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At least 469 records · Page 26Linked to original sources

USGS2025

Environmental conditions influencing the abundance of the salmonid ectoparasite Salmincola californiensis across upper Willamette River Reservoirs, Oregon

The freshwater copepod Salmincola californiensis is an ectoparasite of Pacific salmon and trout ( Oncorhynchus spp.). High levels of infection by this parasite can significantly damage gills and result in blood loss, affecting the fitness and survival of hosts, and it may hinder recovery efforts of threatened and endangered salmonids. Juvenile salmonids that rear in reservoirs have been reported to experience higher rates of infection than their stream-dwelling counterparts. To date, the relationship between reservoir environmental conditions and infection rates remains poorly understood. Here, we evaluated sampling methods designed to capture S. californiensis copepodids, the free-swimming infectious life stage of this parasitic copepod, and develop predictive models of parasite abundance in reservoirs . We used light traps to collect 675 zooplankton samples from various sites and depths in Cougar, Lookout Point, and Fall Creek reservoirs, Oregon, USA during five months in 2020. We tested several predictive models of parasite abundance using environmental covariates obtained concurrently during plankton surveys ( e.g. , temperature, ambient light and water clarity, reservoir plankton profiles, and water flow). Our models showed a strong influence of water temperature on abundance of copepodids, with maximum initial abundance occurring at the mean water temperature 15.2 °C. At that temperature, August abundance was estimated to be 58.6 copepodids per site in Cougar Reservoir, 43.8 copepodids per site in Fall Creek Reservoir, and 3.5 copepodids per site in Lookout Point Reservoir. Water temperature and reservoir outflow both affected population growth of copepodids: increased water temperature was associated with an increase in population growth rate while an increased reservoir outflow was associated with a decrease in population growth rate. The efficacy of our sampling method was influenced by percent of moon fullness, whether the sample site was above or below the thermocline, water temperature, and number of juvenile sculpin fishes ( Cottus spp.) captured in the trap. The mean probability of detecting a single copepodid if one was present was 0.042, but detection probability increased to 0.29 under ideal trap set conditions of warmer water, location above the thermocline, and a full moon. Biologists and managers could use these methods to assess the presence and abundance of S. californiensis in other locations, or to inform reservoir operations to reduce potential salmonid infections.

Oregon↗

USGS2000

Field surveys of Midwestern and Northeastern Fish and Wildlife Service lands for the presence of abnormal frogs and toads

The national distribution of information on the discovery of malformations in Minnesota frogs in 1995 stimulated collection and examination of newly metamorphosed frogs during 1996. By late summer and early fall of 1996, malformed frogs and toads were reported on U.S. Fish and Wildlife Service (USFWS) lands in Vermont (Northeast, Region 5) and Minnesota (Midwest, Region 3). In response to these reports, biologists in USFWS Regions 3 and 5 conducted a survey, during the summer of 1997 to determine the distribution and type of malformations in frogs and toads on selected federal lands. Region 3 personnel surveyed 38 field stations at National Wildlife Refuges (NWR's) and Wetland Management Districts. Malformed frogs and toads were collected at 23 (61%) of the Region 3 sites. External malformations were detected in 110 of 6632 individuals representing seven of 13 frog species and one of three toad species examined for an overall of 1.7% affected (percentages for affected species ranged from 0.4-5.2%). In Region 5, 17 NWR's and one National Park were surveyed. Malformed frogs were collected at 10 (56%) of the Region 5 sites. External malformations were detected in 58 of 2267 individuals representing six of 11 frog species and one of two toad species examined for an overall total of 2.6% affected (percentages for affected species ranged from 1.8-15.6%). The majority of malformations observed in frogs and toads collected in Regions 3 and 5 were partially or completely missing hind limbs and digits (50%)or malformed hind limbs and digits (14%). A few individuals had an extra limb or toe, missing or malformed front limb, missing eye, or malformation of the mandible. Despite small sample sizes at some sites, malformations were confirmed to be present in eight species of frogs and two species of toads on Federal lands in USFWS Regions 3 and 5. Further study is needed to determine the extent and distribution of amphibian malformations in these Regions. Data from this study were provided to the national database on distribution of malformed amphibians.

Iowa, Illinois, Michigan, Minnesnowta, Missouri, O↗

USGS2002

Avian vacuolar myelinopathy: a newly recognized fatal neurologic disease of eagles, waterfowl, and other birds

Wildlife biologists and health specialists have been frustrated by a long list of negative findings in their AVM investigations, however studies continue to provide pieces of information to aid the determination of the cause and its source. Available data indicated that AVM may have been present since at least 1990, occurs in at least five states, has been documented during October through April at sites of wintering populations of birds where the exposure apparently occurs, and has killed at least 90 bald eagles. Birds with AVM have difficulty or inability to fly, swim, walk, or perch, but there has been resolution of clinical signs in some affected coots. The list of affected species continues to grow, but remains confined to wild avians, including bald eagle, American coot, great horned owl, killdeer, Canada goose, mallard, ring-necked duck and bufflehead. The effects of the AVM agent on mammals, including human beings, are unknown. A neurotoxicant of manmade or natural origin is the suspected cause of AVM because no infectious disease agents, such as viruses, bacteria, parasites and prions, have been found, and the lesion and epizootiology of AVM resemble those of toxicoses. Additionally it is documented, experimentally, that exposure to raptors can occur through ingestion of infected coots. Collaborative studies will continue in the effort to identify the cause of AVM, its geographic distribution, and the range of species susceptibility. Hopefully, this information can be used to identify measures that might be taken to reduce the impact of AVM on the wildlife resource. Multiple agencies, institutions, and individuals must rely on each other's expertise in the multidisciplinary approach to this problem, persevere in their efforts and take advantage of serendipity that presents itself during investigations of this newly recognized cause of wild bird mortality.

Arkansas, Georgia, North Carolina, South Carolina↗

USGS2003

Satellite telemetry and wildlife studies in India: Advantages, options and challenges

Greater spatial coverage, accuracy and non-invasiveness of satellite technology make it one of the best tools to track long-distance migrants, which is otherwise difficult using conventional radio telemetry. In this article, we review the evolution of satellite telemetry and its application. We provide examples of three recent studies in India that have demonstrated and created a widespread appreciation of the use and benefits of satellite telemetry among biologists and managers. We also discuss the future prospects of this technology vis-a-vis benefits and challenges in the Indian subcontinent.

Current Science↗

USGS2000

Documenting trans-Himalayan migration through satellite telemetry: A report on capture, deployment, and tracking of bar-headed goose (Anser indicus)

Animal movement and migration studies have made significant progress with the use of telemetry. Conventional radio telemetry has been used in numerous studies in different regions. However, the use of this technology is restricted to species with limited range of movement. Applying this tool for long distance migrants is usually unsatisfactory. Other challenges such as hilly terrain or dense vegetation, where getting signals and following animals often become major constraints. These problems and the need to track long distance migrants, particularly birds, led to the development of other technologies with greater spatial coverage, accuracy and ease of tracking. Satellite telemetry technology has overcome many of these problems and has become a very useful tool. There is a greater recognition of the use and benefits of this technology among biologists, managers, and various conservation organizations. Satellite tracking technology has been used extensively in the Western Hemisphere. However until recently, in the Indian sub-continent the use of this technology was limited to one study in 1994 when three Eurasian cranes ( Grus grus ) were fitted with Platform Terminal Transmitter (PTTs) in Keoladco national Park, Bharatpur and tracked to their Siberian breeding grounds (Higuchi et al ., 1994). It took almost six more years for the next international collaborative project to emerge within India. This project, started in winter 1998-99, was the first long-term project using satellite tracking in India (Higuchi et al. , 1999). Other than these two studies, no effort has been made previously to demonstrate the use of this technology and its application in the Indian subcontinent.

Report↗

USGS1993

A model of the productivity of the northern pintail

We adapted a stochastic computer model to simulate productivity of the northern pintail (Anas acuta). Researchers at the Northern Prairie Wildlife Research Center of the U.S. Fish and Wildlife Service originally developed the model to simulate productivity of the mallard (A. platyrhynchos). We obtained data and descriptive information on the breeding biology of pintails from a literature review and from discussions with waterfowl biologists. All biological parameters in the productivity component of the mallard model (e.g, initial body weights, weight loss during laying and incubation, incubation time, clutch size, nest site selection characteristics) were compared with data on pintails and adjusted accordingly. The function in the mallard model that predicts nest initiation in response to pond conditions adequately mimicked pintail behavior and did not require adjustment.Recruitment rate was most sensitive to variations in parameters that control nest success, seasonal duckling survival rate, and yearling and adult body weight. We simulated upland and wetland habitat conditions in central North Dakota and compared simulation results with observed data. Simulated numbers were not significantly different from observed numbers of successful nests during wet, average, and dry wetland conditions. The simulated effect of predator barrier fencing in a study area in central North Dakota increased recruitment rate by an average of 18.4%. This modeling synthesized existing knowledge on the breeding biology of the northern pintail, identified necessary research, and furnished a useful tool for the examination and comparison of various management options.

Biological Report↗

USGS1977

Some Bayesian statistical techniques useful in estimating frequency and density

This paper presents some elementary applications of Bayesian statistics to problems faced by wildlife biologists. Bayesian confidence limits for frequency of occurrence are shown to be generally superior to classical confidence limits. Population density can be estimated from frequency data if the species is sparsely distributed relative to the size of the sample plot. For other situations, limits are developed based on the normal distribution and prior knowledge that the density is non-negative, which insures that the lower confidence limit is non-negative. Conditions are described under which Bayesian confidence limits are superior to those calculated with classical methods; examples are also given on how prior knowledge of the density can be used to sharpen inferences drawn from a new sample.

Special Scientific Report - Wildlife↗

USGS1999

Miscellaneous parasitic diseases

Free-ranging wild birds are afflicted with numerous other parasites that occasionally cause illness and death. Some of these parasites, such as two of the trematodes or flukes highlighted below, can cause major die-offs. This section about parasitic diseases concludes with descriptions of some additional parasites that field biologists may encounter in wild birds. This listing is by no means complete and it is intended only to increase awareness of the diversity of types of parasites that might be encountered during examinations of wild birds. One should not assume that the parasites found during the examination of bird carcasses caused their death. Because parasites of birds vary greatly in size from a protozoa of a few microns in length to tapeworms of several inches in length and because they can be found in virtually all tissues, body cavities and other locations within the bird, the observation of the parasites will depend on their visibility and the thoroughness of the examination. Therefore, it is generally beneficial to submit bird carcasses to qualified disease diagnostic laboratories to obtain evaluations of the significance of endoparasites or of ectoparasites. The methods that are used to preserve the carcass, tissues, or other specimens can enhance or compromise the ability of specialists to identify the parasite to species, and even to genera, in some instances. Therefore, whenever possible, it is best to contact the diagnostic laboratory that will receive the specimens and obtain instructions for collecting, preserving, and shipping field samples (See Chapters 2 and 3).

Information and Technology Report↗

USGS2002

A field guide to amphibian larvae and eggs of Minnesota, Wisconsin, and Iowa

Apparent worldwide declines in amphibian populations (Pechmann and Wake 1997) have stimulated interest in amphibians as bioindicators of the health of ecosystems. Because we have little information on the population status of many species, there is interest by public and private land management agencies in monitoring amphibian populations. Amphibian egg and larval surveys are established methods of surveying pond-breeding amphibians. Adults may be widely dispersed across the landscape, but eggs and larvae are confined to the breeding site during a specific season of the year. Also, observations of late-stage larvae or metamorphs are evidence of successful reproduction, which is an important indicator of the viability of the population. The goal of this guide is to help students, natural resources personnel, and biologists identify eggs and larval stages of amphibians in the field without the aid of a microscope.

Iowa, Minnesota, Wisconsin↗

USGS1992

Salmonid whirling disease

This paper provides the latest scientific and technical advances in the management of salmonid whirling disease caused by the myxosporean Myxobolus cerebralis (Syn. Myxosoma cerebralis). The complete life cycle of the parasite and the biology of the infective agent to fish, the actinosporean Triactinomyxon stage, are reviewed, and suggested procedures for detection, identification, and control of the disease are discussed. The paper offers sources of information and related reference materials of interest to fish culturists, fishery biologists, and students.

Fish and Wildlife Leaflet↗

USGS2005

Lake whitefish and Diporeia spp. in the Great lakes: an overview

Because of growing concern in the Great Lakes over declines in abundance and growth of lake whitefish (Coregonus clupeaformis) and declines in abundance of the benthic amphipod Diporeia spp., a workshop was held to examine past and current trends, to explore trophic links, and to discuss the latest research results and needs. The workshop was divided into sessions on the status of populations in each of the lakes, bioenergetics and trophic dynamics, and exploitation and management. Abundance, growth, and condition of whitefish populations in Lakes Superior and Erie are stable and within the range of historical means, but these variables are declining in Lakes Michigan and Ontario and parts of Lake Huron. The loss of Diporeia spp., a major food item of whitefish, has been a factor in observed declines, particularly in Lake Ontario, but density-dependent factors also likely played a role in Lakes Michigan and Huron. The loss of Diporeia spp. is temporally linked to the introduction and proliferation of dreissenid mussels, but a direct cause for the negative response of Diporeia spp. has not been established. Given changes in whitefish populations, age-structured models need to be re-evaluated. Other whitefish research needs to include a better understanding of what environmental conditions lead to strong year-classes, improved aging techniques, and better information on individual population (stock) structure. Further collaborations between assessment biologists and researchers studying the lower food web would enhance an understanding of links between trophic levels.

Technical Report↗

USGS1980

Water resources planning under the Fish and Wildlife Coordination Act

This paper briefly discusses the more significant provisions of the Fish and Wildlife Coordination Act (1958). It covers pertinent aspects of legislative history, the development and current status (April 1980) of certain policies relevant to administering the Act, and other matters. It is directed primarily to practicing fish and wildlife agency field biologists, planners, and decisionmakers engaged in water resources development activities under the Act. It is not intended to be exhaustive in its treatment. The Fish and Wildlife Coordination Act provides a basic procedural framework for the orderly consideration of fish and wildlife conservation measures to be incorporated into Federal and Federally permitted or licensed water development projects. The principal provisions of the Act include: 1. a statement of Congressional purpose that fish and wildlife conservation shall receive equal consideration with other project features; 2. mandatory consultation with wildlife agencies with a view to achieving such conservation; 3. full consideration by action of the recommendations stemming from consultation; 4. authority for action agencies to implement such recommendations as they find acceptable. The FWCA in effect amends, conditions, or supplements other Federal laws and is thus closely linked in its application and interpretation. It is similarly linked to Federal planning standards and procedures. Because of this, interpretations tend to be flexible and evolve, adapting to changing situations. The following reference matrix outlines selected sections of the Fish and Wildlife Coordination Act which are of particular relevance to planners.

FWS/OBS↗

USGS1994

Measuring and monitoring biological diversity: Standard methods for amphibians

Measuring and Monitoring Biological Diversity is the first book to provide comprehensive coverage of standard methods for biodiversity sampling of amphibians, with information on analyzing and using data that will interest biologists in general. In this manual, nearly fifty herpetologists recommend ten standard sampling procedures for measuring and monitoring amphibian and many other populations. The contributors discuss each procedure, along with the circumstances for its appropriate use. In addition, they provide a detailed protocol for each procedure's implementation, a list of necessary equipment and personnel, and suggestions for analyzing the data. The data obtained using these standard methods are comparable across sites and through time and, as a result, are extremely useful for making decisions about habitat protection, sustained use, and restoration—decisions that are particularly relevant for threatened amphibian populations.

Book↗

USGS2000

Heron conservation

Herons are large, popular and, in many cases, spectacular birds found in wetlands world-wide, both tropical and temperate, natural and man-made. Some populations are very small and localized, some have decreased, some have expanded their ranges, and a few are pests of human activities. In the fifteen years since the publication of the latest monographic treatment of the family, The Herons Handbook, there has been a tremendous increase in our knowledge of heron status and conservation requirements, set against a backdrop of increasing concern about the future of the world?s wetland habitats. This book provides a comprehensive update following two distinct threads. The status and conservation needs of herons are first presented on a regional basis, in a series of chapters set at a continental or subcontinental scale. Over 200 biologists and heron conservationists have contributed to the data summarized here, and the very latest census and survey results provide the most up-to-date and detailed picture of heron populations currently available. Chapters discussing several critical issues in heron conservation follow, tending to focus on the international nature of the problems.

Book↗

USGS2004

Biodiversity of Fungi : Inventory and Monitoring Methods

Biodiversity of Fungi is essential for anyone collecting and/or monitoring any fungi. Fascinating and beautiful, fungi are vital components of nearly all ecosystems and impact human health and our economy in a myriad of ways. Standardized methods for documenting diversity and distribution have been lacking. An wealth of information, especially regrading sampling protocols, compiled by an international team of fungal biologists, make Biodiversity of Fungi an incredible and fundamental resource for the study of organismal biodiversity. Chapters cover everything from what is a fungus, to maintaining and organizing a permanent study collection with associated databases; from protocols for sampling slime molds to insect associated fungi; from fungi growing on and in animals and plants to mushrooms and truffles. The chapters are arranged both ecologically and by sampling method rather than by taxonomic group for ease of use. The information presented here is intended for everyone interested in fungi, anyone who needs tools to study them in nature including naturalists, land managers, ecologists, mycologists, and even citizen scientists and sophiscated amateurs. Fungi are among the most important organisms in the world; they play vital roles in ecosystem functions and have wide-ranging effects, both positive and negative, on humans and human-related activities. There are about 1.5 million species of fungi. The combination of fungal species and abundances in an ecosystem are often used as indicators of ecosystem health and as indicators of the effects of pollution and of different management and use plans. Because of their significance, it is important that these organisms be monitored. This book is the first comprehensive treatment of fungal inventory and monitoring, including standardized sampling protocols as well as information on study design, sample preservation, and data analysis.

Book↗

USGS1981

Methods of detecting and counting raptors: A review

Most raptors are wide-ranging, secretive, and occur at relatively low densities. These factors, in conjunction with the nocturnal activity of owls, cause the counting of raptors by most standard census and survey efforts to be very time consuming and expensive. This paper reviews the most common methods of detecting and counting raptors. It is hoped that it will be of use to the ever-increasing number of biologists, land-use planners, and managers that must determine the occurrence, density, or population dynamics of raptors. Road counts of fixed station or continuous transect design are often used to sample large areas. Detection of spontaneous or elicited vocalizations, especially those of owls, provides a means of detecting and estimating raptor numbers. Searches for nests are accomplished from foot surveys, observations from automobiles and boats, or from aircraft when nest structures are conspicuous (e.g., Osprey). Knowledge of nest habitat, historic records, and inquiries of local residents are useful for locating nests. Often several of these techniques are combined to help find nest sites. Aerial searches have also been used to locate or count large raptors (e.g., eagles), or those that may be conspicuous in open habitats (e.g., tundra). Counts of birds entering or leaving nest colonies or colonial roosts have been attempted on a limited basis. Results from Christmas Bird Counts have provided an index of the abundance of some species. Trapping and banding generally has proven to be an inefficient method of detecting raptors or estimating their populations. Concentrations of migrants at strategically located points around the world afford the best opportunity to count many rap tors in a relatively short period of time, but the influence of many unquantified variables has inhibited extensive interpretation of these counts. Few data exist to demonstrate the effectiveness of these methods. We believe more research on sampling techniques, rather than complete counts or intensive searches, will provide adequate yet affordable estimates of raptor numbers in addition to providing methods for detecting the presence of raptors on areas of interest to researchers and managers.

Book chapter↗

USGS1982

A workshop on raptor management and biology in Alaska and western Canada - A summary

A workshop on raptor management and biology in Alaska and western Canada was held on February 20, 1981, in Anchorage, Alaska. It was attended by about 50 biologists. The following twofold prime objective was established: (1) To prevent any raptor species from becoming extirpated in any significant part of its present range; and (2) to establish or maintain population levels consistent with the carrying capacity of available habitat. Collateral objectives, specific priorities, potential threats, and research and management needs were discussed, and the ideas that were expressed were listed. Although a draft raptor program was not developed during the workshop, the information and opinions presented by the participants will form a strong foundation and set a correct course for its subsequent formation.

Alaska↗

USGS1987

Field methods to evaluate effects of pesticides on wildlife of the northwestern United States

Field .methods used to evaluate the impact of organochlorine and organophosphate pesticides on wildlife populations in the Pacific Northwest are reviewed. Five field studies, presented in a CASE HISTORY format, illustrate study designs .and thetypes of information collected. The pesticides investigated included DDT, heptachlor, endr1n, and famphur, and the species studied included the American kestrel (Falco sparverius), Canada goose (Branta canadensis}, black--crowned night-heron (Nycticorax nycticorac), and black-billed magpie (Pica pica). Wildlife biologists conducting field studies of pesticides encounter a variety of design and logistics problems. However, a number of procedures are now available to the researcher for field evaluations. The three principa1 types of insecticides (organochlorines (OC's), organophosphates (OP's) and carbamates (CB's) require different field approaches. In this paper, five field studies, conducted by my colleagues and me between 1974 and 1982, in the northwestern portion of the United States (Washington, Oregon, Idaho, and northern Nevada), are reviewed to illustrate procedures for evaluating the effects of these insecticides.on wildlife populations. Althought most OC pesticides were banned in the United States during the 1970's (.for review, see F1eming et al. 1983), we studied several OC applications, including the last major DDT spray project in 1974. Use of OP's and CB's increased during the 1970's and 1980s as the OC's were phased out.

Book chapter↗