(1960) Report of Fisheries Investigations: Resurvey of Waters of Region 8-B

--- Page 1 --- Report of Fisheries Investigations Resurvey of Waters of Region 8-B by Charles T. Menn Assistant Project Leader Dingell-Johnson Project F-6-R-8, Job B-11 January 4, 1960 - December 31, 1960 H. D. Dodgen - Executive Secretary Texas Game and Fish Commission Austin, Texas Marion Toole Kenneth C. Jurgens and William H. Brown Coordinator Assistant Coordinators --- Page 2 --- ABSTRACT Six public lakes in the region rechecked during 1960 were Fort Brown, Llano Grande and Campacuas, Casa Blanca, Delta Orchards and Bentsen State Park Lakes. In Fort Brown Lake at Brownsville, gizzard shad, Dorosoma cepedianumn, showed a relative increase in numbers compared to the previous work done in September, 1959. The largemouth bass, Micropterus salmoides, appear to be thriving. Rough species remain dominant in both Llano Grande and Campacuas Lakes. Blue catfish, Ictalurus furcatus, were found in both lakes in sizable num- bers. Gizzard shad and river carpsuckers, Carpiodes carpio, showed relative increases in numbers in Casa Blanca Lake near Laredo while white crappie, Pomoxis annularis, showed a relative decrease. White bass, Roccus chrysops , were found in this lake for the first time. In Delta Orchards Lake, near Raymondville, game fish comprise more than 50 percent by number but less than 50 percent by weight of the fish taken in netting collections. Gill netting at Bentsen State Park Lake, near Mission, following the chemical treatment of the lake in January, 1960, showed that at lease six small fish survived; five warmouth bass, Chaenobryttus gulosus, and one Rio Grande cichlid, Cichlasoma cyanoguttatum. Work done later in the year, after Rio Grande flood waters entered the lake, showed that gizzard shad and other rough species were present. Periodic catches of white bass at Lake Corpus Christi indicated that they are becoming established. A total of 129,500 largemouth bass finger- lings was stocked in the lake to supplement the existing population. No seining or netting was done. A preliminary trip was made in April to check the water hyacinths on the lower Guadalupe River. No control work was begun or proposed during this segment. --- Page 3 --- Job Completion Report State of TEXAS Project No. F-=6-R-8 Name: Fisheries Investigations and Surveys of the Waters of Region O-B. Job No. Bell Title: Resurvey of Waters of Region 8-B. Period Covered: January 4, 1960 - December 31, 1960 OBJECTIVES To determine the present status of waters and fish populations which have been previously surveyed in Project F-6-R. PROCEDURE Experimental gill nets were used to sample the fish populations. The nets were set at previously established netting stations overnight and run the following morning. In some instances, seining collections were made to supplement netting data. The netted specimens were weighed in grams and measured in millimeters in the field. Sex and sexual development and the occurrence of parasites in the individual specimens were noted and recorded in the field. Seined specimens were preserved in 10 percent formalin and taken to the regional fisheries laboratory at Mathis for iden- tification. A list of the common and scientific names of fish species encountered is included as Table 21. For information purposes a comparison of netting success is included as Table 22, FINDINGS Fort Brown Lake Four experimental gill nets were set in April, 1960, and caught 107 specimens of six species. Gizzard shad comprised 27 percent by number and 45 percent by weight as compared to less than two percent by number and weight in the previous resurvey (F-6-R-7, Job B-1l). Carp, Cyprinus carpio, were found in substantial numbers in the previous work but none wre collected during this period. Following the resurvey work of September, 1959, an effort was made (see Job completion report for Job S-1, Project F=6+R-7) to net as many carp as possible; however, this proved almost useless. Current data tends to show that only small numbers of carp are present in the lake. The game species (channel catfish, largemouth black bass and warmouth bass) ap- peared to be thriving despite the fact that they constituted less than 20 percent of the net collections by number. The black bass comprised 15.89 percent by number and 36.77 percent by weight while bluegill sunfish, Lepomis macrochirus, ranked first by number and third by weight. The recent creel census (see Job completion report for --- Page 4 --- =De Job B-15, Project F-6-R-8) revealed that white crappie are present in the lake but none wre netted in this resurvey. Table 1 shows the numbers and grams of fish taken at each netting station during this resurvey. According to this table, rough species comprised over 80 percent of the net catch although water clarity tends to indicate that they are not yet in criti-~ cal numbers. Four Secchi disk readings ranged from 20- to 334-inches which is weny good for this comparatively shallow ox-bow lake. Table 2 shows the lengths, weights, and "K" factors of fish taken from Fort Brown Lake in April, 1960. No appreciable changes occurred regarding the various fish collected. Seining collections were not made on the lake due to thick growths of submerged vegetation which made seining almost impossible. Submerged vegetation, principally Najas, Chara and Ceratophyllum, remains a pro- blem in this lake. As yet, no summer kill of fish due to the abundance of vegetation has been observed or reported. Most complaints were aired by water skiers, however, the shallow areas along the banks are becoming choked with the weeds and will hinder sports fishing. Some control work through supervising treatment by sportsmen's groups may be done in the spring of 1961 to lessen the problem. Annual treatment will be necessary to obtain an effective control. Liano Grande and Campacuas Lakes In the latter part of August, four netting collections were made on Llano Grande Lake and two additional collections were made in the early part of October. Also, four netting collections were made on Campacuas Lake in October. In: the August collections, rough species comprised over 88 percent by number and over 86 percent by weight of the fish collected in the nets at Llano Grande. Similar information was found in the October collections. Gizzard shad, Dorosoma cepedianum, and spotted gar, Lepisosteus productus, longnose gar, Lepisosteus osseus, and Rio Grande cichlids, Cichlasoma cyanoguttatum, remain about the same as was found in the previous resurvey. However, alligator gar, Lepisosteus spatula, showed a relative decrease and carp showed a relative increase in numbers. Table 3 shows the numbers and weight of fish caught in the nets at Llano Grande Lake during August, 1960, and Table 4 shows the number and weight of fish caught during October. Table 5 shows the minimum, maximum, and average lengths, weights and "K" factors of the fish taken in the nets. No significant changes were noted. Table 6 shows the seining results on Llano Grande. Redhorse shiners, Notropis lutrensis, Rio Grande tetras, Astyanyx fasciatus, and threadfin shad, Dorosoma petenense, all good forage species, were found to be abundant. Collectively, these three species comprised about 61 percent of the collection. Apparently a good stock of blue catfish, Ictalurus furcatus, survived the rotenone treatment of the lake in May, 1959, since they comprised about 10 percent by number in both lakes. --- Page 5 --- w= Six Secchi disk readings were taken on Llano Grande and were found to range from 6- to ll-inches with the majority being less than 10-inches. This comparatively shallow lake coupled with the thick silt bottom and numerous rough fish keeps the turbidity high. Inspection of the far west end of Llano Grande, in October revealed that there was some organic material entering the lake via "Paradise Creek". Only one game species, a blue catfish, was taken in a net in the heavily polluted area; carp and alligator gar were the most abundant species taken in this particular net. A few scattered water hyacinths were seen on Llano Grande Lake but are of minor significance at this time. Occasional rises from rain water runoff wash them down- stream but the stock of hyacinths which are in several drainage ditches, above the lake could cause a serious problem should conditions for their reproduction become favorable. Therefore, the hyacinths should be watched and the appropriate measures applied before they become established in the lake. Bulrushes and cattails are numerous around the perimeter of the lake. Only a small amount of duck weed, Lemna, was seen in Llano Grande; it is far from being a problem however. Many ducks visit this lake in the winter time and are for the most part left unmolested. No doubt the ducks crop the duck weeds sufficiently. Sports fishing has increased somewhat on Llano Grande and the local game warden reports that anglers are taking some nice bass and catfish. No fishermen were seen on the lake when visited. Commercial minnow fishermen from Falcon Reservoir and Medina Lake have been taking large numbers of tetras, Astyanyx fasciatus, from Llano Grande Lake. The once-large tetra population in Falcon Reservoir has diminished considerably and the sizable numbers present in Llano Grande Lake give the tetra much commercial value. Four gill net collections were made on Campacuas Lake during this period and took a total of 96 fish of twelve species. Only channel catfish and blue catfish and two crappie were taken as representatives of game species which accounted for 14.58 percent by number and 10.06 percent by weight of the fish collected. Previous work on Campacuas Lake (November, 1959, see Job Completion Report for Job B-11, F=-6-R=7) took only five species of fish as compared to 12 species taken during this segment. The percentages of rough fish and game fish remained about the same. In the previous re- survey, gizzard shad comprised approximately 52 percent by number whereas presently this species comprised less than 32 percent, a reduction of about 20 percent which . might largely be attributed to a netting error. Table 7 shows the numbers and grams of fish collected during this resurvey period. Table 8 shows the results of the seining collection made on the lake. Threadfin shad comprised over 55 percent of the catch. Table 9 shows the minimum, maximum, and average lengths, weights and "K" factors of the various species netted in Campacuas Lake. As compared to work done a year earlier, there was no substantial change concerning the species. One species, Mugil cephalus, was unrecorded since the rotenone treatment in May, 1959. . However, one specimen was taken in the nets during this resurvey. Secchi disk readings were taken at each netting station and found to range from 8- to 10-inches. This lake being similar to Llano Grande Lake was not expected to be much clearer. --- Page 6 --- ~he Shoreline vegetation, primarily bulrushes, Scirpus, line over half of the lake's shore. No submerged or floating vegetation was seen. Only one fisherman was on the lake at the time it was visited and he was using a trotline to catch some nice blue catfish. No other reports were heard concerning fishing on the lake. One seining collection was made on Llano Grande Lake and one was made on Campacuas Lake. No young bass, indicating reproduction, were found in either seining collection. "Green's Ditch" which is located close to and crosses the Liano Grande Floodway is being widened and concreted as a part of the federal government's “urban renewal program". It remains to be seen what effect this will have on future management of the two lakes. Casa Blanca Lake A total of 17 netting collections was made on this lake in April and July and 797 specimens were netted. Five seining collections were also made. Gizzard shad comprised over 4} percent of the number of fish netted in April as compared to less than 20 percent in the resurvey work done in October and December, 1959. However, gizzard shad comprised only 16.81 percent of the total net catch in July. This wide difference might be attributed to seasonal activity of the shad. River carpsucker, Carpiodes carpio, comprised 8.62 percent by number in the July collection and 20.17 percent in the April collection. In the previous resurvey (October and December, 1959), river carpsucker comprised 12.40 percent of the species collected and thus they appear to have made a relative increase in numbers or possible difference in seasonal activity. Table 10 shows the numbers and grams of fish netted during April, 1960, and Table 11 shows the numbers and grams of fish netted in July, 1960. Table 12 shows the mini- mum, maximum and average lengths, weights, and "K" factors for April and July, 1960. No noticeable changes were found. In July, two white bass were collected in one of the nets close to the dam. It was the first time that this species was collected in this lake. No doubt, these fish were stocked by anglers who, more than likely, got them from the Rio Grande and wanted to do a "good turn". These fish are not expected to spawn in the lake because of their repro- ductive requirements; flowing water is essential for these fish to reproduce successfully. If it were possible to stock large numbers of white bass every two or three years, some natural control of gizzard shad might be accomplished. At the same time, anglers could have more variety and added sport. Five seining collections were made during the course of this resurvey; four in April and one in July. A total of 290 specimens of 10 species was collected in the five collections. Table 13 shows the seining results of April and July. Delta Orchards Lake Eight netting and two seining collections were made on Delta Orchards Lake during the year. Five netting and one seining collection was made in March and the other work was done in December. --- Page 7 --- =5= The "lake" is bisected by Farm-Market Highway 88 and actually consists of two lakes that are joined by a conduit under the roadway. One portion on the west side of the highway consists of approximately 510 acres and the other portion on the east side of the highway consists of about 1,760 acres. The lakes are under the jurisdic- tion of the Hidalgo and Willacy Counties Water Control and Improvement District Number 1. The lakes are open to the public for angling with limitations. A fee of 25 cents per person per day is charged of all persons over 15 years of age. A portion of the money collected is paid the concession manager=game warden and the remainder goes to the Water District. In the first three months of 1960, 7,000 fishing permits had been sold. This is some indication of the popularity of the lake. Five nets set in March took 234 fish of eleven species of which four were listed as game species; blue catfish, bluegill sunfish, white crappie, and freshwater drum, Aplodinotus grunniens. Ordinarily bluegill sunfish and freshwater drum are not con- sidered game species in this area, but Delta Lake is an exception since many anglers take large numbers of these fish the year around. According to Table 14, the game fishes comprised 65.81 percent by number of the net catch but only 28.62 percent by weight. : At the time’ the lakes were resurveyed, it was recommended to the General Manager of the Water District that a commercial fisherman be allowed to take gar, gizzard shad, smallmouth buffalo, carp and mullet with three-inch square mesh gill nets. The Water District granted a six-month contract, from June 6 to December 6, to a commercial fisherman. He will be required to keep a record of the numbers, kinds and approximate weights of fish removed. All catfish taken in the nets were returned to the lake immediately. The lakes were revisited in December and three netting collections were made. Also, one seining collection was made. The nets were set in the east lake at locations previously used. This trip, made following the expiration of the commercial fisherman's contract, was to determine, if possible, what affect the netting had on fish population. Table 15 shows the results of the December netting. Cold and rainy weather prevented making the two additional collections in the west lake. A slight increase, probably a netting error, was found in the relative numbers of game fish taken in the east lake in December as compared to March. However, game fish represented 40.62 percent by weight in the December collections as compared to 28. 514 percent in March. Tables 16 and 17 show the lengths, weights and "K" factors of the fish netted in March and December, 1960. The "K" factors for the white crappie ranged from 1.88 to 2.68 with an average of 2.22 in March as compared to 2.26 to 3.37 in December with an average of 2.64. Thus an increase in the "K" factors was found concerning crappie. A slight increase in "K" factors was found in the blue catfish as well. Table 18 shows the March and December seining collections. During the six-month period the rough fish contract was effective, the netter re- moved an estimated 53,000 pounds of fish, mostly smallmouth buffalo. The breakdown was as follows: 45,000 pounds of buffalo, 6,000 pounds of carp and 2,000 pounds of gars. Still the netting collection of December revealed that buffalo represented 46.56 per- cent by weight of the fish collected. The General Manager of the Water District has assured us that the contract will be renewed soon after the first of the year if the commercial fisherman wishes to do so. => 1 based on the first three nets. --- Page 8 --- be If possible, this lake should be revisited around March 1961, in an effort to gather data similar to the resurvey in March, 1960. The commercial netting should be continued since this seems to be one of the most economical means of managing this lake. Water is pumped from the Rio Grande and is wnscreened. Consequently rough fish gain entrance and remain in the lake until teken out or die of old age. Bentsen State Park Lake This lake was treated with rotenone in January, 1960, to eradicate the existing fish population and restocked with black bass in March. Following the chemical treat- ment, 22 experimental gill nets were set to determine the success of the treatment. It was found that at least six small fish including five warmouth bass, Chaencbryttus wlosus, and one Rio Grande cichlid, Cichlasoma cyancoguttatum, survived the chemical treatment. The lake was practically pumped dry in the late spring as a result of eotton irrigation and then the Rio Grande River flooded into the lake in June, intro- ducing native fish. Attempts by the project leader to screen the gate valve inlets in the dem were not successful. Two netting collections made in August took 24 fish of two species; 11 gizzard shad and 13 black bass (Table 19). The shad undoubtly entered the lake from the Rio Grande since they were mostly adults and none were collected in the post-treatment netting. The black bass ranged from 8- to 10-inches in length and were in good physical condition. At the time this lake was resurveyed in August, 1960, it contained about 6 surface acres of water. Its capacity is aperoximately 96 surface acres. Table 20 shows the seining results at Bentsen State Park Lake. I% was found that smallmouth buffalo are present in addition to the gizzard shad. Only one seining collection was made. The lake was thickly choked with Najas, Potamogeton, and Ceratophyllum. The plant problem should lessen as the lake fills again. If the water level remains as is, ducks and other kinds of wildlife may aid in cropping the weeds. During the spring and summer months, several private citizens who own land adjacent to the lake, pump water to irrigate their crops. Consequently, the lake is always sub- ject to being pumped almost dry. Since the Rio Grande is the lake's only significant source of water and can be taken only during "free water periods", it is imperative to develop an effective means of screening river water before any further development work is undertaken. Lake Corpus Christi On January 8, 1960, an angler caught a white bass in the lower reaches of the Frio River, a tributary of the Nueces River above Lake Corpus Christi. This white bars was apparently stocked in Lake Corpus Christi in the fall of 1958. The specimen was brought to the regional fisheries office for identification. Other catches were reported during the year but since they were not seen, were not confirmed by this office. The perk manager at Lake Corpus Christi State Park reported that another angler caught a white bass weighing about one-half pound near the dam this summer. It appears that this smaller fish might have been-spawmed in the river since a two-year old white bass in this area would normally be expected to be larger. --- Page 9 --- =T= In June 1960, 129,500 black bass fingerlings were stocked in the lower portions of Lake Corpus Christi. Most of the bass were stocked in Pernitas Creek which is approximately one-half mile from the dam. The remainder of the fish were stocked in likely spots around the State Park slough. These fish were supplied by the National Fish Hatchery, Uvalde, Texas. No netting or seining checks were made. Lower Guadalupe River An investigation of the water hyacinth problem in the lower Guadalupe River was made in April, 1960. The river empties into Mission Bay which in turn empties into San Antonio Bay. A number of bayous in the area are completely choked with hyacinths and the borrow ditches along State Highway 35, between Tivoli and Port Lavaca, are likewise filled with the weeds. Up to this time, periodic floods on the Guadalupe River have been sufficient to wash the plants out of the river into the bay, but when Canyon Dam is completed on the upper Guadalupe River, in Comal County, floods may be less severe and thus create a serious hyacinth problem in the lower portions of the river. CONCLUSIONS AND RECOMMENDATIONS Fort Brown Lake will probably need some early summer treatment for submerged vegetation control. A selective gizzard shad kill may become necessary. In the future, the resurvey job will be a more intensive study of previously sur- veyed waters. Work such as we have been doing under the existing resurvey job will be _ done under the reconnaissance job (F-6-R, B-20). The information acquired from this limited study will point out the lakes which will require a more detailed study under the resurvey job. Prepared by Charles T. Menn Approved by 22 Jap tere Cote Assistant Project Leader Director Inland Fisheries Division Date February 20, 1961 --- Page 10 --- -8- Table 1. Results of collections with experimental gill nets, Fort Browm Lake, April 1960. Weights of fish collected eras) Species Stations Percent of =“ [total number} 1 | 2 | 3 4 | Total otal weight Gizzard shad We 95 Channel catfish* 3.31 Largenouth bass* 36.77 Warmouth* 0.14 Bluegills 11.99 Rio Grande cichlids 2,84 totals ee o,n61 | gam | 100.00 Percent game fish 17.75 40.22 Percent rough fish . 62.2 9.78 * Indicates game fish Table 2. Length-weight statistics for fish from Fort Brown Lake, April 1960. Standard length millimeters) Weight (grams) . "kK" Factors Species “iene Gizzard shad 200-325 292 165-794 223-2. 2.04 Channel catfish 370-370 370 1134-1134 2.2h-2,.2h 2.2 Largemouth bass 155-390 271 65-1956 1.75-3.31 2.65 Bluegills 90-150 121 25-160 2.97-5.57 3.99 Rio Grande cichlids 112-160 137 85-215 4.56-6.05 5.31 Warmnouth 118-118 118 50- 50 3.04-3.04 3.04 --- Page 11 --- Table 3. Results of collections with experimental gill nets, Llano Grande Lake, August, 1960. Number of fish collected Weights of fish collected (grams) Percent 0 Total | total weight Species Alligator gar 14.04 Spotted gar 2.28 Gizzard shad 6.61 Smallmouth buffalo 4.38 Carp 58.81 Channel catfish* 0.91 Blue catfish* 11.16 Largemouth bass* 0.76 Warmouth* 0.25 Rio Grande cichlid 0.80 notors____|ee {59 [08 [a6 [05 | 200.00 {57,308 J13,008 [22,208 Jro,930 | 74,528 | 100.00 * indicates game fish ** indicates no weight recorded. --- Page 12 --- =6= Table 4. Results of collections with experimental gill nets, Llano Grande Lake, October 1960. Numbers of fish collected Species Weights of fish collected (grams) [SSCStations | Percent of | sti“‘CStations | Percent of re a total number | 1 [| 2 | Total total weight Alligator gar 1 1 5 2h Spotted gar ) 5 14.67 Longnose gar (0) zZ 5.40 Gizzard shad 3 4 2.48 Smallmouth buffalo 2 2 14.01. Carp 4 1h 47. LY Channel catfish* 1 a8 1.38 Blue catfish* 3 h 8.79 Warmouth* 1 1 0.43 Rio Grande cichlid 2 2 O.46 Totals 18 17 35 100.00 Percent game fish 17.13 10.60 Percent rough fish 82.87 89.40 *Indicates game fish --- Page 13 --- Table 5. Length-weight statistics for fish from Llano Grande Lake, August and October 1960. length (millimeters )| Weight (grams) | Alligator gar 536-974 964-9497 ae 0.62=1.02 0.86 Spotted gar W553 680-1304 1012.71 0.70-0.96 0.81 Longnose gar 723-723 1984-198} 198.00 0.52=0.52 0.52 Gizzard shad 140-298 49Q~ 567 132.68 1.562. 39 1.93 Smallmouth buffalo 320-46) 1361-3799 2105.25 2.56=4..15 3.59 Carp 263-461 567-2495 1389.20 2.12-3.56 2.71 Channel catfish* 300-328 510- 680 595.00 1.88-1.92 1.90 Blue catfish* 263-432 319=1588 769.80 1.38-1.96 1.68 Largemouth bass* 300-300 567- 567 567.00 2.10=-2.10 2.10 Warmouth® 158-170 160- 190 175.00 3.88-4.05 3.97 Rio Grande cichlid 90-141 29= 121 51.47 3. 54=5 46 4. 33 *Indicates game fish Table 6. Seining Results, Llano Grande Lake, October, 1960. Species Numbers of fish collected _ Percent of total Threadfin shad Le bi Rio Grande tetra 12.22 Redhorse shiner 37.78 Variegated cyprinodon Led Mosquitofish 35.56 Sailfin molly ded Rio Grande cichlid he Ll Totals 100.00 --- Page 14 --- se Table 7. Results of collections with experimental gill nets, Campacuas Lake, October 1960. Percent of total weight Species Alligator gar 27.01 Spotted gar 2.74 Longnose gar 1.16 Gizzard shad 6.19 Snallnouth buffalo Carp Channel catfish* Blue catfish* Striped mullet Bluegill — White crappie * Rio Grande cichlid PNMNOOWEAANFOrRN Totals 100.00 Mh OCOOFRNOWN MOON ne OOFRPOCrFOCOOrFWOCONM ise) fee) as ; OO9OOFOWOWUFON Percent game fish Percent rough fish *Indicates game fish Table 8. Seining Results, Campacuas Lake, October 1960. Species Numbers of fish collected Percent of total Threadfin shad 117 55.0 Fk Variegated cyprinodon if 3.33 Mosquitofish 55 26.19 Sailfin molly 1 0.48 Tidewater silversides 30 14.29 Totals 210 100.00 --- Page 15 --- ~13- Table 9. Species Alligator gar Spotted gar Longnose gar Gizzard shad Smallmouth buffalo Carp Channel catfish Blue catfish Striped mullet Bluegill White crappie Rio Grande cichlid Standard length (Millimeters Length-weight statistics for fish from Campacuas Lake, October, 1960. | Weight (grams) | "kK" factors Range Average | __Range | Average | Range | 405-817 465-505 585-585 127-305 292-512 262-179 307-307 232395 27T-2TT 96- 96 254-260 92-132 907-4536 T94- 907 1106-1106 25- 510 794-580 510-3629 567- 567 150-1247 hho- 4ho es 652 1834.64 869.33 1106 203.10 1712.40 1615.89 567 713.91 hho a 581 1 0.72=1.45 0.70-0.81 0.55-0.55 0.80-2.27 3.18-4..35 2.737533 1.95-1.95 1.20-2.12 2.07-2.07 3-95-3.95 2.90-3.97 4 ,78-5.12 Average 0.81 0.77 0.55 1.61 3-75 3.23 1.95 1.74 2.07 3.95 3.44 4.95 --- Page 16 --- - jhe Table 10. Results of collections with experimental gill nets, Casa Blanca Lake, April 1960. dosetan Numbers of fish collected Weights of fish collected (grams) Te Ct~—“‘CStattions ds Percent of [Stations Percent | ay 2 3 eT 5] 6 7 8 [otal | fotal numerf 1[ 2{[ 3) 4 5] 6) 7] 8 | Total [total wt. Threadfin shad bE 3 649 1:51 Gizzard shad 34 | 26 1,921] 7,193 11.63 Smallmouth buffald 54, 3,941) 4,22) 16.15 River carpsucker 51 3 47.07 Carp 4h} 8 8.16 Channel catfish* 0} 0 4,84 Black bullhead Oo; 1 0.10 Largemouth bass* Lt 7 2.81 Redear sunfish* Ove i 0.06 Bluegill Oo} 2 0.14 White crappie* 2a, 4 5.04 Freshwater drum Sil 5 2.16 Rio Grande cichlid 1 ‘| 2 0.33 Totals 59 157 565 100.00 26,303} 31s65 han |s520 29,889] 29,725] 26,247 |28, 774 | 241,503} 100.00 Percent game fish 12.39 12.75 Percent rough fish 87.61 87.25 *Indicates game fish --- Page 17 --- -15- Table 11. Results of collections with experimental gill nets, Casa Blanca Lake, July 1960. Numbers of fish collected Species Pci ji Stations | Percent of ri] 2] 3] 3] 5] Oo] 7| S| Q[fotall Total number[ 17 2f 37 47 5] 6] 7] 8 | 9 | Total total weight Threadfin shad oO} O 0.32 Gizzard shad 10| 2 2.81 Smallmouth buffalo | OF 1 25038 River carpsucker 31 8 18.78 Carp O} 1 2.19 Channel catfish* QO} 1 13.45 Black bullhead QO} 0 1.85 Flathead catfish* 0} 0 2.55 White bass* O| 2 1.06 Largemouth bass* 1] 3 10.60 Bluegill 1] 4 0.49 White crappie* 20; 8 8.91 Freshwater drum oh ie) 11.42 Rio Grande cichlid | O| 2 0.25 rotors | ss bes 200.00 |5,r6o|,68fs0 636,05 ne, 303 13,h13]8,050|1,099 hs,920)s0 a8] 2c0.c Percent of game fish 37.95 36.57 Percent of rough fish 62.05 63.43 *Indicates game fish --- Page 18 --- Table 12. lLength-weight statistics for fish from Casa Blanca Lake, April and July, 1960. [Range | Average |__ Average _| K™ factors ~16= Threadfin shad 115-185 Loy 2.37 Gizzard shad 125-283 hie 410 1.33-2.68 1.88 Smallmouth buffalo 295-445 765-2693 2.98-4.,19 3-29 River carpsucker 265-385 4.54.=1899 1.37-3-77 2.90 Carp 298-60 652-2495 1.98=2.97 2.55 Channel catfish 170-545 80-3402 1.63-2.89 2.07 Black bullhead 225-262 2h5=- 394 2,152.59 2.34 Flathead catfish 485-485 2580-2580 2.26-2.26 2.26 White bass 262275 482= 595 2 ,69-2.86 2.78 Largemouth bass L77-475 122-2742 1.45=3.65 2.50 Redear sunfish 99-115 35- 60 3.61-4.06 3.87 Bluegill 88-130 30- 73 3.00-6.00 3.88 White crappie 98-294 2l- 652 1.69-3.04 2.46 Freshwater drum 185-320 150- 680 1.46-2,88 2.4.25 Rio Grande cichlid 165-180 218- 325 4. .85+5.57 5.22 Table 13. Seining Results, Casa Blanca Lake, April and July, 1960. Numbers of fish collected Species py om - PRPS RE |S a ee eee Percent of total number Threadfin shad 0 75 fe) 39.69 Pugnose minnow @) 1 ) 0.34 Redhorse shiner 0 ) 0 8.62 Variegated cyprinodon 0 0 9) 0.34 Sailfin molly 9) ) @) 0.69 Tidewater silversides 9) 6 @) Shete Largemouth bass 1 9) 0 0.34 Redear sunfish 3 (@) na Ze(D Bluegill 3 2 9 13.10 Mosquitofish ) ) e) 2.41 =a es = --- Page 19 --- Table 14. Results of collections with experimental gill nets, Delta Orchards Lake, March 1960. Numbers of fish collected — Weights of fish collected (grams) Species | __—sStations ——s———sr| Percent of Stations Percent of P af ey 3) 4] 5 | fotalltotal number [IT 27) 3 YT 5 J Total | total wt.. Alligator gar Oo; OF 1] OF 1 15.40 Spotted gar 1] 2] 4] of 6 13.20 Longnose gar 2} 1} Oo} 3] Oo 9.34 Gizzerd shad 3] O| &] 1]22 2.40 Smallmouth buffalo 6) 4] 8] 21 7 28.06 Carp 0 0 1] oO L 2.92 Blue catfish* 6] 3. 91177 1 11.60 Freshwater needlefish}| 1] O] O] O| O 0.06 Bluegill* O| O} Of] OF 5 0.16 White crappie* 6| 8]19] 5] 2 5.91 Freshwater drun* 5136] 3]28] 1 10.95 Totals 30 | 54 | 49 567457 23h 100.00 20,801 28,328] 35,214) 16,960 26,476 27,779 100.00 Percent game fish 65.81 28.62 Percent rough fish 34.19 71.38 *Indicates game fish Table 15. Results of collections with experimental gill nets, Delta Orchards Lake, December 1960. Species Spotted gar Gizzard shad Smallmouth buffalo Carp Blue catfish* Striped mullet White crappie* il pe drum * i} abeo Sane “Numbers of fish collected . Stations a “ | Percent of i 2 3 i a ee ee total weight 2.32 1.62 46.56 5 «65 11.89 3423 ah. 7h L 3-99 WPEFEOONHO ee PER L - FWONrFNDNE eRhowowro 1a) OQRVMIH Totals Percent game fish 73. 40.6 Percent rouch fish 1) pa co OF --- Page 20 --- =18- ta os © Table 16. Length-weight statistics for fish from Delta Orchards Lake, March 19 ‘| _Average_| Average millimeters } Standard leng Alligator gar 985-990 9072-9072 0.93 0.94 Spotted gar 350-654 243-2070 0,530.82 0.66 Longnose gar 550-843 652-2778 0.39-0.57 0.47 Gizzard shad 122-210 39- 169 1.38-2.14 1.63 Smallmouth buffalo 305-410 822-2155 2.29-3.46 2.92 Carp 340-440 794-2637 2.02=3.10 2.56 Blue catfish 130+556 23-2825 0.90-1.88 1.25 Freshwater needlefish 380-380 68- 68 0.12=0.12 0.12 Bluegill 100+110 31l- he 3.10-3.90 3.50 White crappie 110-256 Zu- 342 1.88-2.68 2.22 Freshwater drum 143-262 53- 387 Lo 742.65 2.24 Table 17. Length-weight statistics for fish from Delta Orchards Lake, December 1960. Standard length — ae See ee | Range Spotted gar yh 8-48 652-652 652 0.73=0.73 0.73 Gizzard shad 140-195 ho-148 113.75 1.78-2.00 1.86 Smallmouth buffalo ~ 305-341 992~1701 1188.09 3.17-4.73 3054 Carp 367-367 1588-1588 1588 3.21 Blue catfish 130-545 32-2665 667.60 1.29 Striped mullet 345-345 907-907 907 2.21 White crappie 166-240 122-313 192.91 2.64 Freshwater drum 122-210 38-218 12h .66 2.36 --- Page 21 --- -19- Table 18. Seining results, Delta Orchards Lake, 1960. Species Threadf in shad Gizzard shad Carp Redhorse shiner Tidewater silversides Freshwater needlef ish Striped mullet Bluegill Rio Grande cichlid Totals Fish collected | Maren, 1960 Percent of total December, Fish collected 1960 Percent of total 53°57 --- Page 22 --- =20-@] Table 19. Results of collections with experimental gill nets, Bentsen State Park Lake, August 1960. Numbers of fish collected eC Percent of 2 2 h “Percent of total weight Species Gizzard shad Largemouth bass Table 20. Seining results, Bentsen State Park Lake, August 1960. Species Numbers of fish collected Percent of total Threadfin shad Z 0,38 Smallmouth buffalo 5 1.90 Variegated cyprinodon 12 4.58 Mosquitofish 23 92.76 Warmnouth 1 0.38 Totals 262 100.00 --- Page 23 --- =P] Table 21. Checklist of species referred to in text and tables. Species Alligator gar Spotted gar Longnose gar Threadfin shad Gizzard shad Rio Grande tetra Smallmouth buffalo River carpsucker Carp Pugnose minnow Redhorse shiner Channel catfish Blue catfish Black bullhead Flathead catfish Freshwater needlefish Variegated cyprinodon Mos quitofish Sailfin molly Striped mullet Tidewater silversides White bass Largemouth bass Warmouth Redear sunfish Bluegill White crappie Freshwater drum Rio Grande cichlid Scientific name | Lepisosteus spatula L. productus iL. osseus Dorosoma petenense D. cepedianum Astayanex fasciatus Ictiobus bubalus Carpiodes carpio Cyprinus carpio Opsopoedus emiliae Notropis iutrensis Ictalurus punctatus i. furcatus i. melas Pylodictus olivaris Strongylura marina Cyprinodon variegatus Gambusia affinis Mollienisia iatipinna Mugil cephalus Menidia beryllina Roccus chrysops Micropterus salmoides Chaenob tus gulosus Lepomis microlophus iL. macrochirus Pomoxis annularis Aplodinotus grunniens Cichlasoma cyanoguttatum --- Page 24 --- == Table 22. Success of gill netting on all lakes in terms of numbers and pounds of fish caught. Number Lake and Date of feet of nets Llano Grande August & October, 1960 Campacuas October, 1960 Delta Orchards March & December, 1960 Fort Brown April, 1960 Casa Blanca April & July, 1960 Bentsen State Park January, February, & August, 1960 Average Average number of | number of fish per foot of net fish per net Pounds of | Average pounds of fish per net Average pounds of fish per foot of net 0.327 0.419 0.278 0.151 0.731 0.059