Population Ecology of Invasive Lionfish (Pterois volitans/miles) in the South Atlantic Bight

Invasive species are a top threat to global biodiversity. Lionfish (Pterois volitans/miles) are a marine invasive predator that are now established in the Western Atlantic, Caribbean Sea and Gulf of Mexico. Studies that have documented impacts of lionfish suggest they can reduce fish recruitment and native species biomass by up to 80%. Research on lionfish impacts, biology and ecology is heavily focused in tropical and subtropical systems, with considerably less research effort occurring in the temperate regions of their invaded range, such as the South Atlantic Bight. Lionfish life history estimates are important to modeling lionfish population growth, modeling future dispersal and evaluating the efficacy of different removal strategies. Since lionfish life history will vary with a suite of environmental, biological and ecological factors, estimates of lionfish life history should be collected in all regions of their invaded range. The purpose of this study was to collect baseline information of lionfish biology and ecology in the southern portion of the South Atlantic Bight, an unstudied region for this species. As such, chapter one uses a quantitative approach to determine lionfish life history estimates important to management. Some important results of chapter one are: lionfish are recruiting at one main time throughout the year, growth changes seasonally and the population is relatively young (\u3c 3 years of age). Chapter two takes the first step in determining lionfish impacts in this region by quantifying their diet. The main conclusion of this chapter is that round scad (Decapterus punctatus), sand perch (Diplectrum formosum) and black sea bass (Centropristis striata) are the most important prey items in the lionfish diet. Black sea bass are an important fishery in the South Atlantic Bight, and lionfish could be negatively affecting recruitment. Together, these chapters provide important insight into lionfish ecology in this region and in general

Rising Temperatures, Molting Phenology, and Epizootic Shell Disease in the American Lobster

Phenological mismatchmaladaptive changes in phenology resulting from altered timing of environmental cuesis an increasing concern in many ecological systems, yet its effects on disease are poorly characterized. American lobster (Homarus americanus) is declining at its southern geographic limit. Rising seawater temperatures are associated with seasonal outbreaks of epizootic shell disease (ESD), which peaks in prevalence in the fall. We used a 34-year mark-recapture data set to investigate relationships between temperature, molting phenology, and ESD in Long Island Sound, where temperatures are increasing at 0.4 degrees C per decade. Our analyses support the hypothesis that phenological mismatch is linked to the epidemiology of ESD. Warming spring temperatures are correlated with earlier spring molting. Lobsters lose diseased cuticle by molting, and early molting increases the intermolt period in the summer, when disease prevalence is increasing to a fall peak. In juvenile and adult male lobsters, September ESD prevalence was correlated with early molting, while October ESD prevalence was correlated with summer seawater temperature. This suggests that temperature-induced molting phenology affects the timing of the onset of ESD, but later in the summer this signal is swamped by the stronger signal of summer temperatures, which we hypothesize are associated with an increased rate of new infections. October ESD prevalence was approximate to 80% in years with hot summers and approximate to 30% in years with cooler summers. Yearly survival of diseased lobsters i

Local elites and social control: Building council houses in Stirling between the wars

This article examines the role played by local councillors in constructing new housing in Scotland during the inter-war period. Rather than view local authorities as simply the objective agency of central government's ambitions to construct council houses, we argue that the self-interest and motivations of councillors have to be recognized as significant factors in this process. It is argued also that the concerns of private landlords were neither ignored nor sacrificed in the rush to build new housing. Rather, given that councils remained dominated by local business men, many of whom were private landlords, councillors acted in ways to protect their own material and class interests. In so doing, they consciously, if implicitly, shaped the social geography of twentieth-century Scotland

Explore, Exploit or Listen: Combining Human Feedback and Policy Model to Speed up Deep Reinforcement Learning in 3D Worlds

We describe a method to use discrete human feedback to enhance the performance of deep learning agents in virtual three-dimensional environments by extending deep-reinforcement learning to model the confidence and consistency of human feedback. This enables deep reinforcement learning algorithms to determine the most appropriate time to listen to the human feedback, exploit the current policy model, or explore the agent's environment. Managing the trade-off between these three strategies allows DRL agents to be robust to inconsistent or intermittent human feedback. Through experimentation using a synthetic oracle, we show that our technique improves the training speed and overall performance of deep reinforcement learning in navigating three-dimensional environments using Minecraft. We further show that our technique is robust to highly innacurate human feedback and can also operate when no human feedback is given

Genetic Homogeneity of the Invasive Lionfish Across the Northwestern Atlantic and the Gulf of Mexico Based On Single Nucleotide Polymorphisms

Despite the devastating impact of the lionfish (Pterois volitans) invasion on NW Atlantic ecosystems, little genetic information about the invasion process is available. We applied Genotyping by Sequencing techniques to identify 1,220 single nucleotide polymorphic sites (SNPs) from 162 lionfish samples collected between 2013 and 2015 from two areas chronologically identified as the first and last invaded areas in US waters: the east coast of Florida and the Gulf of Mexico. We used population genomic analyses, including phylogenetic reconstruction, Bayesian clustering, genetic distances, Discriminant Analyses of Principal Components, and coalescence simulations for detection of outlier SNPs, to understand genetic trends relevant to the lionfish’s long-term persistence. We found no significant differences in genetic structure or diversity between the two areas (FST p-values \u3e 0.01, and t-test p-values \u3e 0.05). In fact, our genomic analyses showed genetic homogeneity, with enough gene flow between the east coast of Florida and Gulf of Mexico to erase previous signals of genetic divergence detected between these areas, secondary spreading, and bottlenecks in the Gulf of Mexico. These findings suggest rapid genetic changes over space and time during the invasion, resulting in one panmictic population with no signs of divergence between areas due to local adaptation

Impact of Disease on the Survival of Three Commercially Fished Species

Recent increases in emergent infectious diseases have raised concerns about the sustainability of some marine species. The complexity and expense of studying diseases in marine systems often dictate that conservation and management decisions are made without quantitative data on population-level impacts of disease. Mark-recapture is a powerful, underutilized, tool for calculating impacts of disease on population size and structure, even in the absence of etiological information. We applied logistic regression models to mark-recapture data to obtain estimates of disease-associated mortality rates in three commercially important marine species: snow crab (Chionoecetes opilio) in Newfoundland, Canada, that experience sporadic epizootics of bitter crab disease; striped bass (Morone saxatilis) in the Chesapeake Bay, USA, that experience chronic dermal and visceral mycobacteriosis; and American lobster (Homarus americanus) in the Southern New England stock, that experience chronic epizootic shell disease. All three diseases decreased survival of diseased hosts. Survival of diseased adult male crabs was 1% (0.003-0.022, 95% CI) that of uninfected crabs indicating nearly complete mortality of infected crabs in this life stage. Survival of moderately and severely diseased striped bass (which comprised 15% and 11% of the population, respectively) was 84% (70-100%, 95% CI), and 54% (42-68%, 95% CI) that of healthy striped bass. The disease-adjusted yearly natural mortality rate for striped bass was 0.29, nearly double the previously accepted value, which did not include disease. Survival of moderately and severely diseased lobsters was 30% (15-60%, 95% CI) that of healthy lobsters and survival of mildly diseased lobsters was 45% (27-75%, 95% CI) that of healthy lobsters. High disease mortality in ovigerous females may explain the poor recruitment and rapid declines observed in this population. Stock assessments should account for disease-related mortality when resource management options are evaluated. © 2017 by the Ecological Society of America

Researching the home using architectural and social science methods

This article explores the possibilities of using innovative, interdisciplinary methods for understanding home-making. Drawing on a study of Claremont Court (1959–1962), a post-war social housing scheme designed by Sir Basil Spence in Edinburgh, we discuss the methodological potentials of combining architectural and social science methods to study the home. Claremont Court was built in the post-war era as part of Scotland’s social housing drive. It was designed following the principles of ‘cross-class’ living in order to foster a sense of community. In subsequent years, inhabitants of the court have adapted their dwellings in numerous ways and the population of the court has changed dramatically. But, while meanings of home and understandings of the division between public and private have been reconfigured, the spatial layouts of the dwellings continue to shape residents’ sense of home. To explore how residents make home at Claremont Court, we use ‘facet methodology’, which opens up new ways of thinking about the research process through a ‘playful’ approach to epistemology. In doing so, we develop an innovative approach which combines architectural methods (including survey drawings and visual mappings of both dwellings and communal areas) with social science methods (including ‘traditional’ interviews and walk-along interviews). To conclude, we discuss the possibility of widening the scope of qualitative research by bringing architectural and social science methods into dialogue through visual methods, in order to attend to spatial and material aspects of the home. We argue that our novel cross-disciplinary approach broadens understandings of home, by bringing attention to the unspoken dimensions of physical space, embodied elements of home and what people said about their homes, all of which are central to home-making

Housing theory, housing research and housing policy

Jim Kemeny in 1992 criticised existing housing research for neglecting social theory and being overly positivist and policy focused. The result has been a strengthening of the conceptual basis of housing research in general, but also a growing schism between researchers who focus on policy relevancy and those that pursue more theoretical work. This paper challenges this schism and argues for theoretically based and policy relevant research. First the paper argues that the policy-making process is complex and can vary between different countries, situations and over time. Therefore, it is argued that many styles of research can influence policy in the right circumstances. Second, the paper challenges the idea that there can be theoretically-free housing research arguing that all research has a theoretical foundation even though in many studies it is not explicit. Finally, the paper engages with the debate about where theory for housing research should come from and what it would look like