The toxicity of diquat, endothall, and fluridone to the early life stages of fish

ABSTRACT While most aquatic herbicides have undergone some toxicity testing for effects on non-target aquatic organisms, little of this testing has been conducted on early life stages of gamefish found in lakes undergoing treatment. Commercial formulations of diquat, endothall, and fluridone were selected for acute toxicity testing using very early life stages of walleye (Stizostedion vitreum), largemouth bass (Micropterus salmoides), and smallmouth bass (Micropterus dolomieu). In addition, the rates of diquat photodegradation and uptake by sediment were determined. These results were used to predict diquat concentrations in lakes of various depths. The results of the toxicity tests were compared to the predicted concentrations. Diquat, with 96-h LC50s of 0.74-4.9 mg/L, was more toxic to these early life stages than endothall or fluridone, with 96-h LC50s of 16-130 mg/L and 1.8-13 mg/L respectively. The LC50s for endothall and fluridone were at least one order of magnitude greater than the labeled application concentrations. As the LC50s for diquat were very close to the predicted concentration, the safety margin for the use of diquat appears to be very small

Identification of genetic variants associated with Huntington's disease progression: a genome-wide association study

Background Huntington's disease is caused by a CAG repeat expansion in the huntingtin gene, HTT. Age at onset has been used as a quantitative phenotype in genetic analysis looking for Huntington's disease modifiers, but is hard to define and not always available. Therefore, we aimed to generate a novel measure of disease progression and to identify genetic markers associated with this progression measure. Methods We generated a progression score on the basis of principal component analysis of prospectively acquired longitudinal changes in motor, cognitive, and imaging measures in the 218 indivduals in the TRACK-HD cohort of Huntington's disease gene mutation carriers (data collected 2008–11). We generated a parallel progression score using data from 1773 previously genotyped participants from the European Huntington's Disease Network REGISTRY study of Huntington's disease mutation carriers (data collected 2003–13). We did a genome-wide association analyses in terms of progression for 216 TRACK-HD participants and 1773 REGISTRY participants, then a meta-analysis of these results was undertaken. Findings Longitudinal motor, cognitive, and imaging scores were correlated with each other in TRACK-HD participants, justifying use of a single, cross-domain measure of disease progression in both studies. The TRACK-HD and REGISTRY progression measures were correlated with each other (r=0·674), and with age at onset (TRACK-HD, r=0·315; REGISTRY, r=0·234). The meta-analysis of progression in TRACK-HD and REGISTRY gave a genome-wide significant signal (p=1·12 × 10−10) on chromosome 5 spanning three genes: MSH3, DHFR, and MTRNR2L2. The genes in this locus were associated with progression in TRACK-HD (MSH3 p=2·94 × 10−8 DHFR p=8·37 × 10−7 MTRNR2L2 p=2·15 × 10−9) and to a lesser extent in REGISTRY (MSH3 p=9·36 × 10−4 DHFR p=8·45 × 10−4 MTRNR2L2 p=1·20 × 10−3). The lead single nucleotide polymorphism (SNP) in TRACK-HD (rs557874766) was genome-wide significant in the meta-analysis (p=1·58 × 10−8), and encodes an aminoacid change (Pro67Ala) in MSH3. In TRACK-HD, each copy of the minor allele at this SNP was associated with a 0·4 units per year (95% CI 0·16–0·66) reduction in the rate of change of the Unified Huntington's Disease Rating Scale (UHDRS) Total Motor Score, and a reduction of 0·12 units per year (95% CI 0·06–0·18) in the rate of change of UHDRS Total Functional Capacity score. These associations remained significant after adjusting for age of onset. Interpretation The multidomain progression measure in TRACK-HD was associated with a functional variant that was genome-wide significant in our meta-analysis. The association in only 216 participants implies that the progression measure is a sensitive reflection of disease burden, that the effect size at this locus is large, or both. Knockout of Msh3 reduces somatic expansion in Huntington's disease mouse models, suggesting this mechanism as an area for future therapeutic investigation

Early mortality and freshwater forage fish recruitment: nonnative alewife and native rainbow smelt interactions in Lake Champlain

We studied the consequences of a nonnative species introduction and changes in temperature on early mortality and recruitment of native rainbow smelt (Osmerus mordax) and nonnative alewife (Alosa pseudoharengus) in Lake Champlain using a simulation model. Distribution patterns of adults and young-of-year (YOY) fish were predicted using a model based on observed distribution of different age groups as a function of temperature and light profiles simulated on a daily basis. Mortality rates averaged over the growing season were calculated as a function of fish densities and overlap between adults and YOY. Survival of YOY rainbow smelt and alewife depended on which predator was most abundant. Rainbow smelt YOY mortality rates are highest when rainbow smelt adults are abundant and alewife YOY mortality rates are highest when alewife adults are abundant, potentially allowing coexistence. August and September mortality rates were higher in the climate change scenario because of increased overlap of adults and YOY of both species. These results indicate that accounting for spatiotemporal fish distribution patterns can be important when forecasting the interacting effects of climate change and aquatic invasive species on fish recruitment.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Risk Analysis and Bioeconomics of Invasive Species to Inform Policy and Management

Risk analysis of species invasions links biology and economics, is increasingly mandated by international and national policies, and enables improved management of invasive species. Biological invasions proceed through a series of transition probabilities (i.e., introduction, establishment, spread, and impact), and each of these presents opportunities for management. Recent research advances have improved estimates of probability and associated uncertainty. Improvements have come from species-specific trait-based risk assessments (of estimates of introduction, establishment, spread, and impact probabilities, especially from pathways of commerce in living organisms), spatially explicit dispersal models (introduction and spread, especially from transportation pathways), and species distribution models (establishment, spread, and impact). Results of these forecasting models combined with improved and cheaper surveillance technologies and practices [e.g., environmental DNA (eDNA), drones, citizen science] enable more efficient management by focusing surveillance, prevention, eradication, and control efforts on the highest-risk species and locations. Bioeconomic models account for the interacting dynamics within and between ecological and economic systems, and allow decision makers to better understand the financial consequences of alternative management strategies. In general, recent research advances demonstrate that prevention is the policy with the greatest long-term net benefit

Goals, challenges, and next steps in transdisciplinary fisheries research : perspectives and experiences from early-career researchers

Fisheries are highly complex social-ecological systems that often face 'wicked' problems from unsustainable resource management to climate change. Addressing these challenges requires transdisciplinary approaches that integrate perspectives across scientific disciplines and knowledge systems. Despite widespread calls for transdisciplinary fisheries research (TFR), there are still limitations in personal and institutional capacity to conduct and support this work to the highest potential. The viewpoints of early career researchers (ECRs) in this field can illuminate challenges and promote systemic change within fisheries research. This paper presents the perspectives of ECRs from across the globe, gathered through a virtual workshop held during the 2021 World Fisheries Congress, on goals, challenges, and future potential for TFR. Big picture goals for TFR were guided by principles of co-production and included (i) integrating transdisciplinary thinking at all stages of the research process, (ii) ensuring that research is inclusive and equitable, (iii) co-creating knowledge that is credible, relevant, actionable, and impactful, and (iv) consistently communicating with partners. Institutional inertia, lack of recognition of the extra time and labour required for TFR, and lack of skill development opportunities were identified as three key barriers in conducting TFR. Several critical actions were identified to help ECRs, established researchers, and institutions reach these goals. We encourage ECRs to form peer-mentorship networks to guide each other along the way. We suggest that established researchers ensure consistent mentorship while also giving space to ECR voices. Actions for institutions include retooling education programs, developing and implementing new metrics of impact, and critically examining individualism and privilege in academia. We suggest that the opportunities and actions identified here, if widely embraced now, can enable research that addresses complex challenges facing fishery systems contributing to a healthier future for fish and humans alike

Survival-Enhancing Learning in the Manhattan Hotel Industry, 1898--1980

In this study, we examine how experience at the level of the organization, the population, and the related group affects the failure of Manhattan hotels. We find organizational experience has a U-shaped effect on failure; that organizations enjoy reduced failure as a function of population experience before their founding, but not after; and that related organizations provide experience that lowers failure, but it matters whether their experience is local or non-local, and if it was acquired before or after the relationship was established. These results indicate both the difficulty of applying different types of experience to reduce the risk of organizational failure, and the relevance of experience for the evolution of organizational populations.Organizational Learning, Interorganizational Learning, Organizational Failure, Organizational Ecology, Hotel Industry, Manhattan

The COnvective Precipitation Experiment (COPE): investigating the origins of heavy precipitation in the southwestern UK

A recent field campaign in southwest England used numerical modeling integrated with aircraft and radar observations to investigate the dynamic and microphysical interactions that can result in heavy convective precipitation. The COnvective Precipitation Experiment (COPE) was a joint UK-US field campaign held during the summer of 2013 in the southwest peninsula of England, designed to study convective clouds that produce heavy rain leading to flash floods. The clouds form along convergence lines that develop regularly due to the topography. Major flash floods have occurred in the past, most famously at Boscastle in 2004. It has been suggested that much of the rain was produced by warm rain processes, similar to some flash floods that have occurred in the US. The overarching goal of COPE is to improve quantitative convective precipitation forecasting by understanding the interactions of the cloud microphysics and dynamics and thereby to improve NWP model skill for forecasts of flash floods. Two research aircraft, the University of Wyoming King Air and the UK BAe 146, obtained detailed in situ and remote sensing measurements in, around, and below storms on several days. A new fast-scanning X-band dual-polarization Doppler radar made 360-deg volume scans over 10 elevation angles approximately every 5 minutes, and was augmented by two UK Met Office C-band radars and the Chilbolton S-band radar. Detailed aerosol measurements were made on the aircraft and on the ground. This paper: (i) provides an overview of the COPE field campaign and the resulting dataset; (ii) presents examples of heavy convective rainfall in clouds containing ice and also in relatively shallow clouds through the warm rain process alone; and (iii) explains how COPE data will be used to improve high-resolution NWP models for operational use