TPWD 1963 F-9-R-11 #866: Fisheries Reconnaissance: Fisheries Investigations and Surveys of the Waters of Region 5-A, Project No. F-9-R-11, Job No. B-22

--- Page 2 --- ABSTRACT With certain exceptions, fisheries reconnaissance work on the Nueces River and its chaanel impoundments in 1963 indicated that the channel catfish is present in relative abundance, Fishing pressure on these waters is comparatively light and heavier pressure could be supported, Where channel catfish are not abundant, restocking would be beneficial, On Pinto and Las Moras Creeks, tributaries to the Rio Grande River, public access is restricted, and as a result the streams are of little im- portanc® as a sport fishery. Although the Leona River previously contained a good game fish popu~ lation and supported a much needed fishery for this area, the stream was very low and of little consequence during 1963, Medina Lake net collections show a continuing increase in gizzard shad which comprised 62 per cent of the netted fish in 1963. Channel and flathead catfish accounted for 42 per cent of the total weight of all netted specimens. This lake supports a good population of these catfish and sport fishermen have been taking them in good numbers. Gill netting data for Diversion Lake fails to indicate appreciable benefits from the selective removal of gizzard shad in February 1962 and subsequent planting of young game fish. Survey data for the Medina River and the small impoundment at Castroville show gizzard shad as the dominant single species, Fair numbers of channel and tlathead catfish, largemouth bass and white crappie were present in Castroville City Leke. However, few fish of any species were taken in the yiver and this is attributed to periodic die-offs of fish due to agricultural insecticides and other pollutants, The three lakes in the San Antonio area, namely Woodlawn, Elmendorf and Davis (Esquivel) Lakes, support a heavy fishing pressure and supply a much needed fishery. Insecticide pollution removed most of the game fish population from Davis Lake during 1963. Gill netting data for Falcon Lake indicates that this lake has the most dense fish population of any of the waters covered by this reconnaissance, An average of over 50 fish were taken by each gill net set. White crappie, averaging more than %-pound each, were the most numerous game fish taken, Other game fish present in relative abundance were channel catfish, white bass, blue catfish, and largemouth bass. Gizzard shad were the most abundant of the rough fish species, --- Page 3 --- SEGMENT COMPLETION REPORT State of Texas Name: Fisheries Investigations and Surveys of the Waters of Region 5-A Project No. F-9-R-11 Title: Fisheries Reconnaissance Job No, B-22 . Period Covered: December 1, 1962 through November 30, 1963 Objectives: To conduct limited investigations to obtain current information concerning gross changes in fishing conditions and factors influencing fish populations, Introduction: During the project segment, reconnaissance surveys were conducted on the Nueces River and its lakes in Uvalde, Zavala, Dimmit, and La Salle Counties; Las Moras and Pinto Creeks in Kinney County; Leona River in Uvalde and Zavala Counties; Medina Lake in Bandera and Medina Counties; Diversion Lake in Medina County; Castroville City Lake in Medina County; Medina River in Medina and Bexar Counties; the San Antonio River as well as Woodlawn, Elmendorf, and Esquivel Lakes in Bexar County, A checklist of all fish species collected is presented in Table l. Techniques Used: Specimens in netting samples were collected with standard gill nets composed of 25-foot sections of varying mesh sizes from 1- to 3-inch square mesh, Lengths, weights, and numbers of netted fish were recorded in the field. Fish collected by seining were taken in 12- by 4-foot common-sense minnow seines or with 20- by 6-foot, %-inch mesh, straight seines, and were preserved in 10 per cent formalin solution for later identification and tabu- lation in the laboratory. Since fish populations in more than one body of water were sampled, techniques used and/or findings will be taken up separately for these waters in subsequent segments of this report. NUECES RIVER Techniques Used and Findings: One gill net and six seine samples of fish were taken from the Nueces River and its major tributary, the West Nueces River (Figures 1, 2, and 3 and Tables 2 and 3), Fish samples were also taken from six channel impoundments --- Page 4 --- 2 © «6 o 2 won Dink wwe a adm Table 1, Checklist of fish species used in report, Common Names Alligator gar Spotted gar Longnose gar Threadfin shad Gizzard shad Mexican tetra Smallmouth buffalo River carpsucker Gray redhorse Carp Goldfish Golden shiner Speckled chub Rio Grande shiner Texas shiner Weed shiner Blacktail shiner Red shiner Hybrid shiner Sand shiner Ghost shiner Roundnose minnow Bullhead minnow Stoneroller Channel catfish Blue catfish Black bullhead Yellow bullhead Flathead catfish Blackstripe topminnow Sheepshead minnow Mosquitofish Sailfin molly Tidewater silverside White bass Largemouth bass Warmouth Green sunfish Spotted sunfish Redear sunfish Bluegill Redbreast sunfish Longear sunfish White crappie Logperch Orangethroat darter Greenthroat darter Freshwater drum Rio Grande perch Scientific Names Lepisosteus spatula L, oculatus L. osseus Dorosoma petenense D. cepedianum Astyanax mexicanus Ictiobus bubalus Carpiodes carpio Moxostoma congestum Cyprinus carpio Carassius auratus Notemigonus crysoleucas Hybopsis aestivalis Notropis jemezanus N. amabilis N. texanus N. venustus N. lutrensis N. venustus x N. lutrensis N. stramineus N. buchanani Dionda episcopa Pimephales vigilax Campostoma anomalum Ictalurus punctatus I. furcatus i. melas i. natalis Pylodictis olivaris Fundulus notatus Cyprinodon variegatus Gambusia affinis Mollienesia latipinna Menidia beryllina Roccus chrysops Micropterus salmoides Chaenobryttus gulosus Lepomis cyanellus L. punctatus L. microlophus L. macrochirus L. auritus L. megalotis Pomoxis annularis Percina caprodes Etheostoma spectabile E. lepidum Aplodinotus grunniens Cichlasoma cyanoguttatum --- Page 5 --- FIGURE 1 NUECES RIVER 29°40" REAL EDWARDS COUNTY AN Ik COUNTY r “LAKE ol 7 NUECES A i qt Y KINNEY COUNT COUNT Y [Xz SILVER LAKE Fy a ari f= yew CKETTVICLE LEGEND [234] roaos A SEININ G SITES G) GILL NET COLLECTION SITES an mules --- Page 6 --- FIGURE 2 NUECES RIVER erysTar city & LEGEND ROADS A SEINING SITES 1433 ©) GILL NET COLLECTION SITES e3 ESPANTOSA INSET LAKE ° 1 Zz ‘3 4 pom Pr --- Page 7 --- <5s FIGURE 3 NUECES RIVER LASALLE COUNTY LEGEND ROADS AX seinine sites ©) GILL NET COLLECTION INSET 3 & rn les --- Page 8 --- Table 2. Gill netting results, Nueces River, 1963. Fish Collections | Species | Numbers Weights | | Fish Per Cent Mean "K" Gizzard shad* 13 40.63 12,14 23.81 1,84 Smallmouth buffalo* 5 15.63 29,87 58.63 3.29 River carpsucker* 4 12,50 4,07 7.98 1.96 Channel catfish 1 3.12 0.75 1.46 Tel Largemouth bass 7 21.88 3,94 da tZ 2.09 Redear sunfish 1 312 0.09 0.18 4.10 | Bluegill 1 3.12 | Os Tl 0,22 | 3.86 | | Totals | 32 100.00 | 50.97 | 23,114 100.00 *Indicates rough fish species. Table 3. Seining results, Nueces River, 1963, F Stations — Ts Ts 74 [ 5] 6 | 7 7 Gizzard shad 2 2 Mexican tetra 1 L Texas shiner 1 106 12 21 140 Weed shiner 4, 4 Blacktail shiner 21 ag 24 13 17 31 107 Red shiner 8 | 10 63 81 Ghost shiner lL j } 11 12 Roundnose minnow | 7 7 Bullhead minnow | 16 16 Stoneroller 1 | 1 Channel catfish 4 i 4 Yellow bullhead 3 | 3 Mosquitofish 5 6 1 33. | 14 18 | 77 Largemouth bass 4 19 | 1 | 24 Green sunfish 6 2 3 1 | f 12 Redear sunfish 3 H | 3 Bluegill 6 29 2 24 3 } 12 76 Longear sunfish 1 1 Orangethroat darter 1 1 Greenthroat darter | 2 2 Rio Grande perch 1 3 2 1 | 7 Totals 61 64 | 140 74 172 581 --- Page 9 --- on the river including Lakes Nueces, Silver, North Dam, Espantosa, Harris and Holland. Results of these surveys are discussed separately in the text below. The fish samples from the Nueces River were, with exception of the gill net sample, collected up-stream from the Balcones Escarpment. Below the escarpment the river is intermittent and, except for some deep pools, the river dries up during the summer. The results of the single gill net collection are shown in Table 2 and seining results are shown in Table 3. In seining, the Texas shiner (Notropis amabilis) was the single most numerous species collected, with the blacktail shiner (Notropis venustus) a close second. Bluegills (Lepomis macrochirus) were collected at all seine stations, Largemouth bass (Micropterus salmoides) were observed though not collected at all stations. LAKE NUECES Techniques Used and Findings: Completed in 1963, Lake Nueces is a constant-level, 19 surface acre, clearwater impoundment. It is located in Uvalde County on the upper reaches of the Nueces River (Figure 1) immediately downstream from Camp Wood. At the time of the reconnaissance survey, the fish in the lake represented only those fish that were in the impoundment area prior to inundation. No fish were stocked before the netting and seining collections were made. Channel catfish (Ictalurus punctatus) followed by river carpsuckers (Carpiodes carpio) were the most abundant species taken in nets (Table 4). It is probable that the river carpsucker will become a problem species in the future after they have had an opportunity to spawn and establish themselves in this new reservoir. In seining, it was apparent that a good minnow population dominated by the Texas shiner is present (Table 5). SILVER LAKE Findings: Silver Lake, approximately 10 acres in area, is a large, deep pool with an almost constant water level, located on the West Nueces River (Figure 1), The river in this area is intermittent and normally flows for only a relatively short period after a rain on the watershed. Considering the total number of fish collected (Table 6), netting samples from this lake produced an unusually large number of channel catfish, Spotted gars (Lepisosteus oculatus) were the next most abundant rough fish species taken in nets, --- Page 10 --- Table 4, Gill netting results, Lake Nueces, 1963. Fish Collections Species Mean "K" Spotted gar* Gizzard shad* River carpsucker* Channel catfish Flathead catfish Spotted sunfish Redbreast sunfish Longear sunfish NS NrrPhM Aor 0.56 48 100.00 37.78 17,153 | 100.00 *Indicates rough fish species, Table 5. Seining results, Lake Nueces, 1963. Species Texas shiner Blacktail shiner Red shiner Ghost shiner Mosquitofish Bluegill --- Page 11 --- =§= Table 6. Gill netting results, Silver Lake, 1963, a Fish Collections _ | Numbers | CWeights) ds Mean "KK" | Fish | Per Cent | Pounds | Grams | Per Cent | Species Spotted gar® Longnose gar Smallmouth buffalo* River carpsucker* Channel catfish Elack bullhead* Yellow bullhead* Largemouth bass Warmouth Bluegill Longear sunfish Rio Grande perch* 133 Totals *Indicates rough fish species, Table 7. Gill netting results, North Dam Lake, 1962, ____Fish Collections He . _Numbers | Weights S| Mean "RM |_Per Gent | Pounds | Grams | Per Cent_ Species Spotted gar* Longnose gar® Threadfin shad* Gizzard shac* Smallmouth buffalo*¥ Channel catfish Black bullhead* Largemouth bass Redear sunfish Bluegill White crappie Freshwater crum* oR PP ORP wre wou hm bw ~ un oo Totals Ea *Indicates rough fish species, --- Page 12 --- -l10O= NORTH DAM LAKE Findings: This 310-acre channel impoundment was constructed to store and to divert Nueces River waters for irrigation in the Crystal City area (Figure 2), Therefore, the lake's water level fluctuates a great deal. When net samples were taken, the lake was at a low point and the fish population was concentrated, Of the specimens collected, rough fish species including gizzard shad (Dorosoma cepedianum), longnose gar (Lepisosteus osseus), spotted gar and smallmouth buffalo (Ictiobus bubalus) dominated the fish population (Table 7), Small white crappie (Pomoxis annularis) and largemouth bass are the dominant game fish species, Channel catfish should be restocked in this area of the Nueces River. ESPANTOSA LAKE Findings: Espantosa Lake, located in Dimmit County south of Crystal City, is 600 acres in area and is also a channel impoundment on the Nueces River (Figure 2). Like North Dam Lake, it too fluctuates a great deal and was low at the time of sampling, Gill netting results varied somewhat from North Dam Lake in that fresh- water drum (Aplodinotus grunniens) was the second most abundant species taken (Table 8). Small white crappie were the most abundant game fish taken in netting. Because of extreme fluctuation in water levels, maintenance of a sport fish population is next to impossible, but stocking of additional channel catfish would be beneficial, HARRIS LAKE Findings: Like the other channel impoundments in this section of the Nueces River (Figure 3), Harris Lake, measuring 125 acres in area, was built for irrigation purposes and is subject to fluctuation. However, not too much irrigated land is located in this area of La Salle County and therefore the fluctuations in water level are not too severe. Netting results (Table 9) indicate an abundance of gars in the lake, including the longnose,spotted, and alligator gars (Lepisosteus spatula), Game fish apparently are poorly represented in Harris Lake, HOLLAND LAKE Findings: Holland Lake is the farthest: downstream of the channel impoundments on --- Page 13 --- -ll- Table 8, Gill netting results, Espantosa Lake, 1963. Fish Collections Mean "K" | Fish | Per Cent | Pounds | Grams | Per Cent | Spotted gar* Longnose gar* Gizzard shad* Smallmouth buffalo* Channel catfish Redear sunfish White crappie Freshwater drum*¥ Rio Grande perch* 1 239 024 *Indicates rough fish species. Table 9. Gill netting results, Harris Lake, 1963. Fish Collections Species Numbers Weights Mean "kK" Fish Per Cent | Pounds Alligator gar* Spotted gar* Longnose gar* Gizzard shad* Smallmouth buffalo* Channel catfish Largemouth bass Warmouth Bluegill White crappie Freshwater drum* Rio Grande perch* MMe MRM wow bh *Indicates rough fish species. --- Page 14 --- «]2= the Nueces River in Region 5-A (Figure 3). It is located near the southern county line of La Salle County and is 250 acres in area, Netting indicated a fairly abundant white crappie population (Table 10) and seining indicated some spawning success for largemouth bass in this lake (Table 11). The relative abundance of game fish is borne out by the fairly high fishing pressure observed, PINTO CREEK Findings: Pinto Creek, a small tributary of the Rio Grande, is located in the southwest corner of Kinney County (Figure 4). Except for the lower three miles, the creek flows only after rains on the watershed, Permanent water in the lower portion of the creek is affected by large numbers of rough fish which enter the area during rises on the Rio Grande River. From netting results, it is apparent that the longnose gar is the dominant fish species present and that river carpsuckers are present in abundance (Table 12). Channel catfish are also present in limited numbers, Of the fish collected in seines, the mosquitofish (Gambusia affinis), the bluegill, and the red shiner (Notropis lutrensis) were the most numerous. species taken (Table 13). LAS MORAS CREEK Findings: Las Moras Creek (Figure 4) begins at Las Moras Springs at Brackettville, in Kinney County, and flows in a southwesterly direction, entering the Rio Grande River near the northwestern corner of Maverick County. The springs arise at the Balcones Fault, have an average flow of 50 cubic feet per second, and have never been known to cease flowing. The fish population, sampled only by seining, is typical of this type of habitat (Table 14), The most common fish collected was the round nose minnow (Dionda episcopa). Other commonly collected fish species were the Texas shiner (Notropis amabilis), the mosquitofish and the blacktail shiner. Though not present in the seining collections, it is known that Las Moras Creek supports a good fishery for sunfishes and largemouth bass, LEONA RIVER Findings: Arising from springs within and immediately below Uvalde, in Uvalde County, the Leona River (Figure 5) flows in a southerly and then southeasterly direction to its confluence with the Frio River near Derby in Frio County. Formerly this stream provided a locally important fishery, during the study period, --- Page 15 --- wi Ge Table 10. Gill netting results, Holland Lake, 1963, Fish Collections Species Numbers Weights Mean "K" Alligator gar* Spotted gar* Longnose gar* Gizzard shad* Smallmouth buffalo* Channel catfish Warmouth Redear sunfish White crappie Freshwater drum* *Indicates rough fish species. es OwWOrPrPsA NS EOS oO be Table 11. Seining results, Holland Lake, 1963. Blacktail shiner Red shiner Mosquitofish Tidewater silverside Largemouth bass Redear sunfish Bluegill --- Page 16 --- ilies FIGURE 4 PINTO AND LAS MORAS CREEKS BRACKETTVILLE KINNEY COUNTY ~ bt = — Oo | oO x“ oO w fw > << LEGEND ZX SEINING SITES G) GILL NET COLLECTION SITES ol ROADS INSET --- Page 17 --- -15- Table 12, Gill netting results, Pinto Creek, 1963, Fish Collections Species Numbers Mean "K" Per Cent in Longnose gar* Gizzard shad*¥ Smallmouth buffalo* River carpsucker* Gray redhorse* Carp* Channel catfish Freshwater drum* to *Indicates rough fish species. Table 13, Seining results, Pinto Creek, 1963. Species Gizzard shad Texas shiner Red shiner Bullhead minnow Mosquitofish Largemouth bass Warmouth Green sunfish Bluegill White crappie Rio Grande perch --- Page 18 --- -16- Table 14, Seining results, Las Moras Creek, 1963, Stations Species a Se ie Oa a a Gizzard shad Mexican tetra Texas shiner Blacktail shiner Hybrid shiner Red shiner Round nose minnow Mosquitofish Sailfin molly Green sunfish Redbreast sunfish Table 15. Gill netting results, Leona River, 1963. Fish Collections Species Mean "K" | Fish | Per Cent | Pounds | Grams | Per Cent | Gizzard shad* Smallmouth buffalo* River carpsucker* Channel catfish Black bullhead* Yellow bullhead* Largemouth bass Green sunfish Redear sunfish Bluegill Longear sunfish Rio Grande perch* PNUFPP RPP wDPeE A *Indicates rough fish species. --- Page 19 --- Rs i FIGURE 95 LEONA RIVER UVALDE ZAVALA COUNTY COUNTY LEGEND ROADS A SEINING SITES (2) GILL NET COLLECTION SITES INSET a | °o 1 2 3 4. moles 28 50% --- Page 20 --- “15 however, the springs had stopped flowing and the river was confined to pools. Gill net samples were taken from the two major pools, one in Uvalde County and the other in Zavala County near Batesville (Table 15). Based on the limited fish collections from the Leona River, gizzard shad are present in relative abundance and channel catfish, largemouth bass and various sunfishes are also relatively common, If the present period of low rainfall continues, the stream will probably dry up as it did prior to 1957. MEDINA LAKE Techniques Used and Findings: A total of 36 gill net collections were taken from stations established on Medina Lake (Figure 6) during previous years. During the study period, Medina Lake varied in lake area from 2,486 to 1,489 surface acres. The gizzard shad population which has been increasing in Medina Lake for a number of years made up 62 per cent of the total number of fish netted (Table 16). Game fish, including channel and flathead catfish, white and largemouth bass, and white crappie comprised 57 per cent of the total weight of fish netted, Of this, channel and flathead catfish accounted for 42 per cent, Although only six flathead catfish were collected in net samples, the lake supports a good population of them and sport fishermen have caught good numbers of this species with some individuals weighing as much as 87 pounds. During the study period, a total of 366 longnose gars were taken in nets. Since 322 of these were taken during one netting trip and since over 200 were taken from only two nets, these fish would have unduly biased the results of gill netting from Medina Lake during 1963. There were therefore not included in Table 16, Had they been included, longnose gars would have comprised 31.69 per cent of the total fish netted and 69,57 per cent of their weight, In aver- aging the numbers of longnose gars collected in gill nets during the other two collection trips, this species comprised 7.72 per cent of the total number of fish netted;:a figure which is believed to be much closer to the norm for this lake. In collections from three seine stations on Medina Lake, blacktail and redfin shiners and bullhead minnows were the most numerous species taken (Table 17). DIVERSION LAKE Techniques Used and Findings: Twenty-three gill net collections were taken from the 181 surface acres of Diversion Lake, which is located just below Medina Lake on the Medina River (Figure 6). Following a rotenone treatment of Diversion Lake for the selective removal of gizzard shad in February 1962, large numbers of largemouth bass, channel catfish and redear sunfish were stocked in an effort to increase the overall --- Page 21 --- -19- COUNTY FIGURE 6 MEDINA RIVER — MEDINA AND LAKES by is) on BANDERA MEDINA LAKE Lal DIVERSION ~~ ~] RER z=] 2 a 3 O;, 0 OU @ MEDINA BEXAR LEGEND ROADS A SEINING SITES CAST ROVI ‘@) GILL NET SITES INSET --- Page 22 --- 36s Table 16, Gill netting results, Medina Lake, 1963, Fish Collections _ Species | Numbers {—————CWetights i]s Mean "RK" | Fish Per Cent Gizzard shad* Smallmouth buffalo* Gray redhorse* Carp* Channel catfish Flathead catfish White bass Largemouth bass Redear sunfish Bluegill White crappie *Indicates rough fish species, Table 17. Seining results, Medina Lake, 1963. SiR a ee ee Gizzard shad Blacktail shiner Red shiner Bullhead minnow Mosquitofish Sailfin molly Largemouth bass Green sunfish Redear sunfish Bluegill Longear sunfish Rio Grande perch acces --- Page 23 --- =2l- game fish population. Current netting data fails to indicate that benefit resulted from the treatment and subsequent planting of young game fish. In fact, the percentage of game fish taken in netting samples decreased from 19.6 in 1962 to 11.0 in 1963 (see Table 5 in Job Completion Report for Job B-22, D-J Project F-9-R-10 and Table 18 in this report). Furthermore, gizzard shad which accounted for 64.5 per cent of the netted fish in 1962 increased to 66.8 per cent in 1963, In seining collections from Diversion Lake, the most numerous species collected was the blacktail shiner (Table 19). CASTROVILLE CITY LAKE Findings: Castroville City Lake is a small, 20-acre, channel impoundment on the Medina River within the city limits of Castroville (Figure 6). Netting results from fisheries reconnaissance work in 1963 indicated that gizzard shad and smallmouth buffalo were the most abundant species present, However, game fish species are represented in fair numbers by channel and flathead catfish, largemouth bass, and white crappie (Table 20). MEDINA RIVER Techniques Used and Findings: Current reconnaissance work on the Medina River includes that portion of the streem from Diversion Lake Dam into its confluence with the San Antonio River (Figures 6 and 7). In all, two gill net and eight seine collections were taken from this portion of the river. The results of netting are inconclusive in that only 57 specimens were taken (Table 21). The river is known to suffer from die-offs of fish due to agricultural insecticides and other pollutants and this may account for the scarcity of fish in the netting collections, In seining, the red shiner was the most abundant single species collected and accounted for 877 of the 1,356 specimens taken (Table 22). Sailfin mollies (Mollienesia latipinna) were the next most abundant species taken in seines. WOODLAWN LAKE Techniques Used and Findings: Woodlawn Lake is a 40-acre lake located at the head of Alazan Creek, in a residential section of western San Antonio (Figure 8). A total of 16 gill net collections were made at four stations on Woodlawn Lake during the study period. Game or panfish comprised 69.8 per cent of the total number and 75.6 per cent of the total weight of the fish collected (Table 23). These data compare favorably with data from the previous year when game and panfish comprised 58.5 per cent of the number and 42.6 per cent of the weight of the netted specimens (see Table 7 in the report for Job B-22, F=-9=R-10). --- Page 24 --- a22= Table 18. Gill netting results, Diversion Lake, 1963. Fish Collections |___Numbers {| Weights Mean "K" | Longnose gar* Gizzard shad* Smallmouth buffalo* Carp* Channel catfish White bass Largemouth bass Warmouth Green sunfish Bluegill White crappie Rio Grande perch* *Indicates rough fish species, Table 19. Seining results, Diversion Lake, 1963. Blacktail shiner Red shiner Bullhead minnow Largemouth bass Bluegill Redbreast sunfish --- Page 25 --- -23- Table 20, Gill netting results, Castroville City Lake, 1963. Fish Collections Species Mean "kK" Spotted gar* Gizzard shad* Smallmouth buffalo* Gray redhorse* Channel catfish re ODF FPWUU UF h& Flathead catfish Largemouth bass Warmouth Bluegill White crappie ke *Indicates rough fish species, Table 21. Gill netting results, Medina River, 1963. Fish Collections Species Pana cr ie ee TR oa Mean "Kk" |_Per Cent _| Longnose gar* Gizzard shad* Smallmouth buffalo* Gray redhorse* Channel catfish Yellow bullhead* Flathead catfish Largemouth bass Bluegill *Indicates rough fish species, as YH KF RK WWW Dw --- Page 26 --- -24- r | = 7 . : re) iy ov 3” oO a) a a FIGURE 7 MEDINA RIVER BEXAR COUNTY ANTONIO C 29°57 LIMITS LEGEND [ei] ROADS A SEINING SITES C) GILL NET COLLECTION SITES INSET sre Ez Oo L 2 4 4 awles --- Page 27 --- 2255 Table 22. Seining results, Medina River, 1963. 5 . Stations ESE re ae e e Gizzard shad Mexican tetra Gray redhorse Speckled chub Texas shiner Blacktail shiner Red shiner Sand shiner Channel catfish Flathead catfish Blackstripe minnow Bullhead minnow Sailfin molly Spotted sunfish Redear sunfish Bluegill Redbreast sunfish Longear sunfish Logperch Table 23, Gill netting results, Woodlawn Lake, 1963. Fish Collections Mean "kK" | Fish | Per Cent [Pounds [| Grams | Per Cent | Carp* Goldfish* Golden shiner* Channel catfish Black bullhead* Yellow bullhead* Flathead catfish Largemouth bass Warmouth Green sunfish Redear sunfish Bluegill Redbreast sunfish Longear sunfish White crappie Rio Grande perch* *Indicates rough fish species. --- Page 28 --- “0G WOODLAWN LAKE ss OA ELMENDORFE i LAKE _ ate Po oe \ LEGEND -) Po ve oO. A feay A. 5/8] ROADS A SEINING SITES Q@) GILL NET COLLECTION INSET o tL 2 c <4, S SAN Ay ESQUIVE ANTONIO CYL LAKE at . e 6 ye SITES 3 4 miles FIGURE 8 SAN ANTONIO RIVER — WOODLAWN , ELMENDORF , AND ESQUIVEL LAKES ° 2° L 2 v an » x yo. > tet | > ie) ~ K |: S oO or YU = w | mS Le) > S = MEDIN iS rar --- Page 29 --- -~?2] = Because of its location and good access, Woodlawn Lake supports very heavy fishing pressure and supplies much needed recreation for young anglers or other persons unable to fish outside of the City of San Antonio. Therefore, continu- ing efforts should be made to provide good fishing in this lake, Judging from the average weights of catfish, both channel and flathead, stocking of these species has been quite successful and should be continued, Spot creel census checks indicate the overall rate of catch to be 0.75 fish per man-hour of fishing. In seining at two stations on Woodlawn Lake, bluegills accounted for more than half the collected specimens (Table 24), ELMENDORF LAKE Techniques Used and Findings: Elmendorf Lake is eight acres in surface area and is located at the head of Apache Creek, a tributary of the San Antonio River, in the western section of San Antonio (Figure 8). Because of its location and good access, heavy fishing pressure is exerted on its fish population. In three gill net collections during the study period, only 22 specimens were taken (Table 25). Of these, eight were small bluegills and three were largemouth bass. The bass weighed a total of 7.6 pounds, or an average of 2% pounds each, a good average weight considering the location of the lake and the amount of fishing pressure, In seining, sailfin mollies accounted for 89 of the 113 specimens collected (Table 26), That no small largemouth bass were seined indicatesa need for restocking. DAVIS (ESQUIVEL) LAKE Techniques Used and Findings: Davis Lake is a l4-acre channel impoundment situated on the San Antonio River, in the south-central portion of San Antonio (Figure 8). During 1963, two series of three gill net sets and one seining collection were made on the lake. The major portion of the specimens collected by gill nets were taken in the first netting series. In October 1963, a fish kill, caused by insecticide pollution, removed most of the game fish population. Large numbers of largemouth bass, weighing up to 5 pounds, and channel catfish, weighing up to 12 pounds, were destroyed, Because of this fish kill, the fish population represented by the data in Table 27 did not exist at the end of 1963. Seining in Davis Lake is difficult at best, but seining results (Table 28) also reflect the effect of the insecticidal kill of fish in the lake, A recom- mendation to have the lake restocked has been made and efforts to control insecticidal kills need also to be made by the proper authorities. ff --- Page 30 --- o8- Table 24, Seining results, Woodlawn Lake, 1963. Golden shiner Red shiner Black bullhead Mosquitofish Largemouth bass Redear sunfish Bluegill Longear sunfish Redbreast sunfish Rio Grande perch ae WrewWwWworrRUuFFR =~ i Table 25, Gill netting results, Elmendorf Lake, 1963. Fish Collections Species i Mean "K" Per Cent Golden shiner* Black bullhead* Largemouth bass Bluegill Rio Grande perch* *Indicates rough fish species, Table 26. Seining results, Elemendorf Lake, 1963. Mosquitofish Sailfin molly Green sunfish Bluegill Rio Grande perch --- Page 31 --- u2G Table 27, Gill netting results, Davis Lake, 1963, Fish Collections Species Numbers Weights Pounds | Grams | Per Cent Alligator gar* Spotted gar* Carp* Goldfish* Channel catfish Black bullhead* Yellow bullhead* Largemouth bass Warmouth Green sunfish Redear sunfish Bluegill Longear sunfish White crappie Rio Grande perch* *Indicates rough fish species. Table 28, Seining results, Esquivel Lake, 1963, Red shiner Mosquitofish Sailfin molly Rio Grande perch --- Page 32 --- a30e FALCON LAKE Techniques Used and Findings: Thirty-nine gill net collections were made on Falcon Lake during 1963, Netting stations established during the previous segment were used as sites of collections, In addition, 12 seining collections at 4 stations were made during this reconnaissance survey. Collection data indicates a fairly dense fish population in Falcon Lake with an average of over 50 fish taken by each gill net set. Of the total fish collected, game fish composed 31.88 per cent by number (Table 29) as compared to 34.73 per cent for 1962. White crappie, averaging more than %-pound each, were the most numerous game fish taken comprising 11.67 per cent of the total number and 9.45 per cent of the total weight collected. Other game fish taken in relative abundance were channel catfish, white bass, blue catfish, and largemouth bass. Of the rough fish species collected by gill netting, the gizzard shad was the most frequent with 49.12 per cent by number and 21.95 per cent of the total weight. Other rough fish species taken in relative abundance were freshwater drum and longnose gar. The longnose gar accounted for the largest per cent of the total weight of all species collected with 26.30 per cent. A total of 3,770 specimens were collected by seining on Falcon Lake (Table 30). The tidewater silverside was the most numerous single species taken with 1,074 specimens. The threadfin shad, red shiner, and gizzard shad were also present in substantial numbers. Discussion When analyzing collection data and field notes for this job, fisheries problems for this region (reported in Segment Completion Report Job D-l, Project F=-9=R-11) become apparent. An over abundance of rough fish is evident in most gill net collection tables of this report. The lack of public access is recognized in the unharvested channel catfish and other game species in some of the waters covered by this report. Also, field notes show very few fishermen were present during the survey of any of the waters except Lakes Nueces, Holland, Medina, and Falcon. These waters, except Falcon Lake, have adequate public access, but lack in development of cabins and other public camping facilities. The severe water fluctuation of most impoundments studied, the Leona River and the portion of the Nueces River below the Balcones Escarpment, are the direct result of excessive irrigation and normal low rainfall for this area, The fish kills reported in the Medina River and Davis Lake result from insecticides and other polluting agents. --- Page 33 --- «31- Table 29, Gill netting results, Falcon Lake, 1963. ____ Fish Collections _ en Po Per Cent Species Alligator gar* Spotted gar* Longnose gar* Threadfin shad* Gizzard shad* Smallmouth buffalo* River carpsucker* Carp* Channel catfish Blue catfish Black bullhead* Flathead catfish White bass Largemouth bass Redear sunfish Bluegill White crappie Freshwater drum* Rio Grande perch* Totals [602,128 Table 30. Seining results, Falcon Lake, 1963, Threadfin shad Gizzard shad Mexican tetra River carpsucker Speckled chub Rio Grande shiner Blacktail shiner Red shiner Bullhead minnow Sheepshead minnow Mosquitofish Sailfin molly Tidewater silverside Redear sunfish Bluegill White crappie Rio Grande perch ; 1 al 5 ee ER --- Page 34 --- -32- The results of uncontrolled commercial netting on Falcon Lake can be found when analyzing Table 29, The 131 channel catfish collected by gill netting averaged a mere 0.3 pound, 81 blue catfish averaged 0.8 pound and 96 white bass averaged 0.4 pound each. In addition, the largemouth bass collected from Falcon Lake averaged 0.7 pound. It is believed that these small sizes are the direct result of unrestricted commercial netting on this impoundment. Contrarily, the greater than usual average size of crappie in Falcon Lake is probably due to extreme cropping of this species by netting. Work is being done at present to alleviate some of the above problems, However, a concerted effort by all agencies concerned will be necessary before solutions to all these problems will be forthcoming, \ — . Legte- Prepared by Elgin M. C, Dietz Approved by CZ ime Project Leader - Coordinator Date September 4, 1964 Kenneth C, Jurgens Regional Supervisor