Lloyd L. Smith

Formation of Year Classes in Largemouth Bass

Abstract Early life history of largemouth bass (Micropterus salmoides) at Lake George and adjoining sloughs, Anoka County, Minnesota, is described. Bass spawning first occurred 2-5 days after mean daily water temperature exceeded 60° F. Two hundred and sixty-six nests were found on needlerush, waterlily roots, humps of fibrous material, aquatic vegetation, and sand in 10 to 62 inches of water. Egg survival at time of hatching varied from 0 to 94 percent. Percentage of successful nests from a single spawning period varied from 0 to 100. Number of fingerlings per brood 2 weeks after rising from the nest varied from 500 to 12,715 fish with mean brood size of 5,600 in 1956 and 1957 and 3,600 in 1958. Analyses of bag-seine catches showed 1.0, 5.5, 10.0, and 1.3 fingerlings per 1,000 square feet in 1955, 1956, 1957, and 1958, respectively. Number of yearlings in the four year classes at the beginning of the second summer of life were 0.05, 0.42, 0.93, and <0.05 per 1,000 square feet. Year classes were weak in 1...

Early Life History of the Northern Pike, Esox lucius L., with Special Reference to the Factors Influencing the Numerical Strength of Year Classes

Abstract The early life history of northern pike was studied to determine the relationship of adult pike abundance to the strength of resulting year classes and the existence and chronology of critical survival periods, along with the nature and origin of the mortality mechanisms involved. Adult abundance and the strength of the resulting year classes were not directly related. Two critical survival periods were located, one during the embryo stage between fertilization and closure of the blastopore, and the second between hatching and the termination of the alevin stage. The mortality during these periods may result from toxic concentrations of iron compounds or from excessively rapid temperature change. Growth, food utilization, and oxygen, ammonia, and sulfide levels in the nursery slough did not appear to influence survival. Greatest survival of naturally reared fingerlings will result from stabilization of water levels in the nursery areas. Water is required for at least 3 months after egg deposition...

Factors Affecting Abundance of Lake Herring (Coregonus artedii Lesueur) in Western Lake Superior

Abstract A field and laboratory study was conducted in 1965–1968 to investigate factors affecting lake herring (Coregonus artedii Lesueur) abundance in western Lake Superior. Commercial landings in November-December in the Duluth-Superior area dropped from 1,117,000 pounds in 1954 to 2000 pounds in 1966. Wisconsin catches also declined markedly. Abundance and fishing intensity indices decreased with landings. Commercial catches and abundance of chubs (Coregonus spp.) and smelt (Osmerus mordax) increased simultaneously with the herring reduction. Biological characteristics of Duluth-Superior and Apostle Islands (Wisconsin) herring stocks were examined and compared. Herring eggs were more abundant and viable in the latter area, and laboratory hatching success was significantly greater for Apostle Islands eggs. Herring larvae were generally more abundant and smaller in the Apostle Islands; distribution and growth did not differ between areas. Abundance of larvae in both areas declined sharply in June-July. A...

Factors influencing acute toxicity estimates of hydrogen sulfide to freshwater invertebrates

Abstract Acute bioassay tests of hydrogen sulfide were run on Assellus militaris Hay, Crangonyx richmondensis laurentianus Bousfield. Gammarus pseudolimnacus Bousfield. Bactis vagans McDonough. Ephemera simulans Walker and Hexagenia limbata (Serville). Size and type of test chamber, type of substrate for barrowing forms or those seeking shelter in gravel, oxygen concentration, pH, and season of collection influenced the sensitivity of organisms. Hydrogen sulfide exposure at sublethal levels reduced feeding activity of Gammarus . Data indicate that test conditions should approximate natural habitat conditions as closely as practical. The most acceptable 96-h LC 50 hydrogen sulfide concentrations for the various species are: Assellus 1.07 mg 1 −1 Crangonyx 0.84 mg 1 −1 . Gammarus 0.059 mg 1 −1 . Baetis 0.020 mg 1 −1 . Ephemera 0.316 mg 1 −1 , and Hexagenia , 0.111 mg 1 −1 . Chronic exposure tests now in progress suggest that the no-effect levels are 8–12 per cent of the 96-h LC 50 .

Some Factors Influencing Toxicity of Linear Alkylate Sulfonate (LAS) to the Bluegill

Abstract Some factors influencing toxicity of linear alkylate sulfonate (LAS) on the early life history stages of the bluegill, Lepomis macrochirus (Rafinesque), were studied in raw Mississippi River water under ambient conditions and under controlled conditions in well water. Median response varied from 0.2–10 mg/1 LAS with the life history phase and environmental conditions. Variation in estimation of TLm values within and between similar tests was small in comparison to the influence of external factors. The most important environmental factors related to lethal threshold concentration of LAS were dissolved oxygen, water hardness, and acclimation to LAS. High temperature decreased the median tolerance limit only during tests of short exposure. Sublethal concentrations of LAS increased toxicity of fuel oil mixtures while bentonite suspensions up to 200 mg/1 had little influence on LAS toxicity. The most sensitive stage of development was the feeding sac-fry, while the most tolerant stage was the newly h...

Effect of hydrogen sulfide on northern pike eggs and sac fry

Abstract A series of bioassays were conducted to test the effect of H2S at two concentrations of oxygen on northern pike (Esox lucius L.) eggs and sac fry. At an oxygen concentration of approximately 2 ppm mean median tolerance limits (TLm) for eggs were 0.411, 0.076, 0.038, 0.034, and 0.030 ppm H2S for 24, 48, 72, 96 hours, and for the duration of the embryonic period, respectively. At an oxygen concentration of approximately 6 ppm mean median tolerance limits (TLm) were 0.181, 0.046, 0.041, 0.037, and 0.032 ppm H2S for 24, 48, 72, 96 hours, and for the duration of the embryonic period, respectively. Mean TLm values for sac fry were 0.035, 0.016, 0.012, and 0.009 ppm H2S at 2 ppm oxygen and 0.160, 0.047, 0.030, and 0.026 ppm H2S at 6 ppm oxygen for 24, 48, 72, and 96 hours, respectively. Eggs subjected to H2S resulted in increasing percentages of sac fry with anatomical malformations. Sac fry hatched from eggs held at the higher H2S concentrations were smaller than the controls. Sac fry subjected to H2S ...

First-Year Growth of the Largemouth Bass, Micropterus salmoides (Lacépède), and Some Related Ecological Factors

Abstract First-year growth of largemouth bass taken from Lake George and adjoining slough, Anoka County, Minnesota, during a 4-year period was described. Illumination, water chemistry, abundance of bass fingerlings, yearlings, and other fish did not influence growth rate or total seasons growth. Total length at end of season varied from 56 to 85 millimeters and was contingent upon length attained on August 1, which was directly related to total temperature experience to that date. Rates of embryo development, sac-fry growth, and fingerling growth during the first 4 weeks and again at the end of the season were directly related to the mean daily water temperature. Growth rate during the first 2 weeks after rising was directly related to amount of food in stomachs, and near the end of the season to the ratio of large organisms to small organisms. Differences in relative condition factor (Kn) between areas in a single year were directly related to stomach weight, while differences in condition among years w...

Effect of Pulpwood Fiber on Oxygen Consumption and Swimming Endurance of the Fathead Minnow, Pimephales promelas

Abstract Sublethal levels of suspended conifer groundwood impaired oxygen uptake and swimming ability of fathead minnows (Pimephales promelas). In fiber-free water active metabolism at 15, 18, and 21 C was 11.7, 13.0, and 14.9 mg O2/kg of fish per min, respectively, when oxygen was not limiting. Fiber suspensions of 100 to 800 ppm were tested, and at 21 C for each doubling in fiber concentration, active metabolism was reduced by about 1.3 mg/kg per min and the decrease was about the same at all dissolved oxygen (D. O.) levels. At 15 C, for each doubling in fiber concentration, active metabolism was reduced by 1.0 mg/kg per min at low D. O. levels (2.5 ppm) and by 0.2 mg/kg per min at high D. O. levels (9.0 ppm). Swimming endurance was reduced by suspended fiber with the effect being greatest at low D. O. levels. Hematocrit rose by approximately 2 for each doubling in concentration of suspended fiber and rose by 1.4 for each 1 ppm decrease in D. O. Gill-cleaning reflexes increased markedly with increase in...

Survival of Walleye Eggs and Fry on Paper Fiber Sludge Deposits in Rainy River, Minnesota

Abstract Investigations of paper-fiber sludge deposits in the Rainy River, Minnesota, below paper mills were made to determine water characteristics over them with reference to survival of walleye (Stizostedion v. vitreum) eggs and fry and occurrence of bottom fish-food organisms. Sampling of water from the fiber-sludge water interface to the surface showed gradients in oxygen as great as 0.1 ppm to near saturation, and in dissolved sulfides from 0.8 to 0.0 ppm. The most rapid gradient of these materials was in the bottom 20 mm. Levels of sulfides were most affected by current velocity and showed little relation to temperature or season. Walleye eggs placed in test trays on fiber mats had lower survival than those placed 12 inches above the mats and those placed on mineral substrates. Eggs and fry placed on mats died within 48 hours. Laboratory bioassays showed that sulfide levels of 0.3 ppm under controlled conditions approximating river conditions were acutely lethal to Gammarus pseudolimnaeus and walle...

Early Life History of the Yellow Perch, Perca Flavescens (Mitchell), in the Red Lakes, Minnesota

Abstract The early life history of the yellow perch, an important commercial species in the Red Lakes, Minnesota, has been studied with special reference to length at scale formation, growth rate during first season of life, and food habits as they relate to growth and survival. Scales are fully imbricated in the area of 12th to 14th lateral line scales at 24 millimeters total length. There is a wide annual varition in first seasons growth which is not correlated with growth in older fish. Body-scale relationship is rectilinear from 24 to 280 millimeters. Length-weight relationship during the first year is expressed by the equation W = 0.6198 × 10−5 L3.1251 which is very similar to that describing the relationship in later years. Stomach analysis indicates food is primarily plankton but in some seasons fish may be strongly dependent on bottom forms. Variations in food availability appear to be associated with changes in growth and may have a major influence on survival.