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Advances in the hydrogeochemistry and microbiology of acid mine waters

The last decade has witnessed a plethora of research related to the hydrogeochemistry and microbiology of acid mine waters and associated tailings and waste-rock waters. Numerous books, reviews, technical papers, and proceedings have been published that examine the complex bio-geochemical process of sulfide mineral oxidation, develop and apply geochemical models to site characterization, and characterize the microbial ecology of these environments. This review summarizes many of these recent works, and provides references for those investigating this field. Comparisons of measured versus calculated Eh and measured versus calculated pH for water samples from several field sites demonstrate the reliability of some current geochemical models for aqueous speciation and mass balances. Geochemical models are not, however, used to predict accurately time-dependent processes but to improve our understanding of these systems and to constrain possible processes that contribute to actual or potential water quality issues. Microbiological studies are demonstrating that there is much we have yet to learn about the types of different microorganisms and their function and ecology in mine-waste environments. A broad diversity of green algae, bacteria, archaea, yeasts, and fungi are encountered in acid mine waters, and a better understanding of their ecology and function may potentially enhance remediation possibilities as well as our understanding of the evolution of life.

International Geology Review↗

Toward the simulation of the effects of the Great Lakes on regional climate

This paper describes a set of numerical experiments aimed at evaluating the feasibility of applying a version of the National Center for Atmospheric Research-Pennsylvania State University regional model (MM4) to regional climate simulation over the Great Lakes Basin. The objectives of this initial modeling investigation are 1) to examine whether the MM4 can capture the primary forcing exerted by the Great Lakes on the regional climate and 2) to evaluate what model resolution and configuration are needed to simulate such forcing. Simulations over the Great Lakes region are conducted with and without representation of the lakes at four model gridpoint resolutions ranging from 15 to 90 km. One experiment at 60-km resolution is discussed in which a one-dimensional thermal eddy diffusion model is interactively coupled to the MM4 to represent the lakes. Initial and lateral boundary conditions necessary to drive these simulations are provided by European Centre for Medium-Range Weather Forecasts (ECMWF) analyses of observations. All simulations conducted are 10 days in length, from 22 December 1985 to 1 January 1986. When driven with data from ECMWF analyses of observations, the climate version of the MM4 reproduces the basic characteristics of the distribution of lake-effect precipitation over the Great Lakes Basin. Differences between simulations with and without the lakes represented indicate that the lakes accounted for approximately 25% of the precipitation over the basin during the 10-day period simulated. Over localized areas, identified as the major snowbelts downwind from the lakes, lake effects were responsible for 50%–70% of the precipitation. Basinwide precipitation did not vary greatly among the simulations with resolutions of 60, 30, and 15 km, although biases between model results and station observations did decrease slightly with increasing model resolution. Basinwide maximum and minimum temperature biases decreased more markedly with finer resolution. In the snowbelt regions downwind from the lakes, precipitation was underforecast at all four model resolutions, but precipitation generally increased with finer resolution. Differences between the results from the simulations at the three finest resolutions were greater over snowbelt regions than over the basin as a whole. A simulation was conducted with the MM4 coupled to a lake model in an interactive two-way nested configuration. The implementation of this coupling was accomplished in a straightforward manner, with no model tuning required, and added very little to the computation time needed for the MM4 system. This coupled modeling system was found to produce realistic distributions of lake surface temperatures, evaporation rates, and ice thicknesses across the lakes. In climate simulations where the MM4 is nested in a general circulation model (GCM), we believe that the use of this coupled modeling system is preferable to specifying lake parameters by interpolation from GCM output. The next step in this work is to conduct a simulation of at least one annual cycle over the region to more fully test the coupled MM4-take model system.

Great Lakes region↗

Evaluating unsupervised methods to size and classify suspended particles using digital in-line holography

Substantial information can be gained from digital in-line holography of marine particles, eliminating depth-of-field and focusing errors associated with standard lens-based imaging methods. However, for the technique to reach its full potential in oceanographic research, fully unsupervised (automated) methods are required for focusing, segmentation, sizing and classification of particles. These computational challenges are the subject of this paper, in which we draw upon data collected using a variety of holographic systems developed at Plymouth University, UK, from a significant range of particle types, sizes and shapes. A new method for noise reduction in reconstructed planes is found to be successful in aiding particle segmentation and sizing. The performance of an automated routine for deriving particle characteristics (and subsequent size distributions) is evaluated against equivalent size metrics obtained by a trained operative measuring grain axes on screen. The unsupervised method is found to be reliable, despite some errors resulting from over-segmentation of particles. A simple unsupervised particle classification system is developed, and is capable of successfully differentiating sand grains, bubbles and diatoms from within the surf-zone. Avoiding miscounting bubbles and biological particles as sand grains enables more accurate estimates of sand concentrations, and is especially important in deployments of particle monitoring instrumentation in aerated water. Perhaps the greatest potential for further development in the computational aspects of particle holography is in the area of unsupervised particle classification. The simple method proposed here provides a foundation upon which further development could lead to reliable identification of more complex particle populations, such as those containing phytoplankton, zooplankton, flocculated cohesive sediments and oil droplets.

Journal of Atmospheric and Oceanic Technology↗

Copper determinations on samples of alluvium and caliche from the rocky Range, Beaver County, Utah

A study of the distribution of copper in transported alluvium on a pediment of the Rocky Range, Beaver County, Utah, undertaken to determine whether known copper deposits in bedrock concealed by alluvium could be detected by geochemical methods, was reported in Geological Survey Research 1960 ( Erickson, R.L., and Marrenzino, A.P., 1960, Geochemical prosecting for copper in the Rocky Range, Beaver County, Utah; U.S. Geol. Survey Prof. Paper 400-B, p. B98-E101). The attached map and table supplement that paper by giving the locations at which the samples were collected and the analytical determinations of copper in the samples.

Utah↗

The first 50 years of the North American Breeding Bird Survey

The vision of Chandler (Chan) S. Robbins for a continental-scale omnibus survey of breeding birds led to the development of the North American Breeding Bird Survey (BBS). Chan was uniquely suited to develop the BBS. His position as a government scientist had given him experience with designing and implementing continental-scale surveys, his research background made him an effective advocate of the need for a survey to monitor pesticide effects on birds, and his prominence in the birding community gave him connections to infrastructure—a network of qualified volunteer birders who could conduct roadside surveys with standardized point counts. Having started in the eastern United States and the Atlantic provinces of Canada in 1966, the BBS now provides population change information for ∼546 species in the continental United States and Canada, and recently initiated routes in Mexico promise to greatly expand the areas and species covered by the survey. Although survey protocols have remained unchanged for 50 years, the BBS remains relevant in a changing world. Several papers that follow in this Special Section of The Condor: Ornithological Advances review how the BBS has been applied to conservation assessments, especially in combination with other large-scale survey data. A critical feature of the BBS program is an active research program into field and analytical methods to enhance the quality of the count data and to control for factors that influence detectability. Papers in the Special Section also present advances in BBS analyses that improve the utility of this expanding and sometimes controversial survey. In this Perspective, we introduce the Special Section by reviewing the history of the BBS, describing current analyses, and providing summary trend results for all species, highlighting 3 groups of conservation concern: grassland-breeding birds, aridland-breeding birds, and aerial insectivorous birds.

The Condor↗

The sterile-male-release technique in Great Lakes sea lamprey management

The parasitic sea lamprey (Petromyzon marinus) has been a serious pest since its introduction into the Great Lakes, where it contributed to severe imbalances in the fish communities by selectively removing large predators (Smith 1968; Christie 1974; Schneider et al.1996). Since the 1950s, restoration and maintenance of predator-prey balance has depended on the Great Lakes Fishery Commission (GLFC) sea lamprey management program. Initially, management relied primarily on stream treatments with a selective lampricide to kill larvae, on barriers to migration, and on trapping to remove potential spawners (Smith and Tibbles 1980). By the late 1970s, however, it was clear that the future of sea lamprey management lay in development of a larger array of control strategies, including more alternatives to lampricide applications (Sawyer 1980). Since then the only new alternative to chemical control to reach operational status is the release of sterilized male sea lampreys. Research on the concept began at the USGS, Hammond Bay Biological Station in Millersburg, MI (HBBS) during the 1970s (Hanson and Manion 1980). Development and evaluation continued through the 1980s, leading to the release of sterilized males in Great Lakes tributaries since 1991 (Twohey et al. 2003a). The objectives of this paper are 1) to review the implementation and evaluations of sterile-male-release technique (SMRT) as it is being applied against sea lampreys in the Great Lakes, 2) to review our current understanding of its efficacy, and 3) to identify additional research areas and topics that would increase either the efficacy of SMRT or expand its geographic potential for application.

Report↗

The roles of large top predators in coastal ecosystems: new insights from long term ecological research

During recent human history, human activities such as overhunting and habitat destruction have severely impacted many large top predator populations around the world. Studies from a variety of ecosystems show that loss or diminishment of top predator populations can have serious consequences for population and community dynamics and ecosystem stability. However, there are relatively few studies of the roles of large top predators in coastal ecosystems, so that we do not yet completely understand what could happen to coastal areas if large top predators are extirpated or significantly reduced in number. This lack of knowledge is surprising given that coastal areas around the globe are highly valued and densely populated by humans, and thus coastal large top predator populations frequently come into conflict with coastal human populations. This paper reviews what is known about the ecological roles of large top predators in coastal systems and presents a synthesis of recent work from three coastal eastern US Long Term Ecological Research (LTER) sites where long-term studies reveal what appear to be common themes relating to the roles of large top predators in coastal systems. We discuss three specific themes: (1) large top predators acting as mobile links between disparate habitats, (2) large top predators potentially affecting nutrient and biogeochemical dynamics through localized behaviors, and (3) individual specialization of large top predator behaviors. We also discuss how research within the LTER network has led to enhanced understanding of the ecological roles of coastal large top predators. Highlighting this work is intended to encourage further investigation of the roles of large top predators across diverse coastal aquatic habitats and to better inform researchers and ecosystem managers about the importance of large top predators for coastal ecosystem health and stability.

Florida;Georgia;Massachusetts↗

Prey of the Peregrine Falcon (Falco peregrinus cassini) in Southern Argentina and Chile

The Peregrine Falcon (Falco peregrinus cassini) in Patagonia attracted wide interest two decades ago when there was a focus on determining the taxonomic position of the Pallid Falcon (also called Kleinschmidt's falcon and Tierra del Fuego falcon; formerly named Falco kreyenborgi). In 1981, however, the pallid falcon was confirmed to be a pale color morph of the peregrine, and since that time, little work has been conducted on this color morph. Continent-wide research has continued and has yielded a fair understanding of the breeding distribution of the Peregrine Falcon in South America. Also, two preliminary food habits studies on the peregrine have been completed in Patagonia. Together those papers provided a list of 23 species observed as prey, and McNutt listed another eight species seen pursued (but not captured) by peregrines. The purpose of this paper is to assemble all that has been published on peregrine food habits for Patagonia and Tierra del Fuego and to add to that list from our 1980 and 1981 expeditions.

Journal of Raptor Research↗

When do climate services achieve societal impact? Evaluations of actionable climate adaptation science

To cope with complex environmental impacts in a changing climate, researchers are increasingly being asked to produce science that can directly support policy and decision making. To achieve such societal impact, scientists are using climate services to engage directly with stakeholders to better understand their needs and inform knowledge production. However, the wide variety of climate-services outcomes—ranging from establishing collegial relationships with stakeholders to obtaining specific information for inclusion into a pre-existing decision process—do not directly connect to traditional methods of measuring scientific impact (e.g., publication citations, journal impact factor). In this paper, we describe how concepts from the discipline of evaluation can be used to examine the societal impacts of climate services. We also present a case study from climate impacts and adaptation research to test a scalable evaluation approach. Those who conduct research for the purposes of climate services and those who fund applied climate research would benefit from evaluation from the beginning of project development. Doing so will help ensure that the approach, data collection, and data analysis are appropriately conceived and executed.

Sustainability↗

Flood effects on an Alaskan stream restoration project: the value of long-term monitoring

On a nationwide basis, few stream restoration projects have long-term programs in place to monitor the effects of floods on channel and floodplain configuration and floodplain vegetation, but long-term and event-based monitoring is required to measure the effects of these stochastic events and to use the knowledge for adaptive management and the design of future projects. This paper describes a long-term monitoring effort (15 years) on a stream restoration project in Glen Creek in Denali National Park and Preserve in Alaska. The stream channel and floodplain of Glen Creek had been severely degraded over a period of 80 years by placer mining for gold, which left many reaches with unstable and incised streambeds without functioning vegetated floodplains. The objectives of the original project, initiated in 1991, were to develop and test methods for the hydraulic design of channel and floodplain morphology and for floodplain stabilization and riparian habitat recovery, and to conduct research and monitoring to provide information for future projects in similar degraded watersheds. Monitoring methods included surveyed stream cross-sections, vegetation plots, and aerial, ground, and satellite photos. In this paper we address the immediate and outlying effects of a 25-year flood on the stream and floodplain geometry and riparian vegetation. The long-term monitoring revealed that significant channel widening occurred following the flood, likely caused by excessive upstream sediment loading and the fairly slow development of floodplain vegetation in this climate. Our results illustrated design flaws, particularly in regard to identification and analysis of sediment sources and the dominant processes of channel adjustment.

Alaska↗

Assessing the effects of microbial metabolism and metabolities on reservoir pore structure

The effect of microbial treatment on pore structure of sandstone and carbonatereservoirs was determined. Understanding how different bacterial strains and their metabolic bioproducts affect reservoir pore structure will permit the prudent application of microorganisms for enhanced oil recovery. The microbial strains tested included Clostridium acetobutylicum, a polymer-producing Bacillus strain, and an unidentified halophilic anaerobe that mainly produced acids and gases. Electrical conductivity, absolute permeability, porosity and centrifuge capillary pressure were used to examine rock pore structures. Modifications of the pore structure observed in the laboratory cores included pore enlargement due to acid dissolution of carbonates and poare throat reduction due to biomass plugging. This paper shows that careful selection of microbes based on proper understanding of the reservoir petrophysical characteristics is necessary for applications of microbially enhanced oil recovery. These methods and results can be useful to field operators and laboratory researchers involved in design and screening of reservoirs for MEOR. The methods are also applicable in evaluation of formation damage caused by drilling, injection or completion fluids or stimulation caused by acids.

Conference Paper↗

Geometric quality assessment of lidar data based on swath overlap

This paper provides guidelines on quantifying the relative horizontal and vertical errors observed between conjugate features in the overlapping regions of lidar data. The quantification of these errors is important because their presence quantifies the geometric quality of the data. A data set can be said to have good geometric quality if measurements of identical features, regardless of their position or orientation, yield identical results. Good geometric quality indicates that the data are produced using sensor models that are working as they are mathematically designed, and data acquisition processes are not introducing any unforeseen distortion in the data. High geometric quality also leads to high geolocation accuracy of the data when the data acquisition process includes coupling the sensor with geopositioning systems. Current specifications (e.g. Heidemann 2014) do not provide adequate means to quantitatively measure these errors, even though they are required to be reported. Current accuracy measurement and reporting practices followed in the industry and as recommended by data specification documents also potentially underestimate the inter-swath errors, including the presence of systematic errors in lidar data. Hence they pose a risk to the user in terms of data acceptance (i.e. a higher potential for Type II error indicating risk of accepting potentially unsuitable data). For example, if the overlap area is too small or if the sampled locations are close to the center of overlap, or if the errors are sampled in flat regions when there are residual pitch errors in the data, the resultant Root Mean Square Differences (RMSD) can still be small. To avoid this, the following are suggested to be used as criteria for defining the inter-swath quality of data: a) Median Discrepancy Angle b) Mean and RMSD of Horizontal Errors using DQM measured on sloping surfaces c) RMSD for sampled locations from flat areas (defined as areas with less than 5 degrees of slope) It is suggested that 4000-5000 points are uniformly sampled in the overlapping regions of the point cloud, and depending on the surface roughness, to measure the discrepancy between swaths. Care must be taken to sample only areas of single return points only. Point-to-Plane distance based data quality measures are determined for each sample point. These measurements are used to determine the above mentioned parameters. This paper details the measurements and analysis of measurements required to determine these metrics, i.e. Discrepancy Angle, Mean and RMSD of errors in flat regions and horizontal errors obtained using measurements extracted from sloping regions (slope greater than 10 degrees). The research is a result of an ad-hoc joint working group of the US Geological Survey and the American Society for Photogrammetry and Remote Sensing (ASPRS) Airborne Lidar Committee.

Conference Paper↗

Proceedings of a workshop on the development and evaluation of habitat suitability criteria: A compilation of papers and discussions presented at Colorado State University, Fort Collins, Colorado, December 8-12, 1986

The development of reliable habitat suitability criteria is critical to the successful implementation of the Instream Flow Incremental Methodology (IFIM), or any other habitat based evaluation technology. It is also a fascinating topic of research, for several reasons. First, the “science” of habitat quantification is relatively young. Descriptions of habitat use and partitioning can be traced back to Darwin, if not further. Attempts to actually quantify habitat use can be found predominantly during the last two decades, with most of the activity occurring in about the last five years. Second, this work is challenging because we are usually working with fish or some other organism that lives out of sight in an environment that is foreign to humans. Most of the data collection techniques that have been developed for standard fisheries work are unsuited, without modification, for criteria development. These factors make anyone involved in this type of research a pioneer, of sorts. Pioneers often make new and wonderful discoveries, but they also sometimes get lost. In our opinion, however, there is an even more rewarding aspect to criteria development research. It seems that the field of biology has tended to become increasingly clinical over the years. Criteria development demands the unobtrusive observation of organisms in their natural environment, a fact that allows the biological to be a naturalist and still get paid for it. The relative youth and importance of habitat quantification have resulted in rapid advancements in the state of the art. The expansion of methods is vividly demonstrated simply by comparing the two Instream Flow Information Papers written on the subject in 1978 and in 1986. One of the missions of the Aquatic Systems Branch (formerly the Instream Flow Group) is to serve as a clearinghouse for new techniques and methods. In keeping with this role, a workshop was conducted during December 1986 to discuss current and newly evolving methods for developing and evaluating habitat suitability criteria. Participation in this workshop was largely by invitation only. The objective was to obtain insights into problems and possible solutions to criteria development, from the perspective of professionals closely involved with the subject. These proceedings of that workshop are intended to supplement the information contained in Instream Flow Information Paper 21, "Development and Evaluation of Habitat Suitability Criteria for Use in the Instream Flow Incremental Methodology." The workshop was closely arranged in five sessions, roughly following the outline of Information Paper 21. The first session dealt with various aspects of study design and how they can influence the outcome of a study. Session two investigated techniques for developing criteria from professional judgment, and some of the problems encountered when personal or agency prejudice enters the picture. Session three concentrated on field data collection procedures, whereas session four examined methods of converting field data into curves. Field verification studies were discussed in session five. Each presentation in the workshop was followed by a question and answer period of 15 to 30 minutes. These discussions were recorded, transcribed, and appended to the end of each paper in these proceedings. We have attempted to capture the essence of these discussions as accurately as possible, but hope that the reader can appreciate the difficulty in translating a free-ranging discussion (from a barely audible tape) to something that makes sense in print. These question and answer sessions constitute the peer review for each of the papers. This provides the reader with the unique opportunity to review the interactions between authors and reviewers.

Book↗

Final report on the assessment of the U.S. Geological Survey’s bureauwide Research Grade Evaluation (RGE) process

The U.S. Geological Survey (USGS) formed the internal Research Grade Evaluation (RGE) Review Team in May 2017. The Team undertook a 2-year comprehensive review of RGE practices and policies at the USGS that included (1) the first-ever quantitative assessment of the USGS workforce evaluated under the RGE process, (2) a benchmarking meet­ing in March 2018 of the USGS and 11 other Federal science agencies to compare how each conducts research scientist evaluation, and (3) extensive surveys of four internal stakeholder groups. The Team recommends that the RGE review process emphasize the importance of outcomes resulting from a scientist’s efforts, rather than focusing on easily quantified outputs such as peer-reviewed papers, presentations, and posters. Thus, the Team recommends that a scientist’s work be assessed according to contributions and impacts in three areas: (1) scientific understanding, (2) the missions of the U.S. Geological Survey and the U.S. Department of the Interior, and (3) society more broadly. The Team developed (1) new formats for the Research Scientist Record (RSR) and Development Scientist Record (DSR) that match the Office of Personnel Management’s guidelines for factor scoring and (2) new findings templates to pro­vide more meaningful feedback to scientists.

Open-File Report↗

Introduction to “Global tsunami science: Past and future, Volume III”

Twenty papers on the study of tsunamis are included in Volume III of the PAGEOPH topical issue “Global Tsunami Science: Past and Future”. Volume I of this topical issue was published as PAGEOPH, vol. 173, No. 12, 2016 and Volume II as PAGEOPH, vol. 174, No. 8, 2017. Two papers in Volume III focus on specific details of the 2009 Samoa and the 1923 northern Kamchatka tsunamis; they are followed by three papers related to tsunami hazard assessment for three different regions of the world oceans: South Africa, Pacific coast of Mexico and the northwestern part of the Indian Ocean. The next six papers are on various aspects of tsunami hydrodynamics and numerical modelling, including tsunami edge waves, resonant behaviour of compressible water layer during tsunamigenic earthquakes, dispersive properties of seismic and volcanically generated tsunami waves, tsunami runup on a vertical wall and influence of earthquake rupture velocity on maximum tsunami runup. Four papers discuss problems of tsunami warning and real-time forecasting for Central America, the Mediterranean coast of France, the coast of Peru, and some general problems regarding the optimum use of the DART buoy network for effective real-time tsunami warning in the Pacific Ocean. Two papers describe historical and paleotsunami studies in the Russian Far East. The final set of three papers importantly investigates tsunamis generated by non-seismic sources: asteroid airburst and meteorological disturbances. Collectively, this volume highlights contemporary trends in global tsunami research, both fundamental and applied toward hazard assessment and mitigation.

Pure and Applied Geophysics↗

Moving from generalisations to specificity about mangrove-saltmarsh dynamics

Spatial and temporal variability in factors influencing mangrove establishment and survival affects the distribution of mangrove, particularly near their latitudinal limit, where mangrove expansion into saltmarsh is conspicuous. In this paper the spatial variability in mangrove distribution and variability in factors influencing mangrove establishment and survival during the Quaternary period are reviewed, focussing on research at latitudinal limits in Australia and mainland USA. Despite similarities in the response of mangrove to some drivers, the expression of these drivers is both spatially and temporally variable, demonstrating the need for analyses of mangrove-saltmarsh dynamics to move beyond generalisations and incorporate regional and local-scale specificity. We propose i) that precursory recognition that ‘correlation does not mean causation’ is inadequate and assumptions, caveats, and limitations should be clearly articulated in correlative studies; ii) experimental design in manipulative experiments must also articulate the spatial and temporal scale to which the analysis is relevant; and iii) analyses that draw from a range of methods will provide greater confidence. Integrated research programs that transect spatial and temporal scales and incorporate a range of techniques are essential to improve projections. Mangrove-saltmarsh distribution research should move beyond simple models that assume equilibrium between realised and fundamental niches.

Wetlands↗

Melded integrated population models

Integrated population models provide a framework for assimilating multiple datasets to understand population dynamics. Understanding drivers of demography is key to improving wildlife management, and integrated population models have informed conservation practices for many species of conservation concern. Motivated by multiple surveys of lesser prairie-chicken ( Tympanuchus pallidicinctus ), we developed a flexible integrated population modeling framework for assimilating demographic data with multiple surveys of abundance. Measurements of abundance are derived from aerial and ground surveys that vary in their observational uncertainty, sampling design, temporal coverage, and survey effort. Our proposed integrated population model draws from the strengths of each survey and prevents their sampling biases from compromising inference. We facilitate posterior inference for our integrated population model using chained Markov melding, which induces the joint distribution for all data sources by linking inference across several submodels. Using Markov melding, we extend the modeling framework previously proposed for analyzing the individual data sources while still obtaining joint Bayesian inference. We fit the melded model with a multistage Markov chain Monte Carlo algorithm that decreases run time and improves mixing. We assimilate data from several state and federal wildlife agencies and over a dozen independent researchers to infer lesser prairie-chicken abundance and vital rates across its entire range over the last 18 years. Supplementary materials accompanying this paper appear online.

Colorado, Kansas, New Mexico, Oklahoma, Texas↗

Do toxic substances pose a threat to rehabilitation of lake trout in the Great Lakes? A review of the literature

Toxic substances have been suspected of being one of the causes of Great Lakes lake trout reproductive failure. Because toxic substances are present in the Great Lakes basin, managers should be aware of the role of contaminants in preventing lake trout rehabilitation. This paper summarizes studies which have sought to establish a relation between toxic substances and lake trout mortality or morbidity, and offers recommendations for future research and management. The review suggests that exposure to toxic substances has the possibility of affecting the species' rehabilitation. A variety of toxic substances, specifically organochlorine compounds, concentrated in lake trout eggs, fry, and the environment, have affected the hatching success of lake trout in the laboratory, but the strength of the relation between toxic substances and lake trout mortality and morbidity in the field remains unclear. In order to clarify this relation, more information is needed on lake trout physiology, biochemistry, behavior, and genetics. An interdisciplinary workshop should be convened to evaluate existing evidence by epidemiological methods, to set priorities for further research, and to develop management strategies.

Journal of Great Lakes Research↗