Publications

Intersex occurrence in freshwater fishes was evaluated for nine river basins in the United States. Testicular oocytes (predominantly male testes containing female germ cells) were the most pervasive form of intersex observed, even though similar numbers of male (n = 1477) and female (n = 1633) fish were examined. Intersex was found in 3% of the fish collected. The intersex condition was...

The timing of spawning in fish is tightly linked to environmental factors; however, these factors are not very well understood for many species. Specifically, little information is available to guide recruitment efforts for endangered species such as the sturgeon. Therefore, we propose a Bayesian hierarchical model for predicting the success of spawning of the shovelnose sturgeon which...

We previously demonstrated that there were significant differences in the egg thiamine content in lake trout Salvelinus namaycush fed two Lake Michigan prey fish (alewife Alosa pseudoharengus and bloater Coregonus hoyi). Lake trout fed alewives produced eggs low in thiamine, but it was unknown whether the consumption of alewives affected other nutritionally important components. In this...

Amphibians in terrestrial environments obtain water through a highly vascularized pelvic patch of skin. Chemicals can also be exchanged across this patch. Atrazine (ATZ), a widespread herbicide, continues to be a concern among amphibian ecologists based on potential exposure and toxicity. Few studies have examined its impact on the terrestrial juvenile or adult stages of toads. In the...

Concerns about indoor air quality and the potential effects on people living in these environments are increasing as more reports about the toxicities and the potential indoor air exposure levels of household-use chemicals and chemicals fromhousingandfurnishingmanufactureinairarebeingassessed. Gas chromatography/mass spectrometry was used to confirm numerous airborne contaminants...

This report presents the results of a contaminant monitoring survey conducted annually by the Missouri Department of Conservation to examine the levels of selected elemental contaminants in whole-body fish, fish fillets, fish muscle plugs, and fish eggs. Whole-body, fillet, or egg samples of catfish (Ictalurus punctatus, Ictalurus furcatus, Pylodictis olivaris), largemouth bass...

Clopyralid (3,6-dichloro-2-pyridinecarboxylic acid) is a pyridine herbicide frequently used to control invasive, noxious weeds in the northwestern United States. Clopyralid exhibits low acute toxicity to fish, including the rainbow trout (Oncorhynchus mykiss) and the threatened bull trout (Salvelinus confluentus). However, there are no published chronic toxicity data for clopyralid and...

Mini (15.2 cm) semipermeable membrane devices (SPMDs) were used successfully in 169 streams from six metropolitan areas of the US to sequester hydrophobic organic compounds (HOCs) that are indicative of urbanization. A microscale assay the P450RGS, which responds to compounds that bind to the aryl hydrocarbon receptor (AhR), and the Fluoroscan, a chemical screen for polycyclic aromatic

This study focused on identifying the sex of lake sturgeon by measuring the sex hormones estradiol and testosterone, and the phosphoprotein vitellogenin (Vtg) in blood plasma by radioimmunoassay and enzyme-linked immunosorbent assay, respectively, and evaluating these techniques as tools in lake sturgeon population management. Surveys of the St Clair River (SCR) lake sturgeon population...

We compared the extent to which exotic species are associated with horse trails, old roads, and intact communities within three native vegetation types in Ozark National Scenic Riverways, Missouri. We used a general linear model procedure and a Bonferroni multiple comparison test to compare exotic species richness, exotic to native species ratios, and exotic species percent cover across...

Organochlorine pesticide and total polychlorinated biphenyl (PCB) concentrations were measured in largemouth bass from the Tombigbee River near a former DDT manufacturing facility at McIntosh, Alabama. Evaluation of mean p,p???- and o,p???-DDT isomer concentrations and o,p???- versus p,p???-isomer proportions in McIntosh bass indicated that DDT is moving off site from the facility and...

To fully utilize semipermeable membrane devices (SPMDs) as passive samplers in air monitoring, data are required to accurately estimate airborne concentrations of environmental contaminants. Limited uptake rate constants (kua) and no SPMD air partitioning coefficient (Ksa) existed for vapor-phase contaminants. This research was conducted to expand the existing body of kinetic data for...