TPWD 1967 F-3-R-14 #1102: Basic Survey and Inventory of Fish Species in Sam Rayburn Reservoir

--- Page 1 --- = JOB COMPLETION REPOR‘ if i i | As required by FEDERAL AID IN FISHERIES RESTORATION ACT THXAS Federal Aid Project No. F-d3-R-14 Region $-B Fisheries Studies Job No. B-22 Basic Survey and Inventory of Fish Species in Sam Rayburn Reservoir Project Leader: Joe H. Toole J. R. Singleton Hxecutive Director Texas Parks and Wildlife Department Austin, Texas Marion Toole Hugene A. Walker D-J Coordinator Director, Wildlife Services March 15, 1967 --- Page 2 --- ABSTRACT A total of 51 species were collected during seining and netting activities on Sam Rayburn Reservoir during the 2 segment period of this study. Twenty-nine species of fish were netted from the Reservoir this segment. Twelve game fish species were collected and 17 rough fish species as compared to 12 game fish species and 15 rough fish species taken in 1965. All the game fish species exhibited a high coefficient of condition. Sam Rayburn Reservoir has become one of the most popular fishing lakes in Region 3-B. Bass and crappie fishing has been excellent with many fishermen catching limits. Numerous camping and launching facilities have been built by the U. S. Corps of Engineers and the U. S. Forest Service. Many recreational areas are under construction at present. Netting data compiled during both segments indicate considerable increases in game fish numbers during the spring and summer months. These increases are primarily due to the collection of young fish which suggests that successful spawning has occurred. In review of these data further stocking of largemouth bass and crappie is not recommended. Sufficient field data have been collected to establish criteria for game and rough fish populations and the need for further stocking of game fish. It is therefore recommended that this job be terminated. --- Page 3 --- FINAL REPORT State of Texas Name: Region 5-B. Fisheries Studies Project No. F--3-R-14 Title: Basic Survey and Inventory of Fish Species in Sam Rayburn Job No. B-22 Reservoir Period Covered: February 1, 1966 - January $1, 1967 OBJECTIVES : To gather fundamental information on the newly impounded waters of Sam Rayburn Reservoir in relation to their physical, chemical and biological aspects. HISTORY : Sam Rayburn Reservoir was authorized by the River and Harbor Act of March 2, 1945. Work was begun on the dam in 1957 and completed in 1965. The earth filled dam is located on the Angelina River, 25.2 river miles above its confluence with the Neches River and approximately 10 miles northwest of Jasper, Texas. The dam has a height of 120 feet above the stream bed, a 30 foot crown, and a overall length of 19,430 feet. The dam has an uncontrolled spillway of 2,200 feet. The upstream slope of the dam is protected from eorsion by rip-rap. Water was impounded in April, 1965. At the top of the power pool, elevation 164.0 feet, the lake will cover an area of approximately 114,500 acres with approximately 560 miles of shore line. The present surface acreage is approximately 80,000 - 90,000. Sam Rayburn Dam is designed as a multi-purpose dam providing water conservation, hydro-electric power, flood control, recreation, and benefits to navigation. Hatchery fish were stocked in the reservoir in 1965 and 1966. Listed below are the species and number that have been stocked to date. Largemouth bass 461,000 Warmouth 80, 000 Redear sunfish 530, OOO Longear sunfish 40,000 Crappie 7,000 PROCEDURES : A collecting trip was planned for each month of the segment. Data collected each month included gill netting results and seining collections. --- Page 4 --- =o Netting Methods Experimental gill nets were used for all netting. These nets are 150 feet long and 8 feet deep with mesh size ranging from 1 to 3% inches in 25 foot sections. The nets were set out in the afternoon and picked up the following morning. All netted fish were separated according to species, then counted and weighed. Sexual condition and stomach contents were also recorded. Coefficients of condition ("K" factor) of game fish species were calculated. Seining Seining collections were made with a 26 foot by 6 foot bag seine with + inch mesh and a 15 foot by 4 foot bag seine with 1/8 inch mesh. Fish Collections A total of 51 species, representing 14 families were collected from Sam Rayburn Reservoir as shown in Table 1. This is an increase of 22 species and five (5) families over the previous segment. Netting A total of 2,132 fish made up of 29 species were collected by netting. The smallmouth buffalo (Ictiobus bubalus) was the most numerous species collected with a total of 667 (31.29 per cent). Figure 1 shows a sample of smallmouth buffalo. Black bullhead (Ictalurus melas) was by number the second most numerous species collected with 246 (11.54 per cent). The most numerous game fish species netted was the black crappie (Pomoxis nigromaculatus ) with 194 (9.10 per cent). Smallmouth buffalo had the highest percentage by weight (26.15 per cent) with the carp (Cyprinus carpio) having the second highest per cent by weight (19.59 per cent). Figure & shows some of the 209 carp taken during the 1966 segment. Table 2 contains the number, per cent of number, weight and per cent of weight of the total netting results during the 1966 segment. Table 3 contains the number, per cent of number, weight and per cent of weight of the total netting results during the 1965 segment. Table 4 is a chart showing the monthly catch of individual species. Table 5 indicates the coefficient of condition ("K" factor) for each species of game fish collected. All species of game fish collected were in good condition. Figure 4 shows a sample of largemouth bass (Micropterus salmoides) taken in January 1967. Seining Collections Six seining collections were made this segment consisting of 60 seine drags. A total of 1,640 specimens, representing 55 species were collected. Seining conditions have improved this segment due to the water level becoming more stable and killing the small brush along the marginal areas of the lake. Table 6 gives the number of each species taken by seining this segment. --- Page 5 --- Il. TI. IV. VI. ~3- Table 1 A Checklist of Sam Rayburn Reservoir Fish Species Family: LEPISOSTHIDAH - Gar 1. Lepisosteus spatula - alligator gar 2. Lepisosteus occulatus - spotted gar 5. Lepisosteus osseus - longnose gar Family: AMIITDAE - Bowfin 4. Amia calva - bowfin Family: CLUPEIDAE - Herrings 5. Dorosoma petenense - threadfin shad 6. Dorosoma cepedianum - gizzard shad Family: ESOCIDAR ~ Pickerels 7. Hsox americanus - grass pickerel 8. Es ox niger ~- chain pickerel Family: CATOSTOMIDAH - Suckers and buffalofishes 9. Cycleptus elongatus - blue sucker 10. Ictiobus cyprinellus - bigmouth buffalo ll. Ictiobus bubalus - smallmouth buffalo 12. Carpiodes carpio - river carpsucker 13. Minytrema melanops ~ spotted sucker 14. Hrimyzon sucetta - lake chubsucker Family: CYPRINIDAH - Shiners and minnows 15. Cyprinus carpio - carp 16. Notemigonus crysoleucas - golden shiner 17. Notropis atherinoides - emerald shiner --- Page 6 --- VII. VIII. IX. XI. 18. Lo. 20. 20. 26. -4- Table 1 (continued) A Checklist of Sam Rayburn Reservoir Fish Species Notropis fumeus - ribbon shiner Notropis chalybaeus - ironcolor shiner Notropis texanus - weed shiner Notropis amnis - pallid shiner Notropis venustus - blacktail shiner Notropis lutrensis - redhorse shiner Notropis stramineus - sand shiner Notropis atrocaudalis - blackspot shiner Jotropis maculatus - taillight shiner Family: AMBIURIDAE - Freshwater catfishes at. 28. 29. 50. ol. Ictalurus punctatus - channel catfish Ictalurus furcatus - blue catfish Ictalurus melas - black bullhead Ictalurus natalis - yellow bullhead Pylodictis olivaris - flathead catfish Family: CYPRINODONTIDAH - Killifishes and topminnows oe. Fundulus notatus - blackstripe topminnow Family: POECILIDAER - Mosquitofishes Oo8. Gambusia affinis - mosquitofish Family: ATHBERINIDAH - Silversides o4. Labidesthes sicculus - brook silversides Family: APHRHEDODERIDAE - Pirate perch 55. Aphredoderus sayanus - pirate perch --- Page 7 --- XII. XIII. XIV. -5- Table 1 (continued) A Checklist of Sam Rayburn Reservoir Fish Species Family: CENTRARCHIDAE - Black basses and sunfishes 36. oT. 58. 59. 40. 41. 42. 43. 44, 45. 46. 47. 48. Micropterus punctulatus - spotted bass Micropterus salmoides - largemouth bass Chaenobryttus gulosus - warmouth Lepomis cyanellus - green sunfish Lepomis punctatus - spotted sunfish Lepomis microlophus - readear sunfish Lepomis macrochirus - bluegill sunfish Lepomis humilis - orangespotted sunfish Lepomis auritus - redbreast sunfish Lepomis megalotis - longear sunfish Pomoxis annularis - white crappie Pomoxis nigromaculatus - black crappie Centrarchus macropterus - flier Family: PHRCIDAER - Perches and darters 49. 50. Percino caprodes - logperch Etheostoma gracile - slough darter Family: SCIAHENIDAH- Croakers, drum, and weakfishes Sl. Aplodinotus grunniens - freshwater drum --- Page 8 --- -6- Table 2 Netting Collections from Sam Rayburn Reservoir - 1966 Species Alligator gar Spotted gar Longnose gar Bowfin Gizzard shad Grass pickerel Chain pickerel Bigmouth buffalo Smallmouth buffalo River carpsucker Spotted sucker Lake chubsucker Carp Golden shiner Channel catfish Black bullhead Yellow bullhead Flathead catfish Spotted bass Largemouth bass Warmouth Spotted sunfish Redear sunfish Bluegill sunfish Number 25 34 42 93 48 48 667 55 209 14 246 55 34 75 110 Per Cent No. Lis 08 . 59 97 56 ts) .05 «09 229 29 .05 . 58 14 . 80 .05 . 66 . 04 48 25 25 . 59 . 52 .05 .05 16 Weight 255. 67. 99. 329. 132. 638. 41. 478. Ad. 104. 40. 19. o4. Ls 20% 56 94 87 94 wed .o7 . 06 Ol 65 75 81 87 45 13 24 56 56 8i7 .135 99 88 2d 7 18 Per Cent Weight 9.65 2.78 4.09 13.51 0.34 0.02 0.04 5.41 £6.15 0.07 1.71 0.03 19.59 0.01 1.03 4.28 1.65 0.81 O.17 2.290 0.73 0.01 0.02 1.03 --- Page 9 --- -7- Table 2 (continued) Netting Collections from Sam Rayburn Reservoir - 1966 Species Number Per Cent No. Weight Per Cent Weight Redbreast sunfish 6 0.28 1.32 0.05 White crappie 130 6.10 43.18 Le TT Black crappie 194 9.10 31s 57 1.29 Flier 14 0.66 1.50 0.06 Drum 17 0.80 35.38 1.45 eee Totals RUG 100.00 2442.38 100.00 Table 3 Netting Collections from Sam Rayburn Reservoir - 1965 Species Number Per Cent No. Weight Per Cent Weight Alligator gar 121 15.67 493.19 54.56 Spotted gar 25 2.82 29.31 2.05 Longnose gar 44 4.97 77.37 5.42 Bowfin 96 10.84 184.64 12.93 Gizzard shad 6 0.68 6.57 0.47 Blue sucker 1 Gis de ae 15 0.19 Bigmouth buffalo 15 1.47 26.12 1.83 Smallmouth buffalo 138 15.60 145. 67 10.21 River carpsucker 22 2.49 5.26 0.37 Spotted sucker 3 0.34 2.50 0.18 Lake chubsucker 1 O.11 0.19 0.02 Carp 239 27.00 280.62 19.66 Channel catfish 14 1.58 18.75 1.31 --- Page 10 --- -8- Table 3 (continued) Netting Collections from Sam Rayburn Reservoir - 1965 Species Number Per Cent No. Weight Per Cent Weight Blue catfish 8 0.91 56.13 2.53 Black bullhead 49 5. 535 20.08 1. 56 Yellow bullhead 9 LOX fs HL 0.50 Flathead catfish 9 1.02 29.29 2.05 Spotted bass ra 0.23 2.68 0.19 Largemouth bass 8 0.90 9.57 0.66 Warmouth Al 2.57 4.44 0.31 Bluegill sunfish 16 1.81 5.56 0.25 Redbreasted sunfish 3 0.34 0.26 0.02 Longear sunfish 1 0.12 0.19 0.01 White crappie le 1.56 10.24 0.72 Black crappie 8 0.90 Old 0.22 Flier iL O..12 0.25 0.02 Drum 15 1.70 25.12 1.76 Totals 885 100. 00 1427.10 100. 00 Food Most of the fish stomachs examined contained some type of food. The most common food items found were small shad and crayfish. Seining col- lections and the sighting of many schools of small shad indicates that there is a good supply of forage fish available for the game fish species. --- Page 11 --- gg 900 vt 60¢ GG L99 8Y oP £6 ov ve So Tey, OL, ve 96 9G GT “uer 6T et es £6 ‘9eq ‘AON OT el L9 GT OT "400 ol T G o "ydeg *3ny L &T Ge g ng eune 6c ae 8T et Len 8T 9T OT Vc -ady setoedg Tenptatpul fo yoyeg AT ULUOW v aL OL 6c 9G reN 96 o6T “qou sseq peyzodg UsTsPeo peseyuryela pesuLTTnqd MOTT Sx pesuTtng yoerTg, ysTszeo Teuueyp Jeutys ueptoy dieg Jeyonsqnyo ayey Jeyons pe yzodg Jeyonsdzeo JeATy oTesFnq YPNouTTeug oTeggnqg yynows tg [eteyotd uteyg [eteyotd sseiy peus puezztqty UT JMO Je3 9ssousuoy Jes peyyodg Jes JoLesttty setoedg --- Page 12 --- -10- cele CLL Sgt ELT TST 66 Let 99 GLT Sel ool 69T EGG STPPOL LT 0 0) 0) T 0 0) @ ) g v g g unig v1 fo) 0) 0 6) 0 0 T ) v 0 0) 6 JOT La v6T 0) T 0) ST eT 8 T 9 OT G ° Sel etddeso yoetg OeT 9 LT 9 6T v ve L TT L fo) aL LT etddeio 04 TUM 9 oO T 0) 0) 0) 0) T T i T T 0) ystguns ysesiqpey OTT G g vT ST OT eT 6 vI L G a 6) ystguns T11enta T 6) 0) 0 0 6) 6) ) T fe) 0 0 0 ystguns reepey T 0 ) T ) 0 0) ) 0 0 0 0 0 ystguns peyqzods Gh T g a g v v 6 ee vI 6 G T yp Now7eM ve 8 a 0 G 0 g ) 8 g ©) 6) i sseq yjnoweds1e7 Teyoy, ‘“uer °00q ° AON a6) ‘-adeg -Sny ATne eune Aeq °ady "IBN 6° Ga setoeds setoedg Tenptatpul fo yoyeg ATYWUOW (penutzuoo ) Py STIe, --- Page 13 --- -ll1- Table 5 Coefficient of Condition ("K" factor) for Sam Rayburn Reservoir Average "K" Species Number "K" Range 1966 1965 Channel catfish 13 1.51 - 3.36 2.16 1.89 Flathead catfish 2 2.20 - 2.63 2.42 2.41 Spotted bass 6 2.17 - 3.20 2 69 5.00 Largemouth bass 41 2.535 - 3.91 3.20 5.03 Warmouth 23 3.18 - 5.32 4.33 4.51 Redear sunfish 1 4.19 4.19 0 Bluegill sunfish 22 5.56 - 6.18 4.78 Deel White crappie 42 1.04 - 5.28 2.94 5.49 Black crappie o7 1.95 - 3.78 3.20 3.25 Table 6 Seining Collections from Sam Rayburn Reservoir 1966 Species Number Dorosoma petenense - threadfin shad 50 Dorosoma cepedianum - gizzard shad 87 Hsox americanus - grass pickerel 9g Hsox niger - chain pickerel ) Minytrema melanops - spotted sucker a Notemigonus crysoleucas - golden shiner 259 Notropis atherinoides - emerald shiner 4 Notropis fumeus - ribbon shiner 4 Notropis chalybasus - ironcolor shiner L Notropis texanus - weed shiner 8 --- Page 14 --- -12- Table 6 (continued) Seining Collections from Sam Rayburn Reservoir 1966 Species Notropis amnis - pallid shiner Notropis venustus ~ blacktail shiner Notropis lutrensis - redhorse shiner Notropis stramineus - sand shiner Notropis atrocaudalis - blackspot shiner Notropis maculatus - taillight shiner Ictalurus melas - black bullhead Ictalurus natalis - yellow bullhead Fundulus notatus - blackstripe topminnow Gambusia affinis - mosquitofish Labidesthes sicculus - brook silversides Aphredoderus sayanus - pirate perch Micropterus punctulatus - spotted bass Micropterus salmoides - largemouth bass Chaenobryttus gulosus ~ warmouth Lepomis cyanellus - green sunfish Lepomis punctatus ~ spotted sunfish Lepomis microlophus - readear sunfish Lepomis macrochirus ~ bluegill sunfish Lepomis auritus - redbreast sunfish Pomoxis annularis - white crappie Pomoxis nigromaculatus ~ black crapple Centrarchus macropterus ~ flier Percina caprodes - logperch Htheostoma gracile - slough darter Number 17 1 4 85 53 1357 66 258 258 28 19 UT 20 il 41 --- Page 15 --- -13- Game and Rough Fish Ratio During this segment 12 game fish species and 17 rough fish species were netted. Of the 2,152 individual specimens taken 589 were game fish and 1,545 were rough fish. By per cent of number this was 27.63 per cent game fish and 72.57 per cent rough fish. This is an increase of 5.99 per cent of game fish by number over the previous segment. The percentage by weight was 9.25 per cent game fish and 90.77 per cent rough fish, an increase of 0.94 per cent of game fish by weight over the previous segment. The smallmouth buffalo was the most common rough fish netted, with 31.29 per cent of the total number. Black bullhead was next with 11.54 per cent of the total number. Table 7 is a comparison of the monthly rough and game fish percentages by number for the 1965 segment. Table 8 is a compar- ison of the monthly rough and game fish percentages by number for the 1966 segment. Table 9 is a comparison of the monthly rough and game fish percen- tages by weight for the 1965 segment. Table 10 is a comparison of the monthly rough and game fish percentages by weight for the 1966 segment. These proportional comparisons in graph form were designed to offer a clearer picture of game and rough fish percentages from monthly collec- tions. As shown in Table 8, a greater number of game fish were collected during the spring and summer months than in the fall and winter. Mean percentage by number of game fish for the 12 month period is 24.74 per cent. Mean percentage by weight of game fish for the 12 month period is 8.70 per cent. The increase in the number of game fish taken in summer collections is due primarily to collection of young fish. This is in- dicated by relatively stable percentages by weight as contained in Table 10 for the summer months. Vegetation Observations of aquatic vegetation in the Reservoir have been made in conjunction with the netting activities. Numerous species of submerged aquatic plants are present in marginal areas but have not attained exces- sive growth to date. Bladderwort (Utricularia sp.) and coontail (Ceratop- hyllum sp. ) are common plants. When conservation pool level is reached in the reservoir marginal water depth will be sufficient in many areas to prevent excessive growth of submerged vegetation. Flat shallows will no doubt become infested with vegetation as the turbidity decreases with stabilizetion. Fishing Success and Recreational Facilities Sam Rayburn Reservoir has become one of the most popular fishing lakes in Rebion 5-B. Bass fishing has been excellent with many fisher- man reporting limits in the 2 to 4 pound class. Crappie fishing has im- proved as both the black and white crappie have shown a good increase in size. Figure 4 is an example of largemouth bass and white crappie from the January collection. Trotline fisherman have reported good catches of both channel and flathead catfish. Sam Rayburn Reservoir should become --- Page 16 --- Figure 1. Thirty pounds of smallmouth buffelo Figure 2. 209 carp netted in 1966 --- Page 17 --- Figure 4. 2 Bas: Largemouth bass and white craprie from January collection --- Page 18 --- TABLE 7 Comparison of Monthly Rough and Game Fish Percentages by Number 1965 a 7 anes D A iH a Mean percentage (82.63) Rough fish Z| ia 7a [fe CPST Eee [NAT yt tN rity ts Pi TT AAT ~ ~ 2 percentage (17.37) rt] Mean Game fish it Pi PN PIN TTT Litt Tey BRIE Deca eaenee " corer Pye ry ESne ERESRREK SERRA S88 S0ee - > SRR SALT TET ee LPN eer Pt A PET eA TT BR SEEER REREREICRE GERE REPRE Rie SEeeeERER AUG. SEPT. PHHH MAY JUNE JULY CI APR. DEC. NOV. OCT. e MAR. TT FEB * No sample taken this month --- Page 19 --- TABLE 8 Comparison of Monthly Rough and Game Fish Percentages by Number 1966 {2} Ae) - Ne} N e Ya & — © By 2 q 5) © h @ Py d ® = COCCI eee IN ae eee SRSENSRR eee Pity TT ESR TERR a 24e Cee ee eee eee TAT TTT TTP | | SERRE PEE ETT Pi Te TEP ty SReRRERe e ai a= ptt tf Mean percentage (24.74) mam am bl | Li TT ye LUT TYE ° Hts [| aaNe it | NSS eee [Sy i” Game fish Zit try PTT Tyrer KET TTT TT Pee Pi Ll jo) oO A Rf 4 oO MAY “JUNE JULY AUG, OCT. NOV. DEC. JAN. SEPT, MAR. APR. --- Page 20 --- TABLE 9 Comparison of Monthly Rough and Game Fish Percentages by Weight 1965 100 FTTT TTY 16, Mean percentage (85.81) Mean percentage (14.19) Rough fish Game fish LE tft SSSR R Eee ee Te CO Pree eee ee << COCCI eee eee ot a poo HEE a a an J eeke cr aan DEC. | 7 aan i NO = LH iz MI x = 7 y uae rT cs a i. r [7 re a : \ ae Rae SECC PPP Pree ERR eae eae PRE RRR BARRE ERERR RRR Shae kas ERERAGS Cee Pepi Suneneeeecues ee i a || Hl i i Hert = vs FEE FEE Be sanrane ‘a HHH Semeenre rH i SEPT. OCT. | NA Nj | x 7 inne aun | H a a CT ro rT a : a AUG. aes : | 7 = i oh H E i ene HH : : PEE rH HEH HE a } ce -| 4 as rE if 3 + a KEE | | | iF =) v as EEE a B . JUNE JULY | : + iv [/ i HH EHH cite HH oH Ht + i \ ‘ HA + 4 i Nae i erat xe A Hy || H MAY HARE : : | y | |_| a AFR. / ; ae rH a a \ | : ae aC FENE Bane ape aus rt A : = 4 | i on ae Se | | a H a | a | a | I] t I ; a a + = = - a oI = = tC _ - = MAR. + . e att PPP pr REECE PT Cee yy rye Cryer PPT TP PET tt SERRE LARK e fo] wt | | ae | Tt = 3 80 HO o 2 & se) 50 30 20 10 0 PER CENT BY WEIGHT * No sample taken this month --- Page 21 --- TABIE 10 Comparison of Monthly Rough and Game Fish Percentages by Weight 1966 Rough fish T : FHL i er = HH Fi AHA : ; : an EE ones Mean percentage (91.30) aS if i a F : HI 90 80 7 6 “ : | [| = || | Coo [EEE NCEE i Mean percentage (8.70) Game fish ee EO HUE LE i PER CENT WEIGHT ONT eee a St MS P| i Snneeea a PSSEEE | | OCT. AUG. SEPT, MAY . JUNE JULY AFR. --- Page 22 --- =18-= an important commercial fishery due to the number of largemouth buffalo, smallmouth buffalo, and carp present. It was reported that commercial fishermen took thousands of pounds of flathead catfish out of the reser- voir during the spring months. Sam Rayburn Reservoir has many fine launching sites and camping areas built by the U. S. Corps of Engineers and the U. S. Forest Service. Many recreational areas are complete and others are under construction at the present time. At present, the lake is approximately 10 feet below the conservation pool level, but most of the launching ramps can be utilized. Conclusions and Recommendations Sam Rayburn Reservoir has become one of the favorite fishing and recreational areas in Region 5-B. Many fine camping and launching areas have been built by the U. 8. Corps of Engineers and the U. S. Forest Service. Although the lake is still approximately 10 feet below the conservation pool level most of the concrete launching ramps can be used. Netting data compiled during both segments indicate considerable increases in game fish numbers during the spring and summer months. ‘These increases are primarily due to the collection of young fish which suggests that successful spawning has occurred. These increases in game fish per cents by number are indicated in Tables 2 and 3. Largemouth bass, white and black crappie were also collected by seining as contained in Table 6. Sufficient protective cover is present in most areas of the reservoir for young fish. In review of these data further stocking of largemouth bass and crappie is not recommended. At this time relatively few channel catfish have been collected by netting and no channel catfish fry or finerlings have been seined. It is therefore recommended that additional stocking of this species be conducted. The many complex factors influencing fish population dynamics in a reservoir make difficult the analysis of collection data. With the rapid increase of habitat area of Sam Rayburn Reservoir the validity of comparing unit net samples for both segments is questionable. It is doubtful that fish populations in the reservoir expanded during 1966 as rapidly as hab- itat area. Therefore numbers of individuals collected per unit of net would decrease although total populations were increasing in the reser- voir. As contained in Table 3, 1965 netting data, and Table 2, 1966 netting data, this is not indicated for most species in the reservoir. Species showing notable decreases in per cent by numbers are carp, alligator gar, longnose gar, and bowfin. In general, netting data indicate good populations of game fish species and sport fishing success is increasing on the reservoir. Fisherman useage to date is far below the potential of the reservoir. It is anticipated that Sam Rayburn will develop into an excellent sport and commercial fishery. --- Page 23 --- -19- Sufficient field data have been collected to establish criteria for game and rough fish populations and the need for further stocking of game fish. It is therefore recommended that this job be terminated. A separate job concerning the effects of paper mill effluent on Sam Rayburn Reservoir is planned for the coming segment. Depew. Loot. Prepared by Roy M. Bamber Approved by HA “Ze fee 7% — Asst. Project Leader f Coordinator Joe EB. Toole Charles EH. Gray Project Leader Fisheries Supervisor Date March 15, 1967