TPWD 1960 F-7-R-8 #572: Experimental Management of the Rita Blanca Lake Fishery: Segment Completion Report, Project F-7-R-8

Segment Completion Report State of TEXAS Project No. F-7-R~8 Name: Fisheries Investigations and Survezs of the waters of Region lmB. Job No. 3-16 _____ Title: Experimental Management of the Rite“ Blanca Lake Fishery Period Covered: Jannarz 12 1960 a December 312 l960 OBJECTIVES To initiate and conduct experimental management practices at Rita Blanca Lake to restore balance through the control of excessive populations of golden shiners and black bullhead catfishes. TECHNIQUES Predation on golden shiners and bullheads, as well as the threatening populations of carp and goldfish, was increased by stocking flathead catfish and predatormsized black bass and crappie in Rita Blanca Lake near Dalhart, Texas. Extensive seining was conducted in an effort to reduce populations of all prObleu matical species. This was accomplished partly by commercial bait seining under the supervision of game wardens and their appointed deputies. Attempts were made with specialized hoop nets and smallemeshed gill nets to cape ture and remove bullhead catfish and large golden shiners. Water levels were controlled by the addition of subusnrface water containing a higher mineral content than that in the lake. This also decreased tarbidity and ion proved habitat for game fishes, as well as fishing conditions for sportsmen. Artificial spawning facilities were installed to enhance reproduction of flathead catfish. Suitable spawning sites were located for all other game fishes so that additional spawning devices can be provided if, or when, they are necessary. These facilities will be placed between the extreme levels at which the water may fluctuate during the spawning season. ' Periodic surveys were conducted so that possible changes in any aspect of the Rite Blanca fishery resulting from these experimental procedures can be detected and recorded. BACKGROUND INFORMATION Experimental Introduction Largemouth Bass - Results of the original basic survey and inventory of species at Rita Blanca Lake in 1957 indicated that largemouth bass comprised only 0.9 percent of the total population. Details of these investigations are given in the Report F-T-Rw5, JOb B~13. Scarcity of this species in Rita Blanca is a significant factor because several sizeable stockings of bass fry and fingerlings have been made during the previous years. It was quite obvious that very few, if any, of these fish sure vived, and those that did survive failed to reproduce. The survey also disclosed that the golden shiner was the most abundant species present, comprising approximately 21 percent of gill net collections and 50 percent of seine collections. Since this species reputedly feeds on fry of other fish, their overabundance may have been responsible for the lack of successful reproduction of bass, crappie and other bottomenesting game fishes. An attempt is being made to re— verse the order of predation by stocking yearling or adult—sized black base, as well as other predatorwtype game fishes which are too large at the time of stocking to be eaten by golden shiners. In April 1959, an undisclosed number of adult bass were transferred from the statewowned lake near Canadian by State fish hatchery personnel. Then on July 23, 1959, an additional 10,000 cannibalmsize bass were stocked by the 0.8. Fish and Wildlife Service Fish Cultural Station at Tishomingo, Oklahoma. These fish,'uhich ranged from H to 7 inches in length, were too large to be eaten by the larger golder shiners, and large enough to begin feeding upon the smaller shiners. Flathead Catfish m In November, 1959, 288 flatheads were captured from Lake Stamford and transferred to Rita Blanca Lake, near Dalhart. This was a very successm ful operation, having lost only three out of the 288 fish that were transported during sub-freezing temperatures. These fish ranged from three to twentyaeight pounds. The average weight was 11.1 pounds and comprised a total weight of 3,171 pounds. The primary purpose of the introduction of these fish, which'were stocked at the rate of one per acre, was to increase predation on golden shiners and bullhead catfish. No restrictions were placed on their capture by sports fishermen, however, which makes them an additional sports fish for the upper Panhandle Region. 0f the 285 flatheads originally stocked in November, 1959, AC have been found dead during the past 13 months by the local game garden and lake management personnel. Causes of this mortality are not known for certain. There are several possibilities, including insecticides and organic pollution from watershed feed lots, Winter freezes kills, foul~hooking and hookmsnallowing. In addition to thonsfound dead, it have been reported caught by sports fishermen. This leaves a total of approximately 230 flats heads in the lake. White Crappie a In July 1960, approximately 6,850 white crappie were seined from Lake McClellan and transferred to Rita Blanca to increase predation on golden shiners. Also a small number of white base were taken during the coining operations and stocked incidentally with the crappie. m3... Manual Controls An attempt to reduce populations of all undesirable species was made by emperiw mental seining operations. Numerous drags were made'with a 200ufoot, onewhslf inch mesh seine at various locations around the lake. Seining was also done at night in the shallow cove areas. Although large numbers of fish were removed by this method, it is slow, restricted, laborious, and too expensive to constitute an effective cone trol measure. In order to reduce labor costs, commercial bait dealers were permitted to seine golden shiners on an'experimental scale under supervision of game wardens and their appointed deputies. More than 200 gallons of shiners, averaging lQO shiners per gallon, or a total in excess of 20,000, were removed on one occasion using this method. An estimated total of 50,000 shiners has been removed by seining operations. Specialized “bullhead nets“ were used on one occasion. These nets consisted of small, doubleethroated hoop nets connected in a series by lead nets. Since these nets caught more crappie than either bullhead catfish or shiners, they were discontinued. Small-meshed gill nets were also tried on two occasions. Although these nets caught numerous bullheads and large shiners, they were too destructive to small channel catfish and crappie. Therefore, their use was discontinued. All undesirable species, including bullheads, shiners, carp, and goldfish, that were caught during these seinings, trapping and netting operations were removed. Habitat Improvements In an effort to decrease turbidity and improve habitat for game fishes, as well as fishing conditions for sportsmen, water levels were controlled by the addition of subwsurface water containing a higher mineral content. This was accomplished by using electrically driven pumps with sininch discharges from two separate wells low sated on the northeast and of the lake. All pumping costs were provided by the courts of Dallam and Hartley Counties. Table 1 gives a chemical analysis of water, shoring the difference in water quality resulting from the addition of subusurface mater. In order to enhance reproduction of flathead catfish, thirty artificial spanning devices were installed in various locations around the lake in June 1960. Concrete culverts (12winches in diameter and 36minches long) were plugged at one end an placed in depths of H» to lOefeet deep. Suitable spawning sites for all game fishes mere low cated and mapped so that artificial facilities can be provided if, or when, they are necessary. These spawning devices will be placed between the extreme levels at mhich water levels may fluctuate during the spawning seasons. FINDINGS AND DISCUSSION Rita Blanca Lake was checkmseined in April and June, and completely resurveyed in May and OctOber in efforts to determine the effects of these experimental management procedures. Percentage composition of species collected by gill nets on May l8 and October 12 -1... is given in Tables 2 and 3 respectively. Approximately 1200 feet of experimental t; gill nets (1— to 3minch mesh) were used on both occasions. The survey conducted in May provided positive proof that flatheads are surviving and thriving in Rita Blanca, at which time 33 of the transplanted flatheads were cape tured. They were released immediately after capture in order to prevent mortality. All were in excellent condition, and on several occasions, males and females were taken very close together in the same net, indicating that they may be pairing—off or mating. However, no indications of flathead reproduction were shown in any of the surveys or seining operations during this period of study. After sufficient time and opportunity to reproduce has been permitted, some of the flathead stomachs will be collected and examined to determine the extent of their depredation on golden shiners and bullhead catfish. Although gill net collections showed a decrease in golden shiners from 70.2 percent in May to 39.1 percent in October, they were extremely abundant in OctOber seine collections. Approximately 35 gallons were taken in three drags with a lOOmfoot, éwinch mesh seine. Seine collections during June, July and October indicated very successful repro» duction of golden shiners. In contrast, there was no evidence of reproduction of largemouth bass, white crappie, or sunfish, even though all crappie and bass taken during the survey in May were ripe and in excellent spawning condition. If these species spawned, most of their fry were prObably consumed by golden shiners. However, a few young-of—theuyear channel catfish were taken in October. Examination of channel catfish stomachs collected in May showed no indication c- predation on shiners. They were feeding principally on insect larvae, huge Daphnia, snails and filamentous algae, probably taken incidentally to feeding on insect larvae. Crappie were also feeding mostly on insect larvae. Only one out of the 13 taken con" tained fish, and it was too well digested to be identifiable. One of the three bass taken contained a bullhead catfish measuring lhO-mm long. . a Only one of the 66 channel catfish examined in the OctOber collection contained a golden shiner. The others were feeding principally on the same items as they were in May except for considerable quantities of sewage organisms, mostly psychoda larvae. Only two of the 57 crappie collected contained golden Shiner remains. Coefficient of condition factors were computed for representative samples of specimens collected by gill nets. These fish were weighed, measured and the stage of gonadal development recorded, in order to detect any progressive changes in condition resulting from experimental management procedures. In order to maintain comparative data, this work'will be done during the same months each year, both before and after the spawning season. Table h presents a comparison of "K" factors of fishes collected in May and October, 1960, with the average of those taken between June and December, 1957- Obviously, all species except male golden shiners and both sexes of carpmgoldfish cross are in better condition than in 1957. This could be caused by several factors, the most probable largest contributing factors being less competition for space re» sulting from the increased water supply, and increase in food production resulting from increased water clarity and coverage of more fertile lake bottoms. rm- me Occasional fish kills continued to occur in Rita Blanca Lake during this segment. Fish of all species, but mostly golden shiners and bullhead catfish, were usually killed following rains on the immediate watershed. Fish mortality was confined primarily to a large bay near the dam which receives runwoff from the feed lot on the hill overlooking the lake. The cause of the fishwkill was assumed to be Cooper-Tex, an insecticide containm ing toxaphene, which is used to control flies and grubs in the watershed feed lots. Since large quantities of barnyard manure is also washed into the lake, oxygen depletion caused by organic decomposition in that immediate area could also have been partially responsible for the kills. Surface bubbling of decomposition gasses was quite noticew able in the upper onemhalf of the receiving cove. It was also interesting to note that most of the channel catfish that were collected in the lower end of the lake were feeding (and thriving) on sewage effluent organisms. Although no extensive damage was done to the fishe; y of Rita Blanca Lake, counts of the investigations were recorded and presented to the State Health Do and officials in charge of the lake so that corrective measures could as “Oflhlfl red t. prevent repetition of the incidents. ace In June 1960, a natural, selective fish kill on goldfish, black bullhead catfish and golden shiners occurred at the upper end of Rita Blanca. Although only undesirable species were affected by this die off, city officials and many of the local spo:r areas were quite concerned about eating the other unaffected game species and with wate1 skiing in the water. An investigation disclosed that all of the moribund and dead fish col1ected tears afflicted by abnormal gill conditions probably caused by a bacteria of the myxoaacaeria group, and commonly referred to as ”gill rot“. The fishnkill lasted for only a short duration, and the fishery suffered no noticeable damage. For additional information concerning details of this fishm kill and findings of the investigation, the reader is referred to the report, F M713 8, JOb O l. RECOMMENDATIONS Although insufficient time has lapsed since the beginning of this project to deter» mine any overwall effects, the benefits derived from raising the water level with harder, sub surface water are obvious. This is a very expensive measure, however, and the cost for continuing may prove to be prohioitive in the future. 1nerefor., con; sideration should be given to other methods of providing the necessary water at a lower cost. In this regard, the following recommendations are offered: 1. If pumping from the existing wells is continued, the water sho old a-e piped directly from the wells to the lake instead of being allowed to fall from the hllifild and flow through open ditches with sandy, pervious cottoms. Since the average evapor w tion rate in Dalhart area is 72 inches per year, there is little doubt that considerable amounts of money are being wasted by allowing water to evaporate and seep back into the soil before it arrives at the lake. 2. Recent investigations at the Dalhart Ci.ty sewage plant disclosed that the effluent is not sufficiently created. Also, discussions city officials revealed -6- plans to improve sewage treatment facilities. If this is accomplished, the treated sewage effluent could be run through a series of oxidation ponds stepped-down from the hillside plant, and utilized as make-up water for Rita Blanca Lake. Since Dalhart uses a sub—surface water supply, this would practically eliminate the neces~ sity of pumping water from the wells at Rita Blanca. Also the lower ponds in the series could be utilized for propagating bait minnows. These minnows could be used to supply the demand for bait at Rita Blanca, and the surplus could be sold elsewhere to help defray other Operational costs. The ponds could also be utilized as rearing ponds for hatchery-produced fry to offset the lack of natural reproduction of game species in the lake. Oxidation ponds should definitely be constructed between the watershed feed lots and the lake to absorb shock—loads of organic matter being washed from the feed lots and to retain lethal insecticides until they oxidize sufficiently to be harmless to fishes. Efforts should be made as soon as possible to determine the extent to which flat- head catfish are feeding on golden shiners and bullhead catfishes. If they are pro» viding satisfactory predation, then every effort should be made to achieve natural reproduction of flatheads in the lake. Otherwise, additional stockings should be made from lakes containing abundant populations of flatheads. Also, stocking of yearling or adult black bass, white bass, and crappie should continue until the golden shiner population is conquered and a desirable balance is established. Manual methods of Shiner removal should be exercised whenever possible, either by Game and Fish Commission personnel or by supervised commercial bait dealers. Thi work should be done in the spring prior to spawning, if possible, but removal of shiners at any time except when.bottom—nesting game species are spawning is desirable. Periodic surveys and studies should continue at Rita Blanca Lake so that changes in any aspect of the fishery, resulting from these experimental management procedures, can be detected and recorded. Prepared by Leo D. Lewis Approved by 222% v/fl‘fl’é Project Leader Dire tor Inland Fisheries Division Date April 25, 1961 Table 1. Chemical analysis of water, showing difference in water quality resulting from addition of sub-surface.water. Lake water Subwsurface water Lake water'- September 18, 1957 June 15, 1960 June 15, 1960 before addition _ _ (after addition- Calcium #6 3o Magnesium n #9 Sodium 5 23 Chloride 1h 7 Sulfate 2k 115 Carbonate O O Bicarbonate 96 Ebb Total solUble salts 185 #68 Table 2. Percentage composition of species collected by gill nets from Rita Blanca lake, May 18, 1960. - Species Number of Percent of _ fish collected total Channel catfish 9.69 Crappie 1.17 Bullhead l3.h6 Golden Shiner 70.20 Goldfish cross 1.08 Largemouth bass .27 Goldfish 1.16 Flathead catfish 2.97 Totals 1,11h 100.00 I... .1111}; 00.00H . mam mHopOB mm. seameaow :P.H SwHMQom 0H.mm amownm oowaow mm.ma wmonaasm mm.w ofimmmno mm.om nmwmpmo Homowno sweep eepeeHHoe case mo poooaom mo hopfioz mofioomm .omma .mH eeeeeeo .eaeo mommam upflm Scam memo HHHm an wopooHHOo mowoomm mo coapflmomsoo omwpomoawm_ .m manna alga i i {‘3 ' ‘2'" 4 a g “1 “"NO 1 J' '5 'Y 3"?9 ’— rs- t":'-1 visa-11 ._ .- T‘ ‘1". 2% =- 1r 55 -~ g; a— .na‘. m ‘6“ 'Q n- a 'T" m a. —. noneseeson cf tigen10H.L n o: 5 Ixytcifi for eita finite «as; sane 6:1o.gi ne’eibe .. f _ “In in. an - 1- M- "3‘4.- J: 1 fl ---1\ ml; collections on “a? 18 and octane: - 3 -900. r»: .. “'1 s a 1.. .1, ., '1 .. .v g . .2. . chattel eecfieaj lozézrtes annotatoa ' “w «flan-MI ‘21-'13- at) «run .456“; ' ‘ m ' '-.. —- -_-.-4 'WI'. mud-'- -- ,. W ma?’ - «won-W mm. Haas.“ mm‘l-"-‘M.wmh——‘kr - .mmm-Jmni-n} v.1..wrwao-4u'am‘se-flwm - -~- 9‘ ”If” f “m "'2 ""° 4579'0 “a r5 ° are '3’ 7 " L? .. t “I 9 ’9‘ {A} r‘. 1 ’3‘ 53 ‘h '3 C3 i m C” ’“i I: 4"“ “'5? 4"} 5. "L' C *..*='*._..-'r J. 1 3“ (211-13391... J: r... o 5 1'... .1 o . 3-. o {13 «.5. o J c k; 5: a g... .,.'- d a “'3 s... o 4 5’ o .1? 5—» o 56>" 5—"- o g i:- c- --’ 4.. “um in NW -"' mks—M o—a— WJ-MM M'JW‘N‘W'W ' 4 ' r I ' mm --‘- . 1957 Average males . -females May 18, 1960 males _females_ October 12, 1960 ' males —..fem81?3 White crappies Pomoxis annularis "K"_factor freuuencies P. 1957 Average males 1 3 1 females _ _ 2 h 3 2 l 1 ~1 1 h 2 .3 2 .1H may 18, 1960 males _females OctOber 12, 1960 males females 2.5 2;._2.7 2.:‘2.9'3.0 3.1’3.2’3.3'3. 0 1. Carp, Ciprinus carpio 9K" factor fre-uenCies 1957 Average males ”females May 18, 1960 No fish taken on last collection Average "K“- - 32513;? 32713?‘ 309 5.0 .1