Publications

Abstract not supplied at this time

U.S. Geological Survey's Biological Resources Disicipline scientists have developed a procedure that could save commercial producers of triploid grass carp between $2000 and $3000 per pond. Since 1983, triploid grass carp have been commercially available for managing aquatic weeds that can cause water quality problems, replace native plants, or impede recreational and commercial use of...

We used morphological characteristics to determine the sex of California Gulls (Larus californicus) nesting at Bamforth Lake, Wyoming. Using univariate and multivariate techniques, we evaluated sexual dimorphism in five external measurements taken from 614 California Gulls: bill length, bill depth, head-bill length, tarsus length, and body mass. Males were significantly larger than...

Twenty-three dead and dying Brazilian free-tailed bats from roosts in downtown Mineral Wells, Palo Pinto County, Texas, were tested for rabies and for anticholinesterase (antiChE) effects of or- ganophosphorus (OP) and carbamate pesticides. Seventeen of the 23 bats tested positive for rabies. The cause of death or dying in five of the nonrabid bats is unknown; however, one of the six...

The objective of this study was to determine whether sediment ingestion or water ventilation was the primary route of uptake for benzo[a]pyrene (BaP) in the gizzard shad (Dorosoma cepedianum), a detritivorous fish. Two experiments were conducted in which fish were exposed to sediments spiked with 1 μg/g BaP. In the first experiment, fish were prevented from feeding by esophagus ligation...

The occurrence and distribution of selected pesticides and their metabolites were investigated through the collection of 837 water-quality samples from 303 wells across the Midwest. Results of this study showed that five of the six most frequently detected compounds were pesticide metabolites. Thus, it was common for a metabolite to be found more frequently in groundwater than its parent...

Abstract not supplied at this time

A nonnormal and heteroscedastic Tobit model is used to determine the primary factors that affect nitrate concentrations in near-surface aquifers, using data from the U.S. Geological Survey collected in 1991. Both normality and homoscedasticity of errors are rejected, justifying the use of a nonnormal and heteroscedastic model. The following factors are found to have significant impacts...

Relative concentrations of aqueous polycyclic aromatic hydrocarbons (PAH) were investigated in an urban creek. Samples were obtained at five sites within a 600-m segment of the creek that is critical habitat for an endangered species of fish. the sampling technique entailed immersion of semipermeable membrane devices (SPMDs) in the water for intervals as long as 64 d. SPMDs are passive...

We describe a lightweight, portable vacuum hand pump apparatus for use in collecting water samples from horizontal intragravel pipe samplers buried in the stream bottom. The apparatus is easily fabricated from relatively inexpensive materials available at many laboratory supply houses.

A geographic information system (GIS) procedure was developed to compile low-altitude aerial photography, digitized data, and land-use data from U.S. Department of Agriculture Consolidated Farm Service Agency (CFSA) offices into a high-resolution (approximately 5 meters) land-use GIS data set. The aerial photography consisted of 35-mm slides which were scanned into tagged information...

No abstract available.