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266 records · Page 15Linked to original sources
USGS1968

Home range and travels

The concept of home range was expressed by Seton (1909) in the term 'home region,' which Burr (1940, 1943) clarified with a definition of home range and exemplified in a definitive study of Peromyscus in the field. Burt pointed out the ever-changing characteristics of home-range area and the consequent absence of boundaries in the usual sense--a finding verified by investigators thereafter. In the studies summarized in this paper, sizes of home ranges of Peromyscus varied within two magnitudes, approximately from 0.1 acre to ten acres, in 34 studies conducted in a variety of habitats from the seaside dunes of Florida to the Alaskan forests. Variation in sizes of home ranges was correlated with both environmental and physiological factors; with habitat it was conspicuous, both in the same and different regions. Food supply also was related to size of home range, both seasonally and in relation to habitat. Home ranges generally were smallest in winter and largest in spring, at the onset of the breeding season. Activity and size also were affected by changes in weather. Activity was least when temperatures were low and nights were bright. Effects of rainfall were variable. Sizes varied according to sex and age; young mice remained in the parents' range until they approached maturity, when they began to travel more widely. Adult males commonly had larger home ranges than females, although there were a number of exceptions. An inverse relationship between population density and size of home range was shown in several studies and probably is the usual relationship. A basic need for activity and exploration also appeared to influence size of home range. Behavior within the home range was discussed in terms of travel patterns, travels in relation to home sites and refuges, territory, and stability of size of home range. Travels within the home range consisted of repeated use of well-worn trails to sites of food, shelter, and refuge, plus more random exploratory travels. Peromyscus generally used and maintained several or many different home sites and refuges in various parts of their home ranges, and frequently shifted about so that their principal activities centered on different sets of holes at different times. Once established, many Peromyscus remained in the same general area for a long time, perhaps for the duration of their lives. Extent of their travels in different directions and intensity of use of different portions of their home ranges varied within a general area in response to habitat changes, loss of neighbors, or other factors. Various authors have obtained both direct and indirect evidence of territoriality, in some degree, among certain species of Peromyscus. Young mice dispersed from their birth sites to establish home ranges of their own. Adults also sometimes left their home areas; some re-established elsewhere; others returned after exploratory travels. Most populations contained a certain proportion of transients; these may have been wanderers or individuals exploring out from established home ranges or seeking new ones. When areas were depopulated by removal trapping, other Peromyscus invaded. Invasion rates generally followed seasonal trends of reproduction and population density. Peromyscus removed from their home areas and released elsewhere returned home from various distances, but fewer returned from greater distances than from nearby; speed of return increased with successive trials. The consensus from present evidence is that ho-ming is made possible by a combination of random wandering and familiarity with a larger area than the day-to-day range. Records of juvenile wanderings during the dispersal phase and of adult explorations very nearly encompassed the distances over which any substantial amount of successful homing occurred. Methods of measuring sizes of home ranges and the limitations of these measurements were discussed in brief synopsis. It was co

Book chapter↗
USGS1990

Effects of arsenate on growth and physiology in mallard ducklings

Arsenic (As) has been found at elevated concentrations in irrigation drainwater and in aquatic plants utilized by waterfowl. Mallard ( Anas platyrhynchos ) ducklings received an untreated diet (controls) or diets containing 30, 100 or 300 ppm As added as sodium arsenate. After 10 weeks blood and tissue samples were collected for biochemical and histological examination. Arsenic accumulated significantly in brain and liver of ducklings fed 100 or 300 ppm but did not result in histopathological lesions. The 300-ppm dietary As concentration decreased overall growth (weight gain) in males, whereas all concentrations of As decreased overall growth and rate of growth in females. Food consumption was less during the first three weeks in the 300-ppm group and during the second week for the 100-ppm group compared to controls. Plasma sorbitol dehydrogenase activity and plasma glucose concentration were higher in the 300-ppm group compared to controls. Plasma triglyceride concentration increased in all As-treated groups. Brain ATP was lower in the 300-ppm group and sodium/potassium-dependent ATPase activity was higher in the 30- and 100-ppm groups. Hepatic glutathione peroxidase activity was lower in the 300-ppm group and malondialdehyde lower in all treatment groups. All treatment levels caused elevation in hepatic glutathione and ATP concentrations. These findings, in combination with altered duckling behavior (increased resting time), suggest that concentrations of As that have been found in aquatic plants (up to 430 ppm dry weight) could adversely affect normal duckling development.

Environmental Toxicology and Chemistry↗
USGS2013

Breaking the speed limit--comparative sprinting performance of brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta)

Sprinting behavior of free-ranging fish has long been thought to exceed that of captive fish. Here we present data from wild-caught brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta), volitionally entering and sprinting against high-velocity flows in an open-channel flume. Performance of the two species was nearly identical, with the species attaining absolute speeds > 25 body lengths·s −1 . These speeds far exceed previously published observations for any salmonid species and contribute to the mounting evidence that commonly accepted estimates of swimming performance are low. Brook trout demonstrated two distinct modes in the relationship between swim speed and fatigue time, similar to the shift from prolonged to sprint mode described by other authors, but in this case occurring at speeds > 19 body lengths·s −1 . This is the first demonstration of multiple modes of sprint swimming at such high swim speeds. Neither species optimized for distance maximization, however, indicating that physiological limits alone are poor predictors of swimming performance. By combining distributions of volitional swim speeds with endurance, we were able to account for >80% of the variation in distance traversed by both species.

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS1990

Effects of boron on growth and physiology in mallard ducklings

High concentrations of boron (B) have been associated with irrigation drainwater and aquatic plants consumed by waterfowl. Day-old mallard ( Anas platyrhynchos ) ducklings received an untreated diet (controls) or diets containing 100, 400 or 1,600 ppm B as boric acid. Survival, growth and food consumption were measured for 10 weeks. At termination, blood and tissue samples were collected for biochemical assays and histological examination. The highest dietary concentration of B caused 10% mortality, decreased overall growth and the rate of growth (sexes combined), whereas lower concentrations of B altered growth only in females. Food consumption was lower during the first 3 weeks in the 1,600-ppm group and during the second week in all B-treated groups compared to controls. Hematocrit and hemoglobin were lower and plasma calcium concentration higher in the 1,600-ppm group compared to controls. Plasma triglyceride concentration was elevated in all B-treated groups. Brain B concentration increased to 25 times that of controls in the 1,600-ppm group. Brain ATP decreased with increasing dietary B. Brain acetylcholinesterase activity and total ATPase activity (in males) were elevated and protein concentration lowered in the 1,600-ppm group. Boron accumulated less in the liver than in the brain but resulted in an initial elevation of hepatic glutathione. These findings, in combination with altered duckling behavior, suggest that concentrations of B occurring in aquatic plants could adversely affect normal duckling development.

Environmental Toxicology and Chemistry↗
USGS2021

Use of non-lethal endpoints to establish water quality requirements and optima of the endangered Topeka shiner (Notropis topeka)

Water quality standards based on sub-lethal effects and performance optima for aquatic organisms, rather than onset of mortality, are more ecologically relevant for management of species of conservation concern. We investigated the effects of hypoxia, temperature (with acclimation), nitrogenous chemical compounds, and chloride on Topeka shiners ( Notropis topeka ) by monitoring behavioral responses to a reduction in oxygen and, using swimming speed, determining thermal optima and onset of effect for concentrations of nitrogenous compounds and chloride. We found ASR 50 (i.e., dissolved oxygen concentrations where 50% of fish use aquatic surface respiration) to be 1.65 mg/L and ASR 90 to be 1.08 mg/L of dissolved oxygen. Optimum temperatures for the species ranged from 17.7 to 28.0 °C, while predicted 100% mortality ranged from 33.7 to 40.3 °C, depending on the temperature at which fish were acclimated prior to experiments. Ammonia and sodium chloride reduced swimming speed at concentrations below known LC 50 values, while nitrite concentrations did not correspond with swimming speed, but rather, post-experiment mortality. This provides insight into where Topeka shiners can not only persist, but also thrive. Although swimming speed may not be a suitable metric for determining the effects of all contaminants, our focus on optima and sub-lethal effects over tolerance allows selections of the most suitable reintroduction site matching the species’ physiological profile.

Environmental Biology of Fishes↗
USGS1982

Auditory evoked potentials in the West Indian Manatee (Sirenia: Trichechus manatus )

Potentials evoked by clicks and tone pips were recorded by fine wires inserted extracranially in four West Indian manatees ( Trichechus manatus ) in air. Sounds were delivered via padded ear phones. Averaging a few thousand trials at 20/s reveals early peaks at N5.4 (‘vertex’ negativity to a frontal reference, at 5.4 ms), P7.6, N8.8, P9.5 — probably equivalent to waves IV and VII of the typical mammalian auditory brainstem response (ABR). Averaging 100 trials at <4/s suffices to reveal a complex sequence of later peaks including N25, P80, N150 and P190; consistent smaller peaks are visible when several hundred trials are averaged. Using tone pips with a rise and fall time of 2–5 ms the carrier frequency becomes important. Evoked potential wave forms are not the same at different frequencies, bringing out the fact that frequency is not a scalar that can be compensated for by intensity. Therefore the method was not used to obtain audiograms; however the largest EPs occur in the range of 1–1.5 kHz. EPs are found up to 35 kHz; almost no evoked potential is discernible at 40 kHz but the undistorted intensity available was limited. This is in reasonable agreement with the theoretical expectation for the upper limit of behavioral hearing from Heffner and Masterton based on head size and aquatic medium. Among several ear phone placements, that over the external auditory meatus was the most effective, but only slightly so. The external canal is presumably fluid or tissue filled and sound enters over a large area. Comparing data for two species on the most effective range of frequencies and the power spectra of their vocalizations, T. manatus is lower than T. inunguis in both respects. The results show the utility and limitations of the method of recording extracranial evoked potentials to sounds, especially for large and valuable animals under makeshift conditions.

Journal of Comparative Physiology A↗
USGS2017

Increased pheromone signaling by small male sea lamprey has distinct effects on female mate search and courtship

Male body size affects access to mates in many animals. Attributes of sexual signals often correlate with body size due to physiological constraints on signal production. Larger males generally produce larger signals, but costs of being large or compensation by small males can result in smaller males producing signals of equal or greater magnitude. Female choice following multiple male traits with different relationships to size might further complicate the effect of male body size on access to mates. We report the relationship between male body size and pheromone signaling, and the effects on female mate search and courtship in the sea lamprey ( Petromyzon marinus ). We predicted that pheromone production in the liver and the liver mass to body mass ratio would remain constant across sizes, resulting in similar mass-adjusted pheromone release rates across sizes but a positive relationship between absolute pheromone release and body mass. Our results confirmed positive relationships between body mass and liver mass, and liver mass and the magnitude of the pheromone signal. Surprisingly, decreasing body mass was correlated with higher pheromone concentrations in the liver, liver mass to body mass ratios, and mass-adjusted pheromone release rates. In a natural stream, females more often entered nests treated with small versus large male odors. However, close-proximity courtship behaviors were similar in nests treated with small or large male odors. We conclude that small males exhibit increased release of the main pheromone component, but female discrimination of male pheromones follows several axes of variation with different relationships to size.

Behavioral Ecology and Sociobiology↗
USGS2015

The dominance of introduced plant species in the diets of migratory Galapagos tortoises increases with elevation on a human-occupied island

The distribution of resources and food selection are fundamental to the ecology, life history, physiology, population dynamics, and conservation of animals. Introduced plants are changing foraging dynamics of herbivores in many ecosystems often with unknown consequences. Galapagos tortoises, like many herbivores, undertake migrations along elevation gradients driven by variability in vegetation productivity which take them into upland areas dominated by introduced plants. We sought to characterize diet composition of two species of Galapagos tortoises, focussing on how the role of introduced forage species changes over space and the implications for tortoise conservation. We quantified the distribution of tortoises with elevation using GPS telemetry. Along the elevation gradient, we quantified the abundance of introduced and native plant species, estimated diet composition by recording foods consumed by tortoises, and assessed tortoise physical condition from body weights and blood parameter values. Tortoises ranged between 0 and 429 m in elevation over which they consumed at least 64 plant species from 26 families, 44 percent of which were introduced species. Cover of introduced species and the proportion of introduced species in tortoise diets increased with elevation. Introduced species were positively selected for by tortoises at all elevations. Tortoise physical condition was either consistent or increased with elevation at the least biologically productive season on Galapagos. Santa Cruz tortoises are generalist herbivores that have adapted their feeding behavior to consume many introduced plant species that has likely made a positive contribution to tortoise nutrition. Some transformed habitats that contain an abundance of introduced forage species are compatible with tortoise conservation.

Galapagos Islands↗
USGS2022

Hydraulics of freshwater mussel habitat in select reaches of the Big River, Missouri

The Big River is a tributary to the Meramec River in south-central Missouri. It drains an area that has been historically one of the largest lead producers in the world, and associated mine wastes have contaminated sediments in much of the river corridor. This study investigated hydraulic conditions in four study reaches to evaluate the potential contribution of physical habitat dynamics to mechanical and physiological stress on native mussel populations. We quantified hydraulic conditions and relative bed stability in previously identified and delineated mussel habitats (MHs) and in the surrounding reaches to refine understanding of the reach-scale (about 1 kilometer) hydraulic characteristics that affect the distribution of mussel aggregations in the river. Two-dimensional hydrodynamic models were compiled for discharge scenarios from base flow (90-percent flow exceedance) to the approximate bankfull discharge (2-year mean return interval peak flow) for the reaches. Discharge, velocity, and water-surface elevation data were collected at all four study reaches at various discharges to calibrate the models across a range of discharges. Shields values to predict incipient motion of the substrate were computed for the MHs and surrounding reaches using bed-surface sediment data collected during this study and previous studies. The distributions of hydraulic values at the range of simulated discharge scenarios were significantly different among the MHs. Depth values in the MHs ranged from 0.03 to 5.7 meters, with parts remaining dry at some lower flow scenarios (for example, 90- and 50-percent flow exceedance). MH velocities and bed shear stresses (shear stresses) reached 3.1 meters per second and 31 newtons per square meter, respectively. Through the range of simulated discharges, velocity and shear stress within the MHs were limited by reach-scale hydraulic behavior. Our calculations predicted sand mobility within at least 50 percent of the wetted area of all four MHs for discharges from the 50-percent exceedance flow to the approximate bankfull discharge, whereas 50th-percentile (median) particle size fraction mobility was only predicted within a small area of one of the MHs at the 2-year peak discharge. These results indicate that finer size fractions are mobile within the four MHs, but the larger framework grains of the substrate are predominantly stable at the most frequent discharges. Our results indicate that suitable mussel habitat on the Big River cannot be identified within a narrow range of velocities, depths, and shear stresses. However, the consistent patterns of sediment mobility and the slow increase of hydraulic forces with increasing discharge within all the MHs indicate that flushing flows at low discharges and coarse sediment stability at higher discharges are important for habitat suitability in the Big River. These patterns of sediment mobility are comparable among the robust and depauperate MHs, indicating that the depauperate beds are likely not impaired by bed instability or siltation. Coarse sediment stability up to bankfull discharges further indicates that bed instability is not widespread in these modeled reaches and is likely not related to the spatial distribution of mussels in these locations.

Missouri↗
USGS1968

Population characteristics and physical condition of alewives, Alosa pseudoharengus, in a massive die-off in Lake Michigan, 1967

The length, age and sex compositions of dead and dying alewives collected in June 1967 at six locations in southern, central, and northern Lake Michigan are compared with those of fish taken in experimental trawls at five locations in April and June 1967. Behavior at the time of death, condition of the body and gonads, stomach contents, and the incidence of Saprolegnia and subcutaneous hemorrhages also are described for alewives in the dieoff. The length distributions of alewives in the dieoff and trawl collections were similar and bimodal. Yearlings made up 25 and 42 percent of the respective collections. The average age of adults (age-group II and older) were nearly identical in the dieoff and trawl collections (3.5 and 3.6 years, respectively). Both collections were dominated by age-groups III and IV. The average lengths of adult alewives in age-groups II to V in the dieoff were smaller than or identical to those in the trawl collections. In all collections females were consistently older (0.4 year) than the males and larger at the greater ages. The sexes were almost equally represented among age-II and older fish in the dieoff. Despite the presence of Saprolegnia and hemorrhages on some fish, alewives in the dieoff appeared robust. Spawning attrition could not have been a major cause of the dieoff because many immature yearlings died and 80 percent of the dead adults were unspawned. The presence of rapidly digestible zooplankton in the stomachs of dead alewives indicated that many fish were feeding just before death. About 20 percent of the alewives in the selected samples of fish from the dieoff were infected by Saprolegnia; twice as many females were infected as males. The fungus was randomly distributed among the size groups. Hemorrhages may have been a symptom or physiological response to the cause of the dieoff because they affected a much higher percentage of the dying alewives (47 percent) than did fungus. Occurrence of the hemorrhages did not differ significantly between the sexes or among the size groups.

Technical Report↗
USGS2022

Taming the temperature: Sagebrush songbirds modulate microclimate via nest-site selection

Understanding species’ responses to temperature via behavior, and the factors affecting the extent of behavioral responses, is a critical and timely endeavor given the rapid pace at which the climate is changing. The young of altricial songbirds are particularly sensitive to temperature, and parents may modulate temperatures at nests via selection of nest sites, albeit to a largely unknown extent. We examined whether sagebrush-obligate songbirds, that reproduce within an open ecosystem with wide temperature fluctuations and span a range of body sizes, selected their nest sites on the basis of temperature. We further investigated whether nest predation risk and ambient conditions modulated temperature-based choices. We placed temperature loggers at nest sites and in unused but available nest niches and nest shrubs along a known predation-risk gradient and used nearby weather stations to determine ambient temperatures. The two smaller-bodied birds, Brewer’s Sparrow ( Spizella breweri ) and Sagebrush Sparrow ( Artemisiospiza nevadensis ), selected nest shrubs and niches that were warmer and less variable relative to unused sites whereas the larger bodied species, Sage Thrashers ( Oreoscoptes montanus ), did not. Brewer’s Sparrows and Sage Thrashers dampened selection for warmer nest sites when temperatures experienced during the nest-site prospecting period were warmer. None of the three species altered nest-site selection with respect to temperature in response to ambient temperature variability or our index of nest predation risk. The microhabitat characteristics that most influenced temperatures at nests varied across species. Our results suggest that songbirds can modulate temperatures at nests to some extent, and such responses can vary depending on the conditions experienced prior to nest initiation. Responses also varied across species, likely reflecting different physiological tolerances. The extent to which breeding birds will be able to continue to proximately influence temperature via nest-site choices likely will depend on the extent and rate of future climatic shifts.

Ornithology↗
USGS2023

Effects of lead exposure on birds breeding in the Southeast Missouri Lead Mining District

Lead mining in the Southeast Missouri Lead Mining District began in the 1700s and continued for nearly 300 years; the waste piles associated with smelting, mining, and milling of lead ores have released metal residues that have contaminated soil and water in the region. Previous studies in the district have indicated potential harm to wildlife, including birds, because of elevated lead concentrations associated with mining. Exposure to soil-borne lead was correlated with elevated lead concentrations in tissues, inhibition of δ-aminolevulinic acid dehydratase (δALAD), and renal lesions in birds foraging on ground-dwelling invertebrates at contaminated sites (compared to reference sites) in the Southeast Missouri Lead Mining District. This study assessed reproductive outcomes for songbirds exposed to soil-borne lead in the district, examined the relation between lead concentrations in soils and in tissues of ground-feeding birds and prey species, and compared the results to literature-based toxicity thresholds for lead that are associated with negative effects in birds. Three lead-contaminated sites and three reference sites (with background concentrations of lead and no known mining inputs) were compared in two ways: individually to all other sites or by site type. Additional effects of lead exposure were evaluated by examining concentrations of biomarkers (oxidative stress, lipid peroxidation, and deoxyribonucleic acid damage) in liver tissues, δALAD inhibition, and renal and hepatic microscopic lesions in birds from lead-contaminated and reference sites. Lead concentrations in soil were site-dependent and were also generally heterogeneous within the lead-contaminated sites. Between 17 and 74 percent of all soil samples at contaminated sites had lead concentrations that exceeded a threshold (1,000 milligrams per kilogram [mg/kg] lead in soil) previously associated with adverse physiological effects in birds in the Southeast Missouri Lead Mining District. Lead concentrations in mixed invertebrates from lead-contaminated sites (282 to 2,230 mg/kg dry weight [dw]) indicated that consuming soil-dwelling prey species is a potential exposure pathway for adult birds and their broods. At lead-contaminated sites, lead concentrations in 40.5 percent of blood samples (adults and their broods) were within a subclinical effects range (0.9 to 2.3 mg/kg dw), and 18.7 percent of samples had lead concentrations that exceeded clinical effects criteria (greater than 2.3 mg/kg dw). In contrast, only 2.6 percent of blood samples from reference sites were within the subclinical effects range for lead; all other blood samples from the reference sites had lead concentrations representative of background concentrations (less than 0.9 mg/kg dw). Subclinical and clinical threshold exceedances for lead concentrations in livers and kidneys were similarly more prevalent at the contaminated sites compared to the reference sites. Lead concentrations in blood were positively correlated with lead concentrations in soil, livers, and kidneys. Lead concentrations in blood were negatively correlated with δALAD activity; greater than 50 percent of the birds collected at lead-contaminated sites exhibited injury via greater than 50 percent inhibition of δALAD in blood compared to birds at reference sites. Birds with elevated lead concentrations in tissues also exhibited enhanced oxidative stress. Microscopic lesions in the livers and kidneys of birds had similar rates of occurrence at the contaminated and reference sites, and lesion prevalence could not be directly linked to lead exposure. Reproductive success was monitored at 585 nests, and 3 out of 5 species had reduced nest success associated with elevated lead concentrations in soil; habitat measures did not help explain nest success. Reduced nest success may have resulted from greater nest predation resulting from neurological and behavioral effects of lead exposure. Ultimately, these lines of evidence indicate that bird health and reproduction have been negatively affected by exposure to lead-contaminated soils in the Southeast Missouri Lead Mining District.

Missouri↗
USGS1998

Possible mechanisms for sensitivity to organophosphorus and carbamate insecticides in eastern screech-owls and American kestrels

Effects of a single dietary exposure to fenthion and carbofuran on the survival, feeding behavior and brain ChE activity of eastern screech-owls, Otus asio and American kestrels, Falco sparverius , were evaluated. Birds were exposed to fenthion (23.6–189.0 ppm) or carbofuran (31.7–253.6 ppm) via meatballs. Carbofuran-exposed owls ate either ≤10% or ≥80% of the meatball whereas all kestrels ate ≤10% of the meatball before exhibiting acute signs of toxicity. Fenthion-exposed owls and kestrels displayed a wide spectrum of meatball consumption (<10–100%). Significant brain ChE inhibition was observed in dead and surviving kestrels exposed to fenthion and carbofuran and dead owls exposed to fenthion ( P <0.0001). Brain ChE activity of owls exposed to carbofuran that survived was not different from that of controls ( P =0.25). Data suggest: (1) slow feeding on a carbamate-contaminated item may provide limited protection from the toxicity of the chemical at certain rates of exposure; (2) the degree of ChE inhibition at neuromuscular junctions may be critical in determining the sensitivity of a species to a carbamate insecticide; (3) sensitivity may be a function of the ChE affinity for the carbamate inhibitor; and (4) the importance of neuromuscular junction ChE depression in determining the sensitivity of an animal may be species-specific.

Comparative Biochemistry and Physiology, Part C: P↗
USGS2023

Mussel mass mortality in the Clinch River, USA: Metabolomics detects affected pathways and biomarkers of stress

Biologists monitoring freshwater mussel (order Unionida) populations rely on behavioral, often subjective, signs to identify moribund (“sick”) or stressed mussels, such as gaping valves and slow response to probing, and they lack clinical indicators to support a diagnosis. As part of a multi-year study to investigate causes of reoccurring mortality of pheasantshell ( Ortmanniana pectorosa; synonym Actinonaias pectorosa ) in the Clinch River, Virginia and Tennessee, USA, we analyzed the hemolymph metabolome of a subset of mussels from the 2018 sampling period. Mussels at the mortality sites were diagnosed in the field as affected (case) or unaffected (control) based on behavioral and physical signs. Hemolymph was collected in the field by non-lethal methods from the anterior adductor muscle for analysis. We used ultra-high-performance liquid chromatography with quadrupole time-of-flight mass spectroscopy to detect targeted and untargeted metabolites in hemolymph and compared metabolomic profiles by field assessment of clinical status. Targeted biomarker analysis found 13 metabolites associated with field assessments of clinical status. Of these, increased gamma-linolenic acid and N -methyl- L -alanine were most indicative of case mussels, while adenine and inosine were the best indicators of control mussels. Five pathways in the targeted analysis differed by clinical status; two of these, purine metabolism and glycerophospholipid metabolism, were also indicated in the untargeted analysis. In the untargeted nalysis, 22 metabolic pathways were associated with clinical status. Many of the impacted pathways in the case group were catabolic processes, such as degradation of amino acids and fatty acids. Hierarchical clustering analysis matched clinical status in 72% (18 of 25) of mussels, with control mussels more frequently (5 of 16) not matching clinical status. Our study demonstrated that metabolomic analysis of hemolymph is suitable for assessing mussel condition and complements field-based indicators of health.

Tennessee, Virginia↗