Larry Brown (Former Employee)

We documented species' distributions, size structure of populations, abundance in mainstem and tributary streams, habitat use, and diets of prickly sculpin, Cottus asper, and coastrange sculpin, C. aleuticus, in the Eel River drainage of California, to determine the processes allowing coexistence of these very similar fishes. We observed prickly sculpins at 43 sites and coastrange...

The southernmost populations of coho salmon Oncorhynchus kisutch occur in California where native coho stocks have declined or disappeared from all streams in which they were historically recorded. Coho salmon previously occurred in as many as 582 streams, from the Smith River near the Oregon border to the San Lorenzo River on the central coast. Information on the recent presence or...

In 1991, the U.S. Geological Survey (USGS) began to implement a full-scale National Water-Quality Assessment (NAWQA) program. The long-term goals of the NAWQA program are to describe the status of and trends in the quality of a large, representative part of the Nation's surface- and ground-water resources and to identify the major natural and human factors that affect the quality of...

The California roach Lavinia symmetricus is a small cyprinid native to Central California. Populations of roach are presently isolated from one another due to degradation of stream habitats between them. We examined eight populations, each from a tributary system of the San Joaquin River, to determine if morphological differences existed among them. These tributaries are now isolated...

Shifts in microhabitat selection by rainbow trout Oncorhynchus mykiss were related to seasonal and ontogenetic factors in a small stream characterized by short riffles, small pools, and boulder substrate. Resource availability did not differ significantly between summer and November sampling dates for most variables related to water velocity, substrate, and cover, although depths were...

All basaltic lava flows of the Albuquerque Volcanoes (lat.: 35.2°N, long.: 253.2°E), Albuquerque-Belen Basin, New Mexico, record a short excursion/polarity episode. K-Ar isotopic age determinations (weighted average: 155 ± 47 ka) and evaluation of soil profiles on flow surfaces suggest the late Pleistocene (circa between 250 and 80 ka) as the time of extrusion. Results from 63 sites in a...