TPWD 1972 F-2-R-19 #1435: Job Completion Report: Evaluation of a Catchable Trout Fishery, Federal Aid Project No. F-2-R-19

JOB COMPLETION REPORT As required by FEDERAL AID IN FISHERIES RESTORATION ACT TEXAS Federal Aid Project No. F-2-R-l9 FISHERIES INVESTIGATIONS REGION 2-B Job No. E-9, Evaluation of a Catchable Trout Fishery Project Leader: Darrell W. Butler Clayton T. Garrison Executive Director Texas Parks and Wildlife Department Austin, Texas Lonnie J. Peters Robert J. Kemp, Director Chief, Inland Fisheries Fish and Wildlife Division May 9, 1973 ABSTRACT Catchable rainbow trout, Salmo gairdneri, were stocked in the Guadalupe River below Canyon Reservoir during March, 1966 by the Texas Parks and Wildlife Department in cooperation with the Lone Star Brewing Company when it was established that the deep discharge from Canyon Reservoir might provide suitable conditions for a cold water species of fish. Creel census indicated a return of 59 per cent of the 6,000 rainbow trout stocked during the seven month period following the stocking. Studies during the period of experimental stockings indicated that the tailrace waters would provide suitable conditions for trout during most years unless severe drought conditions existed. Catchable trout were provided by the Lone Star Brewing Company until 1969 at which time trout.were provided by the U. S. Bureau of Sports Fisheries and Wildlife. Catchable rainbow trout have been stocked in the fishery every spring and fall at a rate of approximately 9,000 per year. Over 60,000 have been stocked since the program began. The program has proven to be a great boost to the economy of the area and increased the fishermen utilization of the river over 2000 per cent in the first years of the fishery. Creel census has indicated a slight decrease in utilization since the beginning of the program and it appears that publicity of the stockings has a great influence upon fishermen harvest and utilization. JOB COMPLETION REPORT State of Texas Name: Region 2-B Fisheries Studies Project No. F-2-R-l9 Title: Evaluation of a Catchable Trout Fishery Job No. E*9 P. S. OBJECTIVE: To determine the desirability of maintaining a "put-and-take” fishery of catchable rainbow trout, Salmo gairdneri, in the tailrace waters of the Guadalupe River below Canyon Dam, Comal County, Texas. SEGMENT OBJECTIVES: 1. To determine the per cent return of stocked fish. 2. To determine the length of time a plant of trout contributes to the fishery. 3. To determine the average catch per man hour of fishing. 4. To determine the average catch per fishing trip. 5. To determine the average length of time per fishing trip. 6. To determine the economic factors involved, namely, the value of the returns. 7. To determine, through water quality studies, the continuance of Canyon Dam tailwaters to provide suitable trout habitat. 8. To determine, through bottom sample studies, the available food supply for a trout pOpulation. 9. To determine the utilization of available food by the trout. PROCEDURES: 1. Studies were conducted on the 11 miles of Canyon tailrace waters concerning gradient, average width, average depth, riffle areas, pool areas, aquatic vegetation, species of rough fish and game fish, etc. 2. Water quality studies were run weekly to determine continuing suit— ability of the water for trout. Dissolved oxygen, carbon dioxide, alkalinity, and temperature were recorded. 3. Bottom samples were collected at various stations monthly. 4. Creel census was conducted after each stocking and the trout fishery was creeled approximately every two hours from dawn until dusk" A creel card (Figure l) was filled out on each fisherman and a post card (Figure 2) given to him to fill out and mail at the end of that creel day. The creel census was conducted for at least five consecutive days and two consecutive weekends following each drop, with creel check coming every other weekend thereafter. An economic evaluation sheet (Figure 3) was filled out on every tenth fisherman. FINDINGS: Physical Characteristics of the Tailwater The Guadalupe River has its origin on the Edwards Plateau in south central Texas and flows southeastward through steep hills and limestone bluffs that characterize the region. This study was accomplished on a section of the Guadalupe River 12 miles northwest of New Braunfels, Comal County, Texas. The study area begins at the stilling basin of Canyon Reservoir and continues for 10.93 miles downstream. The stream has a gradient of 2.5 feet per mile, an average width of about 100 feet, and average depth of approximately 4 feet. The last figures will vary with the releases from Canyon Reservoir. The stream is clear to slightly murky and is composed of approximately 50 per cent riffles and 50 per cent pools. The stream bed is predominately gravel and limestone. Some silt deposits are found in the upper reach of the study area and in natural pools and in the five pools created by low water dams located at various points on the streams section. Water Quality Characteristics Eight temperature and water sample stations were established along an 11 mile stretch of the tailwaters. These stations are at intervals of approximately 1.2 miles (Figure 4). Weekly temperature and water samples were taken at each station -from 1966 to 1968. Periodic readings were taken before and after these dates. Water quality of primary concern, other than temperature, was dissolved oxygen, alkalinity, carbon dioxide, and pH. Turbidity and hydrogen sulfide concentrations were determined as the need arose. The average temperature by season and flow is illustrated in Figures 5 through 8. These graphs portray the seasonal fluctations of temperatures at low flows as well as the almost stable temperature reading at high flows regardless of atmospheric temperature. An over-all average temperature at each station regardless of season or flow is illustrated in Figure 9. Dissolved oxygen concentrations fluctuated very little throughout the entire . stream. A high of 13.0 ppm.was recorded at stations 4, 5 and 6 in mid-April, 1967. This occurred when the water release was the highest recorded since impoundment. A low of 7.0 ppm.was recorded in midsMay, 1967. This occurred just shortly after the release gates had been closed for repair. Normally, dissolved oxygen concen- trations ranged from 8.0 to 10.0 ppm. Total alkalinity ranged from 171.0 ppm to 222.0 ppm. Rate of water flow or season had little affect. Carbon dioxide concentrations ranged from 5.0 ppm to 0.00 ppm. The high readings usually occurred at 10w flows in the long deeper pools. Lower concen- trations were recorded as the flow increased. Average pH of the fishery was 7.6. FIGURE 3 ECONOMIC INFORMATION FORM FILLED OUT BY CREEL CLERK ON EVERY TENTH FISHERMAN Economic Information State City Main reason for trip Boat: Type Length Motor (hp) Rental fees: Boat $_ '_ Motor $ Launching $ License: Yes No Gas and oil purchased for boat: Gallons Cost $ Meals purchased today: Number Cost $ Light refreshments purchased for today: Cost $ Ice for today's trip: Pounds Cost $ Lodgingplace last night . Cost $ Bait and tackle purchased for today's trip: Natural bait $ Artificial lures $ Hooks $ Sinkers $ Line $ Floats $ Swivels $ Dip net $ Stringer $ Other $ Miles traveled today Mileage cost (calculated) License cost $ Total trip expenditure $ Remarks: Excessive turbidity was encountered only when heavy rainfall was experienced on the trout area. The gradient of the stream plus the amount of release eased this situation in a short period of time. Hydrogen sulfide, in trace amounts, was encountered at Station # 1 during July and August in 1967 and at other periods the following years when the lake was stratified. The water quality studies indicate that the tailrace area will provide suitable trout habitat during most years. There is the possibility of severe droughts occurring periodically which might affect the lower reaches of the present trout fishery, but these conditions can be overcome by alteration of stocking procedures. Temperature of the water would be affected most by a cutback in the releases from Canyon Dam, while dissolved oxygen seems to vary with different releases. Bottom Fauna Characteristics The results of the bottom sample collections are given in Table l of this report. As can be seen, Ephemeroptera and Diptera are readily available in the stream and these two, along with Tricoptera, are most significant in the demands of rainbow trout. Limited stomach sampling indicated that the preferred diet of the fish seemed to be Tric0ptera where available, but the fluctuation of the water level due to releases, many forms of terrestrial insects were also consumed by the trout. From all indications the food supply, in the form of invertebrates, in the Canyon tailrace area is more than adequate for the trout fishery. Aguatic Vegetation A list of the aquatic vegetation found in the study area can be found in Table 2. Native Fish Population The bulk of the fish population in this section of the river consists of rough fish; namely, longnose gar, gizzard shad, river carpsucker, and gray redhorse suckers. Game fish in the reach are channel catfish, flathead catfish, largemouth black bass, Guadalupe spotted bass, and numerous Species of sunfish. Other species found in the river include stonerollers, mosquitofish, logperch, dusky darter, darters, and various minnows and shiners. Large pOpulations of rough fish existed in the trout fishery until the past few years. It appears that cold water released from the reservoir has resulted in decreased numbers of all Species of native fish. Although various species are still collected, their numbers do not compare with those collected during the first years of the trout fishery. A list of the native fish found in the trout fishery can be found in Table 2a. Creel Census Results Extensive creel census was conducted from segments 15 through 18 to determine angler harvest and per cent return of the stocked fish. After this time only spot creel checks were made to determine continued use of the fishery. momm Hmm qu mam ma mom wmqa ONH omma HmHOH mm.m mm mm mm om NN.N \‘TNOOOHOOOOOOOOO Muir—i N mm q. q—l oqm ma ON mo.m _ eo.m mH.o «H o o H H o H o 0 OH mH o o N mm H N H o o o o H o o o o o o o H s o o o o 0 mm o H HH oH mm mm He mm _ mm o x 0mm Hm Nm om com um He mm cam How He NH NH a so . mam mmH No.0mm mo_ummm O\ N \‘t' \OO‘OOOOOOOOHOI—io \roxm Nr—lr‘s 'r-{u—i Chd'mLfiO" ra r—I mo_w5< mo_HH:h mo_mnnh mm on um mom 0H mmm no _ Mnmz :unoe wed mHmEHdm mo groans HmHOH mmdm2<m EOHHom MMHfianmH zowzmo H mHemH demo owmwusmflom .EU UHmDU ZH HzmzmomqmmHm AmHOH .mm manumomzum mumumwamm mumumonwwz mmdflunudm mmeHHHHmeoam mwommomm wwwaomsm meoaHeaee mucumEmz wmwwsnomnnmm mumumoomam mumnOpO mwoaouummo mwommomamm mwumHHonunh mumumomaoo mumudoowuH mnmumwm muomaoowwao muwudopmfiwsdm wwwm :mwm wwwm momnaaoz mumuumm mummwuum noumz meHmemnom mmsomwg mwuomm umumsfimmnm nmwmmmuo mfiuospnnom mwnom mauosmnnou wmuameomaD mmufla neumz mmwammcoum HmmEmQ @ mmwamnowmnm magnum mammmse nouwsfimmum . mau03umfim om>umH mam mmfiumom mewammwpwmo moflfim mEMOchsou wmucmsmmm mmHHmkmz mfimz neroo Scientific Name Chara vulgaris flypha latifolia Potamogeton natans Potamogeton pectinatus Najas guadalupensis Zizaniopsis milacea Nuphar g2. Nasturtium._p. Jussiaea _p. Myriophyllum heterophyllum Taxodium distichum Populus g2. Carya illinoensis Quercus g2. Lepisosteus osseus Dorosoma cepedianum Salmo gairdneri Carpiodes carpio Moxostoma congestum Notropis _pp. Compostoma anomalum Ictalurus punctatus Pylodictus olivaris Gambusia affinus Micropterus punctulatus Micropterus treculi Micropterus salmoides Lepomis spp. Hydropterus spp. Percina caprodes Etheostoma spp. Table 2 Checklist of Vegetation Aquatic Plants Terrestrial Plants Table 2a Checklist of Fishes Common Name muskgrass cattail boradleaf pondweed sago pondweed bushy pondweed southern wild rice water lily watercress water primrose parrot feather bald cypress cottonwood pecan oak longnose gar gizzard shad rainbow trout river carpsucker grey redhorse sucker shiners stoneroller channel catfish flathead catfish mosquitofish spotted bass Guadalupe River spotted bass largemouth bass sunfish darters logperch darters FALL -----50 cubic ft/ sec. 8 -.......... 250 cubic ft./sec. ..........500 cubic fh/sec. u.'7 m 3 u L O 0 :61 .n锓_ ‘.-.-. .p’wg-TL: - ""'"'"""— -“—o a. “‘1’". ’0‘, I‘I‘Vfl.‘.#. "'-”' 55 5° 1 2 3 4 ' 5 6 7 ' 3 9 10 11 River Miles Below Dam Figure 5 . -Water temperature vs miles of river downstream, at three different flow rates from September through December. 80 ._____.50 cjjt 75 T'""'""' 150. c.f.s. Spring 85 50 c.f.s. ---- 100 c.f.s. 80 75 3' i. 70 s ”a .. _,.—“' E 65 1"” 8. av’"’.‘- E , “as”, 0 flr’fl‘. 60 --'""’ l- ,f’.’ as .a"" 55 .pv"' 50 l 2 3 4 5 6 7 3' 9 10 ll River Miles Below Dam Figure 7. -Water temperature vs miles of river downstream at two' flow rates from April through June. 35 Summer —--50 c.f.s. 80 — --- 175 c.f.s. ----- 400:15. n.75 O I 2 .2170 ',av‘ 2 W... 0 . up” ....---‘ n65 ____.‘___.HM._,,__...- E «*7:.—---- ” fligfl.—r h. Ign::=*'wfi"r 60 .__.a— 9’ . r'::3—-“'r 1‘ 2 3 4 5 6 7 8 9 10 11 River Miles Below_qu - Figure 8. -Water temperature vs miles of river downstream at three flow rates from July through September.