Christina A. Murphy

United States Geological Survey | USGS · Maine Cooperative Fish And Wildlife Research Unit

Fish passage out of reservoirs is a critical issue for downstream movement of juvenile salmonids and other migratory species. Reservoirs can delay downstream migrations by juvenile salmon for months or years. Here, we examine whether a novel management activity implementing annual short‐term draining of a reservoir to streambed improves timely down...

Biological invasions threaten species and ecosystems worldwide. Impacts from invasions are especially prevalent in freshwaters, where managers have struggled to contain the problem. Conventional approaches to managing invaders focus on prevention and control. In practice, these measures have proven to be variably effective. Control or eradication o...

Regulated rivers downstream of dams often exhibit highly modified thermal regimes in addition to modified hydrologic regimes; downstream river temperatures can be seasonally much warmer or cooler than unregulated streams. Selective water withdrawals can be used to minimize thermal impacts to downstream reaches. However, other water quality paramete...

Secondary production, the growth of new heterotrophic biomass, is a key process in aquatic and terrestrial ecosystems that has been carefully measured in many flowing water ecosystems. We combine structural equation modeling with the first worldwide dataset on annual secondary production of stream invertebrate communities to reveal core pathways li...

Abstract Complex predator–prey interactions over time have the potential to limit survival of threatened native species. Reservoirs created by large dams in temperate ecosystems are sites where both coldwater and warmwater fish species overlap in distributions, forming assemblages that would not occur under natural settings. For example, in many we...

Documenting species invasions and assessments of ecological changes depend on detection. Here, we present a simple design of a plankton light trap with specific wavelength LEDs and modifications. We used PVC pipe to create standardised small, rigid, low-cost traps that can be deployed in lentic habitats. With a cost of under $30 US each, including...

We studied the impacts of clear cut timber harvest over six-years, focusing on aquatic macroinvertebrate response using a BACI design. Data were collected before and after logging throughout a stream network to examine both local and downstream effects of upstream treatments. Sites were located in fishless headwater tributaries, fish-bearing tribut...

Recognizing some of the women who have contributed to fisheries science and the American Fisheries Society.

Salmincola californiensis is a Lernaeopodid copepod parasitizing Pacific salmon and trout of the genus Oncorhynchus. Salmincola californiensis is of increasing concern in both native and introduced ranges because of its potential fish health impacts and high infection prevalence and intensity in some systems. Discrepancies in the documented life hi...

Natural history collections provide a wealth of information beyond the scope of their initial purpose, including a historical window into host–parasite relationships. For example, collections can reveal historical infections of fishes by the freshwater gill‐maggot Salmincola californiensis, a parasite of increasing concern because of negative effec...

The importance of zooplankton as a food resource for higher trophic levels, including threatened and endangered salmon species, highlights the need to improve our understanding of the mechanisms that structure reservoir food webs. Pelagic plankton are the dominant primary and secondary producers in reservoirs experiencing extreme water level fluctu...

Linked foraging and bioenergetics models allow for increased understanding of fish growth potential and behavior by incorporating prey availability coupled to environmental conditions including temperature and prey visibility. To inform our understanding of growth and vertical migration patterns of Chinook Salmon inhabiting lentic ecosystems, we li...

Large dams and their respective reservoirs provide renewable energy and water security, but also can profoundly alter riverine ecosystems. Here, we present evidence of changing aquatic food web structure in the seasons following short-duration, extreme manipulation of water levels in a reservoir (i.e., draining of the reservoir to the original rive...

One-way ANOVA—Tukey multiple pairwise-comparisons for d15N signatures. (DOCX)

δ15N data for Largemouth Bass. (DOCX)

δ15N data for Rainbow Trout. (DOCX)

Largemouth Bass Gut content sampling. (DOCX)

Summer light extinction coefficients from study reservoirs. (DOCX)

Fish community structure in study reservoirs. (DOCX)

Macroinvertebrate and Cladoceran densities in Fall Creek, Hills Creek and Lookout point reservoirs. (DOCX)

The successful establishment of an aquatic invasive alien species can be mediated by a suite of environmental factors, including climate and anthropogenic disturbance. Dams and reservoirs are thought to promote freshwater fish invasion success through hydrological alterations but the evidence for their role in the global invasion of Largemouth Bass...

High-head dams throughout the Willamette River Basin, Oregon create deep reservoirs that undergo inter-seasonal and intra-seasonal water-level fluctuations (WLFs). The magnitude of WLFs is dependent on competing objectives of flood control, recreation, and water releases to maintain downstream habitat and facilitate migration of Endangered Species...

Eastern Mosquitofish (Gambusia holbrooki) is an invasive and globally widespread species that is considered highly tolerant. We used species distribution models (SDMs) to assess factors, including the role of anthropogenic perturbation, that mediate its invasion on a regional scale. A better understanding of the important large-scale factors may he...