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Retrospective Theses and Dissertations

Environmental Sciences

Fisheries biology

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Full-Text Articles in Life Sciences

Effects Of Environmental Estrogens On Reproductive Biology Of The Fathead Minnow , Robert Bruce Bringolf Jan 2002

Effects Of Environmental Estrogens On Reproductive Biology Of The Fathead Minnow , Robert Bruce Bringolf

Retrospective Theses and Dissertations

Since the early 1990s, environmental estrogens have been recognized as an important environmental threat. Wastewater of 10 aerated lagoon treatment facilities in Iowa was evaluated for estrogenic activity using a short-term caged fathead minnow exposure and a plasma vitellogenin (Vtg) assay. Plasma Vtg results indicated that wastewater entering the three-lagoon systems was estrogenic to male fish, but with serial passage through the lagoons, the estrogenic activity decreased to a level that was not sufficient to induce vitellogenesis. Wastewater retention time in the lagoons may have been a key treatment factor.;Feral fathead minnows captured at aerated lagoon wastewater treatment facilities ...


Assessment Of Diet And Consumption Dynamics Of The Adult Piscivorous Fish Community In Spirit Lake, Iowa , Hongsheng Liao Jan 2001

Assessment Of Diet And Consumption Dynamics Of The Adult Piscivorous Fish Community In Spirit Lake, Iowa , Hongsheng Liao

Retrospective Theses and Dissertations

We explored differences among four well-known indices (%W, %O, %N, and %IRI), plus a modified %IRI (%MIRI), examined diet and consumption dynamics of black crappie (Pomoxis nigromaculatus), largemouth bass (Micropterus salmoides), northern pike (Esox lucius ), smallmouth bass (Micropterus dolomieui), walleye (Stizostedion vitreum), and yellow perch (Perca flavescens ) in Spirit Lake, Iowa, in 1995--1997. %W and %MIRI emphasizes importance of large prey taxa, even when relatively rare in diets, whereas %O and %N emphasize small prey common in diets. %IRI yielded intermediate results. Using %IRI, we found that the most important prey taxa overall were yellow perch, Decapoda, and Amphipoda. Largemouth ...


Toxicity Of Chlorpyrifos Adsorbed On Clay And Humic Acid To Larval Walleye , Todd Alan Phillips Jan 2000

Toxicity Of Chlorpyrifos Adsorbed On Clay And Humic Acid To Larval Walleye , Todd Alan Phillips

Retrospective Theses and Dissertations

Agricultural production poses one of the most serious threats to the continued ecological integrity of environmental systems and has been charged as the activity most responsible for loss of fish species in streams. Although all anthropogenic stressors affecting aquatic ecosystems have not been isolated, suspended solids, sediment, and pesticides are believed to be major factors. The objectives of this dissertation were to: (1) evaluate sources of variability in measuring cholinesterase activity, (2) determine the most sensitive life stage of walleye exposed to chlorpyrifos, (3) evaluate the bioavailability of chlorpyrifos adsorbed on humic acid (HA) and Panther Creek (PC) clay to ...


Hydrological Variation Along The Missouri River And Its Effect On The Fish Community , Mark Alan Pegg Jan 2000

Hydrological Variation Along The Missouri River And Its Effect On The Fish Community , Mark Alan Pegg

Retrospective Theses and Dissertations

The Missouri River has been subjected to human alteration for over 150 years and the flow regime is one physical attribute that has drastically changed as a result of alteration. Likewise, using flow characteristics has been identified as a driving variable to describe fish community structure in lotic systems. Therefore, my goal was to assess fish community structure in the Missouri River system in relation to flow. I first used a time series approach to examine daily mean flow data from 10 gauging stations on the Missouri River, and tested for differences associated with human alteration. Daily mean flow over ...


Factors Affecting Cholinesterase Activity In Aquatic Animals , Sheryl Linn Beauvais Jan 1997

Factors Affecting Cholinesterase Activity In Aquatic Animals , Sheryl Linn Beauvais

Retrospective Theses and Dissertations

Organophosphorus insecticides (OPs) are extensively used throughout the world to control crop pests. OPs are highly toxic to aquatic animals and can enter aquatic systems that drain agricultural watersheds, but assessment of an aquatic system's exposure to OPs is difficult as these compounds are non-persistent. Timing of sample collections and expense of analyses make direct monitoring of these insecticides problematic. A reliable and sensitive indicator of OP exposure and resulting toxic effects is needed to integrate across exposure events. A good candidate for the indicator is inhibition of cholinesterase (ChE) enzymes; OPs cause acute toxicity primarily through inhibition of ...


Behavior Of Larval Walleye , Phillip Warren Rieger Jan 1995

Behavior Of Larval Walleye , Phillip Warren Rieger

Retrospective Theses and Dissertations

High resolution cinematography was used to observe larval walleye (Stizostedion vitreum) behavior in laboratory aquaria. Observations focused on gas bladder inflation (GBI), first-feeding, and cannibalism. Four discrete phases of developmental behavior were observed: surface suspension (from hatch to 40 TU); a GBI phase (40-100 TU) with constant, rapid anquilliform swimming at the water surface; a first-feeding phase (100-240 TU) with slower, more subcarangiform swimming throughout the water column in search of food; and, a fully exogenous phase (after 240 TU) when the larvae move to the bottom of culture tanks and easily consume sinking feed particles that come within close ...


Effects Of Cadmium On Juvenile Bluegill (Lepomis Macrochirus) Foraging Behavior And Growth , Michael D. Bryan Jan 1993

Effects Of Cadmium On Juvenile Bluegill (Lepomis Macrochirus) Foraging Behavior And Growth , Michael D. Bryan

Retrospective Theses and Dissertations

Standardized toxicity testing protocols for assessing chemical hazards to aquatic organisms inadequately consider behavioral effects of toxicants; yet, organisms behaving abnormally in the wild experience reduced growth, fitness, and higher mortality. This study determined the effects of cadmium (0, 30, 60, 120, and 240 [mu]g/L) on juvenile bluegill (Lepomis macrochirus) foraging behavior in three 28-d functional response experiments, and one 24-d multi-prey experiment. The study also examined how cadmium-altered behaviors contributed to reduced growth rates. Different sizes of Daphnia magna and D. pulex were used as prey in these experiments. The rate of change (i.e., trends over ...


Histological And Ultrastructural Studies Of Larval And Juvenile Lampsilis (Bivalvia) From The Upper Mississippi River , Becky Ann Lasee Jan 1991

Histological And Ultrastructural Studies Of Larval And Juvenile Lampsilis (Bivalvia) From The Upper Mississippi River , Becky Ann Lasee

Retrospective Theses and Dissertations

Histological and ultrastructural studies describing early life history stages of freshwater unionid bivalves and studies evaluating impacts of chemical contaminants on early growth are lacking. This study examined larval and juvenile shell ultrastructure of Lampsilis ventricosa using scanning electron microscopy (with observations of Pleurobema cordatum), described morphology of internal organs of laboratory-reared L. ventricosa and evaluated effects of cadmium on juvenile survival, growth and development. Postmetamorphic (juvenile) shell was added to peripheral edges of the larval shell. Initial juvenile shell growth was rapid and coincided with shell deposition into larval shell pores. Glochidia metamorphosed while encapsulated on gills of fish ...


Metallothionein And Bioaccumulation Of Cadmium In Juvenile Bluegills Exposed To Aqueous And Sediment-Associated Cadmium , William Gregory Cope Jan 1991

Metallothionein And Bioaccumulation Of Cadmium In Juvenile Bluegills Exposed To Aqueous And Sediment-Associated Cadmium , William Gregory Cope

Retrospective Theses and Dissertations

I evaluated metallothionein (MT), free (unbound) hepatic cadmium and whole body cadmium as indicators of cadmium exposure in juvenile bluegills Lepomis macrochirus in laboratory tests. Two types of cadmium exposure were tested; aqueous and sediment-associated. In the aqueous tests, fish were exposed to cadmium (0.0 to 32.3 [mu]g/L) in an intermittent-flow diluter. The experimental design for the aqueous exposure was completely randomized and included two replicates in each of eight treatments (seven cadmium exposures and one water control). In the sediment-associated cadmium test, fish were exposed to resuspended river sediment containing 1.3 to 21.4 ...


A Physiological Approach To The Sublethal Effects Of Cadmium In Lampsilis Ventricosa , Teresa J. Naimo Jan 1990

A Physiological Approach To The Sublethal Effects Of Cadmium In Lampsilis Ventricosa , Teresa J. Naimo

Retrospective Theses and Dissertations

Previous studies of contaminant effects on freshwater mussels have been restricted to tissue contaminant concentrations and distribution among tissues. Although no standardized toxicity tests are available, acute toxicity tests have been conducted on freshwater mussels. Chronic toxicity tests which mimic the continuous low-level contaminant exposure these organisms may receive in nature are needed. A physiological approach was taken in this study to examine the sublethal effects of cadmium (0, 30, 100 and 300 ug/l) on the metabolic activity of adult Lampsilis ventricosa. A 28-day toxicity test was conducted using a proportional diluter. Ten mussels were placed into each of ...


Environmental Quality And Fish Community Ecology In An Agricultural Mountain Stream System Of Taiwan , Ching-Ming James Wang Jan 1989

Environmental Quality And Fish Community Ecology In An Agricultural Mountain Stream System Of Taiwan , Ching-Ming James Wang

Retrospective Theses and Dissertations

A 1.5 year environmental and faunal analysis was conducted in headwater streams of the upper Ta-chia River in mountainous central Taiwan. The area had distinct wet and dry seasons owing to monsoonal-typhoonal rainfall patterns. Compared to natural stream areas, agriculturally impacted reaches had greater discharge fluctuation, warmer temperatures, higher turbidity, increased nutrient loads, and reduced bedform diversity;Stream biotic communities varied according to local habitat characteristics. Coldwater algae existed mainly within natural stream reaches while eutrophication indicators occurred abundantly at agriculturally impacted sites. Large-bodies shredder-collector and predatory insects inhabited natural stream areas while smaller scraper-collectors were dominant in an ...


Sublethal Toxicant Effects On Fish Foraging Behavior: A Mechanistic Approach , Mark B. Sandheinrich Jan 1988

Sublethal Toxicant Effects On Fish Foraging Behavior: A Mechanistic Approach , Mark B. Sandheinrich

Retrospective Theses and Dissertations

Previous studies of toxicant effects on fish foraging behavior have taken a strictly empirical approach which had little basis in ecological theory and did not allow development of a testable hypothesis a priori to field verification of laboratory results. A mechanistic approach was taken in this study to examine the sublethal effects of four copper concentrations (0, 25, 150, 1800 ug/l) on the foraging behavior of bluegill Lepomis macrochirus. Twelve separate laboratory experiments were conducted. Two experiments assessed copper effects on the reaction distance of bluegill to untreated zooplankton. Ten experiments were done to assess copper effects on the ...


Ecological Factors Affecting Muskellunge (Esox Masquinongy) Reproduction In Midwestern Lakes , Michael Paul Dombeck Jan 1984

Ecological Factors Affecting Muskellunge (Esox Masquinongy) Reproduction In Midwestern Lakes , Michael Paul Dombeck

Retrospective Theses and Dissertations

Natural reproduction of muskellunge Esox masquinongy has failed in many waters that formerly supported self-sustaining populations. Laboratory studies showed high muskellunge egg mortality associated with high biological oxygen demand (BOD) substrates where hypoxic conditions developed at the substrate-water interface. Measured dissolved oxygen concentration (DO) at the substrate-water interface in muskellunge spawning sites in eight midwestern lakes showed that four lakes had high DO (mean, 6.0-8.4 mg/liter) and little microstratification, and support self-sustaining muskellunge populations. The remaining four lakes showed extreme DO microstratification and hypoxia (mean, 0.4-2.4 mg/liter) at the substrate-water interface. Populations of the ...


Importance Of Backwater Area Confluences To The Fishes And Macroinvertebrates Of The Upper Mississippi River, Pool 13, William A. Sheaffer Jan 1984

Importance Of Backwater Area Confluences To The Fishes And Macroinvertebrates Of The Upper Mississippi River, Pool 13, William A. Sheaffer

Retrospective Theses and Dissertations

No abstract provided.


The Effect Of Impounding A River On The Pesticide Concentration In Warmwater Fish , Siu-Yin Theresa Leung Jan 1979

The Effect Of Impounding A River On The Pesticide Concentration In Warmwater Fish , Siu-Yin Theresa Leung

Retrospective Theses and Dissertations

No abstract provided.


Some Toxicological Effects Of Phosphate Esters On Rainbow Trout And Bluegill , Sutham Sitthichaikasem Jan 1978

Some Toxicological Effects Of Phosphate Esters On Rainbow Trout And Bluegill , Sutham Sitthichaikasem

Retrospective Theses and Dissertations

No abstract provided.