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At least 271 records · Page 15Linked to original sources
USGS2011

Thiaminase activity and life history investigations in American shad in the Columbia River

American shad Alosa sapidissima fry were successfully transplanted from the Atlantic to the Pacific coast in 1871 and have subsequently proliferated. The Columbia River population is in the millions, yet few investigations have been conducted to better understand their life history, population dynamics, or potential impacts on other species. In 2007 and 2008 we captured American shad from the Columbia River to assess levels of thiaminase activity and to characterize some aspects of American shad life history. Thiaminase levels in age-0 and adult fish were high and ranged from 4,113-20,874 pmol/g/min. Ages of spawning American shad ranged from 3-7 years and iteroparity was approximately 33-36% in the spawning population. Males were typically younger and smaller and had a higher degree of iteroparity than females.

Oregon, Washington↗
USGS2001

Early life history attributes and run composition of PIT-tagged wild subyearling Chinook salmon recaptured after migrating downstream past Lower Granite Dam

Seaward migration timing of Snake River fall chinook salmon ( Oncorhynchus tshawytscha ) smolts is indexed using subyearling chinook salmon passage data collected at Lower Granite Dam. However, not all of the subyearlings are fall chinook salmon. For six years, we recaptured wild subyearling chinook salmon smolts, which had been previously PIT tagged in the Snake River, to genetically determine if the fish were offspring of spring and summer (hereafter, spring/summer), or fall chinook salmon. Springfall chinook salmon comprised over 10% of the samples of recaptured smolts in five of six years. For these five years, we used discriminant analysis to determine run membership of PIT-tagged smolts that were not recaptured (i.e., not sampled for genetic identification). Accuracy of the discriminant analysis models, based on genetically identified smolts, varied between 75 and 85%. After using discriminant analysis to classify run membership for each PIT-tagged smolt that was not genetically identified, we compared early life history attributes between fall and spring/summer chinook salmon and calculated annual run composition. The life history attributes we studied overlapped, but spring/summer chinook salmon reared along the shoreline of the free-flowing Snake River earlier, were larger, and began seaward migration earlier than fall chinook salmon. Spring/summer chinook salmon made up from 15.1 to 44.4% of the tagged subyearling smolts that were detected passing Lower Granite Dam. As a result, the presence of spring/summer chinook salmon makes migration timing for the fall chinook salmon seem earlier and more protracted than is the case. If wild subyearling spring/summer chinook salmon smolts are not considered, fall chinook salmon abundance at Lower Granite Dam will be overestimated.

Washington↗
USGS1959

Life history of the sea lamprey of Cayugaf Lake, New York

A life history study of the sea lamprey, Petromyson marinus Linnaeus, in Cayuga Lake, N.Y., was conducted during 1950, 1951, and 1952. One of the major objectives was to obtain biological data concerning this endemic stock of sea lampreys for comparison with the newly established stocks in the Great Lakes. Sexually mature sea lampreys captured on their spawning migration in Cayuga Inlet were the basis of much of this study. Such items as meristic counts, body proportions, body color, sex ratios, lengths and weights, fecundity, rate of upstream travel, effect of dams in retarding upstream movement, nesting habits, parasites, predators, estimates of abundance, and morphological changes were based on mature upstream migrants. Sea lampreys were procured by weir and trap operations and captured by hand. Tagging and marking' programs each spring made it possible to determine movements and morphological changes of individual lampreys, in addition to estimating the number of upstream migrants. Growth of parasitic-phase sea lampreys was estimated from measurements of specimens captured in Cayuga Inlet and Cayuga Lake proper. The incubation period of lamprey eggs and the habits of ammocoetes and transforming lampreys were ascertained from specimens kept in hatchery troughs and raceways. Length-frequency and weight-frequency distributions, together with the length-weight regression, of ammocoetes from Cayuga Inlet were utilized for estimating the duration of their larval life. Lake trout, Salvelinus n. namayc"Ush (Walbaum), from Cayuga Lake and Seneca Lake were the subject of an inquiry into the effects of sea lamprey attacks. Incidence of sea lamprey attacks on the white sucker, Catosto7llus c. commerson/: (LacepMe), was investigated. Three methods are suggested for reducing the number of sea lampreys in Cayuga Lake.

Fishery Bulletin of the U.S. Fish and Wildlife Ser↗
USGS1994

Demographic and life history characteristics influence the cytonuclear composition of mosquitofish populations

Experimental laboratory crosses and population experiments reveal significant differences in individual life-history traits and population demography between two related species of mosquitofish, Gambusia affinis and G. holbrooki . With respect to life-history traits, progeny from G. holbrooki exhibit larger size at birth and earlier age at sexual maturity than do progeny from G. affinis parents. With respect to demography, populations of G. holbrooki exhibit higher recruitment and carrying capacity and loser overwinter mortality than do populations of G. affinis . These differences help t explain the dramatic changes in cytonuclear genotype frequency observed in replicated experimental hybrid populations of Gambusia monitored over 52 weeks. These experimental results are interpreted in the context of introgression patterns previously studied indirectly from distributions of cytonuclear genotypes in a natural mosquitofish hybrid zone.

Book chapter↗
USGS2006

Variation in spring nearshore resident fish species composition and life histories in the lower San Joaquin watershed and delta

Providing freshwater to human populations while protecting or rehabilitating ecosystem health is a significant challenge to water resource managers and requires accurate knowledge of aquatic resources. Previous studies of fish assemblages in the San Francisco Estuary and watershed have focused on specific habitat types, water bodies, or geographic subregions. In this study, we use seining data from two monitoring programs to provide an integrated view of spring nearshore resident fish species composition and life history characteristics in five regions: the San Joaquin River, the upper Sacramento River, the lower Sacramento River, the northern Sacramento-San Joaquin Delta (North Delta), and the Interior Delta. Data for the period March-May from 1994 to 2002, showed that spring species composition of the San Joaquin River was very different from the other four regions. Total catch in the San Joaquin River was dominated by small, short-lived batch spawning alien species (93%), particularly red shiner Cyprinella lutrensis (>75% of total catch). The upper and lower Sacramento River were very similar in species composition and life history characteristics and less dominated by alien fish (<45% of total catch). Ordination of species percentage abundances by non–metric multidimensional scaling confirmed that the major gradient was from assemblages dominated by native species to assemblages dominated by alien species. Two-way analysis of variance of ordination scores indicated that spatial variability was more important than annual variability in explaining patterns in species composition. The potential benefits of San Joaquin River native fish restoration appear high because there is so much potential for improvement; however, it is unclear how to best manipulate the system to achieve such restoration. Addressing such uncertainties is necessary if society desires the reservation and restoration of native biodiversity as human demands on water resources increase.

California↗
USGS2003

A review of lake trout (Salvelinus namaycush) restoration in Lake Ontario from an early life history perspective

The authors conclude that small numbers of lake trout spawned successfully each year during 1992-97 in Lake Ontario, although this has yet to result in a trend of increasing natural reproduction. Juxtaposed with the high abundance of mature fish (Selgeby et al., 1995), the situation in Lake Ontario suggests a reduction in reproductive efficiency. This could result from mortality factors that may to a certain extent be density independent because recruitment has remained flat in the face of increasing spawner abundance. According to RESTORE, such factors are likely acting during the first year of life. Accordingly, the authors herin review the evidence that former barriers to lake trout reproduction in Lake Ontario that act as early-life-stage bottlenecks have been removed. In addition, the authors review other potential new barriers for which there has only recently been enough information to judge their relative importance.

Book chapter↗
USGS2019

Interactive effects of severe drought and grazing on the life history cycle of a bioindicator species on the edge of its range

Recurring drought and grazing are ecological drivers of semi-arid grasslands on the Southern High Plains, USA; however, ecological drivers are currently undergoing human-induced alterations, which likely have implications for wildlife. We used the lesser prairie-chicken (Tympanuchus pallidicinctus), an iconic grouse species that exhibits a boom-bust life history strategy, on the Southern High Plains, USA, as a bioindicator of main and interactive effects of severe drought and grazing. This region encompasses the southern and westernmost part of the lesser prairie-chicken range and experienced the worst drought on record in 2011. We surveyed lesser prairie-chicken leks (i.e., communal breeding grounds) across 12 years that represented 7 years before the 2011 drought ("pre-drought") and 4 years during and following the 2011 drought ("post-drought"). Grazing was annually managed with the objective of achieving ≤50% utilization of above-ground vegetation biomass. We used lek (n = 49) count data and covariates of weather and managed grazing to: 1) estimate long-term lesser prairie-chicken abundance and compare abundance pre-drought and post-drought; 2) examine annually the influence of drought (modified Palmer Drought Index), temperature, the number of days with maximum temperature >75th percentile, and precipitation on long-term lesser prairie-chicken survival and recruitment; and 3) assess and compare the influence of grazing on lesser prairie-chickens pre-drought and post-drought. Lesser prairie-chicken abundance was nearly 7 times greater pre-drought than post-drought, and population declines were attributed to decreased survival and recruitment. The number of days with temperature >75th percentile had the greatest effect, particularly on recruitment. The population exhibited a substantial bust during 2011 and 2012 without a boom to recover in 4 post-drought years. Adaptive grazing positively influenced the population pre-drought, but had no effects post-drought. Results suggest that the severe drought in 2011 may have been beyond the range of environmental conditions to which lesser prairie-chickens, and likely other species, have adapted. Land management practices, such as grazing, should remain adaptive to ensure potential negative influences to all species are avoided. Increasing habitat quantity and quality by reducing habitat loss and fragmentation likely will increase resiliency of the ecosystem and individual species.

Southern High Plains↗
USGS2010

Sensitivity of early life stages of freshwater mussels (Unionidae) to acute and chronic toxicity of lead, cadmium, and zinc in water

Toxicity of lead, cadmium, or zinc to early life stages of freshwater mussels (fatmucket, Lampsilis siliquoidea ; Neosho mucket, L. rafinesqueana ) was evaluated in 48‐h exposures with mussel larvae (glochidia), in 96‐h exposures with newly transformed (5‐d‐old) and two‐ or six‐month‐old juvenile mussels, or in 28‐d exposures with two‐ or four‐month‐old mussels in reconstituted soft water. The 24‐h median effect concentrations (EC50s) for fatmucket glochidia (>299 µg Pb/L, >227 µg Cd/L, 2,685 µg Zn/L) and 96‐h EC50s for two‐ or six‐month‐old fatmucket (>426 µg Pb/L, 199 µg Cd/L, 1,700 µg Zn/L) were much higher than 96‐h EC50s for newly transformed fatmucket (142 and 298 µg Pb/L, 16 µg Cd/L, 151 and 175 µg Zn/L) and Neosho mucket (188 µg Pb/L, 20 µg Cd/L, 145 µg Zn/L). Chronic values for fatmucket were 10 µg Pb/L, 6.0 µg Cd/L, and 63 and 68 µg Zn/L. When mussel data from the present study and the literature were included in updated databases for deriving U.S. Environmental Protection Agency water quality criteria, mussel genus mean acute values were in the lower percentiles of the sensitivity distribution of all freshwater species for Pb (the 26th percentile), Cd (the 15th to 29th percentile), or Zn (the 12th to 21st percentile). The mussel ( Lampsilis ) genus mean chronic value was the lowest value ever reported for Pb (the 9th percentile) but was near the middle of the sensitivity distribution for Cd (the 61st percentile) or Zn (the 44th percentile). These results indicate that mussels were relatively sensitive to the acute toxicity of these three metals and to the chronic toxicity of Pb, but were moderately sensitive to the chronic toxicity of Cd or Zn compared to other freshwater species.

Environmental Toxicology and Chemistry↗
USGS2016

Sensitivity of lake sturgeon ( Acipenser fulvescens ) early life stages to 2,3,7,8-tetrachlorodibenzo- P -dioxin and 3,3′,4,4′,5-pentachlorobiphenyl

The aquatic food web of the Great Lakes has been contaminated with polychlorinated biphenyls (PCBs) since the mid-20th century. Threats of PCB exposures to long-lived species of fish, such as lake sturgeon ( Acipenser fulvescens ), have been uncertain because of a lack of information on the relative sensitivity of the species. The objective of the present study was to evaluate the sensitivity of early–life stage lake sturgeon to 3,3′,4,4′,5-pentachlorobiphenyl (PCB-126) or 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD) exposure. Mortality, growth, morphological and tissue pathologies, swimming performance, and activity levels were used as assessment endpoints. Pericardial and yolk sac edema, tubular heart, yolk sac hemorrhaging, and small size were the most commonly observed pathologies in both TCDD and PCB-126 exposures, beginning as early as 4 d postfertilization, with many of these pathologies occurring in a dose-dependent manner. Median lethal doses for PCB-126 and TCDD in lake sturgeon were 5.4 ng/g egg (95% confidence interval, 3.9–7.4 ng/g egg) and 0.61 ng/g egg (0.47–0.82 ng/g egg), respectively. The resulting relative potency factor for PCB-126 (0.11) was greater than the World Health Organization estimate for fish (toxic equivalency factor = 0.005), suggesting that current risk assessments may underestimate PCB toxicity toward lake sturgeon. Swimming activity and endurance were reduced in lake sturgeon survivors from the median lethal doses at 60 d postfertilization. Threshold and median toxicity values indicate that lake sturgeon, like other Acipenser species, are more sensitive to PCB and TCDD than the other genus of sturgeon, Scaphirhynchus , found in North America. Indeed, lake sturgeon populations in the Great Lakes and elsewhere are susceptible to PCB/TCDD-induced developmental toxicity in embryos and reductions in swimming performance.

Environmental Toxicology and Chemistry↗
USGS2017

Acute toxicity of polyacrylamide flocculants to early life stages of freshwater mussels

Polyacrylamide has become an effective tool for reducing construction-related suspended sediment and turbidity, which are considered to have significant adverse impacts on aquatic ecosystems and are a leading cause of the degradation of North American streams and rivers. However, little is known about the effects of polyacrylamide on many freshwater organisms, and prior to the present study, no information existed on the toxicity of polyacrylamide compounds to native freshwater mussels (family Unionidae), one of the most imperiled faunal groups globally. Following standard test guidelines, we exposed juvenile mussels (test duration 96 h) and glochidia larvae (test duration 24 h) to 5 different anionic polyacrylamide compounds and 1 non-ionic compound. Species tested included the yellow lampmussel ( Lampsilis cariosa ), an Atlantic Slope species that is listed as endangered in North Carolina; the Appalachian elktoe ( Alasmidonta raveneliana ), a federally endangered Interior Basin species; and the washboard ( Megalonaias nervosa ), a common Interior Basin species. We found that median lethal concentrations (LC50s) of polyacrylamide ranged from 411.7 to >1000 mg/L for glochidia and from 126.8 to >1000 mg/L for juveniles. All LC50s were orders of magnitude greater (2–3) than concentrations typically recommended for turbidity control (1–5 mg/L), regardless of their molecular weight or charge density. The results demonstrate that the polyacrylamide compounds tested were not acutely toxic to the mussel species and life stages tested, indicating minimal risk of short-term exposure from polyacrylamide applications in the environment. However, other potential uses of polyacrylamide in the environment (e.g., wastewater treatment, paper processing, mining, algae removal) and their chronic or sublethal effects remain uncertain and warrant additional investigation.

Environmental Toxicology and Chemistry↗
USGS1993

Sensitivity of early-life stage golden trout to low pH and elevated aluminum

Early-life-stage golden trout ( Oncorhynchus aguabonita aguabonita ) were exposed to acid and Al to examine the response and determine the sensitivity of a western, alpine salmonid to conditions simulating an episodic pH depression. Freshly fertilized eggs, alevins, and swim-up larvae were exposed for 7 d to one of 12 combinations of pH and Al, and surviving fish were held to 40 d post-hatch to determine the effect of exposure on subsequent survival and recovery. Golden trout are sensitive to conditions simulating episodic acidification events typically observed in the field. Significant mortality occurred when the pH of test waters was below 5.0 in the absence of Al or when pH was 5.5 in the presence of 100 μg/L total Al. Behavioral impairments were sensitive indicators of low pH and Al stress. Impaired locomotory and feeding behavior occurred at pH 5.5 without Al and at Al concentrations > 50 μg/L. In contrast, growth, RNA-to-DNA ratio, and whole-body ion concentration were relatively less sensitive indicators of sublethal acid and Al stress.

Environmental Toxicology and Chemistry↗
USGS1998

Photoenhanced toxicity of a carbamate insecticide to early life stage anuran amphibians

Aican clawed frog ( Xenopus laevis ) and gray tree frog ( Hyla versicolor ) embryos and tadpoles were exposed to sublethal levels of carbaryl, a broad-spectrum insecticide, and ultraviolet radiation to determine interactive and sublethal effects. Ultraviolet intensity (UV-B [285–320 nm] plus UV-A [321–400 nm]) was controlled with various types of plastic filters and quantified with a scanning spectroradiometer. Significant differences in swimming activity and mortality of both species were evident during the 96-h experiments. Ultraviolet-B radiation alone and carbaryl in the presence of UV-B significantly decreased swimming activity of both species. As little as 1.5% intensity of ambient solar UV-B radiation photoactivated carbaryl. Toxicity of 7.5 mg/L carbaryl increased by 10-fold in the presence of UV-B in all species and life stages tested. Our results indicate that photoenhancement by solar UV-B radiation should be considered when evaluating the toxicity of contaminants to amphibians and other organisms.

Environmental Toxicology and Chemistry↗
USGS2023

Bioavailability and toxicity models of copper to freshwater life: The state of regulatory science

Efforts to incorporate bioavailability adjustments into regulatory water quality criteria in the United States have included four major procedures: hardness-based single-linear regression equations, water-effect ratios (WERs), biotic ligand models (BLMs), and multiple-linear regression models (MLRs) that use dissolved organic carbon, hardness, and pH. The performance of each with copper (Cu) is evaluated, emphasizing the relative performance of hardness-based versus MLR-based criteria equations. The WER approach was shown to be inherently highly biased. The hardness-based model is in widest use, and the MLR approach is the US Environmental Protection Agency's (USEPA's) present recommended approach for developing aquatic life criteria for metals. The performance of criteria versions was evaluated with numerous toxicity datasets that were independent of those used to develop the MLR models, including olfactory and behavioral toxicity, and field and ecosystem studies. Within the range of water conditions used to develop the Cu MLR criteria equations, the MLR performed well in terms of predicting toxicity and protecting sensitive species and ecosystems. In soft waters, the MLR outperformed both the BLM and hardness models. In atypical waters with pH <5.5 or >9, neither the MLR nor BLM predictions were reliable, suggesting that site-specific testing would be needed to determine reliable Cu criteria for such settings. The hardness-based criteria performed poorly with all toxicity datasets, showing no or weak ability to predict observed toxicity. In natural waters, MLR and BLM criteria versions were strongly correlated. In contrast, the hardness-criteria version was often out of phase with the MLR and, depending on waterbody and season, could be either strongly overprotective or underprotective. The MLR-based USEPA-style chronic criterion appears to be more generally protective of ecosystems than other models.

Environmental Toxicology and Chemistry↗
USGS2023

Using multiple metal mixture models to predict toxicity of riverine sediment porewater to the benthic life stage of juvenile white sturgeon (Acipenser transmontanus)

Five metal mixture dose–response models were used to predict the toxicity of porewater to young sturgeon at areas of interest in the Upper Columbia River (WA, USA/BC, Canada) and to evaluate these models as tools for risk assessments. Dose components of metal mixture models included exposure to free metal ion activities or metal accumulation by biotic ligands or humic acid, and links of dose to response used logistic equations, independent joint action equations, or additive toxicity functions. Laboratory bioassay studies of single metal exposures to juvenile sturgeon, porewater collected in situ in the fast-flowing Upper Columbia River, and metal mixture models were used to evaluate toxicity. The five metal mixture models were very similar in their predictions of adverse response of juvenile sturgeon and in identifying copper (Cu) as the metal responsible for the most toxic conditions. Although the modes of toxic action and the 20% effective concentration values were different among the dose models, predictions of adverse response were consistent among models because all doses were tied to the same biological responses. All models indicated that 56% ± 5% of 122 porewater samples were predicted to have <20% adverse response, 25% ± 5% of samples were predicted to have 20% to 80% adverse response, and 20% ± 4% were predicted to have >80% adverse response in juvenile sturgeon. The approach of combining bioassay toxicity data, compositions of field porewater, and metal mixture models to predict lack of growth and survival of aquatic organisms due to metal toxicity is an important tool that can be integrated with other information (e.g., survey studies of organism populations, life cycle and behavior characteristics, sediment geochemistry, and food sources) to assess risks to aquatic organisms in metal-enriched ecosystems. Environ Toxicol Chem 2023;00:1–12. Published 2023. This article is a U.S. Government work and is in the public domain in the USA.

Environmental Toxicology & Chemistry↗
USGS2024

Ion exchange processes for CO2 mineralization using industrial waste streams: Pilot plant demonstration and life cycle assessment

An attractive technique for removing CO 2 from the environment is sequestration within stable carbonate solids (e. g., calcite). However, continuous addition of alkalinity is required to achieve favorable conditions for carbonate precipitation (pH>8) from aqueous streams containing dissolved CO 2 (pH<4.5) and Ca 2+ ions. In this study, a pH-swing process using ion exchange was demonstrated to process 300 L of produced water brine per day for CO 2 mineralization. Proton titration capacities were quantified for aqueous streams in equilibrium with gas streams at various concentrations of CO 2 (pCO 2 =0.03–0.20 atm) and at various flow rates (0.5–2.0 L min −1 ). Energy intensities for the process were determined to be between 30 and 65 kWh per tonne of CO 2 sequestered depending on the composition of the brine stream. A life cycle assessment was performed to analyze the net carbon emissions of the technology which indicated a net CO 2 reduction for pCO 2 ≥0.12 atm (−0.06–−0.39 kg CO 2 e per kg precipitated CaCO 3 ) utilizing calcium-rich brines. The results from this study indicate the ion exchange process can be used as a scalable method to provide alkalinity necessary for the capture and storage of CO 2 in Ca-rich waste streams.

Chemistry Select↗
USGS2019

Freshwater tidal forests and estuarine wetlands may confer early life growth advantages for delta-reared Chinook Salmon

Large river deltas are complex ecosystems that are believed to play a pivotal role in promoting the early marine growth and survival of threatened Chinook Salmon Oncorhynchus tshawytscha . We used a fish bioenergetics model to assess the functional role of multiple delta habitats across a gradient of salinities and vegetation types, where consumption and growth rate potential (GRP) were considered as proxies for habitat quality. We subsequently compared our model output to empirical, or realized , growth estimates from scale circuli. In terms of consumption, prey energy density (ED prey ) was 46–86% higher in tidal freshwater forest than in any other habitat type, while estimated consumption rates (expressed as proportion of maximum daily consumption; P cmax ) were positively correlated with FL. These size‐related differences in P cmax led to a noticeable increase along a freshwater‐to‐saline gradient from roughly 0.25 in tidal freshwater forest to 0.55 in the offshore subtidal zone, yet despite higher observed P cmax values in nearshore and offshore habitats, the tidal freshwater forest and emergent salt marsh demonstrated the highest modeled GRP values. Similarly, realized growth rates for fish caught in tidal freshwater forest were up to 0.5% higher per day than for fish caught in the offshore area, but habitat‐level differences were overshadowed by allometry and rearing origin. Scales from unmarked fish (assumed to be of wild origin) indicated that they grew, on average, 11% faster than did hatchery fish; however, these differences were subtle and were more obvious at fork lengths <100 mm. Our results suggest that tidal forests and emergent marshes may offer early life growth advantages for wild Chinook Salmon, but that wild and hatchery fish can compensate as they move seaward by opportunistically consuming greater quantities of low‐energy density prey, taking advantage of pulses of larval forage fish, or by spending time in multiple interconnected habitat types.

Transactions of the American Fisheries Society↗
USGS2021

Life history and population dynamics

Lake charr Salvelinus namaycush life history and population dynamics metrics were reviewed to evaluate populations inside ( n = 462) and outside ( n = 24) the native range. Our goals were to create a database of metrics useful for evaluating population status and to test for large-scale patterns between metrics and latitude and lake size. An average lake charr grew from a 69-mm length at age-0 ( L 0 ) at 89 mm/year early growth rate ( ω ) to 50% maturity at 420 mm ( L 50 ) at age 8 ( t 50 ), and then continued to grow toward a 717-mm asymptotic length ( L ∞ ). L 50 was positively correlated to ω , whereas t 50 was inversely correlated to ω . Lake charr grew slower toward larger size and older age in northern latitudes and larger lakes than in southern latitudes and smaller lakes. Population density (number/ha) and yield density (kg/ha) decreased with lake size, and yield and total annual mortality ( A ) decreased with latitude. Native populations grew slower ( ω ), were heavier at 500 mm ( W 500 ), matured at shorter L 50 , grew to a shorter L ∞ , and suffered lower annual mortality A than non-native populations. Our review and database should be useful to managers and researchers for quantifying lake charr population status across the species range.

Book chapter↗
USGS2006

Toxicity of synthetic musks to early life stages of the freshwater mussel Lampsilis cardium

Polycyclic musk fragrances are common additives to many consumer products. As a result of their widespread use and slow degradation rates, they are widely found in aquatic environments. This study reports on the lethal and sublethal toxicity of the polycyclic musks AHTN (Tonalide??) and HHCB (Galaxolide??) to glochidial (larval) and juvenile life stages of the freshwater mussel Lampsilis cardium (Rafinesque, 1820). In glochidia, 24-h median lethal concentrations (LC50s) ranged from 454 to 850 ??g AHTN/L and from 1000 to >1750 ??g HHCB/L (water solubility). Results for 48-h tests were similar to the 24-h tests. In 96-h tests with juveniles, we did not observe a dose-response relation between mortality and either musk. However, the growth rate was reduced by musk exposure. The median effective concentrations (EC50s, based on growth) were highly variable and ranged from 108 to 1034 ??g AHTN/L and 153 to 831 ??g HHCB/L. While all adverse effects occurred at concentrations that are much greater than those reported in natural waters (low ??g/L to ng/L), these results indicate the potential for adverse effects on these long-lived organisms from exposure to synthetic musk fragrances. ?? 2006 Springer Science+Business Media, Inc.

Archives of Environmental Contamination and Toxico↗