TPWD 1957 F-2-R-4 #325: Inventory of Species Present in Lake Austin, Texas

STA‘KEw Texas “ROJQQT k0 EPRQ a -T Ob Bu PF*”OD FQQQQQQW thruufih NH" 199 gum-unn- WW 4"- -mmw.mfir Job Completion Ronrt JOhn Ea Tilton Assistant Project Leader Inventory of Species Present in Lake Austin, TEXflSo OEJE”T 6E8 TQ thQflminQ the species present and 1th.1 rQlQLiVQ aerdQ. 1 {3B TEE JIWA'LIO‘I A19hnugn origifiallv schedulezd to run frem February 1,1996 thxwau h Janaarv 1 t prnjaef was Lefim1n1tnd on June 1,1956 bEterial CJllECEQE darjr:1g TQQ . . -. 1h QQQ1Q9§ anh QQQ with QQ.tQ availale £10m TQQQQ GQQQ Qua F1 1h CQQQ1111QQ QQQQQQQ éuring L991 11611914, apr 11d suffiei.Qnt fQ1 fihQ perQQt1 f ~=M-\ n ‘3 was leL31ha.t thQ timQ alJQQQ11Q to thiQ wronQt could 0Q mQ1Q S 1 4: Q: {1- 5.14: 0 iii; Mo .U - 3 v F: --. r QerLE’ o 1‘” . 1 prmfifiably Qant QQ QQb EQR, E: erwmQQta Q1Q1rom Qf BJUQ Qk Bag. 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Q, 1.. 9:3 000 act-re fog-31;, 31:13; (39175311113) approximately 3,000 surface acres. Although 20 miles in length, the lake has a maximum width of slightly more than onewfourth mile with a maximum depth of sli tly over 50 at near the Tom Miller Dam. With the exception of the old riveI channel, the lake is relatively shallow and above the confluence of Bull Creek, water depths rarely exceed 15 feet even in the channel. The lake itself if situated in the rugged limestone hills of eastern Travis County. The surrounding country, with the exception of that portion which lies in a populous area of Austin, is cedar covered ranch country largely used for production of goats and cattle. The entire lake is incorporated in the city limits of Austin although bank areas in most sections are not included in the city limits. VESETATI ON AND COVER Aquatic vegetation, particularly myriophyllggwgp., is a constant problem to boat Operators and fishermen. The shallou waters encourage luxuriant growth of the aquatics. To combat the vegetation problem the city of Austin lowers the water level of the lake in February and early Harsh for a period of approximatel.y three was? Is. The vegetation was definitely retarded during the spring months, although during May the proolem was again becoming ac.ute and will undoubtedly be a major problei.befcre the fall montcs The heavy growth of 36 VEEgphyl EE§_1o the shoreline areas provides abundant cover for the young of many courier parT.iculai rJy the centrarchids. Little other natural cover is arr“lacis in Lake Au”..a, as the lake is sprimarily confined.to the second bank of the 1g.nal Coloraoo Rive.r bed which. was relatively Tree of heavy timber and brush. Some willow, alia niyra, is present and the heavy root syst QT‘ i . mac-.xaemm-vm: .mgm / V h w a.s do the natural rock and rock crevices of the lake. Limited names rs brushe flpil;es have been added by indi.vidual land owners in. an attempt to improve fishing around priva ate docks. ln addition, Game and Fish Commission Ffim rsonnel, sit the permission of cooperating land owners, half out willows to provide cover in the T’Lvike y Crash area of the lake. This work was done in 1951 and some cover Was still pie; at du.1ing the l955 s gm‘ pa: Tied. {a G} imfl COITDITION Lake Austin receives its water from.Lake Travis through the generators of mansm field Dam. The water entering Laize Austin comes from a depth of over loo feet and the time of discharge irom.the generators is cold and oxygen deficient. The water is througrly aerated in the first hundred ys.rds by extremely swift currents over rubble and boulder bottoms Tsomhundred yards below the actual point of dischar e the vets: contains a satisfactory oxygen content. fiuri ng the four month study p*ll0& no adve thermal or chemical conditions sale noted. Water temps stain. varied slightly tithn a S6“F high, n Feb1uary to EZOF hi sh in Mar. During the segment *ciiod no n.-surable tempw erature difference Teas found between the surface anal 10 feet. Dissolved oxygen averaged 9.2 ppm with a high oI 10.13 ppm and a low of 8. h ppm. Edssolved carbon dioxide was consi .tently low with a high 01? three ppm in M rch. The pE'varisdf from.7.8 to 8.6 ppm, with an arera age of 8.2. Throughout the segment period the water was quite clear due to the filtering action of the five lakes above the in. undment. FISH COLLECTIONS A total of 33 specimens were found to occur in Lake Austin and a checklist of species is included in Table lo Records are available on 763 netted specimens from Lake Austin including 396 individuals from the 195lm53 period and the 367 specimens taken during the short 1956 segment periodo Of the 763 fish total, 613 or BOchT percent were rough or forage speciesa Desirable game species including channel catfish, blue catfish, flathead cat» fish, shite bass, the centrarchid bass and White crappie made up only 11,92 percent of the total, with channel catfish accounting for over half of this figure. The giszard shad was the most abundant species with 296 individuals or 35,26 percent of total numbers. Freshwater drum with 1&9 individuals or 19052 percent of total numbers would appear to rank second in abundancea However, one 200 foot gill not set produced 137. of the la? individuals, predominantly sexually mature males in spawning condition, Quite probably the net set was made in the path of a spanning migration and this figur does not represent a true relative abundance figure for this species. In total weight rough and forage species, excluding sunfish, contribute-d 80a013 pounds-of the gin-3.06 total or 8531 percent, Smallmouth buffalo made up 35 31 percent of the total weight wi.th 336 82 pounds, The giasa ard shed was second with 15 99 percent of total se3 got 01 150 76 pounds Game soot ice , excluding sunfish, contributed only 13°63 percent of total weight ith channel catfish again making up about 50 percent of this figure Table 2 gives the number of specimens taken in gill nets, by month during the short 1956 segment period and includes total numbers and percent of total number, Table q 3 presents the same information for the 1951w 53 period out is broken down into quarterly d rather than monthly totals, Gables h and 5give the Wto al waivht and pe.rcent of total sseight figures for the two collecting periods: Tabl e 6 presents a consolidated total including total number, percent of number, total weright, and percent of total we ight by species for all us: tted specimens from the two collecting pesn ode Table 7 shows the success of gill netting in terms 0f number and pounds Of fifih fan the 1955 gegment period onlyo a comparison of results from the two collecting periods shows reasonably similar f3gures fo r most species, However, smallmouth buffalo, giszard shad, and freshwater drum show significc ntly different resul.ts The freshwater drum relative abundance figure has been explained but the great variation in relative abundance of smallmouth buffalo is not understood From observations of the catch of commercial fishermen it is known that a lat gs p: pulstion is present and ma n3 sale seen spa awningi 'n shallow sloughso Although gill nets core set at renders over tl“*e late very few buffalo were tsaena From observes tions of commercial catches and spawning concentrations the small mouth buffalo is unm doubtedly more abundant than the collecting figures for the 1956 segment ariod would indicatca althou gh nctt ing insulis fo ccard shad sho on strikingly different results, it is probably a difference in lfld‘“ldvcl 5 inc and not abundance, As shown in the 1951m53 h. seining collections the gizaard shad.was abundant in Lake Austin at that time but the bulk of the population was composed of young shad, too small for gill net capture. During the 1956 segment period few small shad were taken. Although still very abundant in the lake, the pOpulation is primarily composed of large adults easily taken by nets. Apparently some factor or combination of factors has reduced the shad spawn or young during the previous year, leaving a population of large individuals. Seining produced a total of 7,778 Specimens during the combined collecting periods. Of this number, only 72h individuals were taken during the 1956 period. Twentyufour seining collections were made and frequently less than 15 specimens would be taken at a station. The most abundant species taken in the seining collections was the gizzard shad with 2,721 individuals or 34.98 percent of the total. Second in abundance was the spot- tail shiner. Of the more important game species only the spotted and largemouth bass were abundant, with a combined total of 399 individuals or 5.11 percent of the total seined specimens. All sunfish combined made up 23.27 percent, with the bluegill accounta ing for over 50 percent of the sunfish taken. Table 8 gives the number of s ecinens taken in seines during the 1956 collecting period. Table 9 presents the same informaw tion for the l95lw53 period and Table l0 is a consolidated total for all seining collec— tions. DISCUSSION Lying Within the city limits of Austin and easily accessible from all sections of the city, Tnok.e Austin has become a maior recreational area. The lake shore is eaten” civclycevsio a=l with ooth permanent homes and weekend cottages. Wit h the trcnendods in.crease in boat traffic, wa ter skiing and other aquatic sports over the past fear years, the ardent fisnsrtsn have iurned to the quieter waters of the l.arger lakes in the Colorado chain. ins configuration of the lake Ji~olf leaves little room.for the fiche rmen. Narrot and lacking the sloughs and inlets of the larger lakes, it is very difficult to-escape the violent waLes of the fast moving motor boats. letting on Lake.Austin was accomplished by setting nets as near dark as posse ible and retri eving them before daylight L:o the morning, as working with nets during daylight hours was seriously hampered by the heavy traffic. Fishing pressure on Lake Austin was extremely light during the short L,gmwnt period on noi deli.n.g the lake a proximity to a population center of nearly 200, 000. Overabundant aquati.c vegvtation, a lai:ge rough f sh population, cror'ing or available wate -r b3 many boating en husiasts, all combine to discourage the fishermen. Becaugae of its location near a population center of this nice, Lane Aus.in scold sour beconc a very popular laLe and draw a far lrrgc- shale of the local anglers. nevzral vea'c ago fishing was very popular on the Male as i.t was possible for Austin Residents to fish the lake before working hours in the no sing and after fire in the afternoon. To mean tb.e fishing public back to the lore, some form of equalis ation for available water between iinhermen and othesr aquatic sports enthusiasts would be necessary. dpeed shooting and heav; fishing pressure are not compatible on this lake. The one most important problem in restoring good fishing is undoubtedly ough fish control» The extremely large rough fish and forage fish population supplies .ne lake with an overebundant natural food souroe for the game fish pepulation‘ What effect the annual lowering of the lake, during the early spring, has on the game fish pepulation was not ascertained but it is doubtful that there is any adm verse effecto. Further study of Lake Austin is recommended when a feasible plan for rough fish control has been proveno Present procedures for rough fish eradication would be difficult to carry out on Lake Austin because of the city water supply and the number of residences and business establishments on or near the lake shoreo SUMMARY lo Lake Austin, a 3,000 surface acre impoundment on the Colorado River was inm ventoried for species presento In addition, relative abundance estimates were made for the fish populationo 2° Collestions from the 1956 short segment period and data from.l951ml953 Tefas Game and Fish Commission records were used for this reporto 3o Rough and forage species excluding sunfish were found to constitute over 80 percent of the collected materiala So Channel oatfieh were the most numerous game fish taken by gill nets while slash base were tea most numerous in the seine collectionsa 6o Heary boat traffic and numerous water skiers tend to discourage fishermen from using the lakeo Table 1. Checklist of Species Found to Occur in Lake Austin. Scientific Name Lepisosteus os seus 'mmx Doro om_a cepedianum__ Ictiobus bubalus myt— Carpi iodes ca arpig Morostoma congestun Cflri nus (3 8.11310 N0t,£&§PEE3 c:ysoleucas* Ops0pgoodus emiliaef Notroois roseus Noircpjs Venus tus Not1ir spis luirensis my. mun LII-w um: Jm Inn Inmennales vigilax* mm W. «nu-ram m Mint-Wm” Pimeohal sprom—las* SST-- -wmwm Campo<+0ma a.nom.alum* mun—um Haw-1 WWW Iotalurus punctatus mm: mummy“ Airman-m Ictalurus furcatusm mmflmM- m“ .— Ameioru" natalism ”mun; mt mm 1 mm Filoujiias O11VMLLS 9' msxmmr l' ”*7 “BMW?“ L1H rwmwm huroutrs notatus mu: mmm.&w_'< .7.1.'.' EM: 1::— \rmezagmu-m _ w! 0 iv sameness eiilnis "waving-mm...»- or” 1': MW .-..'.;;.-«IuDI mura- 5111;; (3211 WE:- OPS n.- .J‘MA‘I' an...— 5.1“. :uim‘mm- “Luisa-OWNED"! micro Tn.us runcTulat sf an eman- rm: wanna 13-5 “mm-mm “LTJ Mi” gpterus ureculi “when.“ k ””1; *1? am cm...- M-AM-{J- Microeler s salmoides 1.5.1.1»th- maul-cs: am...“ can: Chaenwbryw us _coronarius ‘(mmgn' 1.:- Le “we“ cyenellus ulna-w .n hum—Irma m. .m Lepomrs panctaiusi ”.mmmm Lspofii microLiphus Wild-FLA .mw A.“ manna" I:L,!1,:i.£3 111,8.C J WC {311.1 1.118 324-“ -'-'. -. c: “mu4.mu'mmmu_ Le nr3~ euritus Lenoris 1e aloti Ema”. ,, ; Jfimlj “M— Pomosis annularis an.“ Parr; ina caurodesf mum gm Mamas-c mplooino us gru.nniens 1mw1m¢unmflmm-m3mmmfmmmw Cicul- one cyanogutta m. Common Name longnose gar gizzard shad smallmouth buffalo river carpsucker gray redhorse sucker EurOpean carp golden shiner pugnose minnow central weed shiner spottail redhorse shiner parrot minnow fathead minnow stoneroller channel catfish blue catfish yellow bullhe sad flathead catfish blackstripe tepminnow common mosquitofish white bass Kentucky spotted bass Texas spotted bass largemouth black bass warmouth green sunfish spotted sunfish redear sunfish bluegill sunfish yellosbreasted sunfish longear sunfish white crappie logperch freshisater drum Rio Grande perch * Species taken in Lake Austin in l921e1952 by Texas Game and Fish Commission personnel but not taken in this segment. .‘Wm gas-him ' . ml “(“7“ Table 2. Number of Specimens Taken by Gill Nets From Lake Austin, February 1956 through May 1956. ”WWW-m -_'n_-n-.—a -.-:.' .mm-twumem-w- .-.' mm Fish Species February March April May Total ' L' «mu-.3- .m'l.m 1.: .x u an. amp-“Mm “rm"mmmmm Mm WWW mung“ rum-r um run-mm max-Luz M Longnose gar O O 3 31 3h Gizzard shad A6 #9 ' 57 56 ' 208 Smallmouth buffalo O 3 2 2 7 River oarpsucker h ll , 6 26 Gray redhorse sucker 0 3 O O 3 EurOpean carp O 2 O 2 a Channel catfish 6 2 A 5 17 Blue catfish O l 3 O 4 Yellow bullhead l l. O 0 2 White bass 1 2 l O 4 use spotted bass 0 O 2 O 2 Largemouth blank bass 0 l l l 3 Wasmouth 0 l 3 O A Redear sunfish 0 l 0 l 2 Bluegill sunfish 0 0 13 22 3S Longear sunfish 0 O l O 0 White crappie 0 1 5 . ' 1 7 Freshwater arum 0 O 2 l 3 Rio Grande persh 0 0 l 0 1 Totals 58 78 I 103 128 367 WWWW’w-flwafl'wn ”min a“ amm‘mnmvmwmmmmmmwm 9-25 56.68 1.90 7-09 0.81 1.09 A.6h 1.09 0.5M 1.09 0.55 0.81 100.00 JMM‘u-mr- % of Total m film. m: V M' “W“ “”4“?“ i .mm ”cm—”Warm”- Miran-«Mn may Hmem w. mafiamw 0w wwwawtwbm awrmw 6% uHHH wwdfi wwefi WfiWQ wcmHHfi» Efid waH fiWfiGfimw m?fl£fifi% mew, P.» I! ill... .Ilullll. EIII!.E¢I‘ Fin-I’ll Kr xiiil E!!! .ii .iu.ifiiiil!i‘.lgi in] Iii. Wumw mwmopmm 2m% H fiwwofimw bfimr H Hwfiosmw Eww H HWHQSWW. bfim. H wdwmfimw Hoé. H mem Howww w 0% aome QSH% mH» HmmH Ooflg wow HmmH QSHw wHu Hmmm OQHQ we» Hmmm . fiwwosmw Zoe iIIEMNU. wH mem Hebmbomm mmw m H m o m Ha m.mw mwmmmwm mwma m m WA 9 My my Hm.ro mamwwaosww dcwwmpo o 0 WW mm . m «o H4.mm wwdmw aWHfimfionH Hm m HH w m ww m.m mmm% Hmmwowmm mfionH o H p. o o m o.WH mswommmw nwww o o _r _ o o r H.0H .QfimbbmH odeHmfi . Ho 3 m m HH . ww m.mw stm omfiwwmw H m H H m a H.flq WHm&Wmm@ omHWHmW H o o o H m o.mo EWHHm dmmm m _ m H H H 4 H.44 HmwmmEOCHW deow dmmm o O H o H m o.mH wmmmmd mSBWHmW o O H o o H O¢Mm mysmmwpp mnwwwmw m o w _ o .o ww w.mm Wobmmmfl m55mew m o o O o m O.mH SWHHQ owmwdwm H o H o H w 0.4m wwmmwzmama maze Fwd : . m o o Pym mm.ma wOHmHm wmm mm me pm w: wmm_._ Hoo.oo Ea! i Table 5. Pounds of Each Fish Species Taken by Gill Nets From Lake Austin, February 1956 through May 1956. mum—”mm“ ammwmmu Fish Species February Larch April May Total % of Total Longnose gar 0.00 0.00 5.06 52.45 57.50 15.88 Gizzard shad 29.88 26.50 38.50 33.56 125.54 32.36 Smallmouth buffalo 0.00 9.38 5.69 10.50 25.57 7.07 River Carpsucker 7.13 19.98 10.25 11.00 58.32 13.3%- Gray redhorse sucker 0.00 11.00 0.00 0.00 11.00 3.0M European carp 0.00 12.81 0.00 8.13 20.98 5.78 'Chapnel catfish 9.81 2.91 5.75 16.00 35.50 9.53 Blue catfiah 0.00 9.88 8.1 0.00 17.63 8.87 Yellow bullhaad 0.63 0.81 0.00 0.00 1.88 0.50 White bass 0.63 2.50 0.50 0.00 3.63 1.00 T. ; spattea bass 0.00 0.00 0.50 0.00 0.50 0.14 Largamouth basa 0.00 0.69 2.88 0.50 4.07 1.12 warmouth 0.00 0.13 0.38 0.00 0.51 0.15 Radear suhfish 0.00 0.06 0.00 0.19 0.25 0.06 B1ueg111 sunfish 0.00 0.00 2.38 3.06 5.11 1.51 Longaar sunfish 0.00 0.00 0.13 0.00 '0.13 0.03 White crappie 0.00 0.13 2.94 0.25 3.3 0.92 Freshwater drum. 0.00 0.00 1.75 0.50 2.25 0.62 Rio Granda perch 0.00 0.00 0.63 0.00 0.63 0.18 Totals #8.08 96.33 81.53 136.13 362.07 100 00 m mm-mem_ mu- "m HO. 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