Skip to main content
U.S. flag

An official website of the United States government

Theses

Browse more than 100 theses authored by our scientists going back to 1959 and refine search by topic, location, year, and advanced search.

Filter Total Items: 158

Accumulation and fate of mercury in an Everglades aquatic food web

This project examined the pathways of mercury (Hg) bioaccumulation and its relation to trophic position and hydroperiod in the Everglades. I described fish-diet differences across habitats and seasons by analyzing stomach contents of 4,000 fishes of 32 native and introduced species. Major foods included periphyton, detritus/algal conglomerate, small invertebrates, aquatic insects, decapods, and fi
Authors
William F. Loftus

Barotropic and baroclinic convergence zones in tidal channels

No abstract available.
Authors
John C. Warner

Effects of introduced crayfish on selected native fishes of Arizona

The virile crayfish (Orconectes virilis), an aggressive polytrophic species, has been introduced into many Arizona streams. I investigated competition and predation between this crayfish and several native Arizona fishes. I conducted field experiments to assess competition for food between crayfish and fish, and laboratory experiments to examine competition for shelter and food, and predation. In
Authors
J. Carpenter

Survival and brood rearing ecology of emperor geese

Emperor Geese (Chen canagica) breed on the Yukon-Kuskokwim Delta in an area inhabited by three other goose species. Whereas populations of other geese increased since the mid 1980s, Emperor Goose numbers remained low. Because survival and habitat selection by broods of Emeperor Geese had not been studied previously and numbers of predatory Glaucous Gulls (Larus hyperboreus) had recently increased,
Authors
Joel A. Schmutz