TPWD 1963 F-7-R-11 #836: Job Completion Report: Experimental Management of the Lake Rita Blanca Fishery, Project No. F-7-R-11, Job No. E-3

JOB COMPLETION REPORT As required by FEDERAL AID IN FISHERIES RESTORATION ACT TEXAS Federal Aid Project No. F-7-R-ll FISHERIES INVESTIGATIONS AND SURVEYS OF THE WATERS 0F REGION I-A Job No. E-3 ExPerimental Management of the Rita Blanca Fishery Project Leader: Lonnie Peters J. Weldon Watson Executive Director Parks and Wildlife Department Austin, Texas Marion Toole Eugene A. Walker D-J Coordinator Assistant Director, Wildlife April 10, 1964 ABSTRACT The experimental management program at Rita Blanca Lake has included three phases of activity. Predator fishes, including white crappie, largemouth bass, black crappie and flathead catfish were stocked to prey on undesirable species. Habitat improvements included installing of spawning facilities for flathead catfish and channel catfish, and brush piles for shelter and protection of white crappie. Manual control of undesirable species consisted primarily of removal by seininga At the beginning of this job, the golden Shiner was the dominating species and comprised up to 70 per cent of the gill net collections“ Predation and parasitism reduced the Shiner population greatly, and during 1961 and 1963 no shiners were taken in gill nets and relatively few were taken by seiningr The bullhead population has remained essentially unchanged, indicating an insufficient amount of predation by flathead catfisho A potentially troublesome pepulation of goldfish has been controlled, The present status of the fishery is goodo Adequate numbers of white crappie (natural spawn) and channel catfish (mostly from hatchery sources) exista Crappie fishing has improved and channel catfish will be harvested in increasing numbers as they attain suitable sizeg Ecological problems have been brought about as a result of changing water quality and a prolonged drought on the lake watershed: JOB COMPLETION REPORT State of Texas Project No. F-7-R-ll Name: Fisheries Investigations and Surveys of the Waters of Region I-A Job No. E—3 Title: Experimental Management of the Lake Rita Blanca Fishery Period Covered January 1, 1963 - December 31, 1963 Objectives: 1. To evaluate the results of previous work. 2. To continue efforts to maintain a balance of controlling excessive populations of black bullheads, goldfish, and golden shiners. 3. To control noxious algae. Techniques Used: Two netting surveys were made during this segment to obtain evaluation data. These data were tabulated and compared with data from previous years to show any changes in relative abundance of fish species that might be attributable to the experimental management practices employed. Seining to reduce overabundant un— desirable species was attempted with limited success. Laboratory experiments were conducted to determine if c0pper sulphate could be used to selectively remove bullhead catfish or to control algae. Findings: Survey results show a definite increase in the white crappie population. In 1962, four surveys_produced 18.52 per cent white crappie. During 1963, two netting surveys produced about 30 per cent crappie. Tables 1 and 2 give the netting results for the two surveys made in 1963. The increase in the crappie population was noted in 1962 from seine sample data which revealed that out of _ 10,719 fish taken with 200- and 300-foot seines, 5,247 were white crappie. In September of 1962, brush piles were placed in the lake to provide added cover. It is apparent that by providing cover and protection, greater survival of young crappie was attained, and that this survival produced the increase in crappie. At present, the white crappie are definitely well established and should provide much added fishing. On August 28 and 29, 1963, considerable seining effort was eXpended to determine spawning success and to attempt to reduce undesirable species. During the two days, 19 hauls were made with a 300-foot one-half inch mesh seine. Since daylight seining failed to produce in appreciable numbers of undesirable Table 1. Percentage Composition by Number and Weight and Average Weight of Fish Taken from Rita Blanca Lake. May 14, 1963. (Four Double—Unit Standard Survey Gill Nets) Species No. % by No. Wt. lbs. % by Wt. Average Wt. Carp 1 0.22 2.05 0.67 2.05 Goldfish 27 6.10 33.33 10.94 1.23 Hybrid Carp 9 2.03 23.66 7.76 2.63 Channel Catfish 29 6.54 64.02 21.01 2.21 Black Bullhead 275 62.08 46.24 15.17 0.17 Flathead Catfish 8 1.81 97.04 31.85 12.13 White Bass 2 0.45 2.78 0.91 1.39 Largemouth Bass 4 0.90 15.04 4.94 3.76 Bluegill 1 0.23 0.24 0.08 0.24 White Crappie 86 ‘1/ 19.41 20.21 6.63 0.24 Black Crappie 1 0.23 0.11 0.04 0.11 Totals 443 100.00 304.72 100.00 Game fish 1] 131 29.57 199.44 65.45 Rough fish 312 70.43 105.28 34.55 1/ Note that 150 white crappie taken from the gill nets during this survey were immediately released back into the lake and are not included in this table. Table 2. Percentage Composition by Number and Weight and Average Weight of Fish Taken from Rita Blanca Lake. Aug. 27, 1963 (Four Double-Unit Standard Survey Gill Nets) Species No. Z by No. Wt. lbs. % by Wt. Average Wt. Carp 1 0.20 4.71 2.60 4.71 Goldfish 24 4.80 27.75 15.34 1.15 Hybrid Carp 2 0.40 4.02 2.22 2.01 Channel Catfish 5 1.00 6.43 3.55 1.29 Black Bullhead 374 74.80 70.24 38.82 0.19 Flathead Catfish 5 1.00 52.54 29.04 10.51 White Crappie 83 16.60 13.80 7.63 0.17 Black Crappie 6 1.20 1.44_ 0.80 0.24 Totals 500 100.00 180.93 100.00 Game.fi5h 99 19.80 74.21 41.02 Rough fish 401 80.20 106.72 58.98 W species, several seine drags were made at night between the hours of 9 p.m. and 1 a.m. It was thought that rough species might have been entering the shallows at night to feed, so better success was expected at this time. Such was not the case and neither day nor night seining was of much value in reducing rough.fish. Table 3 gives a comparison of seining results in 1962 and 1963. Note that bullheads show a considerable increase, but very few young-of-the-year were taken which indicates limited spawning success of bullheads this year. Fish Stocking Due to a lack of channel catfish spawning success during the last three years, a heavy stocking of hatchery-reared fish was made. About 30,000 catfish, ranging from 4 to 6 inches in total length, were made available from the Austin National Fish Hatchery. These fish were in excellent condition when stocked and should provide much fishing, provided survival and adequate growth are attained. Earlier in 1963, 3,500 channel catfish and 800 black crappie were seined from a ranch lake and were transported to Rita Blanca. The black crappie has shown rapid growth in this lake, but no reproduction was ever noted and the population has been greatly reduced. This stocking of black crappie was an effort to get the species reestablished. It is known that the black crappie is less likely to overpopulate lakes in the Texas Panhandle than is the white crappie, and, therefore, is considered a better fish for this area. Flathead Catfish Complete data concerning the growth of flatheads in Rita Blanca Lake during the past year are lacking due to the fact that no tagged flatheads were recovered during the latter part of the segment. Netting of flatheads was purposely post- poned until late in the segment when the water temperature would be cooler. Experience has shown that there is much less injury and mortality from netting in colder months. However, during the latter part of this segment, other duties and a prolonged ice cover on the lake prevented netting. A critical problem in obtaining growth data lies in the fact that the gill tags used to mark the fish are not staying attached. At Lake Marvin, where all of the 49 flatheads that were stocked were tagged with gill tags, recent recoveries of these fish show that only one out of five fish has retained its tag. It is now realized that better tagging or marking methods should have been employed, but in March 1962 when the 97 flatheads were transferred to Rita Blanca Lake, gill tags were the only type immediately available. Presently, a study is under way to determine the success with tatooing and subcutaneous tags. 0f the 30 flatheads recovered from Rita Blanca Lake this segment, 17 were tagged. The amount of data provided by these recoveries indicate that the rate of weight increase is considerably slower than that shown by previous data. Table 4 gives the tag numbers and weight change data for tagged fish recovered this year. Table 5 gives the length-weight data for those additional fish that were marked during this segment. Average rate of weight increase data have been collected seven times since the tagged flatheads were released in March 1962. The time periods between release and recoveries have ranged from 2.to 17 months. Actual recovery dates were 2, 4, 7, 9, 10, 12, 14, and 17 months following the date of tagging. Relative weight changes noted last year were minus 4 per cent in May (two months after release), plus 30 per cent in July (four months after release), plus 41 per cent in October (seven months after release) and plus 23 per cent in December (nine months after release). The 41 per cent increase shown in October was based on only two fish recovered during that month and may not be representative. In 1963, recoveries were made in March (one year after release), May (14 months after Table 3. Comparison of Seining Results 1962 and 1963. (300—foot one-half inch mesh) 1963 1962 Species No. % by No. %_by No. Relative Change from 1962 Carp 5 0.17 0.14 + 0.03 Goldfish 251 8.68 10.21 - 1.53 Hybrid Carp 24 0.83 0.47 + 0.36 Golden Shiner 444 15.37 9.02 + 6.35 Plains Minnow 2 0.07 0.00 + 0.07 Fathead Minnow 20 0.69 0.06 + 0.63 Channel Catfish 126 4.36 0.40 + 3.96 Black Bullhead 1,655 57.26 28.34 + 28.92 White Bass 0 0.00 0.05 - 0.05 Largemouth Bass 93 3.22 1.58 + 1.64 Green Sunfish l 0.04 0.00 + 0.04 Bluegill 11 0.38 0.59 - 0.21 Orangespotted Sunfish 2 0.07 0.00 + 0.07 Hybrid Sunfish 0 0.00 0.18 - 0.18 White Crappie 254 8.79 48.96 - 40.17 Logperch 2 0.07 0.00 + 0.07 Black bullheads comprised 57 per cent of the seine collections this year. Golden shiners totaled 15 per cent, goldfish and crappie about 8 per cent each. Largemouth bass at 3 per cent and channel catfish at 4 per cent were the only other species of importance. In comparing these figures with data from last year, important changes in relative abundance occurred in golden shiners (6 per cent increase), bullheads (29 per cent increase), channel catfish (4 per cent increase), and white crappie (40 per cent decrease). The great decrease in relative abundance of white crappie indicates limited spawning success this year, but this may be good since a general lack of forage exists and gill netting indicates an abundance of adult crappie already present. Growth rate and physical condition of crappie were decreasing and added crappie would probably have resulted in overpOpulation and stunting. Habitat Improvement Additional catfish spawning devices were placed in Rita Blanca Lake during this segment to enhance natural reproduction of this species. Last year, 40 such devices were placed in the lake in scattered areas surrounding the lower lake section where boating and skiing activity is very heavy during the spawning Season. Since the Spawning of channel catfish may have been discouraged by the heavy activities of boating and skiing in all areas in the lower lake, this year all of the spawning devices (50) were placed in the upper end of the lake where both boating and skiing are prohibited. The spawning devices were placed in 2 to 3 feet of water at sites extending from the barrier cable marking the restricted area to the extreme upper end of the lake. Channel catfish spawning success will be noted during the next year in an effort to determine whether natural reproduction has occurred. HmUHm b. Tag Number moMH moum mmom ono mama ammo momM mmmw mono mwmw mmmM mono mmow mmoM ammo mmmo mama Month Tagged in 1962 Kmunw 2m% Kenn? Keen? Emma: 2m% Keno: Zeno: Keen? Keen: Zmuor Keno: Zeno: Zeno: Zeno: Zeno: Zmuor macaw: amen Month Recovered 1963 Zeno: Emma: Keno: Zeno: Keno: Kenn? Keno: Zeno: Emma: Zeno: Zm% 3m% 3m% me 3m% me mcmcmn mom mHmnrmmmm Wmoo<mumm Number of Months Between Tagging and Recovery HM Ho HM HM HM Ho HM HM HM HM He He He He Ho Ho Hm Standard Length when Tagged moo owe woo mom mmm mMo omo mum moo 0M0 ohm mmm mmo moo mMo Weight in Pounds when Recovered Hm.um Hb.mm Hb.oo Hm.Mm w.mo u.om Ho.oo “.00 Ho.mo ©.mo HM.mo Ho.Mm Hw.Mm Ho.oo Hm.Mm m.um u.oo Ho Hoow Millimeters Increase in Standard Length hm Hm Mo MM Ho Mo mo +++++ + +++++++++ Pounds 111 Weight Change 9 U1LpLAJ CDC) 0 O c>cnc>c>c>c>t‘r‘uifi~ C>Hihik3£*K)C)h>U10\ c> NOOU‘I CD b.wm M.wo H.Mm o.ww 0.0m o.Mo H.bw Percentage Increase in Body Weight (Average) o.M©N HH.MDN Mo.wa Average Weight when Tagged HH.Hb HH.mw “.00 Average Weight When Recovered HM.MN HM.o© m.bw Average Percentage Increase in mm. Standard Length M.DHN b.0MN ©.©MN Table 5. Length-Weight Data from Flathead Catfish in Rita Blanca Lake, Tagged Since December 1962. Subcutaneous Date Tagged SL_§mm1 Wt. (lb) Gill Tag Tatoo No. Wire Tag Code August 26, 1963 600 8.93 6385 550 6.72 6383 585 10.44 6379 680 18.00 6397 March 6, 1963 834 34.50 6374 640 13.26 6375 722 25.50 6360 723 21.50 6663 January 31, 1964 521 6.83 6381 1 000101 730 18.96 6377 2 000110 787 23.00 6386 3 000111 742 22.25 6391 4 001000 557 7.77 6395 5 001001 WW release) and August (17 months after release). Relative weight changes for these three collections were 1.29, 11.94 and 20.43 per cent respectively. Relative weight changes as shown in Figure 1, show a cyclic trend which is undoubtedly related to seasonal changes in the condition of the fish. Data indicate that the flatheads reach a peak in physical condition (fatness) in September and October and rapidly lose weight throughout the winter and reach a low point in condition in early spring. The average growth in standard length at the end of one year was 2.41 per Cent or 0.6 inch based on eight fish. Individual increases ranged from zero to 6.82 per cent for the same group. The average growth increment was about one inch (total length). McCoy 2/ reported on the growth rate of flathead catfish in 21 Oklahoma lakes and gives 3.0 as the average annual increment in total length for flatheads in age group seven, which is the probable average age of the fish collected at Rita Blanca. COpper Sulphate Tests Laboratory tests using copper sulphate at concentrations of 2.5 to 4.5 ppm were made to determine if selective control of bullheads would be possible. Six 5-gallon containers were used, one of which was a control. The five re- maining containers were treated at 2.5, 3.0, 3.5, 4.0 and 4.5 ppm. Test fish in each container included two individuals of white crappie, golden shiners, channel catfish, and black bullheads. After three days duration, the test showed 2/ McCoy, 1953. The Rate of Growth of Flathead Catfish in Twenty-one Oklahoma Lakes. Prog. 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Relative Changes in Body Weight of Flathead Catfish in Rita Blanca Lake. Figure 1. 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IIIIIIIIIIIIIIIIIIILIIIIIIIIII IIIIIIIIIIIIIIIIII'IIIIIIIIIIIIIIIIIIIIII-IIIIIIIo ‘0 ‘M— Q t afi/woqg QNQOA‘BJ N ‘5 Y o gV *3 L K M ac *3 2 we 2 AG. Q ‘d no selectivity on bullheads at any concentration, and 4.0 and 4.5 ppm killed all test fish. Laboratory tests in 1958 - 1969 under Job E—l showed that bullheads could be selectively killed with copper sulphate, but this was before the be- ginning of addition of sub-surface water, which has increased the carbonate content of the lake water. The failure to get selective results during this year is due to the high carbonate content which tied up the Cu+2 in the form of insoluble c0pper carbonate. In reference to algae control, however, there was a definite difference in water color in the test containers at the end of the test. Water in the control container remained greenish in color while in all the treated containers the water turned a brownish color. Effective algae control appeared to have been obtained at all concentrations of c0pper sulphate used. Summary and Conclusions Job E-3 under Project F-7~R was initiated in 1959. Problematical species at Rita Blanca Lake included the black bullhead catfish, golden shiners and goldfish, all three of which are difficult to completely eradicate with toxicants. While the population of undesirable Species was relatively high, there was also a good population of channel catfish develOping, and a lake renovation at the time would have destroyed the many channel catfish as well as other game species present. Fishing had been poor at the lake and local pressures were for a total kill, but through the insistence of the 'biologist; the total kill was postponed in favor of an experimental management program. The lake was small enough to afford a good Opportunity to begin such a program, and by using various manage- ment practices such as the stocking of predator fish. habitat improvement, and removal of rough species with nets and seines, the fishery could be rehabilitated to an acceptable level. At the beginning of this study, the golden Shiner was the major problem due to its extreme overabundance. Gill net collections included as high as 70 per cent large shiners. Production of sunfishes and minnows was very low, due to competition with the shiners for food and space and predation by the shiners on eggs and fry. Commercial seining of shiners was encouraged and project personnel did as much seining as time permitted in an effort to reduce not only shiners but other rough species. Introductions of predaceous Species to feed on smaller shiners included stocking white and black crappie and largemouth bass. Flathead catfish were stocked to feed on the larger shiners, goldfish and bullheads. Habitat improvement was designed to enhance reproduction and survival of game Species. From year to year, varying amounts of work was done on each of the three phases of the experimental program. Stocking of predators was the most active phase of the program at the beginning and included transferring some 10,000 white crappie from Lake McClellan, 10,000 advanced bass fingerlings from