TPWD 1969 F-2-R-16 #1248: Job Progress Report: Evaluation of Catchable Rainbow Trout Fishery, Project No. F-2-R-16

--- Page 1 --- JOB PROGRESS REPORT LO gk As required by FEDERAL AID IN FISHERIES RESTORATION ACT TEXAS Federal Aid Project No. F-2=-R-16 REGION 2-B FISHERIES STUDIES Job No. E-9: Evaluation of Catchable Rainbow Trout Fishery Project Leader: Richard L. White J. R. Singleton Executive Director Texas Parks and Wildlife Department Austin, Texas Marion Toole Eugene A. Walker D-J Coordinator Director, Wildlife Services October 7, 1969 --- Page 2 --- Abstract A total of 7,000 rainbow trout was stocked in the tailrace waters of Canyon Reservoir, Comal County, Texas in the spring of 1968. Creel census operations indi- cated an angler harvest of 35 per cent of the number stocked. Water quality studies and bottom sampling indicated the continuance of the area as suitable trout habitat. Fishermen harvest of 3,000 trout stocked in the late fall of 1968 was about 30 per cent. Despite the per cent harvest being lower than pervious years (owing to high water releases from the reservoir hindering fishermen efforts) the fishery was still felt to be quite successful. Project personnel recommend that it be continued. --- Page 3 --- Job Progress Report State of Texas Project No. Fe2-R-16 Name: Region 2-B Fisheries Studies Job No. E-9 Title: Evaluation of Catchable Trout Fishery Period Covered: February 1, 1968 to January 31, 1969 Background: In April 1966, rainbow trout, Salmo gairdneri, were purchased by the Lone Star Brewing Company, San Antonio, Texas, and stocked with the assistance of project personnel in the tailrace waters below Canyon Dam, Comal County, Texas. This action was instigated by the private concern after they had learned that the Canyon Reservoir Project Report (February 1960 prepared by the Branch of River Basin Studies) indicated the possibility of the trout fishery in the cold tailrace waters below tne dam. A 3-year stocking program including approximately 32,000 catchable trout donated by Lone Star Brewing Company ended with the May 1968 stocking of 7,000 fish. Evaluation through creel census of the 1967 stocking indicated a 59 per cent harvest of the trout. The initiation of this trout fishery provided better than 10,000 man hours of fishing in a 7-month period in an area where heretofore it would have been less than 500 man hours for the same period of time. The increased fishing pressure also pro- vided an economic boost of over $10,000 per year for the immediate area in terms of fishing tackle, bait, food, etc., purchased. Water quality studies, bottom fauna studies, and monthly sampling of the trout indicated that the tailrace continued to provide suitable trout habitat. Further background on this preject may be found in Job Progress Report E-9, Project No. F-2-R-15, Evaluation of Catchable Rainbow Trout Fishery, 1968. Objectives: 1. To determine the per cent of return of stocked fish. 2. To determine the length of time a plant of trout ccntributes 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. --- Page 4 --- ~2e 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: Approximately 7,000 eight to nine-inch rainbow trout were fineclipped (right pelvic) by project personnel on a trip in May 1968 to the Amyx Trout Farm, Rockbridge, Missouri. The trout were held at the hatchery for 26 days to observe any mortality or disease outbreak. Malachite green was flushed through the raceways 4 times during this period to inhibit disease and fungus. Twenty-six fish died in the raceways during this period. On May 27, 1968 approximately 3,500 trout were stocked in the Canyon tailrace and a like number were stocked on May 30, 1968. Figure 1 illustrates the trout stocking stations over the 8.9-mile area. Creel census operations began immediately and each drop site was checked every 2 hours from dawn until dusk. A creel census card, Figure 2, was filled out on each fisherman and a post card, Figure 2a, was also given to him to fill out and mail in at the end of the fishing day. This post card method allowed project personnel to compile total catch on the fishermen who left the area between creel census rounds. The creel census was conducted for 5 consecutive days and 2 consecutive weekends following each drop, with creel checks every other weekend thereafter. In conjunction with the creel census, an economic evaluation sheet, Figure 3, was filled out on every tenth fisherman. This procedure was included to determine what the trout fishery lent to the economy of the immediate area. Limited bottom sampling was carried out on the tailrace area to determine available food for the trout. High water impeded more extensive bottom sampling. The samples were preserved in 70 per cent alcohol solution and returned to the San Marcos Laboratory for identification. Water quality studies were periodically run on the tailrace in order to deter- mine the continuing suitability of water for trout. Dissolved oxygen, carbon dioxide, alkalinity, and temperature were recorded. Findings: Creel census procedures and compilations used in this report are described in Job E-9, Fe2-R-15, Evaluation of Catchable Rainbow Trout Fishery. The total harvest estimate was obtained by the regression method described by Leslie and Davis (1939) which is based on the principle that population size can be estimated from the day to day decline in catch per unit of effort as the population size decreases. In the application of this method, daily catch per man hour (Y axis) has been plotted against cumulative catch (X axis) of marked fish. --- Page 5 --- aon FIGURE 1. CANYON ITY tly RIVER ROAD « Grop sites o water sample sites --- Page 6 --- -ii- FIGURE 2. FISH CENSUS... PARKS AND WILOLIFE DEPARTMENT DAT LAKE NAME COPTIONAL) ———————____——sSsSsSsSsSSsSSSFFHOURS FISHED: MORNING—-—— AFTERNOO CITY. AT TOTAL HOURS FISHED. ane paras mame bot oot a BELOW LIST NUMBER FISHES CAUGHT UNDER THEIR NEAREST SIZE avaaiai fen [7] a | ot [ vor] vi [ra"[ra7 | 14*]15"[167]17" [18"|19"] 20°] 21°| 22"| 23°] 247] “| warceo rrour | ss—é<isSCSESC‘adYS STs ST SCT CT oT | UT cT hT hT hE TT Re a Os Oa GO GQ GD GG GGG DG a nS GD SD Gs OG DG A GG GG SuNFIBH ns Os ee ee Oe ee OG GQ GG GG GG CATFISH ne Ges aan es ee GO GG eG AGG — eee ee ee ee OS Pe ee Oe Ges es eee es Re A eG GG GG rT |tytey tyre ttt tet ft ft ft ft ff rT TTT™CSmt CMTC TdT cE TOTAL TT |fyytTt_etettt tt | ft ft tf | |] ft REMARKS KIND OF FISHING NUMBER OF FIGH CAUGHT WITH: FCHEDKS PLUGB__ Ss WI NNW TIT. eoaT c3) «SHORE C2) «PIER C3) TROLLING CD ___ ed STILL FISHING £3 CASTING C2 FLY FIGHING C2 SPINNE CRAYFISH OTHERS? WADE C } ART. FLIEQW____—E™—M WLW WORM BE SSSSSSSeSSSSSSSSSSSSSSSSSSSFSSSsSeSeSeSeSeSeSeSSSeSsSeFeFeSeSeSeSeFe FIGURE 2a. I ep eprint ADDRESS. NO. TROUT CAUGHT __NO. MARKED TROUT. NO. HOURS FISHED REMARKS : --- Page 7 --- FIGURE 3. ECONOMIC INFORMATION FORM FILLED OUT BY CREEL CLERK ON EVERY TENTH FISHERMAN Economic Information State City pee 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 $ pier Miles traveled today Mileage cost (caluclated) License cost $ Total trip expenditure $ Remarks; --- Page 8 --- =6- The projected catch on weekends was calculated to be 1,406 fish. Data and compilations for this projection are given in Tables 1, la, amd Graph 1. The projected catch of trout on weekdays was calculated to be 1,017 fish. Data and compilations for this projection are given in Tables 2, 2a, and Graph 2. The sum of these 2 projections, 2,423 fish, reveals an angler harvest cf 35 per cent of the 7,000 fish stocked in May 1968. These trout contributed to the fishery approximately 5 months with some limited catches being recorded as late as November. It should be noted, that there are some carry-overs of fish from one stocking to the next, and "contributing to the fishery" terminates when the catch per man-hour reaches zero for the first time. The decrease in fishing pressure was directly proportional to the increase in days following the stocking. , The average catch per man hour for the census period for weekends and weekdays was 0.47 and 0.56 respectively. The catch per man hour decreased steadily over the next few months. During the census period, weekend fishermen spent an average of 3.84 hours per trip and harvested 1.79 fish, while the weekday angler averaged 2.16 fish and 3.70 hours per trip. The data used in these projections were collected from May through July, although the census was continued into August 1968. In the regression method employed, it is necessary to use the data which decreases in a rather uniform manner, and for this reason, the data from May through July were used. During the period from May 30, 1968 through July 28, 1968 there were approximate- ly 1,141 fishermen censused with an economic sheet filled out on every tenth one. The fishermen spent an average of $4.36 per fishing trip. This figure did not include the cost of gasoline used in making the trip, but rather represents only what the angler spent in the immediate area for bait, tackle, food, ice, etc. Since the census was run on an every-other-weekend basis, it would be valid to assume that the total number of anglers would approximately be 2,000 over this period. This represents an economic boost to the area of approximately $8,720 by the trout program during the 4-month period. The fishery provided approximately 6,000 man hours of fishing during the period from May 30, 1968 to July 28, 1968. On May 26, 1968, a 17-inch, 3-pound rainbow trout with an 11%-inch girth was caught in the fishery by Mr. A. M. Benke of San Antonio, Texas. On June 22, 1968, Mr. Ron Sharp, San Antonio, Texas, landed a 21%-inch, 4 3/4=-pound rainbow which had a 13-inch girth. These fish were determined to be from 1 of the 1966 stockings since neither of these fish were fin-clipped in any manner. All of the fish, except the 1966 stockings, had been fin-clipped. Approximately 3,000 trout from the U. S. Fish and Wildlife Service were stocked in the river on October 21, 1968, Limited creel census operations indicated an approximate harvest of 30 per cent of the fish over the winter months. Inclement weather inhibited the harvest on this particular stocking, but these trout did provide good fishing until early spring. --- Page 9 --- 600T 066 126 TS6 O06 £88 918 VEL 969 LLY GLZ 9L yo re) aeATIeTNuNny) Ayteq ueoW UC GT CC ~ at Le LG 98 BL LE T9L 0UC Sl yo we) Ayted TeqIoOL 920‘T VET TL 97T 99 9S 61 €6 Let 90Z TEL OST GE TE? Tél 181 18 62% 68 ELE Siva GLE 991 CES G9 sSainoy sinoy Je [suy esn TeI0], s]uno) os WOT poepuedxy 986 092 °T STeqOL 81°0 TI €9 gz ATOL Z1°0 L 09 Le Aqne 0v°0 CT LE yT ATor 81°0 OT 9¢ EL Aine €1°O OT cl og eunr 8€°0 ay SII 6c aunr LE°O 17 OTT 9g eunr €7°0 €v O01 Gq eunr 09°0 78 Ov 6 eunr 6S°O GL 821 g eunr S9°0 SET 602 z eunc 99°0 IIT LOT Teun ano Je, suy Jeg yore9 qNOTL TeIOL qoqe9 sista) Uo Uses Aiewwung snsued [9eIQ JNoAL puayeem I °1qeL peusty sanoy a7eq --- Page 10 --- Table la Mean Daily 9 Cumulative Catch xX Catch Per Hour = Y XY 76 5,776 0.66 50.16 275 75,625 0.65 178.75 477 227,529 0.59 281.43 626 391,876 0.60 375.60 734 538,756 0.43 315.62 816 665,856 0.37 301.92 887 786,769 0.38 337.06 930 864,900 0.13 120.90 951 904,401 0.18 171.18 971 942,841 0.40 388.40 990 980,100 0.12 118.80 1009 1,018,081 0.18 181.62 =X = 8742 sx? = 7,402,510 =Y = 4.69 ZXY = 2,821.44 ax? = 76,422,564 N= 12 (ZX) (ZY) = (8,742) (4.69) = 40,999.98 ZXY - (2X) (Y) Slope of line = b= N 2 (2x)? 1 N = 2,821.44 = 3,416.66 7,402,510 - 6,368,547 -595.22 1,033,963 -0.000575668 In the formula Y = a + bX, we now have b and can find a by substituting the average values for X and Y in the formula. x= = Se = 728.5 2 on la - 4.69. N i200 ~Ct:t« 9 rl tl © ll o =< ° 5 -) wo Ke) ll a + (-0.000575668) (728.5) or 0.39 tl a + (0.41937414) 0.80937414 ie} 5 ie) ll --- Page 11 --- -9- Table la (continued) The equation of the line is : Y = 0.8093747 + (-0.0005756688) (X). If we set Y (catch per hour) = 0 (which it theoretically will become only when no more fish are to be caught, then; 0 = 0.80937414 + (-0.000575668) (X) then, X = 0.80937414 = 1,405,968 = 1,406 0.00057567 or X = 1,406 = estimated eventual return of marked fish on weekends. --- Page 12 --- CATCH PER ANGLER HOUR OF TROUT 1.10 1.05 1.00 0.95 0.90 -10- Graph l WEEKEND PROJECTED CATCH o a ra) @ X,Y a o © i) @ © @ { ss s88g888 8 8 8 8 8 8 8 a oN “ ral \-) © an ra) = Nn o od ~~ Ft wl CUMULATIVE CATCH Fig. Regression line of catch per hour pbotted against cumu lative catch, 1500 --- Page 13 --- «(i= G1¥ ELL 9EL GL9 679 909 69S €€S 69% C9E 092 80T “aa aATIeTNuND Aj teq ubow 82 94 62 6£ ce cv O€ L6 LTT 88 91¢ “yo3e9 AT ted TeI0], s}yuno) osf Wor; popuedxy 6L 89 LE 89°0 1? LL 6T 8E°O CC LOT 8S GE°O LT OL 61 by°O GS? €¢ 82 08°0O 02 OL 6Z 07°O 61 OT 09 €6°0 TY Ler G9 66°0O LG Shy 09 19°0 cS HOE SST TZ°0O 90T ~sinoq sanoy Inoy ieTsuy yNoIL TeIOL Jez, 3uy esn Jeg yo ze) TeIOL qoqe9 snsue) Uo Usaeg Azewung snsuad [eei9 4nozyl Aepyoom Z P1921 8¢ 67 Lg Ge LY va, 69 G8 671 ~ peysty sanoq TI 9une OL eunr ZL sune 9 aunr g eune --- Page 14 --- -12- Table 2a Mean Daily 2 Cumulative Catch x Catch Per Hour = Y XY 362 131,044 0.92 333.04 469 219,961 0.93 436.17 533 284,089 0.40 213.20 569 323,761 0.80 455.20 606 367,236 0.44 266.64 642 412,164 0.35 224.70 675 455,625 0.38 256.50 702 492,804 0.33 231.66 736 541,696 0.68 500.48 773 587,529 0.35 270.55 =X = 6,067 x? = 3,825,909 xy = 5.58 >XY = 3,188.14 (zx)? = 36,808,489 N = 10 (2X) (ZY) = (6067) (5.58) = 33,853.86 2X 2Y 2XY_-_N EX? - (zx)2 N Slope of line = b 3,188.14 - 3,385.39 3,825,909 - 3,680,849 197.25 145,060.00 -0.00135978 In the formula Y = a + bX, we now have b and can find a by substituting the average values for X and Y in the formula. KX = X = 6067 = 606.7 Y=¥Y = 5.58 = 0.558 N 10 N 10 Y =a = bX or 0.558 = a + (-0.00135978) (606.7) or 0.558 = a + (-0.8249797394) or a 1.38298 --- Page 15 --- «lB Table 2a (continued) The equation of the line is: Y = 1.38298 + (-0.00135978) (X). If we set Y (catch per hour) ® 0 (which it theoretically will become only when no more fish are to be caught, then: O = 1.38298 + (-0.00135978) (%) then, X = 1.38298 0.00135978 or X = 1,017 = estimated eventual return of marked fish on weekdays. --- Page 16 --- CATCH PER ANGLER HOUR OF TROUT 1.10 1,05 1,00 0.95 0.90 Fig. 100 -14- Graph 2 WEEKDAY PROJECTED CATCH tS =) 2 [=] =) fo} °o oO °o i) od N *“) = ed et ol 200 300 400 500 3 = 700 800 1400 CUMULATIVE CATCH Regression line of catch per hour plotted against cumulative catch, 1500 --- Page 17 --- i =15- Limited bottom sampling, owing to high water releases, revealed continuing availability of _Ephemeroptera, Diptera, and Tricoptera as 2 source of food for the rainbow trout in the fishery. Water quality studies continued to reveal suitable conditions for rainbow trout in the fishery. Dissolved oxygen readings ranged from 8-12 ppm throughout the area during 1968. The temperature ranged from a minimum of 49° F. at the first drop site in February to a maximum of 68° F. at the last drop site in July. During 1968 the average temperature at the head of the fishery was 56° F. and 59° F. at the lower end of the area. Although the water temperature downstream is somewhat affected by the releases from the dam, the dissolved oxygen varies imperceptibly with different release rates. Discussion: The total harvest of trout by fishermen during 1968 was down some 24 per cent from the previous year. This decrease in harvest is attributed to the magnitude of the releases from the dam during and following the spring stocking. Releases of 600 to 100 cfs made the tailrace waters quite turbulent and swift, and although the fish were not affected, the high water flow did hinder anglers efforts. Prime bank fishing areas were also inundated by the high water release, and wade fishing was all but impossible owing to the velocity of the water. Future stockings will be scheduled so that this detrimental aspect can be avoided. The decrease in angler harvest this year as compared to 1967 can also be attributed to the fact that there was no daily bag limit in 1967, whereas this year the daily bag limit was set at 5. In 1969 the bag limit will probably be raised to 10 per day. Fisherman access to the fishery area continues to be a problem, however, the stockings are being made in areas where access exists. This does, however, eliminate some areas which would be prime habitat and fishing sites. A study has been made of the areas which would be most suitable for acquisition and development into fishing areas. The 2 large trout harvested during 1968, supplemented by numerous catches of 1% to 2-pound trout, point out the ability of the fish to thrive in the Canyon Lake Tailrace. In the samplings of the population with electrofishing gear, project personnel have noted that almost all of the fish collected are in peak condition. Recommendations: Because of the success of the program to date, it is recommended that this job be continued for another segment. It is also recommended that definite aims be set to alleviate the access problem which exists on the fishery. ve oote Prepared by: Richard L. White _—s—s—sAppproved by: Vlparecore 1 Project Leader “Coordinator __RICHARD L. WHITE Date: October 7, 1969 _ Inland Fisheries Supervisor --- Page 18 --- - 16- Four-pound twelve-ounce trout on the right was stocked two years ago. At the time of its stocking it was the same size as the fish on the left. --- Page 19 --- =T7« Project personnel stocking rainbow trout in the tailrace waters of Canyon Lake. --- Page 20 --- - 18= References Annonymous. 1960. Canyon Reservoir Project Report, United States Department of Interior, Fish and Wildlife Service. 14 pp. Fisk, Leonard. 1966. Creel Census Method for Catchable Trout Fisheries. inland Fisheries Management, California Department of Fish and Game. pp. 187-192. Keuhne, R. A. 1955. Stream Surveys of the Guadalupe and San Antonio Rivers, Texas Game and Fish Commission Inland Fisheries Series No. 1. pp. 56. Leslie, P. H. and D. H. Davis. 1939. An attempt to determine the absolute number of rats on a given area. Jour. Anim. Ecol., Vol. 8, No. 2, pp. 21-20. McAfee, W. R. 1966. Rainbow Trout. Inland Fisheries Management. California Department of Fish and Game. pp. 192-216. Pfitzer, D. W. 1960. Investigations of Waters Below Large Storage Reservoirs in Tennessee. Tennessee Game and Fish Publication. 230 pp. Sharpe, F. Phillip. 1962. Creel Census of a Put-and-Take Trout Stream in the Cumberland Mountains of Tennessee. Jour. of Tenn. Acad. of Sci. Vol. 37, No. 1, pp. 8-14. White, Richard L. 1968. Evaluation of Catchable Rainbow Trout Fishery. Texas Parks and Wildlife Department. D-J Federal Aid Project Fe2-R-15, Job E-9, Mimeo. 24 pp.