TPWD 1958 F-2-R-5 #396: An Inventory and Creel Census of the Fishes of Lake Inks, Texas

JOB COMPLETION REPORT m Investigations Projects State of TEXAS Project No. F235 Name: Fisheries Investigations and Surve s of the Waters of Region 6—B. Job No. B—lh Title: An Inventory and Creel Census of the Fishes of Lake Inks Texas. Period Covered: February 1 1957 - June 30 1957 ABSTRACT: An inventory and creel census of the fishes of Lake Inks was conducted during the period from February through June 1957 primarily to determine the effectiveness of rough fish control work done under Job l6a-l, Project F-lM-le. Gill net results during March and May of 1957 indicated a noticable decrease in the abundance of gizzard shed, the species which had been the Object of selective control work in November of 193$. Illaddition, there was improvement in the angler's rate of catch for most species. However, prolonged rain caused serious flooding and over 1,282,000 acre feet of water were discharged through the lake from.Lake Buchanan in the period from may through June l957. With this tremendous influx of flood waters, many hundreds of thoum :ands of shad were seen entering the lake through Open floodgates on Buchanan Dam, the lake above Inks. Because of the influx of shed with the flood, it was soon apparent that the study could no longer provide information concerning the effectiveness of the rough fish work done the previous year. For this reason the job was terminated as of June 30, 1957. OBJECTIVES: To determine the relative abundance of the species present; to estimate the total catch; to determine the relative abundance of each species in the total catch and to deters mine the effectiveness of rough fish control work as done under'Job loa-l, Project Fith. TECHNIQUES: Inventory of Species . Insofar as was practicable, the work of the previous two segment periods was con- tinued except that netting collections were made on an everywother~month basis. Net colw lections were taken from the now long-established net stations in march and may and were discontinued because of the heavy flooding and the termination of the job at the end of June. No seine collections were made during the period the job was in effect because of high water and the inability of field crews to find suitable locations to seine. 2. Creel Census Creel census work was continued as usual on an every—fifth—day basis. 'Unfort- unately, however, little could be done in the way of creel census work during the period when Lake Inks was being flooded. During the rest of the study period it was necessary to seek out the fishermen wherever they were on the lake because they were not using the established census stations. The formula used in estimating the total angler”s catch is the same as was used in all previous segment periods on this job. (See reports for Job suit, Project F2R3 and Fast). FINDINGS: Inventopy of Species Table 1 contains the results of netting collections made in March and may of 1957. In all, a total of 558 specimens weighing 521.5 pounds was taken in 2,000 feet of experi~ mental type gill nets. These nets were each 125 feet in length with five sections of webbing ranging from,3/4 inch square mesh to 3 inches square mesh in 25 foot sections. A total of 16 nets were set for one night each at the eight established net stations. In the order of their abundance in the net collections the species taken were: gizzard shad Dorosoma cepedianum), channel catfish (Ictalurus unctatus), river carpsucker (Carpiodes ca 105, white creppie (Pomoxis annularisi, smallmout buffalo (Ictiobus bubalus),longnose gar Le.isosteus osseus), white bass (Roccus chrysops), bluegills (Lepgmis macrochirus), carp (Cyprinus ca 105, largemouth bass (Micropterus salmoides), freshwater drum (Aplo w inotus grunniensi, redear sunfish (Lepgmis microlophusi, warmouth (Chaenobryttus gulosus), and grey redhorse suckers (beostoma congestum . Creel Census A total Of-657 fishermen were interviewed during the period from February through June 1957. These fishermen took a total of 2,h28 fish in 2,205 hours for an average rate of catch of 1.1 fish per man hour of fishing (Table 2.). In addition, the catch from h trotlinss were examined during the same period. A total of only 6 fish were taken during the 68 trotline hours for a rate of catch of only 0.09 fish per trctline hourCTable 3.). Of the fishermen interviewed, it was learned that, with the exception of a few fish caught with flyrods (fly fishing is very rarely done on this lake), casting from the shore was the most successful method of fishing employed by Lake Inks fishermen during the study period (Table h.). Mbst fishermen using this particular method of fishing fished in the tailrace waters below Lake Buchanan at the head of Inks Lake. The next most sucw cessful method used was still fiShing from the shore (Table h.). Here again most of this type of fishing was done in the swift tailrace waters below Buchanan Dam during periods when the turbines were running at capacity. The most easily taken group of species is as usual the sunfishes. These were taken at the rate of h.59 fish per man hour by shore fishermen but only at the rate of 0.8 fish per man hour by boat fishermen (Table 5.). This discrepancy is easily explained in that most boat fishermen spend their time fishing for other'species and tend to avoid sunfish wherever possible. ' The single species most frequently taken by Inks Lake anglers was the white bass This species was caught at the rate of 1.92 fish per man hour by shore fishermen and 1.81 fish per man hour by boat fishermen (Table 5.). Channel catfish were next, being caught at the rate of 1.18 and 0.97 fish per man hour by boat and shore fishermen respectively (Table 5.). As usual live bait was the most effective type of bait in taking numbers of fish. Minnows and worms together took more than all of the other types of baits combined. Art» ificial lures, however, accounted for nearly a third of the fish taken during the study period (Table 6.). In all, it was estimated that boat and shore fishermen together caught a total of 78, #76 fish during the period from February 1,1957, through June 30, 1957. Of this total 20 ,h77 fish were caught by persons fishing from boats and 57,999 were caught by shore fishermen (Table 7.). The estimated total catch of 78, #76 fish weighed an estimated 63,608 pounds (Table 8.). In terms of per-acre yield, Lake Inks anglers took 70. 61 pounds of fish per acre from the lake during the five months of the study. Naturally, since white base were the most abundantly taken species they accounted for the greatest portion of the total weight, and though, on a per-acre yield basis this species was taken at the rate of h2.59 pounds per acre, it must be emphasized that most of these fish were caught in the tailrace waters below Buchanan Dam at the head of the lake. The white bass, which made up nearly half of the total fish in the oracle of Lake Inks anglers, were on the average 12.9 inches in total length (Table 9.). The channel catfish taken during the census period were 11.6 inches long on the average. Black bass, i.e., largemouth bass, and white crappie had average total lengths of 13.6 and 8.1 inches respectively. It is estimated on the basis of the sample taken that 18,39h fisherman fished on Lake Inks during the 150 days from February through June 1957. Of this total, over 10,000 fishermen fished during June (Table 10.). This is explained by the fact that during the other spring months large amounts of water were being discharged through the flood gates of Buchanan Dam and an estimated 1,282,000 acre feet of water passed through Lake Inks at a maximum discharge rate of 56,000 c.f.s. This caused a maximum.rise of 12 feet on this normally constant level lake. The average number of persons in the fishing parties which come to Lake Inks was found to be 2. 2 persons for parties fishing from.boats and 2. 0 persons fishing from the shore (Table 11). In Table 12 the home towns and counties of residence are given for the persons who were interviewed by creel census personnel during the study period. As would be expected the majority of the fishermen contacted reside in Central Texas, however, 5% out of the 25h Texas counties and two other states were represented in the sample. DISCUSSION: During the time that Inks Lake was under study it became apparent that two major fisheries problems existed in the lake. They were the increasing abundance of forage in the form of gizzard shed and the overabundance of submerged aquatic vegetation which, dur~ ing portions of the year, was making fishing extremely difficult from the shoreline and was cutting off boat fishermen from some of the more desirable and productive stretches of shoreline. In the first short segment period of study it was found that gizzard shad comm prised more than 51 percent of the total fish taken in nets from July 1955 through Jan- uary 1956. Then in the eight months from February through October 1956, this species increased in abundance to the point where it comprised 66 percent of the total netted catch (See report for Job B-lh, Project F2Rh). In order to combat this increasing abundance of gizzard shad it was decided that an attempt would be made to selectively control this species. In November of 1956 rota enone was used in carefully controlled concentrations to reduce this population as much as possible. It was estimated that 50 tons of gizzard shad were destroyed in this 900 acre lake. (See report for JOb l6a—l, Project Flth). Netting samples after the control efforts were made showed a decrease in relative abundance of gizzard shad in the nettable fish pepulation to 53 percent in December 1956. However, an increase to 62 percent was indicated in January 1957 (Table 1). Results of gill netting in March 1957 showed a decrease in abundance of these shad to 57 percent and the results for may 1957 showed a further decrease to 51 percent (Table 1). The average rate of catch by anglers prior to November 1956 was 0.66 fish per man hour of fishing. This was for the period from February through October 1956. After the selective control of gizzard shad was attempted in November 1956, the rate of catch increased to 1.1 fish per man hour for the period from February through June 1957. During May 1957 alone the rate of catch was 1.6 fish per man hour with 1,820 fish in the oracle of only 300 fishermen. The bulk of this catch was white bass, channel catfish, and white crappie (Table 2),(Figure 1). More recent reports indicate that fishing is remaining good and that increasing numbers of largemouth bass entered the catch. ... Unfortunately for the study, in April and May of 1957 an unprecedented rainy season caused a prolonged period of flooding everywhere along the Colorado River. The f area had nearly 30 inches of rain during the twonmonth period and the Lower Colorado River . Authority was forced to Open eight floodgates on Buchanan Dam. This permitted a total of 1,282,000 acre feet of water to flow through Inks Lake during the period from May through June (Figure 2). For approximately 30 days the level of Inks Lake was from six to 12 feet above normal (Figures 3, 4, and 5). With the excessive flow of water through the open flood gates on Buchanan Dam, tremendous numbers of gizzard shad were seen entering the lake. Though many of thee were killed in the trip down the spillway, (Figure 6) many more lived through the ordeal This influx of unwanted fish (Figure 7) soon made it apparent that the population study and creel census being made to test primarily the effectiveness of rough fish control work done under JOb 16awl, Project Flth were no longer able to provide the desired inm formation and the job was terminated as of June 30, 1957. Plans were made to combat the second of the major fisheries problems, the overs abundance of submerged aquatic vegetation, under an experimental job, separate from the 5. inventory and creel census. Hewever, in this case too, the hugh amounts of flood waters have made work on this problem in Inks Lake impossible and unnecessary. As it happened, at the time of the selective control of gizzard shad treatment in November of 1956, the lake was lowered a total of 12 feet. This exposed all of the sub— merged vegetation in the lake and most of it was killed during the short time that the lake was drawn down. After the lake was refilled, what was left of the vegetation became dormw ant for the winter and had not yet begun to grow again in the Spring when the floods came. Then, under six to 12 feet of water during the time when the growing season normally should have begun for these plants, the bulk of the plants apparently died. Thus, sub~ merged vegetation has not been a problem in Inks Lake during the period covered by this report. As a matter of fact, up to the time of this writing, submerged vegetation in this lake is essentially non-existent. CONCLUSIONS: Up to the time of the heavy flooding of May and June, there was some indication that the efforts to control the size of the gizzard shad population had been successful in improving the quality of fishing in Inks Lake. However, such large numbers of gizzard shad were seen entering the lake that further inventory netting results would be inconm elusive. Furthermore, the tremendous improvement in fishing results as shown for Mhy and JUne of 1957 could not be attributed wholly to rough fish control but was in part the result of the flood which apparently stimulated fish to feed and were thus more easily taken by anglers. This was especially true in the case of white bass and channel catfish which were taken in large numbers in the tailrace waters. The improvement over the previous year in the success in fishing for black bass was probably due to the absence of vegetation that permitted more effective fishing of the shoreline areas which had not ~een possible in several years. Prepared by: Kenneth C. 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Hamm.qm _ _ H.rm. mme mmOm.o .H.Ho.. . .mmimm. Table 3. Lake Inks Creel Census - Trotline Fishing Results - These data represent only the fishermen interviewed by Texas Game and Fish Commission personnel during the period February 1957 through June 1957. Month Total Total Fish Total Trotline Fish/Trotline Percent of Trotlines Caught on Heurs Fished Hour Trotlines Trotlines Catching Fish February* March 3 2 50.0 0.01» ,_ 66.66 April* " May 1 1+ 18.0 0.22 100.00 June* - Total n 6 68.0 0 .09 75 .00 Note: * — No creel census interviews were made during these months. W Table A. Lake Inks Creel Census _ Returns in fish and the return per unit of effort in fish caught per man hour or trotline hour for the various methods of fishing - used. These data represent only those trips where a single method of fishing was employed. Total Total Average Type of Fishing February march April may June Fish Effort Rate of Caught in Hrs. Catch Still Fishin Fish 7 0 9 A5 281 3M2 (Boat) Hours 17.0 0 36.0 52.0 265.0 370.0 Rate 0.41 0 0.25 0.87 1.06 0.92 Still Fishing Fish 0 2 158 1H2 1005 1307 (Shore) Hours 18.5 s9.5 60.0 111.0 617.5 856.5 Rate 0 0.0% 2.63 1.28 1.63 1.53 Casting Fish 3h I 78 22 ' 0 281 #15 (Boat) Hours 123.5 233.5 123.5 3.0 95.0 578.5 Rate 0.28 0.33 0.18 0 2.96 0.72 Casting Fish 28 2 0 25 213 268 (Shore) Hours 29.5 0.5 0 5.0 92.5 127.5 Rate 0.9 n.00 0 5.00 2.30 2.10 Fl Fishi Fish 0 0 0 0 0 0 (Boat) Hours 0 0 0 O 0 0 Rate 0 0 0 0 0 0 Fly Fishing Fish 0 0 0 50 O 50 (Shorej Hours 0 O O h.0 0 #.0 Rate 0 0 O 12.5 0 12.5 Trolling Fish 0 0 0 0 6 6 Hours 0 0 0 0 17.0 17.0 Rate 0 0 0 0 0.35 0.35 Trotline Fish 0 2 O t O 6 Hours 0 50.0 0 1 .0 0 68.0 Rate 0 0.0M 0 0.22 0 0.09 10. Table 5. Lake Inks Creel Census ~ Return per unit of effort in fish/man hour or fish/ trotline hour for the various species caught. These data are based only on catches in which a single species was involved and the average rates of catch include only the rates of catch for the months during which that species was ca . t. Total Total Average Type of Fishing February Mhrch April may June Fish Effort Rate of Caught in Hrs. Catch Sunfish Fish - — l w - 1 Boat) Hours - — 12.0 - n 12.0 Rate - - 0.8 - u 0.8 Sunfish Fish ' - - 1t5 78 2 225 (snore) Hours — - 22.0 2h.0 3.0 h9.0 Rate - - 6.59 3.25 o 67 t.59 White Cra ie Fish -; 1 - - - l ZBoati Hours - 5.0 — - - 5.0 Rate "' O 020 " "' "" 0020 white Crap ie Fish - - 2 3 36 A1 {Shore} HOursa - — 2.0 8.0 6.5 12.5 Rate - - 1.0 0.75 5.5A 3 28 Lar emouth bass Fish ~ 36 71 17 1 - 125 iBoatS Hours 118.5 128.0 no.5 2.0 _ 289.0 Rate 0.30 0.55 0.s2 0.50 - 0.A3 Lar emouth bass Fish . 6 2 a - - 8 (Shorej Hours 12.0 0.5 - - n 12.5 Rate 0.50 n.00 - - - 0.6a White bass Fish — - w 1 105 105 ZBoatj Hours _ - - — 58.0 58.0 Rate ""' “‘" m "" l. s 81- 1 s 8.1. White bass Fish 22 1 1 12 257 292 (Shore) Hours 1t.0 ~ 3.0 5.75 129.5 152.3 Rate 1:157 "' 0:533 2909 le98 legg Channel catfish Fish 1 ~ 6 18 73 97 (Boatj— “ Hours - - u.0 36.0 42.0 82.0 Rate ~ - 1.5 0.50 1.7% 1.18 Channel catfish Fish - 3 1 is 71 89 (Shore) Hours - 17.0 h.0 1t.5 56.0 91.5 Rate - 0.18 0.25 0.97 1.27 0.97 Channel catfish Fish _ 2 - h - 6 iTrotlinei Hours - 26.0 - 18.0 — 88.0 Rate - 0.08 - 0.22 — 0.16