 99° on’ €e°t oo°€ 4S°2 ZO° rte) wip 1e;emysel 7s 99° 12° Lae T 9a" go°T SL° fay 0° 6 IeZ esousu0T +0" So” 00°0 10° 00°0 00°0 00°0 To’ z oTesgng YyNouTTeug +S° ST°T o€° La SE°2? GL°S €6° ge: try diep Z9° €9° o€° 46° gr" SL° en’ 12° qZ <deyons esroyper ferp LG°€€ Tene 6Q°9E 10°62 2°29 0S°9% Ze°l9 00° 2) HZET Leyonsdieo JeATYy 99° 02 TL*Te 66°S2 62° HT 99°ST Ga°L2 68°9 SQ° at 928 peys prezzty sosercay 9G-SG6T SS-4yS6T 4S-ES6T eBereay 9G9-GG6T SS-yS6T 4S-ES6T sTenpTATpuL (zequny fq %) suostzeduop Teotzeumy (7usTEM Aq 4%) suostseduoDn 1VYysTOM ° ON soetoeds °ITOALSsSay oTesuy weg roy suotTyetndog ysty Tedtoutag uo eyeq eat .eredwuo0g “OT --- Page 19 --- 19. Comparative Physical Condition of Principal Species of Fish in Sam Angelo Reservoir. 1953-5 1954-55 L955=5 Total "K" Range Avg. "K" No. "K" Range Avg."K" No. "K" Range Avg."K" No. Species No. Gizzard shad 60 1.51-3.12 1.69 80 1.60-210 1.85 34 1.62-2.08 1.84 17h 64.58 1.79 River carpsucker 98 2.03-2.78 2.47 105 2.32-2.64 2.64 hO 2.28-2.60 2.5k 243,50 «6.39 2g Carp 30 2.32-2.71 2.54 y 2.46-2.64 2.60 4h =-2.64-2.69 2.66 38 99 2.60 Smallmouth buffalo 1 2.56 2.59 ) ) ) 1 3.64 3.64 2 06 2.08 Longnose gar 4 2.08 2 °351- 0351 2 2332 >» 332 8 2h 62.94 Gray redhorse sucker 16 2.13-2.85 2.31 4 2.22-2.32 2.27 4 -2.2h-2.30 ©6226 eu. :72 2.28 Freshwater drum 7 2.08-2.50 2.21 6 2.38-2.42 2.40 6 2.31-2.32 2.28 19 49 2.29 Yellow bullheads 7 2.24-2.69 2.47 L 2.10 2.10 1 2.30 2.30 9 25 2.29 White bass 2 0 2.04 18 2.10-2.28 2.23 21 2.30-2.54 2.h0 Ay 1.01 2.22 Flathead catfish y 2.18-2.49 2.22 ) ¢) ) ¢) 0 re) i 12 2.22 Channel catfish 110 + 1.86-2.42 2.18 16 1.88-2.08 1.97 2h 2.08-2.19 2.09 150 3.94 2.07 Largemouth bass 31202. 72-3.84 2.84 7 2.82-3.10 2.92 8 2.7h-2.90 2.82 327 «68.59 2. 86 White crappie 192 =2.13-3.69 2.73 hO }=—2..22-3.64 3.37 7 2.88-3.10 2.90 239 6.34 3.00 Sunfishes (Lepomis) 34 3.00=3.70 3.25 21 3.2h-4.18 4.08 4 -3,52-3.68 3.62 59 1.55 3.65 --- Page 20 --- 20. LOCALITIES HAVING HIGH PERCENTAGES OF GAME FISH IN SAN ANGELO RESERVOIR Largemouth Bass White Bass Largemouth Bass were concentrated along White Bass were taken almost exclusively the cleared sections of the north shore, near the river mouth in the ol d near and in Pot's creek, and where the Pullham Crossing Area. excavation for dam construction created a submerged bank. Channel Catfish were most dense in concentration in the upper lake and along the north shore near the old river channel. White Crappie were very numerous near the islands, along the north shore where mesquite thickets were inundated and near the river mouth Channel Catfish White Crappie --- Page 21 --- al. STOMACH ANALYSIS The following data are included as resulting from the analysis of stomachs containing food; however its reliability may be questioned because of the tendency of several species notably largemouth bass and longnose gar to regurgitate their sto- mach contents when captured in gill nets, or when held in live boxes pending exam- ination. It is considered probable that for some species the small number of stom- achs containing food are inadequate to express the importance of the various food types. The following is on a volumetric displacement basis. Stomach Contents for Principal Species White Bass No. Fish Shad Fish Remains Insects Crustaceans Others Stomachs Examined % 38 Kl 87 12 1. trace silt Largemouth Black Bass 63 80 36 38 16 4 6 White Crappie 84 204 52 11 29 i. 7 Southern Channel Catfish No. Fish Shad Fish Remains Insects Sunfish Algae Others Stomachs Examined Grain 44% 52 118 26 13 13 11 29 Silt and debris A% As shown in the preceding data 443 individual fish were opened for exam- ination of stomach content, gonadal development, and for the existence of internal parasites. Of this sample 247 stomachs were found to contain food. Shad were the most common food for most species and insects were apparently more important than observed in other reservoirs. POPULATION TRENDS AND INFLUENCES White Bass. All evidence obtained during inventory indicated an increasing trend toward dominance by white bass. Apparently the continuous decline in the res- ervoir level did not prevent that species from reproducing successfully as juvenile fish were taken in both netting and seining collections during the last eighteen months prior to completion of field activities. These fish were observed spawning or con- gregating when run-off occurred in the early spring, and were more common in sports- men catches after the first year's work. --- Page 22 --- 22. Largemouth Bass. It is believed that the annual fluctuation of the lake level as anticipated by hydrologists with the U. S. Corp of Engineers and as resulting from the adapted plan for reservoir operation will be sufficiently detrimental to prevent a continuous and successful propagation by this species. As shown in netting and seining collections largemouth bass were reduced during inventory from the most numerous game species to a position of relative unimportance. Seining collections indicated meager spawning activity by this species in the last two years of inventory and sexual development and condition of individuals taken indicated that a relatively low percentage of sexually mature individuals actually spawned during that period. Of 2,237 largemouth bass tagged with mandible tags and released during inventory only six individuals have been recaptured or otherwise recovered. No pertinent data has been obtained from these recovered fish. With the exception of two individuals that were found dead and washed ashore by wave action within thirty-six hours after their release, all fish recovered were taken by sportsmen and had been cleaned before they were exam- ined by Commission personnel. Since caution and reasonable precautions were taken to prevent damage to tagged individuals, it is believed that this type tag is unsatis- factory for this particular study. White Crappie. It is believed that seining and netting collection data do not provide for a proper evaluation of the importance of this species, and this con- tention is supported by creel data. As previously explained under those sub-headings exact duplication of seining and netting collection work was prevented by fluctuation of the reservoir level. Apparently white crappie congregated along the north shore of the reservoir where dense inundated concentrations of mesquite prevented adequate sampling by the methods employed. In the few areas where sampling was possible, a significantly greater number of these fish were obtained. Spawning apparently occurred from late February to April, and as shown in stomach analysis data, fall insects may have a highly significant influence on the rate of growth and sexual development for individuals of this species. Sunfishes (all Lepomis). Of the seven species of sunfish and possible two common hybrids taken during inventory, no species had established what could be termed a permanant dominance, although seining data indicated a trend toward dominance by bluegill sunfish. As discussed in the completion report for the creel census conducted on this reservoir, only during the first eighteen months of inventory were sunfish taken of sufficient size to provide sport and food. Since that time data available indicated that from a utilization standpoint sunfishes in the lake should be regarded in a forage capacity rather than as game fish. Spawning by this group was believed to be from late spring until frost, however fish were observed on or near nests through- out the year. Southern Channel Catfish. As shown in netting and seining collection data channel catfish are statistically the most important game species in San Angelo Res- ervoir following inventory. Condition of this population is regarded as favorable when reservoir conditions are taken into consideration, and apparently reproduction was successful during the spawning periods. Creel data supports this result in sampling. Gizzard Shad. Shad were the most important forage species for all the princi- pal game species in the reservoir, and as such are of basic importance. There is not sufficient data at present to correlate successful reproduction of this species and condition of the principal game species, nor is there adequate data to illustrate the importance of spring run-off and spawning by shad. However all data and evidence obtained during inventory indicated the possibility of such interrelationships and their potential importance on any proposed management effort. --- Page 23 --- 23. River Carpsuckers. Apparently these fish were the most unaffected of any species by reservoir conditions during the inventory period. Condition of this pop- ulation remained greater than "K" values for populations of the same species in other reservoirs and streams. There was an obvious trend toward dominance of this reservoir by these fish. Individuals in advanced stages of sexual development were taken in almost every netting collection, and spawning activity was believed to have occurred immediately following every significant increase in the reservoir capacity. The utility of this species as forage is believed to be insignificant as-none of these fish or identifiable portions of any individual were recovered from the stomachs of the game fish examined, nor is there any known reliable market for these fish when taken commercially. Other Species. Of the remaining species taken during inventory only members of the genus Notropis are of significance in the data obtained. Apparently these shin- ers were of increasing importance as forage, as the number of individuals encountered in stomach analysis increased toward the end of field work. Since the reservoir and much of the contributing watershed were treated with rotenone to remove the existing fish populations prior to impoundment of significant run-off, it is believed that these species were introduced from the extreme upper watershed and/or possibly by bait deal- ers. None were used by hatchery personnel in the restocking program. Gray redhorse suckers decreased during inventory and carp increased numerically. Other species, as longnose gar, freshwater drum, and smallmouth buffalo were too infrequent to be of any apparent importance in considering the reservoir populations. RECOMMENDATIONS 1. No recommendations for constructive action are made at this time because fishing results remain favorable, as indicated by creel census, and because no effec- tive methods are known that might be employed to correct the detrimental conditions that exist. 2. Should an effective control be found for river carpsuckers, it is recom- mended that such a device and/or procedure be employed to curb, control, or eradicate the population of that species. 3. It is recommended that the reservoir be re-surveyed in a period of three to five years, or as may prove practical or expedient. . Prepared by Lawrence S. Campbell Approved by 7 Lrateores ole Project Leader Chief Aquatic Biologist Date July 22, 1957 --- Page 24 --- Tam et Ate H