Description: Parasites with high host specificity maximally depend on their hosts, which should increase the likelihood of coevolution. However, coevolution requires reciprocal selection exerted by the host and the parasite, and thus a considerable level of parasite virulence. In species of the monogenean ectoparasite genus Gyrodactylus consecutive generations are confronted with a single host, which may constrain the evolution of virulence. Transmission, which is often important in the ecology of Gyrodactylus species, may have the opposite effect, but may also lead to the avoidance of coevolutionary arms races. We investigated the potential outcome of coevolution between Gyrodactylus gasterostei Glaser, 1974 and its host, the three-spined stickleback (Gasterosteus aculeatus L.) by determining the strength of genotype by genotype (GxG) interactions on two levels: within and between sympatric and allopatric host populations. To do so, we compared the parasite's infection dynamics on laboratory-reared sympatric (Belgian) and allopatric (German) hosts. We found that a parasite line successfully infected a range of sympatric host genotypes (represented by families), while it failed to establish on allopatric hosts. Phylogeographic studies suggest that neutral genetic divergence between the host populations cannot explain this dramatic difference. Provided that this result can be generalised towards other parasite lines, we conclude that coevolution in this host-parasite system is more likely to lead to local adaptation on the population level than to GxG interactions within populations.

Description: The composition and distribution of squid and fish collected by Rectangular Midwater Trawls in the upper 200 m were investigated during the BROKE-West (Baseline Research on Oceanography, Krill and the Environment-West) survey (January-March 2006) in CCAMLR Subdivision 58.4.2 of the Southern Ocean. A total of 332 individuals were collected, with the most abundant fish species being Pleuragramma antarcticum (34%), Notolepis coatsi (27%) and Electrona antarctica (26%); and the most abundant squid being Galiteuthis glacialis (64%). Abundances of all species were among the lowest recorded using this type of gear. Cluster analysis revealed two distinct communities: a notothenioid-dominated coastal community and an oceanic community dominated by mesopelagic fish and squid. Environmental factors related to this segregation were explored using Redundancy Analysis (RDA). The notothenioid P. antarcticum was associated with shallow areas with high chlorophyll a concentrations. Larval stages of E. antarctica, N. coatsi and G. glacialis were found over deeper water and were positively correlated with higher temperatures and a deeper-reaching mixed layer. Postmetamorphic stages of E. antarctica were caught mostly after sunset and were negatively correlated with solar elevation. The observation of higher densities in the eastern part of the sampling area reflects a temporal rather than a geographical effect. Samples of the three most abundant fishes, E. antarctica, P. antarcticum and N. coatsi, were analysed for gut content. All species fed on a variety of mesozooplankton including copepods, amphipods and euphausiids, which is consistent with previous reports on similar life stages. Mean body energy density was highest for E. antarctica (27 kJ g-1), while it was similar for P. antarcticum and N. coatsi (22 kJ g-1). The high energy content emphasizing the importance as a food resource for top predators in the Southern Ocean.

Description: Entropy, Vol. 20, Pages 4: Fog Computing: Enabling the Management and Orchestration of Smart City Applications in 5G Networks Entropy doi: 10.3390/e20010004 Authors: José Santos Tim Wauters Bruno Volckaert Filip De Turck Fog computing extends the cloud computing paradigm by placing resources close to the edges of the network to deal with the upcoming growth of connected devices. Smart city applications, such as health monitoring and predictive maintenance, will introduce a new set of stringent requirements, such as low latency, since resources can be requested on-demand simultaneously by multiple devices at different locations. It is then necessary to adapt existing network technologies to future needs and design new architectural concepts to help meet these strict requirements. This article proposes a fog computing framework enabling autonomous management and orchestration functionalities in 5G-enabled smart cities. Our approach follows the guidelines of the European Telecommunications Standards Institute (ETSI) NFV MANO architecture extending it with additional software components. The contribution of our work is its fully-integrated fog node management system alongside the foreseen application layer Peer-to-Peer (P2P) fog protocol based on the Open Shortest Path First (OSPF) routing protocol for the exchange of application service provisioning information between fog nodes. Evaluations of an anomaly detection use case based on an air monitoring application are presented. Our results show that the proposed framework achieves a substantial reduction in network bandwidth usage and in latency when compared to centralized cloud solutions.

Description: This report presents a review of the research knowledge and gaps on fish populations, fisheries and linked ecosystems in the Central Arctic Ocean (CAO). The CAO comprises the deep basins of the Arctic Ocean beyond the shelf break, which largely overlap with the High Seas of the Arctic Ocean, i.e. the marine areas outside the Exclusive Economic Zones (EEZs) of the Arctic coastal nations. The authors of the report are members of the European Fisheries Inventory in the Central Arctic Ocean (EFICA) Consortium. This study was funded by the European Commission as an EU contribution to the international cooperation within the Agreement to Prevent Unregulated High Seas Fisheries in the Central Arctic Ocean. The report contains desk-based research, using scientific research data bases as well as any available research performed by the EFICA Consortium partners and EU institutions or others. In Chapters 2-8 the authors review the literature and identify specific knowledge gaps. The gap analyses involve comparisons of actual knowledge with desired knowledge on the fish stocks of the CAO to be able to evaluate possibilities for future sustainable fisheries in the area. Chapter 1 is an introductory chapter, and Chapter 9 presents a holistic gap analysis based on Chapters 2-8 and recommendations for research priorities and the next steps. The critical gap analysis highlights that the knowledge gaps for the CAO are enormous and obstruct any quantitative analyses of its fish stocks. This agrees with the conclusions from the Fifth FiSCAO Report (FiSCAO 2018). While data for the physical environment in the CAO (oceanography, bottom topography and ice-cover dynamics) would be sufficient for fish stock modelling and assessment, there is a massive lack of biological and ecological data. The CAO is not a closed system and some aspects of the shelf seas are of high relevance for the CAO, notably connectivity of fish stocks and fish species moving north with climate warming. Scientific research and monitoring programs are established in the shelf seas, and new data are constantly being produced. Fish stock data are available from scientific projects and monitoring programs for some of the shelf seas (Barents Sea, Bering Sea, and to a lesser extent for the Beaufort Sea and the Chukchi Sea). Data exist also for the Russian shelf seas (Kara Sea, Laptev Sea, East Siberian Sea), but these data are not internationally available, while for the areas north of Canada/Greenland data are missing; they do not exist because of the severe ice conditions there. More data from all shelf seas may be hidden in reports that are not publicly accessible. We recommend to make current knowledge generally available by translating key publications and identification of valuable data reports. Research priorities comprise the collection and analysis of primary data in the CAO, and – to a limited extent – from adjacent waters through collaborations with other Signatories of the Agreement (e.g. on population genetics). Further research priorities include an evaluation of ecosystem vulnerability, social-ecological analyses, i.e. recognizing the close and often complex interactions between humans and nature, and recommendations for governance of the CAO. Fulfilling the 14 specific research priorities mentioned in Chapter 9 to “sufficient knowledge available” could enable the potential, future application of an Ecosystem Approach to Management for the CAO.

Description: The composition and distribution of squid and fish collected by Rectangular Midwater Trawls in the upper 200 m were investigated during the BROKE-West (Baseline Research on Oceanography, Krill and the Environment-West) survey (January-March 2006) in CCAMLR Subdivision 58.4.2 of the Southern Ocean. A total of 332 individuals were collected, with the most abundant fish species being Pleuragramma antarcticum (34%), Notolepis coatsi (27%) and Electrona antarctica (26%); and the most abundant squid being Galiteuthis glacialis (64%). Abundances of all species were among the lowest recorded using this type of gear. Cluster analysis revealed two distinct communities: a notothenioid-dominated coastal community and an oceanic community dominated by mesopelagic fish and squid. Environmental factors related to this segregation were explored using Redundancy Analysis (RDA). The notothenioid P. antarcticum was associated with shallow areas with high chlorophyll a concentrations. Larval stages of E. antarctica, N. coatsi and G. glacialis were found over deeper water and were positively correlated with higher temperatures and a deeper-reaching mixed layer. Postmetamorphic stages of E. antarctica were caught mostly after sunset and were negatively correlated with solar elevation. The observation of higher densities in the eastern part of the sampling area reflects a temporal rather than a geographical effect. Samples of the three most abundant fishes, E. antarctica, P. antarcticum and N. coatsi, were analysed for gut content. All species fed on a variety of mesozooplankton including copepods, amphipods and euphausiids, which is consistent with previous reports on similar life stages. Mean body energy density was highest for E. antarctica (27 kJ g-1), while it was similar for P. antarcticum and N. coatsi (22 kJ g-1). The high energy content emphasizing the importance as a food resource for top predators in the Southern Ocean.

Description: For a better understanding of the role of mesopelagic fish in the Southern Ocean food web, the energy and water content of Bathylagus antarcticus, Electrona antarctica and Gymnoscopelus braueri from the Lazarev Sea were investigated. Mean dry weight energy content of B. antarcticus (20.4 kJ g-1) was significantly lower than in E. antarctica and G. braueri (both 29.4 kJ g-1). In E. antarctica, an increase of dry weight energy density with age was evident from 26.9 kJ g-1 in juveniles of less than 1 year of age to 32.0 kJ g-1 in 3-year-old fish. Water content decreased with size in all three species. Abundant high-energy species such as E. antarctica are at a key position in the food web. Due to a marked influence of age on energy content, population structure can be an important variable in estimates of energy fluxes in the Southern Ocean ecosystem.