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

JOB PROGRESS REPORT @5 As required by FEDERAL AID IN FISHERIES RESTORATION ACT TEXAS Federal Aid Project No. F=2wR-16 REGION ZHB FISHERIES STUDIES Job No. Ew9: 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 DHJ Coordinator Director, Wildlife Services October 7, 1969 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. Job Progress Report State of Texas Project No. F~26R-l6 Name: Region 2~B Fisheries Studies Job No. E-9 Title: Evaluation of Catchable Trout Fisher Period Covered: Februar -l._1968mt9_Januarp-31-H1969. .. 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 the 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 project 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 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. mQB 8. To determine through bottom sample studies the available food supply for a trout pepulation. 9. To determine the utilization of available food by the trout. Procedures: Approximately 7,000 eight to nineminch rainbow trout were finuclipped (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. Twentymsix 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 8.9emi1e 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 detern 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 pepulation 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. 1; drop sites 0 water sample sites RIVER ROAD FIGURE 1. CANYON cm -4- FIGURE 2 . FISH DENBUB . . . PARKS AND WILDLIFE DEPARTMENT DAT LAKE NAME [DPTIDNALJ _.__._._-.______.__.__————_——-———-———————-—-—HDUR8 FISHED: "DRNI~B——~———I——-—— AFTERNDD CITY - A1- TOTAL nouns nan-1:0 SPECIES DTAL MARK --- BELDW LIST NUMBER EIBHEE CAUGHT UNDER THEIR NEAREST mu CAUGHT fl-WEEEWWEEI " mm rm? —-------------------- unmm m. —-------------------I “an“... _-------------------I mm" _-------------------I we“ —-------------------I amm- _-------------------- —-------------------- _-------------------I , _----.---,------------- TOW- —-------------------- REMARK! I I 1 I KIND or rust-two NUMIEROF rIaH CAUGHT WITH: mum" ‘ PLuGa._.__.____.__—_.;MINNows—______cu73m1' IDAT [ 2| IHDIE C I "II C J TROLLIND I: 3 . WINNERS—MGMYFIIHWDTHERB? ITILL FIIHINB I J BAITINB I J FLY.FIIHlNB I: J WAD! t :l ' ART. FLIEI________————WDRM3______________._._______._——— - FIGURE 2a . WW ADDRESS NO. TRGJT CAUGHT ‘ N0. MARKED TROUT N0. HOURS FISHED REMARKS : -------------bll-—-----------------_-I--—_I------u-l--—-—--- FIGURE 3 . ECONOMIC INFORMATION FORM FILLED OUT BY CREEL CLERK ON EVERY TENTH FISHERMAN Economic Information State City W 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 %n_. Other $ Miles traveled today Mileage cost (caluclated) License cost $ Total trip expenditure $ Remarks: WWW“ a6l The projected catch on weekends was calculated to be l,&06 fish. Data and a" compilations for this projection are given in Tables I, la, and 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 of 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 carryeovers 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 l968. 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 includr 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 everymothermweekend 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 17minch, Bwpound rainbow trout with an 11%uinch girth was caught in the fishery by Mr. A. M. Banks of San Antonio, Texas. On June 22, 1968, Mr. Ron Sharp, San Antonio, Texas, landed a 21%ninch, 4 3/4mpound 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 finmclipped in any manner. All of the fish, except the 1966 stockings, had been fineclipped. Approximately 3,000 trout from the U. 8. 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. oOOH 0mm Hum Hmm 0mm mww oflw emu omo who mum on inoumo o>wuoaoeoo magma one: muoooo om: Scum moons mm om oMH H0 ma oNH co mm mm Ga no mo emu hm 00m Hma mm omH mm ow Hmm HNH mm Hma Hm hmH mmm mm flea mum moH sum mum 00H mmH Nmm mo .3oumo.. j.mnsom-.. munom. magma noawow omD HouOH HouOH owm oomaH mHouOH 0H.0 an 00 0N ease no.0 a 00 RN ease 0e.0 0a “0 an sass 0H.0 0H 00 mo ease 0H.0 0H 0s 00 mass 00.0 as man am muse sm.0 H0 one 0H muse me.0 me 00H 0H some 00.0 e0 0am 0 mesa 00.0 me 0mm 0 muse 00.0 00a 00a N muse 00.0 Han N0H a 0use .Hoom uoadnm mom flouwo noose Hones couoo momooo no snow muoeeom momooo Hoono noonH odoxooB H oHan _ oofimwm.muflom. -romco mgr Table la Mean Daily 2 Cumulative CatCh .. __H- ._X. ._ -__.----.CatchMPer_Hour = Y KY 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 2x = 8742 2x2 = 7,402,510 ZY = 4.69 zxv = 2,821.44 2x2 = 76,422,564 N = 12 (2X) (ZY) = (8,742) (4.69) = 40,999.98 ZXY — (2X2 (ZYz Slope of line = b = N 2 __i;itil. ZX - N = 2,821.44 e 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. .2 = E i 8742 2 72895 1, 2.111. = .31é2_. = 0.39 12 N 12.00 '§ = a = bX or 0.39 a + (-0.000575668) (728.5) or 0.39 a + (0.41937414) II or a = 0.80937414