Smallmouth Bass Populations Research Articles

Smallmouth Bass in the Shoals Reach of the Tennessee River: Population Characteristics and Sport Fishery

Abstract The 20-km section of the Tennessee River immediately downstream from Wilson Dam near Muscle Shoals, Alabama, has a national reputation for an excellent sport fishery of smallmouth bass Micropterus dolomieu. Growth, mortality, population structure, and sport-fishery characteristics were determined for this smallmouth bass population from February 1988 to January 1989. This information was used to compare recent characteristics of the fishery with historic characteristics, and to determine if harvest regulations are viable fishery management options. Smallmouth bass displayed good but not exceptional growth rates through age 3, and after age 3 (when the fish were about 300 mm total length) their growth exceeded all other river populations and regional averages. The smallmouth bass population had a high proportional stock density (72), sustained substantial fishing effort (135 h/hectare annually), and experienced high annual mortality (50–57%) that was largely attributable to harvest. Monthly fishin...

An individual-based approach to predicting density-dependent dynamics in smallmouth bass populations

The dynamics of a young-of-the-year cohort of a fish species, smallmouth bass ( Micropterus dolomieui), were modeled using an individual-based computer simulation model. The young-of-the-year fish were simulated from the egg stage until recruitment into the yearling age class. At low initial densities of smallmouth bass in the swim-up larvae stage, recruitment to the yearling age class was roughly proportional to the initial densities of larval fish. However, when the initial densities were sufficiently high decreasing recruitment was observed as a function of further increases in larval density in the model. This occurred because high initial densities prevented all but a small fraction of the smallmouth bass from attaining large enough sizes to escape winter starvation. The addition of significant levels of size-dependent predation greatly altered this result, however. Heavy predation reduced the competition for prey among smallmouth bass and allowed a large number of smallmouth bass to grow rapidly and recruit to the yearling class.

The effects of temperature, pH and water hardness on winter starvation of young‐of‐the‐year smallmouth bass, Micropterus dolomieui Lacepede

Year‐class strength in northern populations of smallmouth bass is strongly influenced by winter starvation of young‐of‐the‐year. We examined starvation among young bass under both winter and summer light and temperature conditions. During starvation, body condition declines to a specific level and then the fish dies. Body condition at death is a well defined function of body size that remains relatively constant over a wide range of environmental conditions. Starvation rate varies systematically with body size, temperature, pH and water hardness. Available stored energy increases more rapidly with body size than starvation rate. Therefore, lifetime under starvation conditions tends to increase with increasing body size. The Q10 for starvation rate over the temperature range 2.5‐8° C is 2.2. Starvation rate increases as pH declines from 7.0‐4.9: the rate at pH 4.9 is ∼ 1.25 times the rate at pH 7 Starvation rate decreases as Ca concentration increases from 1 mgl−1 to 80mgl−1: the rate at 80 mg Ca 1−1 is ∼0.80 times the rate at 1 mgl−1.

Skeletal deformities in smallmouth bass,Micropterus dolomieui, from southern Appalachian reservoirs

Smallmouth bass (Micropterus dolomieui) populations in two of five reservoirs sampled in the southern Appalachian Mountains contained high percentages of individuals with lordosis, kyphosis, or scoliosis. Deformities of the vertebral column occurred in several year classes and varied with fish size; they were absent in small fish, present in 25-30% of the fish 241-300 mm long, and then decreased in occurrence with increased length. Because environmental contamination is often responsible for high occurrences of deformed fish, whole-body concentrations of contaminants, bone development characteristics, and blood plasma concentrations of calcium and phosphorus in normal and deformed fish were measured and compared the results with those for fish from reservoirs where no deformities were found. Vertebrae were significantly weaker and more elastic in deformed than in normal fish, but biochemical properties of vertebrae were similar among the groups tested. Concentrations of pesticides and metals were not elevated in deformed fish, and concentrations of calcium and phosphorus in blood plasma were similar in normal and deformed groups. Most environmental contaminants that have been shown to cause fish deformities could be discounted as causative agents on the basis of these results; however, the exact cause was not determined. Further attempts to diagnose the cause of the deformities were limited by the lack of background information on relationships among bone development processes, types of stresses that cause deformities, and types of bone tissue in fish.

Characteristics of an Unexploited Smallmouth Bass Population in a Missouri Ozark Stream

Abstract An unexploited population of smallmouth bass Micropterus dolomieui in a headwater stream in the Ozark Mountains of Missouri consisted of relatively slow-growing fish at a high density (138 fish at least 150 mm long per hectare). The population size structure had a considerable percentage of large fish (proportional stock density = 41; 100 [number of fish ≥280 mm long/ number of fish ≥180 mm long]) and condition was average (W r = 83; 100 × weight of individual fish/mean weight at length) for smallmouth bass in an Ozark stream. Total annual mortality for fish of ages 3–7 was only 16%. Estimates of biomass (28.9 kg/hectare) and annual production (11.7 kg/hectare) for fish at least 150 mm long were greater than those reported for 10 similar streams. The data suggested that a good-quality, although perhaps speciality, fishery could be maintained with highly restrictive harvest regulations in a headwater Ozark stream.

Effects of acidic water on young-of-the-year smallmouth bass (Micropterus dolomieui)

Smallmouth bass (Micropterus dolomieui) populations are declining in areas vulnerable to anthropogenic acidification. To determine if populations may be lost directly from acid effects (i.e., in isolation from synergists), we performed a laboratory study on the effects of acid exposure on growth, survival and histology of young smallmouth bass (3 to 36 d post swimup). We exposed them to declining, then fluctuating acid levels averaging pH 7.4 (control), 5.7 and 5.0. Substantial decreases in survival were observed, as well as damage to tissues. Survival declined with increasing acidity to 43% of that in controls at pH 5.7 and to 4% at pH 5.0. Histological analysis revealed severe changes in the most acidic treatment, with damage to blood, gill, and epithelial tissue. In contrast, growth was less useful as an indicator of response to acidity. Growth in both length and dry weight was greater at the lower pH levels than in controls. This was probably a reflection of lower survival at the lower pH levels, reduced density, and hence less competition for food. Our results suggest that an increase in environmental acidity is sufficient to cause losses in this species, even in the absence of synergists such as heavy metals.

Optimal Use of Creel Survey Data in Assessing Population Behaviour: Lake Opeongo Lake Trout (Salvelinus namaycush) and Smallmouth Bass (Micropterus dolomieui), 1936–83

Creel survey and independent assessment data on the lake trout (Salvelinus namaycush) and smallmouth bass (Micropterus dolomieui) populations of Lake Opeongo were evaluated. Annual estimates of total mortality, fishing mortality, and abundance were generated for each population over the period 1936–83. Large variations in survey efficiency, angler efficiency, fishing mortality, and abundance were identified over this period. We argue that a creel survey, which is expected to provide reliable information on fish population dynamics, requires an overall study design which includes collection of data on the number and relative efficiency of different kinds of anglers and periodic assessment studies aimed at providing independent checks on both survey effectiveness and population behaviour.

Effects of aluminum and pH on the early life stages of smallmouth bass ( Micropterus dolomieui)

The sensitivity of smallmouth bass Micropterus dolomieui to acidified conditions was examined by exposing recently-hatched fish to pH levels ranging from 5.1 to 7.5 and aluminum concentrations ranging from 32 to 1000 μg l −1. The range of pH and aluminum concentrations included those found in the northern part of the species' range. Acute bioassays (96 h) conducted at a pH of 5.1 and aluminum concentrations ⩾ 180 μg l −1 resulted in total mortality. The LC 50 calculated for this species was 130 μg l −1. At pH values of 6.1 and 7.5, mortality was low (⩽ 20%) regardless of aluminum concentrations. A 30-day chronic toxicity test was conducted at three pH levels (low 5.1, intermediate 5.5–5.7 and high 7.3), each with two aluminum concentrations (approx. 0 and 200 μg l −1). Survival was significantly lower in the test at pH 5.1 with aluminum, and at pH 5.7 with aluminum treatments than in the other treatments. Fish in the pH 5.1 without aluminum treatment had intermediate survival, while fish exposed to pH 5.7 without aluminum, pH 7.3 without aluminum and pH 7.3 with aluminum had high, and similar, survival. Sublethal effects on fish exposed to low pH and aluminum included deformities, reduced activity and abnormal swimming behavior. We conclude that the sensitivity of smallmouth bass to low pH and aluminum concentrations corroborates field investigations linking acidification and aluminum mobilization with depletion of smallmouth bass populations.

An Empirical Model of Size Distributions of Smallmouth Bass

As part of a study of the life cycle of the smallmouth bass Micropterus dolomieui, young of the year were sampled in the Baie du Doré, Lake Huron, during six summers to determine growth after dispersal from nests. Length-frequency distributions were plotted approximately weekly each of the summers. The changes through time of the mean size of fish in each cohort were described by a mathematical model that assumed a size-dependent growth rate and no size-dependent mortality for the fish. The constraint on the model to fit the empirical mean fish sizes through the growing season automatically produced time-varying standard deviations of the size distributions that compared closely to the empirical standard deviations for 5 out of the 6 years. The poor fit to the standard deviations of the sixth year was explicable in terms of unusual data on one sampling date. These results suggest that size dependence of the growth rate was an important mechanism in the spread in the length-frequency distribution and that size-dependent mortality played no significant role in determining the changes in this distribution through the growing season. Because winter mortality of first-year smallmouth bass in northern waters is important in their population dynamics and is size-dependent, the model provides a link in the understanding of smallmouth bass populations and their management.

Population Structure Indices of Largemouth Bass and Smallmouth Bass Determined from Angler Catches

Increased angling effort on black bass (Micropterus dolomieui and Micropterus salmoides) requires more efficient and effective management to maintain the quality of the resource. Baseline data needed to develop effective management policies were collected for largemouth bass and smallmouth bass in 19 lakes and 1 river in Maine, representing 19,000 hectares of water. A card requesting only information on bass was distributed to anglers at bass club fishing tournaments and to the general public at sporting shops, general stores, and fishing lodges. Fishing diaries were given to selected anglers who had received specific instructions. Data were analyzed by the Proportional Stock Density index (PSD), a measure of population size structure. Populations of largemouth bass in eight waters had significant PSD values greater than 60%, indicating too few small fish. In three lakes, PSD was between 40 and 60%, indicating balanced populations. Populations of smallmouth bass in eight waters had significant PSD values greater than 60%, also indicating too few small fish. PSD was less than 40% in two waters, indicating too few large fish. Smallmouth bass in the one river had a PSD between 40 and 60%, suggesting balanced numbers. Regulation changes of increased size limits to increase sizes of predators are recommended for three of eight waters that were analyzed in detail. A slot limit protecting intermediate-size fish is recommended for the river.

Introgressive Hybridization of Smallmouth Bass (Micropterus dolomieui) and Guadalupe Bass (M. treculi)

The introduction of smallmouth bass (Micropterus dolomieui) into the range of the endemic Guadalupe bass (M. treculi) on the Edwards Plateau in southcentral Texas has resulted in hybridization between these species. Sympatric populations of smallmouth bass and Guadalupe bass from two discrete locations on the Edwards Plateau were analyzed on the basis of biochemical genetics and meristics. Electrophoretic and meristic evidence revealed no interspecific hybrids in Lake Travis. It appears that smallmouth bass have not adapted well in this lake, perhaps contributing to the lack of genetic exchange with Guadalupe bass. In contrast, the Canyon Lake populations are actively interbreeding, and diagnostic allozyme loci clearly revealed genetic introgression between these two species. Genetic analysis proved to be a more sensitive tool for detecting F2 or backcross individuals than the meristic index. The genetic integrity of Guadalupe bass appears to be seriously threatened in at least part of its highly restricted range.

The Smallmouth Bass Population and Fishery in a Northern Wisconsin Lake, with Implications for other Waters

Abstract Smallmouth bass (Micropterus dolomieui) were captured in fyke nets and tagged in Clear Lake (342 hectares), Oneida County, Wisconsin, and a creel survey of the sport fishery was conducted. The population, as indicated from catches in the nets and by anglers, was composed mainly of young, small fish; more than 95% were of ages I-IV and less than 300 mm long. Their growth in this oligotrophic lake was slower than that in most other waters, and estimated production per unit recruitment, 1,265 g per 1,000 g, was less than in some other populations. Estimated annual fishing, natural, and total mortality rates were 56, 49, and 77.5%. The mean population estimate for smallmouth bass over 225 mm long was 8.7 fish per hectare, estimated fishing pressure was 36-49 hours per hectare, the catch rate averaged 6 smallmouth bass per 100 hours of effort, and the harvest (estimated in two ways) was 2.1 and 3.8 fish per hectare. Calculation of equilibrium yield per unit recruitment indicated that reducing fishing ...

Accelerated Growth of Smallmouth Bass in a Pumped Storage System

A 12-year study of the smallmouth bass population, Micropterus dolomieui, in a pumped storage reservoir revealed an accelerated growth that was related to the abundance of gizzard shad, Dorosoma cepedianum. Prior to the gizzard shad introduction, the growth of smallmouth bass was generally poorer than that reported for the mid-Atlantic region. Large drawdowns (9 m per day, 15.6 m per week) may have increased the vulnerability of gizzard shad by concentrating both prey and predator. In the lower reservoir, where water levels fluctuated irregularly and much less (up to 1 m per day), smallmouth bass growth was not greatly improved following the introduction of gizzard shad.

Stochastic Simulation of Temperature Effects on First-Year Survival of Smallmouth Bass

The physiological basis for well-known correlations between summer air temperature indices and year-class strength in northern smallmouth bass (Micropterus dolomieui) populations was examined. Field and laboratory studies demonstrated the existence of two critical stages in early life when smallmouth bass are particularly vulnerable to features characteristic of many natural water temperature regimes. The first stage extends from fertilization until the young leave the nest; high mortality results from exposure to extreme temperatures. The second stage extends over the first winter, when the young subsist on accumulated energy reserves. Because the ratio of energy stored to basal metabolic rate increases with size, large fish can withstand winter starvation better than small fish. The results from these and other studies were incorporated into a deterministic model of the relations between temperature and first-year survival of small-mouth bass. Analysis of water temperature time series data from many locations led to the development and parameterization of a stochastic model capable of simulating variations in water temperature characteristic of the littoral zones of typical North American lakes. The stochastic physical and deterministic biological models were used together to assess the effects on first-year survival of changes in climate and of realistic changes in the magnitude and frequency of short-term temperature fluctuations. The model successfully predicted the observed northern limit of the speciesˈ range. It also generated approximate environmental criteria for judging when year-to-year variation in survival, over one or both of the critical life history stages identified, is likely to reach a level sufficiently great to determine the pattern of year-to-year variation in recruitment to the adult stock. The combined model was also used to assess the effects of thermal loading from a nuclear power plant on a particular population.

Growth Rates and Size Distributions of First-year Smallmouth Bass Populations: Some Conclusions from Experiments and a Model

Abstract Growth rates of populations of first-year smallmouth bass (Micropterus dolomieui Lacepede) were studied during the first few weeks of life at temperatures ranging from 15.2 to 32.5 C. In all cases, the average length of fish in each group increased linearly with time, t, in a range from 10 to 30 mm. The variances about these mean lengths increased approximately as t2. A partial differential equation model can be useful in expressing the dynamics of populations in which size distributions are taken into consideration. Applied to our experiment, this type of model shows that both of the observed length-versus-time phenomena are expected if the rates of increase of length of fish are independent of length and that these rates for individual fish are normally distributed about some mean rate of growth. The variance of individual growth rates needed to produce the observed length-versus-time data can be calculated from the model.

The Effects of a Simulated Angler Harvest on Biomass and Production in Lightly Exploited Populations of Smallmouth and Largemouth Bass

Harvests of 13 to 21%, mostly of larger, older fish, were imposed for two years on populations of smallmouth and largemouth bass (Micropterus dolomieui and M. salmoides) that previously had been virtually unfished. Another population of smallmouth bass served as a control. Using trap nets, estimates of the number of bass and their size were made for one year before and two years after initial harvest. From these data, annual natural mortality, growth, standing crop and production were computed. There were no strong and consistent changes in any parameter which could be attributed to reductions in numbers of fish. Changes in growth unrelated to population density apparently resulted in declines of ratios of production to biomass following harvest. Possible causes of the lack of compensatory responses to harvest include the relatively short period of study and time lag in changes in growth and mortality.

Early Survival and Recruitment of Smallmouth Bass in Northern Michigan

Early Survival and Recruitment of Smallmouth Bass in Northern Michigan

An Evaluation of RNA–DNA Ratio as a Measure of Long-Term Growth in Fish Populations

The value of RNA–DNA ratio as a measure of long-term growth of fish populations under semi-natural conditions and when subjected to environmental manipulations was determined. Populations of carp and smallmouth bass of known age distribution were established in artificial ponds maintained at two fertility levels. After 15 months, population growth rates (as percent increase in weight) and RNA–DNA ratios of muscle tissue from selected fish were measured. Each species exhibited a range of population growth rates. The relation between population growth rate and individual fish RNA–DNA ratio for each species was significant. When reproduction occurred, the relation was not significant unless young-of-the-year fish were excluded from population growth rate calculations. Age of fish was also found to have an important effect on RNA–DNA ratio, with the ratio being higher in younger fish.RNA–DNA ratio can be a reliable indicator of long-term population growth in fish when population age structure is known and recruitment is controlled. The method has potential for use in detecting response to environmental changes before growth rate changes become severe.

What Fishermen Look for in a Fishing Experience

What Fishermen Look for in a Fishing Experience

The Influence of Stream Stability on Homing Behavior of two Smallmouth Bass Populations

Abstract The homing behavior of smallmouth bass was studied in two small Ozark streams; Big Buffalo Creek with relatively permanent pools, and Little Saline Creek with many unstable pools continually altered by the shift of chert gravel. The smallmouth bass in both streams normally restrict their movements to limited sections of the streams, usually one distinct pool. In Little Saline Creek, 39 of 97 tagged bass recaptured had deserted their home pools. Of these, 24 were forced to move because their home pools had been eliminated by deposition of chert gravel. It was concluded that the movement of smallmouth bass in Little Saline Creek was directly correlated with the physical stability of the stream. The bass of Big Buffalo Creek moved somewhat more frequently than the bass in the stable pools of Little Saline Creek although the pools of Big Buffalo Creek were comparatively stable during the study period. Fifteen bass made voluntary trips of 100 to 2,845 feet to other pools, and later returned to their h...