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We present on shell-scheme for the 2PI formalism with a particular focus on the renormalized equations of motion. We first revisit the so-called Hartree approximation where we give the counterterms for both the broken and unbroken phases. Moreover, we give explicit formulas for the renormalized three- and four-point functions in the broken phase. We then turn to the sunset approximation, with only scalars and then including fermions. We give explicit formulas for the wave function and mass counterterms. Moreover, we show that, in particular, the two-point functions can be obtained numerically in a fast converging scheme even for large couplings of order one. [ABSTRACT FROM AUTHOR]

Background. The Gotland Basin spawning ground is one of three main spawning areas of Baltic cod, Gadus morhua Linnaeus, 1758. The threshold water parameters for cod development are the salinity exceeding 11‰ and the oxygen level above 2 mL· L–1. Such conditions are only present when the 11‰ isohaline is above the 2 mL· L–1 isooxygen. In such situation the water volume between the isolines is called the “suitable reproduction volume”. When the position of the isolines is reversed, the salinity and the oxygen level of the water layer demarcated by them are below the required thresholds and as such the water is unsuitable for the cod development. We refer to it as the “unsuitable reproduction volume”. The main aim of the presently reported study was to examine whether variations in suitable and unsuitable reproduction habitat estimates could explain the fluctuations in cod recruitment. Materials and methods. The suitable and unsuitable reproduction volumes in the Gotland Basin were estimated based on single point observations at three oceanographic monitoring stations using the contouring software Balthypsograph. To test the spatial hydrological heterogeneity in the Gotland Basin we used 15 observations during 1969–1995 on four stations in each of two transects. The oceanographic monitoring and demersal trawl research survey data from 1974–2012 have been used in analyses. Results. The sufficient reproduction conditions in the southern Gotland Basin persisted only until 1981. In later decades the reproduction potential of the Gotland Basin has decreased. The latest major North Sea water inflows in 1993 and 2003 in the Central Gotland Basin formed the suitable reproduction volume below the layers where cod eggs are floating. A significant relation between the recruit abundance and suitable and the unsuitable reproduction volumes was found only for the Southern Gotland Basin (P < 0.03). Conclusion. We demonstrated that single-point estimates sufficiently quantify the reproduction conditions in the Gotland Basin and thus can be used for estimation of the reproduction volumes. The unsuitable reproduction volume concept can be used as an ecological indicator for egg survival probability in the Gotland Basin. However, it is too premature to re-define the concept of the suitable reproduction volume because it is applicable only to the Gotland spawning ground.

Abstract: The use of archival tags on fish gives information of individual behaviour with an unprecedented high resolution in time. A central problem in the analysis of data from retrieved [...]

Abstract: Recruitment patterns of Baltic Sea sprat (Sprattus sprattus) were correlated to time series of (i) month- and depth-specific temperature conditions and (ii) larval drift patterns inferred from long-term Lagrangian [...]

Background: Hepatitis C virus (HCV) infection is a significant problem in the management of haemodialysis patients. A high prevalence of HCV infection in haemodialysis patients has been reported. Risk factors [...]

Abstract The period of larval drift into a suitable nursery area is considered to be of great significance for recruitment variability in flatfish. Here, a hydrodynamic model coupled with a Lagrangian particle tracking technique was utilized to study the drift from the first feeding larval stage until time of settlement of Central and Eastern Baltic flounder (Platichthys flesus), originating from spawning in the Baltic Sea deep basins, the Arkona- and Bornholm basin (central Baltic Sea), and the Gdansk deep and Gotland basin (eastern Baltic Sea). We examined the spatio-temporal dynamics of the probability to settle in preferred nursery habitat by detailed drift model simulations. The study suggests that the majority of larvae (89% and 74% for Central- and Eastern Baltic flounder, respectively) drift towards coastal areas and settle at metamorphosis ≤20 km from a sandy habitat enabling further migration to a preferred nursery area, i.e. larval drift seems not to be a major bottleneck in recruitment of flounder spawning in the Baltic Sea deep basins. The drift model results suggest that Central Baltic flounder utilize nursery areas mainly in the central and western Baltic, and in the Kattegat, whereas Eastern Baltic flounder mainly utilize the coast in the central and eastern Baltic. Thus, the two stock components seem to use different nursery areas following settlement. Further, in accordance with the "nursery size hypothesis", the model demonstrates that larvae from the Bornholm basin, utilizing areas with extensive distribution of preferred nursery habitat, display the highest relative successful transport to nursery grounds until settling (72% of successfully settled larvae), suggesting that spawning in the Bornholm Basin is of great importance for stock recruitment of deep basin spawning Baltic flounder. Highlights • Predominance of high connectivity between the eastern Baltic flounder nursery grounds for the juvenile stage • Two flounder stock components as separate subpopulations utilize different settlement areas • Traditional sampling methodology unable to resolve spatial juvenile distribution patterns without considering flow dynamics • Spatio-temporal variability of juvenile flounder habitat and density of settled juveniles • Additional habitat indicator: habitat availability for successful juvenile settlement of Baltic flounder [ABSTRACT FROM AUTHOR]

The Baltic Sea is one of the largest brackish water bodies in the world with salinity levels ranging from fresh water conditions in the northeast to full strength saline waters at its transition zone to the North Sea in the west. Most of the water exchange happens in the SW Baltic Sea, the Belt Sea and The Sound where less saline water exits the Baltic Sea at the surface, while higher saline water is entering the Baltic at depth. Thus, the species composition in the Baltic Sea is heavily influenced by the strong salinity gradient, and here several species occur at their limit of their physiological tolerance and preference. In this study, we focused on sightings of the ocean sunfish Mola mola recorded in the western Baltic Sea between 1978 and 2020. This species is regarded as vagrant in the Baltic Sea, i.e., it does not belong to the common species assemblage in this area. Hydrographic conditions, such as water temperature and salinity, were obtained from a highly spatio-temporally resolved hydrodynamic Baltic Sea model, covering a daily resolved 71-year time series. We investigated if the occurrence of M. mola correlates with the dynamics of water mass exchange between the Kattegat/Skagerrak and the SW Baltic Sea. Our analyses show that these occurrences could be related to the presence of anomalously high saline water masses. However, in autumn and winter water temperatures of the western Baltic Sea usually drop below 8 °C with further cooling in January and February to 4–5 °C and during strong winters even down to <2 °C. If M. mola will follow the same strategy as in the North Sea, i.e. migrating southward to avoid lethal temperatures, they will not be successful by entering the Baltic Sea, because during winter months temperature everywhere falls far below their thermal tolerance. As a consequence, southward transport or active migration of M. mola into the Baltic Sea will expose the respective specimens to adverse environmental conditions finally precluding survival. • Linking sightings of Mola mola to physical processes • Novel approach for classification of environmental conditions • Occurrence of Mola mola linked to inflows conditions • Main occurrence of warm water species Mola mola during autumn and winter [ABSTRACT FROM AUTHOR]

Connectivity of pelagic, early life stages via transport by ocean currents may affect survival chances of offspring, recruitment success, and mixing of stocks across management units. Based on drift model studies, transport patterns of particles representing exogenously feeding cod larvae in the transition area between North Sea and Baltic were investigated to (i) determine long-term trends and variability in advective transport of larvae from spawning grounds to juvenile nursery areas, (ii) estimate the degree of exchange between different management areas, and (iii) compare the results with spatial distributions of juvenile cod. The transport of particles showed considerable intra- and interannual variability, but also some general patterns of retention within and dispersion to different management areas. Good spatial overlap of particle end positions, representing potential juvenile settlement areas, with observed distributions of juveniles in bottom trawl surveys suggests that the drift simulations provide reasonable estimates of early life stage connectivity between cod populations in the investigated areas. High exchange rates of particles between management areas of up to ca. 70% suggest that cod populations in the investigated areas are demographically correlated. Results are discussed in relation to their relevance for stock structure, fish stock assessment, and management. [ABSTRACT FROM AUTHOR]

Annual growth zones in cod otoliths from the eastern Baltic stock are less discrete than in other cod stocks leading to biased age reading, which recently led to a failure of age-based assessment in the eastern Baltic cod stock. In this study, we explored the applicability of minor and trace element patterns in cod otoliths for age determination. By first identifying elements of interest in a stock without ageing problems, western Baltic cod, we then tested their applicability on another stock without ageing problems, North Sea cod, and finally applied this knowledge to estimate age of eastern Baltic cod. In western Baltic cod, matching patterns with respect to occurrence of minima and maxima in both otolith opacity and element concentrations were found for Cu, Zn, and Rb, and inverse patterns with Mg and Mn. No match was found for Pb, Ba, and Sr. In the test stock, the North Sea cod, the same patterns in Cu, Zn, Rb, Mg, and Mn signals occurred. All eastern Baltic cod with low visual contrast between growth zones exhibited clearly defined synchronous cycles in Cu, Zn, Rb and Pb. Using a combined finite differencing method and structural break models approach, the statistical significance of the local profile minima were identified, based on which their age could be estimated. Despite extensive environmental differences between the three areas examined, the element concentrations of Cu, Zn, and Rb were strongly correlated in all individuals with similar correlations in all three areas, suggesting that the incorporation mechanisms are the same for these elements and independent of environmental concentrations. [ABSTRACT FROM AUTHOR]