Comparative distribution of the fan mussel Atrina fragilis (Bivalvia, Pinnidae) in protected and trawled areas of the north Aegean Sea (Thermaikos Gulf)

The distribution of the fan mussel Atrina fragilis was studied at two contrasting areas of the north Aegean Sea (Thermaikos Gulf): one routinely trawled and one closed to trawlers for over 25 years. Significant differences were detected between the two areas with decreased values in density and size of A. fragilis individuals at the trawled area. As habitat differences, i.e. sediment composition and bathymetry, had non-significant effect, extensive trawling activities probably explain the observed results

Generative Deep Learning Techniques for Traffic Matrix Estimation From Link Load Measurements

Traffic matrices (TMs) contain crucial information for managing networks, optimizing traffic flow, and detecting anomalies. However, directly measuring traffic to construct a TM is resource-intensive and computationally expensive. A more practical approach involves estimating the TM from readily available link load measurements, which falls under the category of inferential network monitoring based on indirect measurements known as network tomography. This paper focuses on solving the problem of estimating the traffic matrix from link loads by utilizing deep generative models. The proposed models are trained using historical data—specifically, previously observed TMs—and are then leveraged to transform traffic matrix estimation (TME) into a simpler minimization problem in a lower-dimensional latent space. This transformed problem can be efficiently solved using a gradient-based optimizer. Our work aims to examine and test different model architectures and optimization approaches. The performance of the proposed methods is comparatively evaluated over a comprehensive set of suitable metrics on two publicly available datasets comprising actual traffic matrices obtained from real backbone networks. In addition, we compare our approach with a state-of-the-art method previously published in the literature

Redescription of the Mediterranean endemic sea-pen Crassophyllum thessalonicae (Octocorallia: Pteroeididae)

Five colonies of the rare pennatulacean Crassophyllum thessalonicae were recently collected from Thermaikos Gulf (north-east Mediterranean), which allowed a study of their biometry; accordingly, new features are added to the original description of the species. Based on these data the morphological characters that distinguish C. thessalonicae from its congeners are reviewed. © 2011 Marine Biological Association of the United Kingdom

Reproductive Biology of the Invasive Blue Crab Callinectes sapidus in the Thermaikos Gulf (Northwest Aegean Sea, Eastern Mediterranean): Identifying Key Information for an Effective Population Management Policy

The reproductive biology of the invasive blue crab Callinectes sapidus was studied in the Thermaikos Gulf (Northwest Aegean Sea, Eastern Mediterranean). In the two-year survey, 5698 (2897♂/2801♀) crabs were caught with the use of fyke nets. Total sex ratio (♂/♀) reached equality (1.03:1). The female blue crab exhibited a protracted reproductive period. Mature and ovigerous females exhibit short migratory movements from estuarine and inshore waters, where the population mostly congregates (0–3 m), and move to slightly deeper waters (1–3 m) up to 9 m for spawning. A total of 340 ovigerous females were caught. Their number varied both spatially and temporally; they were observed for a 7-month period (April to October) with a clear peak in July–August and at a 3 m depth gradient corresponding to ≈60% of the total number of ovigerous females caught in both years. Size at first sexual maturity (CW50) was estimated at 113.1 mm CW. Average fecundity was ≈790,000 eggs. Experimental trawling showed that inshore waters (<1 m) in the estuaries serve as nursery areas for juveniles. Defining the spatiotemporal and bathymetrical distribution of ovigerous females in any invaded coastal habitat could be considered key information for the implementation of a management policy for the species

GNSS Threat Monitoring and Reporting: Past, Present, and a Proposed Future

Vulnerability of satellite-based navigation signals to intentional and unintentional interference calls for a high-level overview of Global Navigation Satellite System (GNSS) threats occurring globally to understand the magnitude and evolution of the problem. Therefore, a mechanism needs to be developed whereby disparate monitoring systems will be capable of contributing to a common entity of basic information about the threat scenarios they experience. This paper begins with a literature survey of 37 state-of-the-art GNSS threat monitoring systems, which have been analysed based on their respective operational features - constellations monitored and whether they possess the capability to perform interference-type classification, spoofing detection, and interference localisation. Also described is a comparative analysis of four GNSS threat reporting formats in use today. Based on these studies, the paper describes the Horizon2020 Standardisation of GNSS Threat Reporting and Receiver Testing through International Knowledge Exchange, Experimentation and Exploitation (STRIKE3) proposed integrated threat monitoring demonstration system and related standardised threat reporting message, to enable a high-level overview of the prevailing international GNSS threat scenarios and its evolution over time.</jats:p