Bill Mitchell

Contribution of Stocked Advanced-Fingerling Largemouth Bass to the Population and Fishery at Taylorsville Lake, Kentucky

Abstract Fin-clipped largemouth bass Micropterus salmoides averaging 4.2–4.5 in long were stocked annually in 3,050-acre Taylorsville Lake in the fall from 1988 to 1992 at densities ranging from 9.8 to 27.8 fish/acre. Survival of each year-class of stocked largemouth bass from age 0 to age 5 was similar; however, survival from the time of stocking to fall collection varied among year-classes, which suggests density dependence in survival. Optimal stocking density ranged from 9.8 to 12.8 fish/acre based on higher survival and lower production costs. In 1993, after 5 years of stocking, the stocked largemouth bass accounted for 37.6% (<8.0 in), 18.2% (8.0–11.9 in), 24.1% (12.0–14.9 in), and 14.9% (≥15.0 in) of the various size-groups and 24.5% of the total electrofishing catch. Contribution of the stocked largemouth bass in the electrofishing catch declined to below significant levels by the second spring after cessation of the fall stocking program. Corresponding significant increases were detected in the e...

Response of Smallmouth Bass to Regulatory and Environmental Changes in Elkhorn Creek, Kentucky

Abstract Populations of smallmouth bass Micropterus dolomieu in Elkhorn Creek, Kentucky, were managed by means of a 12.0-in minimum length limit from 1978 through 1992. During this period, these populations were characterized as having a poor population size structure dominated by high densities of slow-growing, sublegal fish. In 1993, the length limits were changed on a 16.0-mi section of the main-stem Elkhorn Creek to a 12.0–16.0-in protective slot limit, and the statewide, six-fish creel limit was modified to allow in the creel only two fish greater than 16.0 in. Length and creel limits remained unchanged on the rest of the stream. Both sections of stream were sampled during pre-slot-limit (1990–1993) and slot limit years (1994–2000) to determine whether the protective slot limit improved the quality of sport fishing. Declines in stock densities (catch per unit effort) of 8.0–11.9-in smallmouth bass, initial large increases in the densities of fish within the protective length limit, and increases in t...

Electrofishing Catch per Effort as a Predictor of Largemouth Bass Abundance and Angler Catch in Taylorsville Lake, Kentucky

Abstract The purpose of this study was to determine if catch per unit effort (CPUE) of largemouth bass Micropterus salmoides collected by electrofishing could be used to predict future electrofishing catch rates and angler catch of largemouth bass at Taylorsville Lake, Kentucky. Development of reliable predictive models would aid managers in selecting and evaluating management strategies and in predicting future trends in sport fisheries. Significant (P ≤ 0.10) relations existed between electrofishing CPUE and angler catch of three lengthclasses of largemouth bass. Significant relations also existed among the CPUEs of the size-classes <8.0-, 8.0–11.9-, and 12.0–14.9-in largemouth bass collected in successive years, but not between the CPUEs of 12.0–14.9and 15.0-in or longer largemouth bass collected in successive years.

Differential Growth of Young-of-Year Gizzard Shad in Several Kentucky Reservoirs

Abstract Protracted spawning of gizzard shad Dorosoma cepedianumwas not responsible for the small juvenile shad collected during the fall in two Kentucky reservoirs and one hatchery pond. Gonadosomatic indices of female gizzard shad at Taylorsville Lake and the number of gizzard shad 10 mm and smaller collected in four study lakes did not increase following a mid-July water-level rise. Large numbers of small gizzard shad were collected during the fall at Cave Run and Taylorsville lakes and in one of the hatchery ponds even though spawning was not detected after the normal period. As a result, fall length-frequency distributions of juvenile gizzard shad differed among study lakes and among hatchery ponds. Our data indicated differential and density-dependent growth of young-of-year gizzard shad occurred in the reservoirs and hatchery ponds, and suggested that managers could increase availability of forage by developing techniques to manipulate shad densities.

Changes in Largemouth Bass Populations at Kentucky and Barkley Lakes: Environmental or Regulatory Responses/

Abstract Abundance of largemouth bass Micropterus salmoides increased in Kentucky and Barkley lakes after a 14-and-1 regulation was imposed in 1984. (The 14-and-1 regulation is a 14.0-in minimum-size limit with one fish under 14.0 in allowed in the angers creel.) Standing crops of shad Dorosoma spp. and of all fishes also increased. These increases in fish populations had begun when the minimum-length limit was still 12 in, and they continued after the change to the 14and-1 regulation. The size limit change to 14 in coincided with the onset of the most severe drought in the history of the region, the worst part of which extended from December 1984 to October 1988. The depth of light penetration and water retention time in the two lakes increased significantly during the drought, as did Carlsons trophic state index for chlorophyll a. The increase in primary productivity may have contributed to the increases in fish standing crops observed over the study period. Because of these changes in water quality, ...

Management of Largemouth Bass at Kentucky and Barkley Lakes, Kentucky

Abstract Largemouth bass Micropterus salmoides populations declined in Kentucky and Barkley lakes following a severe drought during Dec 1984–Oct 1988 and below normal rainfall in three of four years during 1989–1992. Regression models developed for both reservoirs indicated that recruitment of largemouth bass to age 1 was positively related to the electrofishing catch per unit effort (CPUE) of large age-0 bass and negatively related to annual rainfall amounts and the CPUE of all sizes of age-0 largemouth bass. These variables explained 73% of the variation in CPUE of age-1 bass at Barkley Lake and 60% at Kentucky Lake. We also developed regression models to estimate the recruitment of largemouth bass to the fishery at age 5 and older. Recruitment to the fishery at Kentucky Lake was positively related to the CPUE of age-1 bass and negatively related to reservoir discharge. This model explained 52% of the variation in recruitment to age 5 and older largemouth bass. Recruitment to age 5 and older fish at Bar...

Stocking Subadult Largemouth Bass to Meet Angler Expectations at Carr Creek Lake, Kentucky

Abstract In response to angler dissatisfaction with the fishery for largemouth bass Micropterus salmoides at Carr Creek Lake, minimum length limits were increased in 1991 from 12.0 to 15.0 in and pellet-reared subadult largemouth bass (mean length = 11.4−12.4 in) were stocked beginning in 1993. Anglers expected catch rates of 12.0 in and larger largemouth bass to increase from 0.24 to 1.18 fish/h and harvest rates to increase from 0.01 to 0.06 fish/h. Fin-clipped largemouth bass were stocked during the fall of 1993 and 1994 and in the spring of 1996 and 1997 at densities of 9.9–10.2 fish/acre. The stocked largemouth bass resulted in an immediate increase in both the population and the catch-and-release portion of the anglers creel. Angler catch rates differed with the time of the year fish were stocked. Angler catch-rate expectations were approached by spring stockings (1.01 fish/h) but not from the fall-stocked fish (0.58 fish/h). Harvest rates did not increase as a result of the stocking program. Survi...

Longitudinal Differences in Electrofishing Catch Rates and Angler Catches of Black Bass in Cave Run Lake, Kentucky

Abstract Study objectives were to relate relative abundance and angler catch of largemouth bass Micropterus salmoides, spotted bass M. punctulatus, and smallmouth bass M. dolomieui (collectively referred to as black bass) to longitudinal variations in trophic conditions in Cave Run Lake, Kentucky. The upper, middle, and lower lake are eutrophic, mesotrophic, and oligotrophic, respectively, according to Carlsons trophic state index, which is based on chlorophyll-a concentrations. Electrofishing catch rates for largemouth bass were significantly greater (P < 0.05) in the upper lake than in either the middle or lower lake in 1985 and 1988. Spotted bass were significantly (P < 0.05) more abundant in both the lower and middle lake than in the upper lake in 1985 and 1988, whereas smallmouth bass were significantly (P < 0.05) more abundant in the lower lake than in either the middle or upper lake in 1987 and 1988. Catch (numbers released plus numbers harvested) of largemouth bass by anglers was significantly (P...

Evaluation of a Differential-Harvest Regulation for Black Bass in Cave Run Lake, Kentucky

Abstract A differential-harvest regulation was imposed in 1985 on black bass at Cave Run Lake, Kentucky. This regulation put a 15.0-in minimum-size limit on largemouth bass Micropterus salmoides and removed the size limit on spotted bass M. punctulatus. Our evaluation of this regulation showed it to be effective in managing black bass in Cave Run Lake. Condition of certain sizes of largemouth and spotted bass decreased, angler exploitation of largemouth bass declined, and angler exploitation of the abundant, slow-growing spotted bass increased. Total weight of largemouth bass harvested in 1989 equaled that observed under the former 12.0-in size limit; and large numbers of quality-size (≥ 12.0 in) largemouth bass were caught and released. Electrofishing catch rates increased for all sizes for largemouth bass but declined for spotted bass 9.0 in and longer.

Responses to Artificial Fertilization at Grayson Lake, Kentucky

Abstract An artificial fertilization program was conducted at Grayson Lake (612 ha) from 1994 through 1997 in an attempt to increase reservoir productivity and increase populations of largemouth bass Micropterus salmoides in the reservoir. In 1994 and 1995, a 162-ha portion of Grayson Lake was fertilized with a liquid high-nitrogen fertilizer. In 1995, the high-nitrogen fertilizer was supplemented with a small amount of a liquid high-phosphorus fertilizer. The area fertilized in 1996 and 1997 was reduced to a 41-ha embayment originally in the area fertilized in 1994 and 1995, and the fertilizer was changed to a liquid high-phosphorus fertilizer. No major changes in the quantities of soluble reactive phosphorus (SRP), total inorganic nitrogen (TIN), or chlorophyll a occurred in the fertilized portion in 1994 or 1995. Bottom-up effects were detected after application of the high-phosphorus fertilizer in 1996 and 1997. Increases in SRP occurred in the fertilized portion of the reservoir in 1996, but because ...