Juvenile salmonids display highly variable spatial and temporal patterns of early dispersal that are influenced by density-dependent and density-independent factors.
Although juvenile coho salmon (Oncorhynchus kisutch) movement patterns in streams and their relationship with body mass and growth have been examined in previous studies, most observations were limited to one...
Juvenile Oncorhynchus mykiss migrate extensively in freshwater during fall. We used individual tagging to study the spatial origin, influences, and outcomes of fall migration on fish that emigrated from summer rearing tributaries during fall (early-emigrants) and those that did not (late-emigrants) in the South Fork John Day River, Oregon. Fall...
Streams that dry during part of the year are common throughout the world, yet studies of the macroinvertebrate assemblages in these types of streams are rare compared to those in permanent streams; and studies that assess the effects of agriculture on temporary stream invertebrates are even rarer. We studied macroinvertebrate...
Rotary screw traps are used throughout the West Coast of North America to capture emigrating juvenile salmonids. Calibrating the capture efficiency of each trap is essential for valid estimates of fish passage. We released Passive Integrated Transponder (PIT) tagged Oncorhynchus mykiss upstream of a rotary screw trap in the South...
Aim: The ecological effects of biological invasions are well documented, but little is known about the effects of invaders on the genetic structure of native species. We examined the phylogeography, genetic variation and population structuring of two galaxiid fishes, Aplochiton zebra and A. taeniatus, threatened by non-native salmonids, and whose...
1. Globally, river systems have been extensively modified through alterations in riverscapes and flow regimes, reducing their capacity to absorb geophysical and environmental changes.
2. In western North America and elsewhere, alterations in natural flow regimes and swimways through dams, levees, and floodplain development, work in concert with fire regime,...
Agricultural practices, including tillage, fertilization, and residue management, can affect surface runoff, soil erosion, and nutrient cycling. These processes, in turn, may adversely affect (1) quality of aquatic resources as habitat for amphibians, fish, and invertebrates, (2) costs of treating surface and ground water to meet drinking water standards, and...
Rivers support some of Earth’s richest biodiversity and provide essential ecosystem services to society, but they are often fragmented by barriers to free flow. In Europe, attempts to quantify river connectivity have been hampered by the absence of a harmonized barrier database. Here we show that there are at least...
We quantified the patterns in macroinvertebrate assemblages and their
associated environmental gradients from 457 least-disturbed wadeable
stream sites across the 48 contiguous United States sampled as part
of US EPA’s National Wadeable Stream Assessment. The majority of the
variation in assemblage composition at the finest taxonomic resolution
was related to...