Phenotypic and social effects on behavioural trade-offs in Eurasian perch

Trading between conflicting demands is a fundamental part in how animals interact with its environment and social surrounding. Knowledge of what factors that are affecting behavioural decisions is central in our understanding of animal adaptation and ecology. This thesis summarizes a series of behavioural experiments investigating how animals compromise behaviours depending on environmental background and context. The focus is on within- and between-population variation in risk-taking and social trade-offs in young of the year and one year old Eurasian perch. Perch behaviour was quantified by observational studies in aquaria, using standardized assays that captured perch boldness and sociability. Perch from different predation backgrounds were compared in common garden experiments, as well as in multi-year inter-population comparisons, to study influence of predation experience on risk-taking phenotype. Results demonstrate predation as an important factor underlying how perch balance risk. Variation in risk-taking phenotype could to a large extent be explained by individual differences in experience of predation, rather than by fixed inherited responses caused by divergent selection. Experience of predation had long lasting effects on perch boldness, but perch were also able to quickly adjust phenotype in response to current conditions, indicating temporal flexibility in how experience shape behaviour. Social context influenced behaviour, with fish being bolder in larger group, and showing higher behavioural conformity. Occurrence of consistent individual variation in risk-taking and social behaviour could be established, confirming the existence of a personality dimension in perch behaviour. The thesis concludes that variation in how perch trade-off conflicting behaviours exists at multiple levels, from population to individual. Behavioural plasticity, even in strongly fitness related traits, is evident, although potential behavioural constraints in the form of consistent individuality is also present

Diurnal periodicity of activity in the spawning perch P. fluviatilis L. [Translation from: Kalamies 1972(7) 3, 1972]

Diurnal periodicity of spawning in the perch so far are rather meagre and found to be partly contrary to experiences of perch anglers. Therefore a study was made on the spawning during a 5-day period in the spring of 1971 in the Kuusamo area. Observations were made during the main spawning season, between 4- 9 June 1971. The perch were often measured, weighed and then released back into the water. The differences between spawning and non-spawning perch were studied as well as the time of roe discharge in a 24 hour period. Activity and environmental factors such as light intensity were also taken into consideration

Will solar radiation management enhance global security in a changing climate?

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The security implications of geoengineering:blame,imposed agreement and the security of critical infrastructure

The prospect of solar geoengineering in response to climate change (on the basis of its supposedly significantly lower cost and/or more rapid impact on global temperature than carbon reduction strategies) raises a number of security concerns that have traditionally been understood within a standard Geo-political framing of security. This relates to unrealistic direct application in inter-State warfare or to a securitization of climate change. However, indirect security implications are potentially significant. Current capability, security threats and international law loopholes suggest the military, rather than scientists would undertake geoengineering, and solar radiation management (SRM) in particular. SRM activity would be covered by Critical National Infrastructure policies, and as such would require a significant level of secondary security infrastructure. Concerns about termination effects, the need to impose international policy agreement 4 (given the ability of 'rogue States' to disrupt SRM and existing difficulties in producing global agreement on climate policy), and a world of extreme weather events, where weather is engineered and hence blameworthy rather than natural, suggest these costs would be large. Evidence on how blame is attributed suggest blame for extreme weather events may be directed towards more technologically advanced nations, (such as the USA) even if they are not engaged in geoengineering. From a security perspective SRM is costly, ungovernable, and raises security concerns of a sufficient magnitude to make it a non-viable policy option

Seasonal variation in the diurnal periodicity of activity of the perch, Perca fluviatilis L. [Translation from: Kalamies 1973(3) 3.]

The most common catch of the amateur angler is the perch and it is the diurnal periodicity of activity (& catchability) which is examined in this study based on earlier articles and manuscripts by the authors. Of all environmental factors, variation in light and temperature are the chief reasons in establishing the times of activity periods. Winter, summer and autumn activity was studied. The spawning perch was found to be more active than the non-spawning perch. The time of day in which the fish may be active is dependant on its ability to sense changes in the external environment. Its adaptation to light is the reason for day-activity in the winter, and also accounts for the fact that hardly any activity occurs between sunset and sunrise when this period exceeds 6 hours

More than a Game: Baseball and Southern Textile Communities 1880-1935

While labor unrest itself is no stranger to American history, the strikes across the Piedmont textile industry in 1934 present a curious case. Throughout the conflict, a sizeable portion of the workers remained loyal to their companies and those who protested returned to the factories within a short period, often to the same management and conditions. Historians Daniel Singal and Trent Watts – in attempting to explain the workers’ willingness to return to work – have offered that the textile industry deliberately recreated the South’s traditional master-slave labor relationship. They suggest that mill management’s paternalistic efforts and persistent attempts to maintain a racially and economically homogeneous white workforce bound the workers’ families to the factories for life. There is a large body of evidence to support this position, however, historians have overlooked a crucial element in their analyses – the game of baseball. Each company, in the spirit of welfare capitalism, sponsored an employee baseball team. My research builds on the scholarship of Thomas Perry and G.C. Waldrep, which documents South Carolina’s mill teams, and examines the importance of these ball clubs to Piedmont mill communities during the tense years preceding the textile strikes. In this project, I assess the impact of welfare capitalism, class consciousness, and Southern politics on mill employees and argue that their beloved baseball teams fostered a sense of togetherness which they could not find elsewhere

Securing Greater Social Accountability in Natural Resource Management

The world is experiencing a historic convergence of increasing demand for natural resources from emerging economies, prices at record levels across various commodity groups, a downward trend in resource supply, serious trends of ecological instability, and the rise of inequality between those who develop and profit from such resources and the communities that host them. As the world convenes in 2012 for the Rio+20 Earth Summit and marks 50 years since the passage of the UN Declaration on Permanent Sovereignty over Natural Resources, natural resources are once again changing the geopolitical landscape of countries around the world. Three and a half billion people?half of the global population?live in 56 resource-rich and resource-dependent developing countries, representing less than one third of the 193 members of the UN. (?)Securing Greater Social Accountability in Natural Resource Management

Effects of shear on eggs and larvae of striped bass, morone saxatilis, and white perch, M. americana

Shear stress, generated by water movement, can kill fish eggs and larvae by causing rotation or deformation. Through the use of an experimental apparatus, a series of shear (as dynes/cm2)-mortality equations for fixed time exposures were generated for striped bass and white perch eggs and larvae. Exposure of striped bass eggs to a shear level of 350 dynes/cm2 kills 36% of the eggs in 1 min; 69% in 2 min, and 88% in 4 min; exposure of larvae to 350 dynes/cm2 kills 9.3% in 1 min, 30.0% in 2 min, and 68.1% in 4 min. A shear level of 350 dynes/cm2 kills 38% of the white perch eggs in 1 min, 41% in 2 min, 89% in 5 min, 96% in 10 min, and 98% in 20 min. A shear level of 350 dynes/cm2 applied to white perch larvae destroys 38% of the larvae in 1 min, 52% in 2 min, and 75% in 4 min. Results are experimentally used in conjunction with the determination of shear levels in the Chesapeake and Delaware Canal and ship movement for the estimation of fish egg and larval mortalities in the field