Award Date

5-2009

Degree Type

Thesis

Degree Name

Master of Public Health (MPH)

Department

Environmental and Occupational Health

First Committee Member

Shawn Gerstenberger, Chair

Second Committee Member

Chad Cross

Third Committee Member

David Wong

Fourth Committee Member

Steve Weber

Fifth Committee Member

Craig Palmer

Graduate Faculty Representative

Timothy Farnham

Number of Pages

103

Abstract

The invasive species, the quagga mussel, Dreissena bugensis, was found in Lake Mead, Nevada-Arizona, USA on January 6, 2007. Since then, researchers have been attempting to quantify the amount of damage these mussels will cause to the lower Colorado River basin. Three projects were implemented in this thesis to research the quagga mussel in Lake Mead. First, a study to determine which types of substrates quagga mussels will grow on preferentially was conducted. Six different substrates, Acrylonitrile Butadiene Styrene (ABS) plastic, High Density Polyethylene (HDPE) plastic, Concrete Underlayment Board (CUB), aluminum, stainless steel and fiberglass, were placed in the Boulder Basin of Lake Mead for approximately one year in a modified randomized block design. Half of the substrates were removed and replaced every two months, and the other half remained in the water for the duration of the study (one year). Mussels had no preference in substrate type, but settlement was limited by depth. Mussel settlement on substrates at depths from 6-28 m was significantly greater than on substrates from 32-54 m. This divergence in depth preference is likely due to the different water quality characteristics at these depths. The second study was conducted to determine concentrations of mercury in quagga mussel soft tissue from Lakes Mead and Mohave. The range of mercury concentrations in mussel tissues was 0.017 -0.074 µg/g dry weight. The final project was designed to educate the public and determine certain characteristics of boaters that utilize Lake Mead. Boaters were asked questions about where their next boating destination would be, if they were aware of quagga mussels and if they cleaned their boat between launchings. Of 236 people interviewed, 81% were aware of quagga mussels, but this number needs to increase. To prevent the spread of mussels to other bodies of water, boater education and awareness is vitally important.

Keywords

Introduced freshwater organisms; Quagga mussel; United States -- Lake Mead

Disciplines

Earth Sciences | Environmental Health and Protection | Environmental Sciences | Fresh Water Studies | Water Resource Management

Language

English

Comments

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