TPWD 1965 F-6-R-12 #995: Fisheries Investigations and Surveys of the Waters of Region 5-B: Job No. B-20 Fisheries Reconnaissance

--- Page 1 --- JOB COMPLETION REPORT As required by FEDERAL AID IN FISHERIES RESTORATION ACT Federal Aid Project No. F-6-R-12 FISHERIES INVESTIGATIONS AND SURVEYS OF THE WATERS OF REGION 5-B Job No. B-20 Fisheries Reconnaissance Project Leader: Charles T. Menn J. Weldon Watson Executive Director Parks and Wildlife Department Austin, Texas Marion Toole Eugene A. Walker D-J Coordinator Assistant Director for Wildlife January 18, 1965 --- Page 2 --- ABSTRACT Seven lakes and a part of the San Antonio River were visited during this segment to see if any appreciable changes in the fish populations had occurred since the previous survey. Blue catfish (Ictalurus furcatus), the only game fish species, comprised 17.24 per cent of the total number and 6.97 per cent of the total weight of the fish taken in the nets in Harlingen City Lake. There appeared to be a re- lative decrease in the game fish, both in numbers and in weight. In Bentsen State Park Lake, rough fish species including spotted gar (Lepisosteus productus), smallmouth buffalo (Ictiobus bubalus), bluegill (Lepomis macrochirus) and Rio Grande perch (Cichlasoma cyanoguttatum) were dominant both in numbers and in weight with 86.36 per cent and 94.31 per cent, respectively. Rough fish, primarily bluegill and gizzard shad (Dorosoma cepedianum) are dominant in Fort Brown Lake Despite their predominance, the bass and catfish are in good condition. Rough fish species including alligator gar (Lepisosteus spatula), spotted gar, longnose gar (Lepisosteus osseus), threadfin shad (Dorosoma petenense), gizzard shad, carp (Cyprinus carpio), freshwater drum (Aplodinotus grunniens) and Rio Grande perch comprised 94.85 per cent of the total number and 95.55 per cent of the total weight of fish taken in Llano Grande Lake. Game fish species showed a relative increase both in numbers and in weight in Campacuas Lake. The game fishes include channel catfish (Ictalurus punctatus), blue catfish, warmouth (Chaenobryttus gulosus), white crappie (Pomoxis annularis) and black crappie (P. nigromaculatus). In Delta Orchards Lake, near Monte Alto in Hidalgo County, game fish species including channel and blue catfish and freshwater drum showed a relative de- crease both in number and in weight. Rough fish species including spotted and longnose gars, gizzard shad, grey redhorse (Moxostoma congestum), yellow bullheads (Ictalurus natalis) and Rio Grande perch were dominant both in numbers and in weight in the San Antonio River. The blue catfish population showed a relative increase in numbers in Lake Corpus Christi. Otherwise, there were no significant changes in the fish pop- ulation. Water hyacinth control work on Lake Corpus Christi should be continued. However, no other developmental or management work is recommended. --- Page 3 --- JOB COMPLETION REPORT State of Texas Project No. _F-6-R-12 Name: Fisheries Investigations and Surveys of the Waters of Region 5-B Job No. B-20 Title: Fisheries Reconnaissance Period Covered: January 1, 1964 through December 31, 1964 __ Objectives: To obtain current information concerning gross changes in fishing con- ditions, and to obtain current information regarding factors influencing fish populations. Techniques Used: Standard, 125-foot long, gill nets and common sense minnow seines were used to sample fish populations. The gill nets consisted of nylon webbing, 8 feet deep, with five 25-foot long sections of 1-, 1%-, 2-, 2%- and 3-inch square mesh. Nets were set overnight at previously established netting stations and fish specimens were taken from them the following morning. The netted specimens were weighed in grams and measured in millimeters in the field, Sex and sexual de- velopment and the occurrence of parasites in the individual specimens were re- corded. Seined specimens were preserved and taken to project headquarters at Mathis for identification. A list of the common and scientific names of fish species taken during this study is included as Table l. Routine water quality analyses were made on the various lakes and a limited check was made of the surrounding area of each lake to determine land usage and possible sources of pollution. The water level data for Lake Corpus Christi were obtained from officials at Wesley Seale Dam. Fisherman usage of the various lakes was determined by talking to camp owners, game wardens and sometimes to fishermen. Public access is available to all the lakes and rivers studied in this segment. --- Page 4 --- -2- Table 1. Checklist of species referred to in text and tables. Common name Alligator gar Spotted gar Longnose gar Threadfin shad Gizzard shad Mexican tetra Smallmouth buffalo Grey redhorse Carp Pugnose minnow Tamaulipas shiner Red shiner Bullhead minnow Flathead minnow Channel catfish Blue catfish Black bullhead Yellow bullhead Flathead catfish Tadpole madtom Blackstripe topminnow Sheepshead minnow Mosquitofish Sailfin molly Amazon molly Striped mullet Tidewater silverside White bass Largemouth bass Warmouth Redear sunfish Bluegill White crappie Black crappie Freshwater drum Rio Grande perch Naked goby Scientific name Lepisosteus spatula Lacépede L. oculatus (Winchell) L. osseus (Linnaeus) Dorosoma petenense (Giinther) D. cepedianum (LeSueur) Astyanax mexicanus (Filippi) Ictiobus bubalus (Rafinesque) Moxostoma congestum (Baird and Girard) Cyprinus carpio Linnaeus Opsopoeodus emiliae Hay Notropis braytoni Jordan and Evermann N. lutrensis (Baird and Girard) Pimephales vigilax (Baird and Girard) P. promelas Rafinesque Ictalurus punctatus (Rafinesque) I. furcatus (LeSueur) I. melas (Rafinesque) I. natalis (LeSueur) Pylodictus olivaris (Rafinesque) Schilbeodes gryinus (Mitchill) Fundulus notatus (Rafinesque) Cyprinodon variegatus Lacépéde Gambusia affinis (Baird and Girard) Mollienisia latipinna LeSueur M. formosa (Girard) Mugil cephalus Linnaeus Menidia beryllina (Cope) Roccus chrysops (Rafinesque) Micropterus salmoides (Lacépéde) Chaenobryttus gulosus (Cuvier) Lepomis microlophus (Gunther) L. macrochirus Rafinesque Pomoxis annularis Rafinesque P. nigromaculatus (LeSueur) Aplodinotus grunniens Rafinesque Cichlasoma cyanoguttatum (Baird and Girard) Gobiosoma bosci Lacépéde --- Page 5 --- Findings: Harlingen City Lake This 20-acre lake is located in downtown Harlingen and is the city's water supply reservoir. Water in the lake originates from the Rio Grande River and reaches the lake through a system of gravity flow irrigation canals. Public angling is permitted on this lake without restrictions or limita- tions, but little fishing is done due to the sizable rough fish population. Netting - Three netting collections were made on this lake in February. All told, 29 fish of five species were taken (Table 2). The game fish species included blue catfish (Ictalurus furcatus) only. Channel catfish (Ictalurus punctatus), white bass (Roccus chrysops), largemouth bass (Micropterus salmoides) and white crappie (Pomoxis annularis) and black crappie (P. nigromaculatus) were all taken in previous surveys but none were found in this survey. Table 2. Results of gill netting, Harlingen City Lake, February, 1964 Species Numbers Per Cent of Per Cent of Taken Number ) ) | Total Weight Longnose gar ‘ a 32 a Gizzard shad 34. 3 5. Smallmouth buffalo ‘ ; 49. Blue catfish* Freshwater drum Per Cent Game Fish Per Cent Rough Fish * Indicates game fish On the basis of the limited netting data, game fish showed a relative de- crease both in numbers and in weight. In 1963, game fish species comprised 22.54 per cent of the total number and 3.64 per cent of the total weight as compared to 17.24 per cent of the number and 6.97 per cent of the weight in 1964. Gizzard shad (Dorosoma cepedianum), freshwater drum (Aplodinotus grunniens), longnose gar (Lepisosteus osseus) and smallmouth buffalo (Ictiobus bubalus), in --- Page 6 --- that order, were the most abundant rough fish species taken. Collectively, they comprised 77.46 per cent of the total number and 96.36 per cent of the total weight of the fish netted. The length-weight statistics of the fish taken in nets are shown in Table 3. The average "K" factors are in line with those of the 1963 recon- naissance survey. Table 3. Length-weight statistics of fish taken with gill nets, Harlingen City Lake, February, 1964 Standard length (mm. Range __Average. Longnose gar 435-860 281-2778 Gizzard shad 163-198 84-168 Smallmouth buffalo | 403-531 Blue catfish 258-292 239-421 Freshwater drum 185-240 145-365 Seining - Seining collections were made at two stations. All told, 152 fish of 7 species were taken in the seining collections (Table 4). Mosquito- fish (Gambusia affinis), red shiners (Notropis lutrensis) and tidewater silver- sides (Menidia beryllina), in that order, comprised 95.40 per cent of the total number. The most noticeable change concerned the threadfin shad (Dorosoma petenense); they comprised less than 1 per cent by number as compared with more than 40 per cent in 1963. This apparent "reduction" is probably due to a seining error. Table 4. Seining results, Harlingen City Lake, February, 1964 Per Cent of Total Number Threadfin shad Red shiner Flathead minnow Mosquitofish Amazon molly Tidewater silverside Naked goby --- Page 7 --- Lake Conditions - Submerged vegetation is lacking due to the turbidity. Shoreline vegetation, however, consists mainly of bulrushes mixed with a few cattails. Secchi disc readings of light penetration ranged from 11 to 13 inches. It is believed that the turbidity is caused by bottom-feeding fishes which keep silt in suspension rather than the prevailing southeasterly wind. Recommendations - Fishermen should be encouraged to fish for catfish and crappie. A commercial fisherman might be necessary and desirable to harvest the rough fish in the near future. Bentsen State Park Lake Netting - Three gill netting collections were made on this lake in May, 1964. The second check, scheduled for November, was not made due to the extremely low water conditions. There were only a few areas where the water was as much as two feet deep. A total of 22 fish of five species was taken in the netting collections. Rough fish species, including spotted gar (Lepisosteus oculatus), smallmouth buffalo, bluegill (Lepomis macrochirus) and Rio Grande perch (Cichlasoma cyanoguttatum) were dominant both in number and in weight (Table 5). The only game fish species taken in the nets, warmouth (Chaenobryttus gulosus), comprised less than 15 per cent of the total number and 5.69 per cent of the total weight. Table 5. Results of gill netting, Bentsen State Park Lake, May, 1964 Numbers Per Cent of Weight Per Cent of Species Taken Total Number ‘pounds Total Spotted gar Smallmouth buffalo Warmouth* Bluegill Rio Grande perch Per Cent Game Fish Per Cent Rough Fish ole mas Indicates game fish --- Page 8 --- Seining - The seining results are shown in Table 6. Mosquitofish and threadfin shad comprised 93.02 per cent of the total number of fish taken. Though there is a good supply of forage fish, it appears that there are few bass and crappie in the lake to crop them. Table 6. Results of seining, Bentsen State Park Lake, May, 1964 Numbers Per Cent of Taken Total Number i) MOoonaoancodaeo Threadfin shad Gizzard shad Red. shiner Sheepshead minnow ~ Mosquitofish Tidewater silverside Bluegill Rio Grande perch The length-weight statistics are shown in Table 7. No appreciable changes were noted for any species. Table 7. ‘Length-weight statistics for fish taken with gill nets, Bentsen State Park Lake, May, 1964 Standard Length mm. Weight (grams "K" Factors Species Spotted gar 479-494 | 0.65-0.82 Smallmouth buffalo | 490-490 4.81-4.81 Warmouth 147-165 142-224 4.46-4.98 Bluegill 94-112 32-59 3.56-4.57 Rio Grande perch 69-144 14-113 3.73-5.20 Lake Conditions - The water level has been extremely low all year. The upper portion of this oxbow lake is dry, but a total of approximately 10 acres of water still remainsin the lake. By November, the lake had gone down even lower than it was in May. For that reason the lake was not checked as originally planned. --- Page 9 --- Recommendations - Since the water level is so erratic, no management or developmental work is proposed or planned. Should a more favorable water supply become available, some management work should be initiated. Fort Brown Lake This 33-acre lake, located in downtown Brownsville, was drained in the spring of 1962, dredged in the summer of that same year and refilled in the fall. The water used in refilling the lake came from the Rio Grande River and contained many undesirable fishes. Therefore, the lake was treated with rotenone to remove all fishes. The state fish hatchery near Brownsville stocked a large number of largemouth bass fingerlings in December, 1962. Netting - Four gill netting collections were made in February, 1964, and took a total of 162 fish of 7 species (Table 8). Of the seven species, three were classed as game fish (channel catfish, white bass and largemouth bass). All told, the game fish species comprised 16.66 per cent of the total number and 37.64 per cent of the total weight. Table 8. Results of gill netting, Fort Brown Lake, February, 1964. Numbers Per Cent of Per Cent of Species Taken Total Number Total Weight Threadfin shad Gizzard shad Channel catfish* White bass* Largemouth bass* Bluegill Rio Grande perch Totals Per Cent Game Fish Per Cent Rough Fish * Indicates game fish The most noticeable change in the fish population since the 1963 check is the presence of rough fish. None were found in the 1963 check, but this year they comprised 83.34 per cent of the total number and 62.36 per cent of the total weight. Doubtless, these fish entered the lake from the Rio Grande which is its main source of water. --- Page 10 --- The length-weight statistics are presented in Table 9. All values are considered normal for fishes in this area of Texas. Table 9. Length-weight statistics of fish taken with gill nets, Fort Brown Lake, February, 1964 Standard Length | mm Weight (grams Species '’" Factors Threadfin shad 119-145 51-78 63 Gizzard shad 187-288 237 163-652 328 Channel catfish 270-388 335 391-1247 840 White bass 205-244 222 306-567 436 Largemouth bass 155-331 241 94-1049) 473 Bluegill 92-111 100 29-67 46 Rio Grande perch 127-127 112-112 Seining - One seining collection was made and took 22 fish of four species (Table 10). Bluegills and mosquitofish, in that order, comprised 90.90 per cent of the collection. One specimen of largemouth bass, approximately 3 inches in length, was taken and indicated that the bass had spawned. In addition to the fish, 46 freshwater shrimp (Palaemonetes sp.) were taken in the collection. Table 10. Seining results, Fort Brown Lake, February, 1964 Per Cent of Total Number Mosquitofish Largemouth bass Bluegill Rio Grande perch Lake Conditions - Secchi disc readings ranged from 19 to 28 inches, as com- pared with 60 to 82 inches a year earlier. This noticeable change is almost certainly due to the abundance of rough fish, most of which are bottom feeders. The higher turbidity should aid in the prevention of excessive submerged vegetation. --- Page 11 --- Chemical analysis of a surface water sample revealed the following: dis- solved oxygen 3.9 p.p.m., carbon dioxide 0.8 p.p.m., pH 8.8, and methyl orange alkalinity 130.0 p.p.m. Recommendations - A selective shad kill would probably be in order within the near future. It would be beneficial to the small game fish. If the sub- merged vegetation becomes worse, control measures will be recommended. Llano Grande Lake Llano Grande Lake, approximately 250 acres in size, is located 5 miles south of Weslaco in Hidalgo County, Texas. Formerly, it was an old stream bed of the Rio Grande River. Reconnaissance surveys were made in April and September, 1964. Each survey consisted of six gill netting collections and one seining collection. Generally, public access is limited to the road crossings, but public angling is permitted without additional local restric- tions. Netting - Twelve gill netting collections were made on this lake. A total of 466 fish of 14 species was taken in the netting collections (Table 11). The game fish species included channel catfish, white bass, largemouth bass, warmouth, white and black crappie. All together, they comprised 5.15 per cent of the total number and 4.45 per cent of the total weight. Table 11. Results of gill netting, Llano Grande Lake, April and September, 1964 Per Cent of Per Cent of Total Number _| Total Weight Alligator gar 1 21 4 60 Spotted gar } 15 22 34 12.24 Longnose gar 2 43 3 35 Threadfin shad 21 51 3 35 Gizzard shad 75 16.09 43 15.33 Carp 39 .37 127. 45.39 Channel catfish* 6 10 | White bass* 21 1 Largemouth bass* 4 Warmouth bass* 7 White crappie* 1 Black crappie* 5 Freshwater drum Ll 8 Rio Grande perch 28 FPOoOrOrOOFRAaADFOWO ie) Ne} OFFS DUNOODFrF AAU NODVODVOVOON UNF RNEH bo oO N Be ONOONNEF WU Per Cent Game Fish Per Cent Rough Fish * Indicates game fish --- Page 12 --- -10- Of the total fish netted, game fish showed a relative increase both in numbers and in weight. In 1963, they comprised 3.70 per cent of the number and 4.20 per cent of the weight as compared with 5.15 per cent of the number and 4.45 per cent of the weight in 1964. Rio Grande perch, gizzard shad, and carp (Cyprinus carpio) are the most abundant rough fish present. All together, they comprised 86.27 per cent of the total number and 78.16 per cent of the total weight. These findings are in line with those of the 1963 survey. The length-weight statistics are presented in Table 12. Spotted gar, threadfin shad, gizzard shad, and warmouth showed slight decreases in ''K" factors, while carp, channel catfish and Rio Grande perch showed increases in "K" factors. Table 12. Length-weight statistics of fish taken with gill nets, Llano Grande Lake, April and September, 1964 eel sht (grams "Kt Flee eee Species Range — Range | Range _ Average | e Range | Range Average | Alligator gar - 2055-2055 Spotted gar - 822-1389 Longnose gar - 465-1276 Threadfin shad - 38-318 Gizzard shad - 144-936 Carp - 57-3600 Channel catfish - 61-2268 White bass - 442-442 Largemouth bass - 217-334 Warmouth - 59-221 White crappie - 159-159 Black crappie - 57-138 Freshwater drum - 1106-1106 Rio Grande perch - 29-198 WWWWWNWENFFr OOO MbWWWHNnNWFrWNHNMOO EO Seining - The seining results are shown in Table 13. The two collections, one was made in April and the other in September, 1964, took a total of 971 specimens of 8 species. Mosquitofish and threadfin shad comprised 91.24 per cent of the total number taken. Both Mexican tetra (Astyanax mexicanus) and red shiners were abundant in the 1960 collections, but were lacking again in this survey. --- Page 13 --- =[1- Table 13. Seining results, Llano Grande Lake, April and September, 1964 Number Per Cent of Species Taken Total Number Threadfin shad 140 14.42 Mexican tetra L 0.10 Red shiner 1 0.10 Sheepshead minnow 30 3.09 Mosquitofish 746 76.82 Sailfin molly L 0.10 Tidewater silverside 41 4.23 Rio Grande perch 11 1.14 Total 971 100.00 Lake Conditions - Twelve Secchi disc readings were recorded on Llano Grande; they ranged from 4 to 11 inches, with a mean average of 8 inches. This comparatively shallow lake coupled with the thick silt bottom and numerous rough fish keep the turbidity high. Bulrushes and cattails are numerous around the shoreline of the lake. But, these plants are not considered a problem. A few water hyacinths have been observed in the past, but none were seen during this survey. Dissolved oxygen ranged from 5.1 to 6.4 p.p.m., carbon dioxide ranged from 1.2 to 2.0 p.p.m., methyl orange alkalinity from 175.0 to 190.0 p.p.m. and pH from 8.0 to 8.2. Recommendations - In view of the high turbidity and nature of the stream, no developmental work is proposed or recommended. A commercial fisherman should be allowed to harvest unlimited numbers of rough fish so long as state and local regulations are complied with. Campacuas Lake Campacuas Lake is located in the same floodway as Llano Grande and covers an area of approximately 120 acres. The lake is located between Weslaco and Mercedes in Hidalgo County, Texas. Netting - Eight gill netting collections were made on this lake in April and September. A total of 149 fish of 14 species weighing 189.1 pounds was taken in the netting collections (Table 14). The game fish species included channel and blue catfish, warmouth, white and black crappie. --- Page 14 --- if Fe Table 14. Results of gill netting, Campacuas Lake, April and September, 1964 ster | Species Taken Per Cent of Total Weight Per Cent of Total Number Alligator gar 4 14.1 Spotted gar 40 84.0 44, Threadfin shad 6 0.5 Gizzard shad 38 11.0 Smallmouth buffalo 3 9.2 Carp 9 13.0 Channel catfish* 9 17.5 Blue catfish* 1 4.6 Striped mullet 2 3.8 Warmouth* 13 2.3 White crappie* 4 Le Black crappie* 1 0.2 | Freshwater drum 14 27.4 Rio Grande perch 5 0.3 Per Cent Game Fish Per Cent Rough Fish * Indicates game fish Since the 1963 survey, game fish species showed relative increases both in number and in weight. In 1963, they comprised 3.75 per cent of the total number and 1.11 per cent of the total weight as compared to 18.78 per cent of the number and 13.64 per cent of the weight in 1964. This "change" in large part is due to the fact that more data are available from the 1964 survey and that the state fish hatchery stocked a sizable number of crappie in the lake. The length-weight statistics are presented in Table 15. Since the 1963 check, there appears to be a relative increase in the average "K" factors of the gizzard shad and smallmouth buffalo. But there appears to be a relative decrease in the average "K'"' factors of the channel catfish, warmouth and freshwater drum. Otherwise, the average "K" factors appear to be the same. --- Page 15 --- Table 16. total numbers taken. collections. Table 15. -13~- Lake, April and September, 1964 aes SCS CCO!™!™*~=<‘“‘ _S™SOSOC;.CCC.....OCOtw#é‘C(SSS!!!CS | Standard Length (mm. ) Alligator gar Spotted gar Threadfin shad Gizzard shad Smallmouth buffalo Carp Channel catfish Blue catfish Striped mullet Warmouth White crappie Black crappie Freshwater drum Rio Grande perch Seining - Table 16. | 318-893 | 336-610 126-135 122-276 280-382 157-352 193-418 438-438 307-335 106-162 152-162 144-144 181-360 94-100 548 508 130 206 322 261 329 438 321 122 156 144 291 98 Length-weight statistics of fish taken with gill nets, Campacuas Numbers Taken Weight (grams) "K" Factors Range Average 251-7598 2718 0.78-1.06 0.90 115-2041 1068 0.61-0.92 0.77 39-49 43 1.74-2.33 1.96 31-417 190 1.52-2.02 1.78 879-2296 1389 3.53-4.11 3.88 120-1361 658 2.82-3.68 3.08 111-2041 882 |; 1.49-2.16 1.85 2098-2098 2098 2.49-2.49 2.49 737-992 865 2.54-2.63 | 2.59 22-184 79 3.19-4.55 3.91 | 115-158 134 | 3.27-3.71 3.51 | 103-103 103 3.44-3.44 3.44 159-1505 887 2.58-2.58 2.58 36-43 40 4.10-4.43 4.28 Two seining collections were made; the results are shown in Sailfin molly (Mollienesia latipinna), threadfin shad, and pugnose minnow (Opsopoeodus emiliae), in that order, comprised 86.89 per cent of the All told, 648 fish of 12 species were taken in the two Seining results, Campacuas Lake, April and September, 1964 Per Cent of Total Number Threadfin shad Mexican tetra Tamalipas shiner Red shiner Mosquitofish Tidewater silverside Bullhead minnow Pugnose minnow Sheepshead minnow Sailfin molly Rio Grande perch Naked goby 185 117 261 10 i) = ODFONADOWONOO ~~ ron ~ --- Page 16 --- “then Lake Conditions - Eight Secchi disc readings were taken; they ranged from 5 to 10 inches with a mean average of 7 inches. Strong, southeasterly winds, coupled with the thick silt bottom and numerous rough fish, keep the turbidity high. As a result, submerged vegetation is not a problem. Shoreline vegetation consists of bulrushes and cattails. Recommendations - A commercial fisherman should be allowed to crop the rough fish. No developmental work is proposed or recommended. Delta Orchards Lake Delta Orchards Lake, a 2,200 acre surface irrigation reservoir near Monte Alto, is a part of the Hidalgo and Willacy County Water Control and Improvement District No. 1. The reservoir contains approximately 20,000 acre-feet of water which is used to irrigate nearly 70,000 acres of farm land. Most of the water comes from the Rio Grande River via a system of gravity flow irrigation canals. Public angling is permitted for a 25-cent fee per person per day. But trotline fishing is prohibited except to certain persons who are issued special permission. Netting - In May and November, 1964, 10 netting collections took a total of 128 fish of 9 species (Table 17). The game fish species taken in the nets included channel and blue catfish, and freshwater drum. Normally, the drum is considered a rough fish species here in south Texas, but it is classed as a game fish in this case because anglers at Delta Orchards Lake harvest them in large numbers the year around. Table 17. Results of gill netting, Delta Orchards Lake, May and November, 1964 Per Cent of i Per Cent of Total Number Total Weight Spotted gar Longnose gar Gizzard shad Smallmouth buffalo Carp Channel catfish* Blue catfish* Striped mullet Freshwater drum* 8 6 4 4 al, 6 «9 a9 wll Per Cent Game Fish Per Cent Rough Fish * Indicates game fish --- Page 17 --- <15- Of the total fish taken in the nets, game fish species comprised 23.43 per cent of the number and 17.18 per cent of the weight. A year before, they comprised 52.91 per cent and 34.24 per cent by number and weight, respectively. Therefore, it appears that there is a definite decrease both in numbers and in weight. Most of this decrease may be attributed to the disappearance of the crappie. For this reason a sizable number of crappie have been stocked by the state fish hatchery at Brownsville. The freshwater drum has also declined, both in numbers and in weight. In 1963, they comprised 17.44 per cent of the number and 8.36 per cent of the weight as compared to 1.56 per cent of the number and 0.50 per cent of the weight in 1964. This "decline" is not under- stood. The average "K'' factors, or indices of physical condition, of all fish remained about the same. The length-weight statistics are presented in Table 18. Table 18. Length-weight statistics of fish taken from Delta Orchards Lake, May and November, 1964 Standard Length (mm. ) Weight (grams) "K' Factors Species Range Average Range Average | Range Average Spotted gar 337-600 | 317-1332 00 Longnose gar 429-885 306-3742 Gizzard shad 125-220 41-219 Smallmouth buffalo 228-437 431-3232 Carp 116-363 49-1446 Channel catfish 827-392 | 567-1021 Blue catfish 164-415 72-1361 Striped mullet 438-479 2155-2778 Freshwater drum 190-209 238-265 Seining - Two seining collections took a total of 914 fish of 13 species (Table 19). Tidewater silversides, mosquitofish, sheepshead minnows (Cyprinodon variegatus) and red shiners, in that order, comprised 91.79 per cent of the total number. The most apparent increase concerned the red shiner. They com- prised 0.27 per cent of the 1963 collections as compared to 13.02 per cent of the 1964 collections. The threadfin shad showed a relative decrease from 13.74 per cent in 1963 to 0.44 per cent in 1964, and the Tamaulipas shiner (Notropis braytoni) comprised 18.60 per cent of the 1963 collections as com- pared to 2.63 per cent in 1964. No other significant changes were noted. --- Page 18 --- =i6- Table 19. Seining results, Delta Orchards Lake, May and November, 1964 Per Cent of Total Number Threadfin shad 4 0.44 Gizzard shad 9 0.98 Mexican tetra 6 0.66 Tamaulipas shiner 24 2.63 Red shiner 119 13.02 | Bullhead minnow 4 0.44 Gulf killifish 4 0.44 Sheepshead minnow 162 17.72 Mosquitofish 251 27.46 Sailfin molly 11 1.20 Tidewater silverside 307 33.59 Rio Grande perch 6 0.66 Naked goby 7 0.76 Lake Conditions - Other than thick growths of algae, aquatic vegetation is lacking in the lake. This may be attributed to the fact that the prevailing strong, southeasterly winds keep the silt in suspension in this shallow lake. Dissolved oxygen values ranged from 2.8 to 3.4 p-p-m., carbon dioxide values ranged from 0.20 to 1.0 p.p.m., methyl orange alkalinity ranged from 130 to 165 p.p.m., and pH ranged from 8.2 to 8.4. All values are considered normal for this area. Recommendations - Since wild fish from the Rio Grande River have access to Delta Orchards Lake, population control work would be ineffective and, there- fore, is not recommended. It is recommended that a commercial fisherman be permitted to harvest as many rough fish as possible. Additional crappie should be stocked if they are needed. San Antonio River Netting - Five gill netting collections were made on the San Antonio River and Cibolo Creek in June, 1964. A total of 77 fish of 9 species weighing 73 pounds was taken (Table 20). Rough fish species, including spotted and longnose gars, gizzard shad, grey redhorse (Moxostoma congestum), yellow bullheads (Ictalurus natalis) and Rio Grande perch were predominant both in number and weight. Of the three game fish species taken, channel and flathead catfish (Pylodictus olivaris) are the most important sport fishes; however, their --- Page 19 --- “1F- numbers are limited. Again, no carp were taken. There was no significant change in the fish population since the basic survey of 1962 (see completion report for Job B-18, Project F-6-R-10). Table 20. Results of gill netting, San Antonio River, June, 1964 | ber Species Taken Per Cent of Total Weight Per Cent of Total Number Spotted gar 7 9.09 11.2 15.34 Longnose gar 7 9.09 9.3 12.74 Gizzard shad 5 6.49 1.5 2.06 Grey redhorse 11 14.29 8.3 11.37 Channel catfish* 12 15.59 11.9 16.30 Yellow bullhead 1 1.30 Oud 0.27 Flathead catfish* 6 7.79 22.9 31.37 Bluegill* 4 5.19 0.4 0.55 Rio Grande perch 24 31.17 703 10.00 Per Cent Game Fish Per Cent Rough Fish * Indicates game fish The length-weight statistics are presented in Table 21. The average "K" factors are in line with those of the 1962 basic survey. Table 21. lLength-weight statistics of fish taken with gill nets, San Antonio River,. June, 1964 Standard Length (mm. ) Weight (grams) "K" Factors Species Range Average Range Average Spotted gar 379-560 459 327-1276 727 0.60-0.86 0.71 Longnose gar 412-675 530 288-1191 602 0. 0.36 Gizzard shad 142-235 196 50-281 172 1. 2.07 Grey redhorse 175-310 237 131-624 341 1. 2.35 Channel catfish 190-439 273 109-1729 448 Ls 1.89 Yellow bullhead | 158-158 158 | 89-89 89 Zs 2625 Flathead catfish | 316-495 443 | 510-2282 1729 1. 1.86 Bluegill 93-98 95 | 35-43 40 4. 4.68 Rio Grande perch | 111-192 73-466 5. 5.94 --- Page 20 --- -18- Seining - Ten seining collections were made during this survey. The results are presented in Table 22. Mosquitofish, red shiners and pugnose minnows, in that order, comprised 92.59 per cent of the seining collection. The red shiners, however, decreased from 62.14 per cent in 1963 to 22.68 per cent in 1964 while the mosquitofish showed an increase from 29.83 per cent in 1963 to 60.42 per cent in 1964. Table 22. Seining results, San Antonio River, June, 1964 Per Cent of Total Number Numbers Taken Species Smallmouth buffalo Pugnose minnow Red shiner Flathead minnow Channel catfish Black bullhead Tadpole madtom Blackstripe topminnow Mosquitofish Sailfin molly Amazon molly Largemouth bass Bluegill White crappie Rio Grande perch COONDODODOOCOONON SD Recommendations - Every reasonable effort should be made to prevent industrial, municipal and soil pollution in the river. This, of course, will require the combined efforts of many people and agencies. The sportsmen will be limited to catfish angling in the river, Cibolo Creek has a moderate population of largemouth bass in addition to a good cat- fish population. Since the catfish is one of the principal game fish species in the river, commercial fishermen should not be allowed to take them and every effort should be made to protect and propagate them. No developmental work is presently proposed or recommended. Lake Corpus Christi Netting - A total of 40 gill netting collections was made on Lake Corpus Christi during January, April, July and October, 1964. All told, these nets took 1,712 fish of 17 species (Table 23). --- Page 21 --- «19% Table 23. Results of gill netting, Lake Corpus Christi, 1964 i Number Per Cent of Weights Per Cent of Species Taken Total Number ounds Total Weight Alligator gar 8 0.47 199.8 11.71 Spotted gar 137 8.00 286.2 16.77 Longnose gar 102 5.96 423.0 24.79 Gizzard shad 549 32.07 181.8 10.65 Smallmouth buffalo BL 1.81 76.0 4.45 Carp 8 0.47 19.0 1.11 Channel catfish* 112 6.54 34.9 2.04 Blue catfish* 360 21.03 234.7 13.75 Flathead catfish* 1 0.06 349 0.23 White bass* 50 2.92 28.7 1.68 Largemouth bass* 6 0.35 6.4 0.37 Warmouth* 2 0.12 0.3 0.02 Redear sunfish* 4 0.23 0.5 0.03 Bluegill 11 0.64 1.2 0.07 White crappie* 109 6.36 58.7 3.44 Black crappie* 26 Ls 52 15.4 0.90 Freshwater drum 196 11.45 136.3 7.99 Per Cent Game Fish Per Cent Rough Fish * Indicates game fish Rough fish species, including alligator gar (Lepisosteus spatula), spotted and longnose gars, gizzard shad, smallmouth buffalo, carp, bluegill, and freshwater drum comprised 60.87 per cent of the number of fish netted and 77.54 per cent of the total weight. In 1963, the rough fish species com- prised 58.81 per cent of the number of fish netted and 72.86 per cent of the total weight. Overall, there does not appear to be any significant change in the fish population since the 1963 reconnaissance survey. Among the individual species, there appears to be a relative decrease in the gizzard shad populations. They comprised 32.07 per cent of the total number taken in 1964 as compared to 36.07 per cent in 1963. Otherwise, there were no significant changes. The principal game fish species include channel, blue and flathead catfish, white bass, largemouth bass, warmouth, white and black crappie. Of these, the blue catfish population showed a relative increase. In 1963, they comprised 18.32 per cent of the total number and 11.50 per cent of the total weight as compared to 21.03 per cent of the number and 13.75 per cent of the weight in 1964. The other game fish species remained about the same as they did a year ago. --- Page 22 --- * iis The white bass have not greatly increased in the last year. This, to a large extent was due to the unfavorable spawning conditions in the river. Crappie and catfish fishing remained good during the year but largemouth bass fishermen had less than good fishing. This was attributed to the extremely low water level during the spring. The length-weight statistics are presented in Table 24. No significant changes were noted. Table 24. Length-weight statistics for fish from Lake Corpus Christi, 1964 Standard Length ae (mm. ) Weight (grams) "K' Factors Species Range Average 9 Range Alligator gar 612-1340 985 2070-26762! 11340 |0.90-1.12 1.04 Spotted gar 289-730 486 190-2665 948 10. 0. Longnose gar 404-983 680 218-5330 1787 | 0. 0. Gizzard shad - 122-272 184 29-455 151 /1. 1. Smallmouth buffalo | 127-438 283 77-3827 1112 | 3. he Carp 265-377 324 510-1644 1077 | 2. 3. Channel catfish 59-370 197 3-936 141 | 0. 1. Blue catfish 135-556 250 33-2892 297 | 1. Ls Flathead catfish 437-437 437 1758-1758 1758 | 2. 2.5 White bass 130-318 194 66-1276 264 | 2. 3. Largemouth bass 216-329 250 263-992 483 | 2. 2. Warmouth 106-127 117 49-74 62 | 3. Bie Redear sunfish 104-134 123 39-112 80 | 3. he Bluegill 97-112 101 32-57 42 |3. 3. White crappie 78-269 191 14-624 248 | 2. 3. Black crappie 113-234 188 45-539 273 | 2. 3. Freshwater drum 120-346 44-1588 2. 2. Seining - Thirty-five seining collections took a total of 20,148 fish of 19 species (Table 25). Tidewater silversides, mosquitofish, gizzard shad and red shiners, in that order, comprised 87.74 per cent of the fish seined. In addition to the large numbers of these fish, they were evenly distributed throughout the reservoir. --- Page 23 --- 1+ Table 25. Seining results, Lake Corpus Christi, 1964 Per Cent of Total Number Numbers Taken Species Threadfin shad O. Gizzard shad L7s Mexican tetra QO. Pugnose minnow 2. Red shiner 10. Bullhead minnow 196 0. Flathead minnow 3 QO. Channel catfish 4 QO. Sheepshead minnow 596 Dew Mosquitofish 5988 29. Sailfin molly 266 1. Amazon molly 516 2 Tidewater silverside 6020 29. Largemouth bass 4 0. Warmouth 8 QO. Redear sunfish 13 Os Bluegill 361 l. White crappie 1 QO. Rio Grande perch Ow Stomach Analyses - Unidentifiable fish remains and shad were found in the stomachs of both alligator and spotted gars. Mostly shad were found in the white bass, white crappie and blue catfish stomachs. In addition to fish remains, a Rio Grande perch was taken from a largemouth bass' stomach. Lake Conditions - The water level reached its lowest point on August 8, 1964, when the level was recorded at 79.77 feet. In July, the gates were closed and the heavy fall rains filled the lake to its new capacity of 94 feet on October 6, 1964 (Table 26). Undoubtedly, the fluctuating water level affected the spawning of centrarchids, especially largemouth bass and crappies. Since there was very little water coming into the lake in the spring, it is doubtful that the white bass had a good spawn. Secchi disc readings of light penetration ranged from 7 to 27 inches. The water was consistently clearer in the lower reaches of the lake. Water analyses were made at two stations and all values were considered normal for this region. --- Page 24 --- ~29 “AON O€ T2 IT T °290 *qdas °Sny 7961 “tequeAoN Ysnory. €96T 796T Aqnge oun ASW [rady yore c@ Cl @ 02 CT OO OCEZ et € 72 V1 4 ¥% HI * Jaquisdeq 7 S@ ST GS S@ STS 927919 GZ STS 97919 9291 9 YUE TTT TTT NEALE NIE TTT ETT ‘ST@AZT 1992eM TASTAYQ sndiog oyeq qed ‘uer “9% PTIFL £961 °20q 08 18 z8 €8 48 $8 98 £8 88 68 06 T6 76 £6 76 Feet above mean sea level --- Page 25 --- 223 Recommendations - Water hyacinth control work should, if at all possible, be continued. The volume of Lake Corpus Christi has increased considerably and the water hyacinths will certainly become a major problem in the near future. No other developmental or management work is recommended. For information purposes a comparison of netting success is included as Table 27. © a i PO poh * e Prepared by Charles T. Menn Approved by LO fpetyrts A bb CCH Project Leader ’ Coordinator Date January 18, 1965 Kenneth C. Jurgens Regional Supervisor --- Page 26 --- aDdgn FON FO 2004 /USTA yO spunog ase1raay JON /USTA yO spunog aBeIdAVy qy3neo YysTZ jo spunod pue zequnu Jo swxz9q UT 8UT}Z}eU TTT3 Jo ssooong 8°90LT O°eL 8°8IZ T'68T T° 182 c° 78 T'1é Z°0S 748ne9 usta Jo spunog FON FO 3004 /4STA Jo Joquny ase IoAVy ON /USTA jo azaquny a3e12AVy y8ne9 UuSsTA Fo zrequny S}eN Fo 90g Fo lequny SION yo zequnyy “£0 PTdPL Tastayg sndiog syeq JeATY OTUORUW ues eye] spzeyoio eITeq aye], senoeduey eyeyT epuerzy oue,Ty eyeyT umorg 410g aye] yrleg 27819 UssjUeg eyey AQIQ usS8uT[aey zo eM jo Kpog