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

Number of Pages

62

Abstract

The ecology of Lake Mead is experiencing an uncertain future since the documented arrival of the invasive quagga mussel. Interactions among constituents of the food web will undoubtedly be altered over time, adversely affecting the popular sport fishery. This study is the first in Lake Mead to present historic trends in lower trophic interactions among threadfin shad and zooplankton before, and shortly after, the arrival of quagga mussels. Shad stomach content analysis revealed cladocerans and copepods were the dominant identifiable food items in Las Vegas Bay and Overton Arm of Lake Mead. Baseline energetics data through the use of stable isotope analysis showed little variation in δ 13 C among larval and adult shad since quaggas were discovered. Fluctuations in δ15 N were more variable over the same span, with 2008 showing highest nitrogen measurements. Historic relative shad abundance and zooplankton biomass data were gathered from multiple agencies for the purpose of comparative analysis. This project was funded by the National Park Service and is part of a long-term monitoring plan in response to quagga mussel influences in the Lake Mead watershed over time.

Keywords

Freshwater zooplankton; Lake ecology—Research; Quagga mussel; Threadfin shad

Disciplines

Environmental Health and Protection | Environmental Monitoring | Environmental Sciences

Language

English


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