TPWD 1962 F-7-R-10 #755: Job Completion Report: Experimental Management of the Rita Blanca Lake Fishery, Project F-7-R-10

--- Page 1 --- JOB COMPLETION REPORT As required by FEDERAL AID IN FISHERIES RESTORATION ACT Federal Aid Project No. F-7-R-10 FISHERIES INVESTIGATIONS AND SURVEYS OF THE WATERS OF REGION I-A Job No. E-3 Experimental Management of the Rita Blanca Lake Fishery Project Leader: Lonnie Peters H. D. Dodgen Executive Secretary Texas Game and Fish Commission Austin, Texas Marion Toole Eugene A. Walker D-J Coordinator Director, Program Planning March 26, 1963 --- Page 2 --- ABSTRACT Changes in the composition of the fish population during this segment were slight. The only important change was that the relative abundance of channel catfish decreased about six per cent, while the relative abundance of black bullheads increased about six per cent. An additional 97 flathead catfish were obtained from the Colorado City Lake, tagged and released in Rita Blanca Lake during this segment. Subsequent recoveries of these fish were made in May, July, October, and December. The tagged flatheads were found to have lost weight during the two-month-period following their release, but recoveries in the following months revealed fairly good weight increases for most fish. A total of 40 catfish spawning devices, made from concrete-weighted five-gallon pails was placed in Rita Blanca Lake to promote better reproduction of channel catfish. Brush piles were installed at four localities to provide added protection to the white crappie population, which appears to be increasing steadily. For the second consecutive year, golden shiners were absent from the gill net collections and were much less abundant in seine samples than they were in previous years. Predation and continued parasitism by an anchor worm, Lernaea sp., has kept the golden shiner population greatly reduced since 1960. --- Page 3 --- JOB COMPLETION REPORT State of Texas Project No. F-7-R-10 Name: Fisheries Investigations and Surveys of the Waters of Region 1-A Job No. E-3 Title: Experimental Management of the Rita Blanca Lake Fishery Period Covered January 1, 1962 - December 31, 1962 Objectives: To initiate and conduct experimental management practices at Rita Blanca Lake, to restore balance in the fish population through the control of excessive populations of golden shiners, black bullhead catfish, and goldfish. Techniques Used: Periodic netting and seining collections were made to determine changes in the composition of the fish population and to evaluate the results of experi- mental management practices previously employed. Additional flathead catfish were stocked to replace those that had died or were taken by fishermen. These additional flatheads, which were stocked in March, were measured, weighed and tagged before being released, in order to provide a means for determining growth rates of this species. Brush piles were installed to provide cover for white crappie. Channel catfish spawning devices were constructed and installed at various locations. Attempts were made to reduce the golden shiner, goldfish, and black bullhead catfish populations by seining. Findings: Fish Collections Four gill net collections were made during this segment to determine com- position changes in the fish population. Basically there has been little change as compared with the data collected during the previous segment, except that channel catfish showed a 6.53 per cent decrease, while black bullheads showed a corresponding 6.81 per cent increase in numbers. For the second consecutive year, golden shiners were absent from the gill net collections. The percentage of game fish in the four net collections made during this segment varied from 8.18 per cent to 68.75 per cent and averaged 26.44 per cent. In percentage by weight, however, game fish accounted for 64.31 per cent. Channel catfish and flathead catfish each accounted for roughly one- fourth of the total weight of fish taken. Bullheads continue to be abundant in numbers but very small in size, averaging 0.17 pounds this year, which is a slight increase over last year's average of 0.15 pounds. Tables 1, 2, 3 and 4 give the percentage composition by number, weight, and the average weight of fish taken by gill nets in February, July, October and December of this year. Table 5 is a composite of Tables 1 to 4. --- Page 4 --- Table 1. Percentage Composition by Number and Weight and Average Weight of Fish Taken From Rita Blanca Lake, February 12, 1962. Per Cent Per Cent by Total by Average Species Number Number Weight Weight Weight River Carpsucker 1 16 3.42 1.04 3.42 Channel Catfish 70 11.02 99.59 30.14 1.42 Black Bullhead 438 68.98 76.82 23.25 0.18 Flathead Catfish 8 1.26 113.53 34.36 14.19 Largemouth Bass 1 - 16 4.08 1.24 4.08 White Crappie 117 18.42 32.93 9.97 0.28 Totals 635 100.00 330.37 100.00 Game Fish 196 30.86 Rough Fish 439 69.14 Table 2. Percentage Composition by Number and Weight and Average Weight of Fish Taken From Rita Blanca Lake,July 27, 1962. Per Cent Per Cent by Total by Average Species Number Number Weight Weight Weight Carp 1 69 3.85 4.18 3.85 Carp X Goldfish 5 3.48 16.75 18.16 3.35 Goldfish 5 3.47 6.89 7.48 1.37 Channel Catfish 18 12.50 31.23 33.87 1.73 Black Bullhead 34 23.61 7.59 8.23 0.22 Flathead Catfish iE 0.69 7.27 7.88 de Zl White Bass 3 2.08 3.75 4.07 Lis 25 White Crappie 76 52.78 14.79 16.04 0.19 Bluegill Sunfish 1 0.70 0.08 0.09 0.08 Totals 144 100.00 92.20 100.00 Game Fish 99 68.75 Rough Fish 45 31.25 Table 3. Percentage Composition by Number and Weight and Average Weight of Fish Taken From Rita Blanca Lake, October 17, 1962. TT Per Cent Per Cent by Total by Average Species Number Number Weight Weight Weight Goldfish 7 2.84 6.41 10.41 0.91 Channel Catfish 7 2.85 L659 18. 82 1.65 Black Bullhead 182 73.99 28.90 46.93 0.15 White Bass 1 0.40 2.10 3.40 2.10 White Crappie 49 19.92 12.59 20.44 0.25 Totals 246 100.00 61.59 100.00 Game Fish 57 23.17 Rough Fish 189 76.83 --- Page 5 --- Table 4. Percentage Composition by Number and Weight and Average Weight of Fish Taken From Rita Blanca Lake, December 20, 1962. Per Cent Per Cent by Total by Average Species __________________ Number __Number Weight Weight Weight _ Goldfish 2 0.45 1.70 1.76 0.85 Channel Catfish 2 0.45 6.19 6.44 3.09 Black Bullheads 402 91.637 61.12 63.54 0.15 Flathead Catfish 2 0.45 12.44 12.93 6.22 White Bass 2 0.46 2.61 2.71 1.30 Largemouth Bass 1 0.22 4.00 4.16 4.00 White Crappie 29 6.60 8.13 8.46 0.28 Totals 440 100.00 96.19 100.00 Game Fish 36 8.18 34.70 Rough Fish 404 91.82 65.30 Table 5, Percentage Composition by Number and Weight and Average Weight of Fish Taken From Rita Blanca Lake by Gill Nets in February, July, October and December 1962, Per Cent Per Cent by Total by Average Species Number Number Weight Weight Weight River Carpsucker 1 0.06 3.42 0.59 3.42 Carp 1 0.07 3.85 0.68 3.85 Goldfish 14 0.96 15.00 3.63 1.07 Carp X Goldfish 5 0.34 6.89 1.21 1.38 Channel Catfish 97 6.63 148.60 26.05 1.53 Black Bullhead 1,056 72.13 174.43 30.58 0.17 Flathead Catfish 11 0.75 133.24 23.36 12.11 White Bass 6 0.41 8.46 1.48 1.41 Largemouth Bass 2 0.13 8.08 1.42 4.04 White Crappie 271 18.52 68.44 12.00 0.25 Totals 1,464 100.00 570.41 100.00 0.39 Game Fish 387 26.44 366.82 64.31 0.95 Rough Fish 1,077 73.56 203.59 35.69 0.19 Seining results indicate that there was a good spawn of white crappie this year. Out of 10,719 fish taken with 200 and 300 foot seines, 5,247 were white crappie. Bullheads taken in seines totaled only 3,038 which is quite a contrast to last year's seining results. Goldfish and golden shiners each comprised about 10 per cent of the seine catch, while all other species were of minor importance. Table 6 gives the seining results on six dates during this segment. There was no evidence of reproduction by either white bass or flathead catfish, and it appears that there was very limited reproduction of channel catfish and largemouth bass. It should be noted that golden shiners were relatively scarce in the seine samples as compared to their abundance in previous years. Prior to 1961, --- Page 6 --- Table 6. Percentage Composition of Fish Taken by a Two-Hundred and a Three-Hundred-Foot Seine From Rita Blanca Lake, 1962. Date Feb. 11 Feb. 12 August 23 Dec. 20 Dec. 21 Dec, 22 Total Species , Number Per Cent Number Per Cent Number Per Cent Number Per Cent Number Per Cent Number Per Cent Number Per Cent Carp 0 0 15 0.51 0) 1 0.03 0) 16 0.14 Goldfish 199 34.26 516 52.49 92 3.12 256 9.64 29 0.93 2 0.48 1,094 10.21 Carp X Goldfish 0 0) ) 0 50 1.60 0 50 0.47 Golden Shiner 301 51.81 205 20.86 378 12.81 4 0.15 79 2.52 0 967 9.02 Fathead Minnow 0 0 7 0. 24 0 0) 0 7 0.06 Channel Catfish 3 0.51 1 0.10 36 1/22 0) 0 2 0.48 42 0.40 Black Bullhead 59 10.16 150 15.26 1,671 56.62 205 7.72 570 18.21 383 91.40 3,038 28.34 White Bass 6) 0) 3 0.10 0) 1 0.04 2 0.48 6 0.05 Largemouth Bass 17 2.92 31 3.16 96 3.25 12 0.46 12 0.38 1 0.24 169 1.58 Bluegill Sunfish 0 11 1.12 0 0 52 1. 66 0) 63 0.59 Sunfish sp. 2 0.34 0 18 0.61 0 0 0) 20 0.18 White Crappie 0) 699 7.01 635 21.52 2,178 82.03 2,336 74.63 29 6.92 5,247 48.96 Totals 581 100.00 983 100.00 2,951 100.00 2,655 100.00 3,130 100.00 419 100.00 10,719 100.00 --- Page 7 --- literally gallons of golden shiners could be taken in one drag with a 300-foot seine. Predation and parasitism have kept this species greatly reduced in 1961 and 1962, Twenty-foot seine results, given in Tables 7 and 8, show that the fathead minnow and the plains killifish were the most abundant minnow species taken. Table 7. Results of Seining With a Twenty-Foot Seine from Rita Blanca Lake, October 17, 1962. Species Number Per Cent Goldfish 1 0.40 Red Shiner 26 10.44 River Shiner 2 0.81 Fathead Minnow 138 55.42 Plains Killifish 81 32.53 Largemouth Bass 1 0.40 Totals 249 100.00 Table 8. Results of Seining With a Twenty-Foot Minnow Seine from Rita Blanca Lake, December 20, 1962. Species Number Per Cent Goldfish 55 14.70 Black Bullhead 225 60.16 Red Shiner 1 0.27 Fathead Minnow 85 22.73 Largemouth Bass 8 2.14 Totals 374 100.00 Habitat Improvement In September 1962, several brush piles were placed in Rita Blanca Lake to aid the crappie population. Brush (mostly green elm), tied in bundles two to three feet in diameter and ten to twelve feet in length, was weighted and sunk in areas having water depths of eight to eleven feet. A majority of these brush piles were located in the deeper water near the dam, and all of the brush piles were located along cables supported by floating barrels. It is hoped that these brush piles will lend protection to small crappie as well as provide fishermen with well-located places to fish for crappie. Figure I shows the locality of the brush piles. A total of 40 channel catfish spawning devices was installed during this segment. These spawning containers, shown in Figures 2 and 3, were made of five-gallon pails weighted with concrete. The spawning devices were located at depths of two to four feet in areas having hard sand or rocky bottoms. They were installed too late to provide spawning places this year, but it is hoped they will promote much-needed natural reproduction of channel catfish in 1963. --- Page 8 --- Concession 0 L ( 4 Srana ’ ; } Saar ro + _ 2 Ve RITA BLANCA : rn poe on LEGEND @ — Gresh piles ea Spawning Cans rr. — Read Figure 1° Map of RiTe Glanca Lake Showing Locations of Brush Piles And Approximate Locetions o¢ Cateish Spawning Cans. --- Page 9 --- Figure 2. A pile of spawning cans ready to be placed in Rita Blanca Lake. Figure 3. A spawning can made of two five-gallon cans with concrete added for weight. --- Page 10 --- Flathead Catfish Introductions The original stocking of flathead catfish was in November 1959, when 285 fish: were transferred to Rita Blanca from Lake Stamford. Reports of these fish having been found dead or taken by fishermen indicated that since 1959 the flathead population had been reduced considerably below the one per acre stocking ratio desired. In March 1962, an additional 97 flatheads were obtained from the Colorado City Lake and released in Rita Blanca. These fish were all tagged, weighed, and measured before being released in order that future re- coveries would show growth rates and weight increases. Figures 4 and 5 show tagged flatheads recovered in December 1962. Several of these tagged flatheads were recovered during this segment and their weights and tag numbers were recorded. In all, 34 recoveries were made. One recovery, by a fisherman, was made on June 27, 1962, about 3% months after the fish were released. All of the remaining recoveries were made with gill nets. Six flatheads were recovered twice during the year. The tagged flathead taken by a fisherman was tag No. 5611 and weighed 8.50 pounds when stocked on March 9, 1962. It was reported to have weighed 11.25 pounds when taken June 27. On May 9, two months after the tagged flatheads had been released, 18 recoveries were made with gill nets. When stocked, these 18 fish ranged from 5.00 to 17.50 pounds and averaged 11.15. All but four of these fish showed weight losses when recovered. Losses in weight ranged from 0.04 for the smallest fish in the group to 2.13 pounds for one of the largest fish. The average weight of the 18 flatheads was 10.69 pounds when recovered on May 9, therefore, the average weight loss per fish was 0.47 pounds for the two month period. In terms of weight loss per pound of body weight, the total weight of the 18 fish was 200.75 pounds when tagged, the total weight loss was 8.42 pounds, so the rate of loss was 0.04 pounds per one pound of body weight. The four fish showing weight gains in May ranged from 9 to 12 pounds in weight when tagged. Their weight gains varied from 0.08 to 1.76 pounds. One of these four was recovered a second time, while three of the fish showing weight losses in May were recovered a second time later in the year. Five tagged flatheads were recovered in July. One fish weighed the same as it did when released, one had lost 0.50 pounds, while three showed good weight gains. These five fish ranged from 4.00 to 9.50 pounds and averaged 8.05 pounds when tagged. When recovered, they ranged from 7.00 to 14.00 pounds and averaged 10.50 pounds. The average weight gain per fish was 2.45 pounds, while the rate of weight gain per pound of body weight was 0.30 pounds increase per one pound of body weight. The fish showing a weight loss of 0.50 pounds had been previously netted on May 9, at which time it showed a 0.79 pound loss, (weight gains or losses are all relative to the fishes' weight when tagged). Injuries to this fish when netted on May 9 probably caused this fish not to gain weight. A similar case was that only one flathead out of eight recovered in December showed a weight loss at that time, and it had also been previously recovered in May. In October, two tagged flatheads were taken. When tagged, one fish weighed 7.50 pounds, the other 14.50 pounds. Their recovery weights were 9.00 and 22.00 pounds respectively. The second fish had gained 7.50 pounds in slightly over seven months, and had been previously recovered on May 9 at which time it weighed 14.19 pounds. --- Page 11 --- Figure 4. Closeup of tagged flathead catfish from Rita Blanca Lake. Note position of tag on Operculum. Figure 5. Field personnel displaying tagged flatheads taken from Rita Blanca Lake. --- Page 12 --- =10- Weight changes of eight fish recovered in December, about nine months after being released, were very erratic. As mentioned, one of these eight fish had previously been netted and showed a weight loss. The seven others showed gains ranging from 0.11 pounds up to 7.00 pounds. The original weights of these fish ranged from 5.75 to 17.50 pounds and averaged 10.13 pounds. When recovered in December, these eight fish ranged from 6.50 to 20.00 pounds, and averaged 12.44 pounds. The average weight increase per fish was 2.31 pounds, and the rate of weight increase per pound of body weight was 0.23 pound increase per one pound of body weight. It is interesting to note that one flathead (tag No. 5630) weighed 8.75 pounds when tagged on March 10. It weighed 14.00 pounds when taken on July 27, but only 12.25 pounds when recovered again on December 20. Although it gained weight very well between March and July, it had lost weight between July and December. Again, this loss may have been due to the fishes' being netted in July. Table 9 lists the length and weights of all the tagged flatheads recovered from Rita Blanca Lake. Table 10 lists the initial and recovery weights of the tagged flatheads, and their average rate of weight change for the period from March 8 to December 20, 1962. Table 9. Weight Changes of Tagged Flathead Catfish Recovered From Rita Blanca Lake, May to December 1962. Tag No. Date Tagged Date Weight When Recovery Weight TGFC-A- in March Recovered Tagged Weight Change 5631 10th May 9 11.00 12.76 1.76+ 5590 9th May 9 12.00 12.76 0.76+ 5645 10th May 9 9.00 9.76 0.76+ 5606 8th May 9 10.75 10.83 0. 08+ 5618 9th May 9 5.00 4.96 0.04- 5641 10th May 9 13.50 13.31 0.19- 5687 10th May 9 9.00 8.71 0.29- 5577 8th May 9 14.50 14.19 0.31- 5574 8th May 9 9.50 8.82 0. 68- 5575 8th May 9 10.50 9.81 0.69- 5573 8th May 9 12.25 11.54 0.71- 5589 9th May 9 7.50 6.72 0.78- 5583 8th May 9 9.50 8.71 0.79- 5633 10th May 9 13.75 12.92 0. 83- 5560 8th May 9 12.75 11.78 0.88- 5639 10th May 9 8.75 7.39 1.36- 5564 8th May 9 17.50 15.40 2.10- 5598 8th May 9 14.00 11.78 2.13- 5630 10th July 27 8.75 14.00 5.25+ 5638 10th July 27 4.00 8.50 4.50+ 5631 10th July 27 11.00 14.00 3.00+ 5563 8th July 27 7.00 7.00 0.00 5583 8th July 27 9.50 9.00 0.50- 5577 8th Oct. 17 14.50 22.00 7.50+ 5634 10th Oct. 17 7.50 9.00 1.50+ --- Page 13 --- «lis Table 9 (continued) Tag No. Date Tagged Date Weight When Recovery Weight TGFC-A- in March Recorvered Tagged Weight Change 5582 9th Dec. 20 12.50 19.50 7. 00+ 5597 9th Dec. 20 12.00 16.50 4, 50+ 5630 10th Dec. 20 8.75 12.25 3. 50+ 5564 8th Dec. 20 17.50 20.00 2.50+ 5624 10th Dec. 20 5.75 6.50 0. 75+ 5603 9th Dec. 20 8.75 9.09 0.34+ 5659 9th Dec. 20 7205 7.16 0. Li+ 5639 10th Dec. 20 8.75 8.49 0.26- Table 10. Weight Changes of Tagged Flathead Catfish Recovered From Rita Blanca Lake, May to December 1962. May July October December Number of Fish Recovered 18 5 2 8 Average Weight When Tagged dds ghd 8.05 11.00 10.13 Average Weight When Recovered 10.19 10.50 15.50 12.44 Total Weight Change of Group -8.42 +12.25 +9.00 +18.44 Average Weight Change Per Fish -0.47 + 2.45 +4.50 + 2.31 Average Weight Change Per One Pound -0.04 + 0.30 +0.41 + 0.23 of Body Weight Food Habits Examination of game fish stomachs revealed that channel catfish fed mostly on insects, insect larvae, and vegetation. "Fish" occurred only once out of 30 stomachs containing food. Crappie fed on crustaceans and insects mostly, while white bass fed mostly on fish. A golden shiner was identified in one white bass stomach. Bullheads were noted to have fed heavily on insect, algae, and crustaceans. Since flathead catfish were returned alive to the lake, there was little opportunity to examine their food habits. However, one flathead that died as a result of being netted was opened. The stomach of this fish contained fish remains easily identified as black bullhead. In another instance, a flathead catfish caught in a gill net had regurgitated its food which became entangled in the net. The regurgitated food of this fish was also the remains of a black bullhead. Tables 11 to 14 give the frequency of occurrence of food items found in the stomachs of fish taken by gill nets from Rita Blanca Lake. --- Page 14 --- =9= Table 11. Frequency of Occurrence of Food Items in Fish Taken from Rita Blanca Lake, February 12, 1962. Number Number Frequency Species Examined Containing Food Food Items Occurrence Channel Catfish 16 14 Eggs 1 Insect Larvae 12 Mud 1 Insect Remains 3 Black Bullhead 11 11 Insect Larvae 8 Mud 2 Fish Remains 3 White Crappie 16 15 Crustaceans 1 Insect Remains 1 Eggs 9 Fish Remains 3 Vegetation 1 Golden Shiner 2 Table 12, Frequency of Occurrence of Food Items in Game Fish Taken From Rita Blanca Lake, July 27, 1962. Number Number Frequency Species Examined Containing Food Food Items Occurrence Channel Catfish 16 10 Mussels 3 Fish Remains 1 Vegetation 1 Insect Larvae 2 Algae 2 Rodent Hair 1 Shrimp 1 Potamogeton 2 Black Bullhead 20 10 Insect Remains 2 Algae 7 Insect Larvae 3 Crustaceans 2 Black Bullhead 1 White Bass 3 2 Fish Remains 1 Golden Shiner 1 White Crappie 25 16 Golden Shiner 1 Insect Remains 7 Vegetation 1 Insect Eggs 3 Algae 2 Crustaceans 6 --- Page 15 --- -13- Table 13. Frequency of Occurrence of Food Items Found in Fish Taken From Rita Blanca Lake, October 17, 1962. Number Number Frequency Species Examined Containing Food Food Items Occurrence Channel Catfish 7 5 Potamogeton 3 Algae 1 Dragon Fly 1 Insect Larvae 2 Plant Leaf an Insect Remains 1 Black Bullhead 25 10 Algae 5 Crustaceans 5 Insect Larvae 3 White Bass 1 1 Insect Remains 1 White Crappie 25 24 Bee 1 Crustaceans 24 Fly 2 Back Swimmer 12 Insect Remains 1 Fish Remains 1 Dragon Fly 1 Table 14. Frequency of Occurrence of Food Items in Fish Taken From Rita Blanca Lake, December 20, 1962. Number Number Frequency Species Examined Containing Food Food Items Occurrence Channel Catfish 2 1 Insect Larvae 1 Insect Remains 1 Black Bullhead 43 20 Insect Larvae 6 Algae 9 Insect Remains 4 Crustaceans 6 Freshwater Shrimp 1 Wood Bit 2 Johnsongrass Seed 1 Sand 1 Mud 1 White Bass 2 1 Fish Remains 1 Largemouth Bass 1 0 None 0 White Crappie 31 23 Crustaceans 16 Insect Remains 4 Fish Remains 2 Golden Shiner 1 --- Page 16 --- ~14- Condition Factors K factors of channel catfish were high in February (2.0) but gradually decreased through the following months. In July the average was 1.8, while in October it was 1.7. White crappie were in fair condition, averaging about 2.8 - 2.9 throughout the year. Bullhead catfish K factors were very high in February (3.0) but, similar to channel catfish, decreased to 2.0 in October. K factors for white bass at 3.3, 3.6, and 3.1 in July, October, and December respectively, were very good. Tables 15-18 give the K factor range and average for species taken by gill nets in February, July, October, and December respectively. Table 15. K Factor Range and Average for Fish Species Taken From Rita Blanca Lake, February 12, 1962. Species Range Average Channel Catfish (23) 1.6 - 2.6 2.0 Black Bullhead (25) 2.2 - 3.6 3.0 Flathead Catfish ( 8) 201 = 2.5 2.3 Largemouth Bass ( 1) 2.7 Qed River Carpsucker ( 1) 2.6 2.6 White Crappie (51) 2.4 - 4.8 3.2 Table 16. K Factor Range and Average of Fish Taken From Rita Blanca Lake, July 27, 1962. Species Range Average Carp X Goldfish ( 5) 3.4 - 4.2 3.9 Goldfish ( 5) 5.0 - 6.6 5.5 Channel Catfish (18) 1.5 - 2.2 1.8 Black Bullhead (20) 2.3 - 3.2 2.6 Flathead Catfish ( 1) 2.1 2.1 White Bass ( 3) 3.1 - 3.5 3a White Crappie (28) 2.6 - 3.7 2.9 Table 17. K Factor Range and Average of Fish Taken From Rita Blanca Lake, October 17, 1962. Species Rang Average Goldfish ( 7) 4.4 - 5.7 4.9 Channel Catfish ( 7) 1.6 - 1.9 1.7 Black Bullhead (25) 1.7 - 2.4 2.0 White Bass ( 1) 3.6 3.6 White Crappie (25) 2.4 - 3.2 2.8 --- Page 17 --- =[5= Table 18. K Factor Range and Average for Fish Species Taken From Rita Blanca Lake, December 20, 1962. Species Range Average Goldfish Male ( 1) 5.4 5.4 Female ( 1) 5.0 5.0 Channel Catfish ( 2) Male 1.5 Lod Female 1.9 1.9 Black Bullhead Male (15) 1.9 - 2.4 2.2 Female (30) 2.0 - 2.8 2.3 White Bass Male ( 2) 2.9 - 3.3 3.1 Largemouth Bass Male ( 1) 3.2 3.2 White Crappie Male (15) 2 - 5 2 2 1 2 aol 3 9 Female (14) 25 - 3. .8 Recommendations: The ecological conditions of Rita Blanca Lake have changed greatly since 1960, especially in regard to aquatic vegetation. During the summer of 1959 and 1960 the turbidity of the water in Rita Blanca was greatly reduced due to the addition of sub-surface water high in dissolved salts. During this period the lake had a moderate growth of pondweed in the upper areas, and filamentous algae was very thick all around the lake. Aquatic organisms such as snails, amphipods, insect larvae, and giant Daphnia were extremely abundant. It was during this period that a tremendous population of channel catfish was reaching maturity. Their growth rate was rapid owing to the presence of an abundance of small organisms. Beginning in 1960 a great change in the flora of the lake occurred. A minute, one-celled algae became abundant, increasing the turbidity to the extent that filamentous algae is now found only in very shallow areas; and higher sub- merged aquatics are non-existent. It is believed that this has had a detrimental effect on the production of game fish species in the last two years. In the spring and summer of 1961 the first year of the noxious algae bloom, fishermen were so highly successful that they drastically reduced the channel catfish population. It is believed that the algae bloom, causing the increased turbidity and subsequent curtailment of the production of food organisms, caused a shortage of food for channel catfish thus allowing the fishermen to greatly reduce the population. The reason for the sudden change in the nature of the lake's vegetation is unknown. A possible cause might have been a change in the nature of the fertility. There has been practically no runoff water entering the lake in the past two years. --- Page 18 --- -16- Rainfall has been very light and areas that were once flooded are now grown up in weeds and grasses. The fertility once received from a watershed feed lot has ceased. One or a combination of factors may have changed the nutrient quality of the lake in favor of the type of algae which has persisted for the past two years. At any rate, if the noxious algae bloom persists in 1963, it might be advisable to attempt to control it with copper sulphate. A treat- ment with copper sulphate at the proper concentration might effect a kill of bullhead catfish as well as control the algae. Laboratory experiments under Job E-1 of this project in 1958-1959 revealed that copper sulphate at 2, 3 and 5 ppm was effective in killing bullheads, while other test fish including crappie, carp, and golden shiners were not apparently affected. See Page 5, Job Completion Report F-7-R-6, Job E-3. Water skiing at Rita Blanca Lake has greatly increased within the last two years, and the constant washing and stirring of bottom sediments in the main area of the lake where skiing is permitted undoubtedly interferes with spawning of the bottom-nesting species. The relatively small portion of the upper end of the lake in which skiing is prohibited, has, for the most part, a muddy bottom not suited to spawning. During the next segment, catfish spawning devices, brush piles, and gravel piles should be located in this protected area to aid reproduction by the game fish population. As previously mentioned, spawning of white bass and flathead catfish has not occurred, and the spawn of channel catfish and black bass has been light. White crappie, however, appear to be increasing. Gill net recoveries of tagged flathead catfish should be continued during the next segment to provide additional data concerning growth of this species in Rita Blanca. For future reference, Table 19 lists all the flatheads tagged during this segment. Periodic surveys with standard survey gill nets should also be continued to determine changes in the fish population and to evaluate manage- ment practices employed. A shortage of time and personnel did not allow the experiments in rearing largemouth bass in wire enclosed areas of the lake. It was originally intended that suitable areas would be screened off and stocked with adult bass to determine if they would spawn, and if so, whether the young bass would survive in the absence of predation from golden shiners. Prepared by Lonnie Peters Approved by YU op eon Liaote . C Project Leader oordinator Date March 26, 1963 Leo D. Lewis Regional Supervisor --- Page 19 --- =17= rc Table 19. Lengths and Weights of T-gged Flathead Catfish in Rita Blanca Lake Tagged March 8, 1962 Tagged March 9, 1962 Tagged March 10, 1962 Tag* L.mm Wt.1b Tag* L.mm Wt.1b Tag* L.mm Wt.1b 5569 650 13.00 5584 510 5.50 5624 515 5.75 5567 555 8.50 5579 520 5.50 5623 550 7.50 5570 840 26.00 5596 650 13.25 5625 640 11.50 5565 620 11.00 5588 560 8.00 5620 610 10.00 5559 710 16.50 5581 290 1.00 5619 560 8.00 5563 520 7.00 5597 640 12.00 5621 660 13.75 5572 540 8.00 5592 470 4.50 5622 550 8.00 5556 700 15.00 5594 240 0.50 5639 560 8.75 5557 590 10.00 5585 670 13.50 5645 610 9.00 5571 750 19.50 5590 620 £12.00 5628 450 4,50 5573 625 12.25 5582 660 12.50 5643 640 12.00 5575 630 10.50 5576 590 5.50 5636 560 8.00 5561 645 12.75 5589 550 7.50 5633 650 13.75 5560 610 12.25 5591 620 10.00 5637 610 9.50 5558 490 6.00 5601 470 7.00** 5649 590 10.75 5574 595 9.50 5602 540 8.75 5626 560 8.50 5566 470 5.50 5603 650 8.75 5627 640 10.75 5562 585 10.00 5604 560 7.75 5638 470 4.00 5600 655 15.00 5605 610 9.25 5644 570 8.50 5599 640 14.00 5606 650 10.75 5635 720 16.25 5564 700 17.50 5607. 650 12.00 5631 640 11.00 5580 500 6.75 5608 740 15.75 5630 610 8. 75x 5587 570 9.25 5609 680 12.50 5629 675 16.50 5593 645 13.25 5610 700 15.25 5634 550 7.50 5578 540 8.50 5611 580 8.50 5642 600 9.50 5586 590 10.50 5612 560 7.50 5648 730 15.00 5583 575 9.50 5613 585 9.00 5650 570 8.00 5595 705 17.50 5614 540 7.00 5632 830 23.50 5577 675 14.50 5615 520 6.50 5646 630 10.50 5598 670 14.00 5616 675 13.00 5640 620 10.25 5617 640 12.00 5641 680 13.50 Tagged May 9, 1962 5618 505 5.00 5647 590 9.00 5654 13.13 5699 830 24.50 5669 11.32 Tagged Dec. 20, 1962 5690 665 13.00 5660 12.09 6319 20.75 5687 590 9.00 5661 12.75 6323 16.50 5670 10.19 6315 5.95 5664 15.73 5674 13.36 5655 11.54 5675 14.85 5659 7.05 * Tags read 'TGFC-A' plus the four digits above. ** Broken Tail **k* Blind in one eye.