TPWD 1967 F-6-R-14 #1111: Experimental Stocking of Largemouth Bass and Threadfin Shad in Ponds in South Texas, Job Completion Report, Federal Aid Project F-6-R-14

JOB COMPLETION REPORT As required by FEDERAL AID IN FISHERIES RESTORATION ACT TEXAS Federal Aid Project Noe F-6—R—l4 FISHERY INVESTIGATIONS — REGION 5-B Job No. E-6 Experimental Stocking of Largemouth Bass and Threadfin Shad in Ponds in South Texas Assistant Project Leader: John M. Travis J. Ra Singleton Executive Director Parks and Wildlife Department Marion Toole ' Eugene A. Walker D—J Coordinator ' Director, Wildlife Services ‘ March 8, 1967 ABSTRACT Monthly collections of largemouth bass were continued at three of the four ponds stocked during a previous segment. Work at the fourth pond was termi- nated. As many specimens as possible were collected at each of the ponds during one day's sampling, with a minimum of ten intended. Lengths and weights were recorded for each specimen prior to its release. Pelvic fins were removed from specimens prior to their release so that they might be identified. Right pelvic fins were removed from first generation bass and left fins were removed from second generation fish. Schnabel's equation for population estimates was applied in a mark and recapture program in order that populations might be estimated. These esti- mates at the Hunter and Retzloff ponds varied from the known number of bass originally stocked. Possible explanations for these discrepancies are that the pond owner at Hunter's allowed friends to fish the pond prematurely thus reducing the number of stocked bass, and a suspected near toxic concentration of sulfates at the Retzloff pond prevented offspring from being produced. The Schnabel estimates are thought to be accurate. Best growth, as indicated by monthly length and length-weight frequencies, occurred at the Hunter pond which had the heaviest stocking ratio. This was contrary to expectations. Growth rates at the Kunitz pond, which was lightly stocked, were probably influenced by the high concentration of undesirable fishes competing directly for food. Undesirable species also occurred at the Hunter pond, however. Fishing success was measured as fish per man—hour. Overall, the ponds may be classified as very good, fair, and poor, with Hunter's pond yielding a catch of 1.82 fish/man-hour, Retzloff's 0.68 fish/manuhour, and Kunitz's 0.53 fish/man-hour. Although fishing success occurred in direct order with the stocking ratios, differences in fishing success among the ponds were not in correct proportion to the number of bass stocked per acre. Possible very turbid water at the Kunitz pond and a lack of offspring of stocked bass at the Retzloff pond. During the past three segments, a number of observations have been made concerning the success of such an experiment. Most important of these obser- vations is that a number of uncontrollable variables affect experimental results. Some of those experienced during this segment are: pond quality, water quality, pond location, presence of undesirable fishes, and pond owner- ship. Due to the inability to locate ponds of identical quality and thus limit these variables, it is felt that the experiment should be carried on for additional segments under more controllable conditions. JOB COMPLETION REPORT State of Texas Project No. Fw6—Rwl4 Name: Fisher‘ investi ations __Re ion 5~B Job No. _ Ew6 Title: Experimental StoCking of La£gg; mouth Bass and Threadfin_Shau ; Period Covered: _ January 1, 1966 to December 31, 1966 Objectives: 1. To determine the stocking ratio presenting the best growth rate for largemouth bass in ponds previously stocked with threadfin shad as forage. 2. To determine the stocking ratio providing the best fishing success in ponds previously stocked with threadfin shad as forage. 3. To determine the stocking rate which produces the best combination of growth and yield of largemouth bass in ponds previously stocked with threadfin shed for forage. Procedures: growth Studies J‘s-m: I. petenense) samples were collected monthly at three of the four originally stocked ponds. Experimental use of one pond was terminated and will be discussed later. Largemouth bass (Micropterus salmoides} and threadfin shad Cgorosoma Bass samples were ordinarily collected by angling with artificial and live baits. Shad and juvenile base were taken with seines. It was intended that no less than ten bass would be collected during each month, but this figure was not attained at times. Length and weight were recorded for most of the bass specimens. The 'weight of some young fish taken during hot weather was not measured for fear that this additional handling would impare their survival. observations on shad growth were made, concern. Only casual since their survival was the basic zield Studies mac. Beginning in September, pond owners'were encouraged to fish the ponds. In order to approximate normal harvest conditions, bass weighing Q00 grams or more collected by project personnel were also removed from the ponds. To estimate bass population densities, the mark and recapture program was continued. Specimens were recorded as either recaptures or nonwrecaptures at time of collection. Bass were marked by clipping a pelvic fin flush with the body u right pelvic for first generation (stocked bass) and left pelvic for second generation (progeny). Pond owners were informed of this program and asked to help by recording the number of clipped bass which they removed. The number of manwhours which project personnel spent angling and the number of bass caught were recorded. Pond owners were-requested to do like— wise, but none supplied any data. Turbidity and water temperature were recorded each month and water analyses conducted bimonthly. Results and Discussion: Growth Studies Several methods are available for determining the pond having the best growth. The choice depends on tima type of growth being measured and the growth criteria. The length-frequency distributions by month given in Figures l-3 provide a measure of absolute growth in terms of length gain per time interval (slope) and allow separation of generations. These data probably give the best short~term presentation of growth. Linear regression of mean standard length on month was computed for the data from the stocked bass. The regression lepes, b, were: Hunter pond, b = 9.2; Retzloff pond, b = 8.00; and Kunitz pond, b = 3.64. In this measure- ment, b = 0.00 indicates no growth. This method is not entirely valid for measuring rate of growth, since the fingerling bass stocked at Kunita pond were larger than those stocked at the other ponds and the growth slope is less for smaller (=younger) fishes and the growth slope is not exactly linear. Tentative interpretation of the growth rates indicates that the stocked bass of the Retzloff and Hunter ponds are growing at a similar rate, but the stocked bass of Kunitz pond are growing considerably slower. No tests of significance will be made until completion of the experiment. Figures 4E6 give the scatter diagrams for length and weight. These include both the stocked bass and their progeny and are not useful for comparisons, since no young have been taken at the Retzloff pond. St. length interval 340-349 330-339 320-329 310-319 300-309 290-299 280-289 1 1 270-279 260-269 1 1 250-259 1 240-249 230-239 220-229 210-219 200_209 190-199 180-189 2 170-179 160~169 1 150-159 1 140-149 1 130-139 120-129 110_119 2 100_109 - 90-99 80m89 70-79 60~69 50-59 40-49 30-39 1 20-29 D.) to N H f—I I—l N LO i—‘HmuP‘Nt—J G\ l—1—P‘O\I—1 H I—ltnbm to H-P‘UJUJ U'ILfli—‘H I—i N HNNNH M H NI—‘NLJJH l—‘Hl—‘N i—‘ 10~l9 0W9 'Aug'Sep OCt Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov bééwrl” 1965 1966 Figure 1 — Length Frequency Distribution for Kunitz Pond St. length interval 340—349 330-339 320-329 310—319 300-309 290-299 280-289 270~279 260—269 250-259 240~249 230-239 220-229 210-219 200-209 190-199 180w189 170~179 160~169 150—159 140-149 130—139 120-129 110—119 100w109 90—99 80—89 70-79 60~69 50~59 40‘49 30~39 20w29 10-19 0w9 2 1 1 1 1 1 2 2 2 1 2 2 2 1 2 3 1 1 1 2 3 3 1 2 5 3 1 1 .2 1 2 1 1 3 4 3 1 1 1 3 1 4 4 3 4 2 2 1 3 5 8 9 1 1 1 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 1965 I I 1966 Figure 2 - Length Frequency Distribution for Retzloff Pond St. length interval 340-349 330-339 320~329 310~319 1 300-309 290~299 280-289 270—279 260-269 250w259 240_249 230~239 1 220_229 210~219 200w209 2 3 190—199 6 11 13 1 180w189 1 10 10 10 2 2 4 l 170~179 3 7 2 3 1 1 160-169 5 3 1 150-159 140-149 1 3 130—139 1 120-129 110M119 100~109 90-99 80~89 70-79 60~69 2 50m59 40m49 3 30_39 20~29 10ml9 0M9 (sh-D Ul-PNN Hmmm Hmmwr—t boxcmto \s leltoro N-f-‘J-‘I—‘N WNU‘INH Nmmi—I r—l r—II—M—JI—w—I N H \1 "Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug sep OCthov Dec“ 1965 1966 Figure 3 - Length Frequency Distribution for Hunter Pond Weight (gm) 500 l 1 480 2 - 1 460 440 420 400 380 360 340 320 300 280 260 240 220 200 180 160 . 1 5 140 120 100 1 80 60 1 1 40 20 2 1 NMO—l—‘KOOJ w-P‘Mbmr—IH HHHr—‘H-DUJt—‘H P‘F‘UJH' tat» I—‘l—‘l—‘N [\JI“1 t-l-P‘l—‘l—‘H O O V 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 St. Length (mm.) Figure 4 — Length-weight Frequency Distribution for Kunitz Pond Weights are given in intervals of 20 grams. Standard lengths are given in interVals of 10 millimeters. Weight (gm) 720 700 680 660 640 620 600 580 560 540 520 500 480 460 440 420 400 380 360 340 320 300 280 260 240 220 200 180 160 140 120 100 80 60 40 20 1 1 1 1 5 2 1 1 1 3 1 1 1 1 1 1 1 l 2 1 3 1 4 1 1 4 1 9 3 2 4 8 1 21 11l20 130 140 150 160 170 180 190 200 210 220 230 240 1 1 1 l 1 1 1 l 1 1 1 2 l 1 2 1 1 5 2 1 250‘260'270"2801"m Figure 5 ~ Length—weight Frequency Distribution for Retzloff Pond Weights are given in intervals of 20 grams. given in intervals of 10 millimeters. Standard lengths are Weight (am) 860 840 1 820 800 780 760 740 720 1 700 1 680 660 . 640 1 1 1 620 600 1 580 560 540 520 500 480 460 440 420 400 380 360 340 320 1 300 280 260 240 2 220 1 200 ' 3 4 2 Nl—IWGO‘H ONKOU'IDN I—‘r—ION—Dmr—I t—‘UJr-‘Nr-‘l—J NHLoI—J e: hJuJeJAD s4 NI—‘l—‘l—1 H'xl-P‘JT-‘JZ‘H 180 ' 5 l 160 1 9 19 140 2 17 9 120 1 100 6 4 80 2 2 60 1 4 1 40 1 20 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 St. Length (mm.) Figure 6 — Length-weight Frequency Distribution for Hunter Pond Weights are given in intervals of 20 grams. Standard lengths are given in intervals of 10 millimeters.