Note on the diameter of otolith nucleus as a characteristic of the population groups of anchovy, Engraulis encrasicolus (Linnaeus, 1758), of the Cantabrian Sea and Galicia

The diameters of the nuclei of anchovy, Engraulis encrasicolus (Linnaeus, 1758), otoliths collected in 1995 and 1998 in the eastern Cantabrian Sea, the western Cantabrian Sea and Galicia (northwest Spain) have been measured to check possible differences in their length and, if they existed, whether they were characteristic of a different growth rate of the population groups of this species. Significant differences among the three regions were found. Although our results must be considered only preliminary, they seem to indicate that such differences can be characteristics of the population groups described in the regions studied.Se ha medido el diámetro del núcleo de otolitos de anchoa, Engraulis encrasicolus (Linnaeus, 1758), recogidos en el Cantábrico oriental, en el occidental y en Galicia durante 1995 y 1998 para comprobar si existían diferencias en su longitud y, si era así, si estas diferencias eran características de los grupos de población de la especie. Los resultados muestran diferencias significativas entre las tres regiones y, aunque deben considerarse solamente como preliminares, parecen indicar que estas diferencias pueden ser propias de los grupos de población de anchoa descritos en las regiones estudiadas.Instituto Español de Oceanografí

Empirical Analysis of Medium Wave Field Strength Prediction in Urban Environments

[EN] This paper presents results obtained from four extensive field trials of medium wave DRM (Digital Radio Mondiale) which were carried out in Madrid (Spain), Delhi (India) and Mexico D.F. (Mexico) using different transmission frequencies. The objective is to provide medium wave field strength spatial variability values for urban environments using empirical analysis methodology. The influence of the transmission frequency on medium wave propagation in urban environments is included. Both, long and short term components of the signal spatial variability are studied characterizing wide, medium and narrow streets, and the attenuation caused by different urban fast variation occurrences is statistically featured. All the results presented in this paper are essential for future network planning of new emerging digital broadcasting services and have been validated using the Generalized Lee Method

Investigations on anchovy (Engraulis encrasicolus Linnaeus, 1758) by the IEO (Instituto Español de Oceanografía) in the northern and central eastern Atlantic

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Empirical Evaluation of the Impact of Wind Turbines on DVB-T Reception Quality

[EN] This paper describes the results of two extensive measurement campaigns for evaluating the potential impact of scattered signals from wind turbines on terrestrial DTV reception quality in the UHF band. A detailed description of the different propagation channels encountered is provided. Furthermore, empirical threshold carrier-to-noise requirements for Quasi Error Free reception in the DVB-T system in the area of influence of a wind farm are presented, and the situations where a significant degradation can be found are identified and characterized.This work has been partially supported by the UPV/EHU GIC 07/110-IT-374-07, by the Basque Government under both the SAIOTEK program and the program for the training of the researcher staff (BFI08.230), by the Spanish Ministry of Science and Innovation under the project NG-RADIATE, TEC2009-14201, and by the Spanish Ministry of Industry, Tourism and Trade under the project ENGINES, TSI-020400-2010-188. ENGINES project is under the Celtic Initiative (Celtic Label CP7-005)

Local indicators for global species: Pelagic sharks in the tropical northeast Atlantic, Cabo Verde islands region

Pelagic sharks are an important bycatch in pelagic fisheries, especially for drifting longlines targeting swordfish. In the Cabo Verde Archipelago (tropical NE Atlantic), pelagic shark catches can reach a significant proportion of the total catches. Due to the increased concern on the status of pelagic shark species, this study was developed to enhance the current knowledge of those sharks in the Cabo Verde region in comparison to the adjacent areas, especially associated with European Union (EU) pelagic longline fishing activity. Stock status indicators for the two main species, blue shark (Prionace glauca) and shortfin mako (Isurus oxyrinchus), were developed, based on fisheries data from logbooks and onboard scientific observers, including analysis of size frequency distributions and standardized catch-per-unit-of-effort (CPUE) indexes over time. The standardized CPUEs have been stable or increasing for both species in the past 10 years, indicating no signs of local depletion. In terms of sizes, the blue shark catch is composed mainly of adults, which can be a sign of a stable population. On the contrary, the catch of shortfin mako is composed mainly of juveniles, which in conjunction of a decrease of mean size might be a cause of concern, highlighting possible overfishing on the species in the region. Thirty satellite tags, 25 archival miniPATs and 5 SPOT GPS, were deployed in the Cabo Verde Exclusive Economic Zone (EEZ), showing that those species are highly mobile. The biomass and size distributions were modeled with spatial and seasonal models (GAMs) identifying locations where juveniles are predominantly concentrated and that should be prioritized for conservation. This work presents new information on the status of pelagic sharks in the Cabo Verde region in the context of those highly migratory species, and can now be used to promote more sustainable fisheries in the region.FCT IF/00253/2014, SFRH/BD/136074/2018, SFRH/BD/139187/2018, EU/MARE/2012/21: “Scientific advice for fisheries beyond EU waters”, specifically within Specific Contract N° 7: “The provision of advice on the conservation of pelagic sharks associated to fishing activity under EU Sustainable Fisheries Partnership Agreements in the Atlantic Ocean”.info:eu-repo/semantics/publishedVersio

Limiting inter-annual variation in total allowable catch strategies. An application to ICES roundfish stocks

This study evaluated through simulation management strategy that stabilise catch levels by setting bounds on the inter-annual variability in Total Allowable Catches (TACs). An integrated modelling approach was used, which modelled both the ‘real’ and observed systems and the interactions between all system components. The modelling framework therefore allowed evaluation of the robustness of candidate management strategies to both the intrinsic properties of the systems, and the ability to observe, monitor, assess and control them. Strategies were evaluated in terms of level of risk (measured as the probability of spawning stock biomass falling below the biomass limit reference level for the stock) and cumulative yield. The simulation approach used provides a powerful tool for the examination of the performance of candidate management strategies. It has shown that better management is not necessarily going to be achieved by improving the assessement, since even with a perfect assessment (where the simulated working group knew stock status perfectly) stocks may crash at fishing levels that standard stochastic projections would suggest were safe. Also explicitly modelling the assessment process can result in quite different outcomes than those predicted by the simple projection traditionally used by stock assessment working groups. This is because the simple projection assumes that the status of the stock in the current year is known without error and that the target fishing mortality can be achieved without error. However, in practice the assessment is based on last years data and the effect of any management measure on SSB is only manifest, following the implementation of the quota, at the end of the following year. The choice of target and fishing mortality levels and minimum stock levels results from ICES interpretation of the precautionary approach. This lead to the definition of fishing mortality and biomass reference points that are intended to prevent over-fishing and to trigger recovery plans when a stock is overfished respectively. Although, fishing mortality and biomass reference points were originally intended to be independent, a fishing mortality level implies a corresponding biomass level. In the case of saithe a fishing mortality of 0.40 (i.e. the FPA level) would drive the stock to Blim, suggesting that the choice of biomass and target reference points are not consistent for this stock

Limiting inter-annual variation in total allowable catch strategies. An application to ICES roundfish stocks

This study evaluated through simulation management strategy that stabilise catch levels by setting bounds on the inter-annual variability in Total Allowable Catches (TACs). An integrated modelling approach was used, which modelled both the ‘real’ and observed systems and the interactions between all system components. The modelling framework therefore allowed evaluation of the robustness of candidate management strategies to both the intrinsic properties of the systems, and the ability to observe, monitor, assess and control them. Strategies were evaluated in terms of level of risk (measured as the probability of spawning stock biomass falling below the biomass limit reference level for the stock) and cumulative yield. The simulation approach used provides a powerful tool for the examination of the performance of candidate management strategies. It has shown that better management is not necessarily going to be achieved by improving the assessement, since even with a perfect assessment (where the simulated working group knew stock status perfectly) stocks may crash at fishing levels that standard stochastic projections would suggest were safe. Also explicitly modelling the assessment process can result in quite different outcomes than those predicted by the simple projection traditionally used by stock assessment working groups. This is because the simple projection assumes that the status of the stock in the current year is known without error and that the target fishing mortality can be achieved without error. However, in practice the assessment is based on last years data and the effect of any management measure on SSB is only manifest, following the implementation of the quota, at the end of the following year. The choice of target and fishing mortality levels and minimum stock levels results from ICES interpretation of the precautionary approach. This lead to the definition of fishing mortality and biomass reference points that are intended to prevent over-fishing and to trigger recovery plans when a stock is overfished respectively. Although, fishing mortality and biomass reference points were originally intended to be independent, a fishing mortality level implies a corresponding biomass level. In the case of saithe a fishing mortality of 0.40 (i.e. the FPA level) would drive the stock to Blim, suggesting that the choice of biomass and target reference points are not consistent for this stock

Cloud Transmission: System Performance and Application Scenarios

[EN] Cloud Transmission (Cloud Txn) System is a flexible multi-layer system that uses spectrum overlay technology to simultaneously deliver multiple program streams with different characteristics and robustness for different services (mobile TV, HDTV and UHDTV) in one RF channel. The transmitted signal is formed by superimposing a number of independent signals at desired power levels, to form a multilayered signal. The signals of different layers can have different coding, bit rate, and robustness. For the top layer, system parameters are chosen to provide very robust transmission that can be used for high speed mobile broadcasting service to portable devices. The bit rate is traded for more powerful error correction coding and robustness so that the Signal to Noise Ratio (SNR) threshold at the receiver is a negative value in the range of -2 to -3 dB. The top layer is designed to withstand combined noise, co-channel interference and multipath distortion power levels higher than the desired signal power. The lowerlayer signal can be DVB-T2 signal or other newly designed system to deliver HDTV/UHDTV to fixed receivers. The system concept is open to technological advances that might come in the future: all new technologies, BICM/Non Uuniform-QAM, rotated constellations, Time Frequency Slicing or MIMO techniques can be implemented in the Cloud Txn lower (high data) rate layer. The main focus of this paper is to thoroughly describe the performance of this newly presented Cloud Transmission broadcasting system.This work has been financially supported in part by the University of the Basque Country UPV/EHU (UFI 11/30), by the Basque Government (IT-683- 13 and SAIOTEK), by the Spanish Ministry of Science and Innovation under the project NG-RADIATE (TEC2009-14201), and by the Spanish Ministry of Economy and Competitiveness under the project HEDYT-GBB (TEC2012- 33302

Fisheries and Prestige. Review and update of studies on the effects of the Prestige oil spill

The Prestige oil tanker sank in November 2002 and leaked around 60 000 mt. of heavy oil (type M-100) into the sea. Immediately after the accident, closed areas were established. Among the fleets affected by the closures were four of the most important in ICES Division VIIIc and Sub-division IXa North (bottom trawl, pair trawl, purse seine targeting sardine and hand line targeting mackerel) as they exploit considerable resources, some outside biological safety limits. A fall in effort was observed in all of them, mainly in the first quarter and in sub-divisions VIIIc West and IXa North, although it failed to lead to a very large reduction in the total annual effort of each of the fleets, with the exception of hand line. Pair trawlers can make two types of fishing trip, but differences in specific composition among the three years analysed were not found in either of them. In the case of trawl, five kinds of fishing trips were identified, and changes were only found in the type that targets Norway lobster, hake, megrim and monk (HMMN), with a fall in the presence of Norway lobster