220 research outputs found

    Presencia de Medregal negro Seriola rivoliana Valenciennes, 1833 y Barracuda Sphyraena sphyraena (Linnaeus, 1758) (Perciformes) en la costa de Galicia

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    En los últimos años, un mayor esfuerzo científico y un contacto más estrecho con el sector pesquero han permitido incrementar en gran medida el número de especies nuevas en aguas de Galicia, muchas de ellas de carácter tropical o subtropical relacionadas probablemente con efectos ligados al cambio climático (Bañón et al., 1997, 2002). En este trabajo se cita por primera vez, en Galicia, la presencia del Medregal negro Seriola rivoliana Valenciennes, 1833 (Carangidae) y se aporta una nueva cita de Barracuda Sphyraena sphyraena (Linnaeus, 1758) (Sphyraenidae)

    First record of Caprella mutica from the Iberian Peninsula: expansion southwards in European waters

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    The caprellid amphipod, Caprella mutica, is a well-known invasive species, originating in the Sea of Japan, which has been rapidly expanding along the coasts of North America, Europe and Oceania for the last forty years. Caprella mutica is frequently associated with man-made structures, especially those dedicated to aquaculture activities, where it can reach high densities of up to 300,000 ind./m2. A well-established population of C. mutica was recently found by SCUBA-divers in Galician waters (north-west Spain) at 6 different man-made floating structures along Ría de Arousa. The record of this species in this location implies a new southernmost limit of distribution, extending the known distribution range in Atlantic European waters and confirming the continuity of the colonization southwards

    Range extension of the Atlantic herring Clupea harengus (Clupeiformes: Clupeidae) southern part of the Northeast Atlantic Ocean

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    The atlantic herring Clupea harengus linnaeus, 1758 is a pelagic clupeid, schooling, plankton-feeding species that inhabits the coastal areas from inshore to well offshore waters, at depths to 200 m (Whitehead, 1986). This target species has been crucial for food security and economic development in northern europe (Martinez-Barrio et al., 2016). Its fishery currently ranks among the five largest fisheries in the world, with nearly 2 million tons of fish landed annually in the last years (Fao, 2010-2019). This species is distributed on both sides of the north atlantic ocean. In the western atlantic, it ranges from labrador to cape Hatteras; in the eastern atlantic, from the northern part of the Bay of Biscay to Greenland, and to the east into the Barents sea (Whitehead, 1985, 1986). In the northeastern atlantic, a large number of intraspecific groups (races, stocks, and populations) are distinguished by their spawning grounds and seasons, otolith morphology and meristic characters (Berg et al., 2017).En prensa0,40

    Micromorphology of egg and larva of Eristalis fratercula, with an updated key of Eristalis species with known third instar larvae (Diptera: Syrphidae)

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    The flower- or hoverflies (Syrphidae) and particularly the subfamily Eristalinae, are known by their importance as pollinators in both natural and agro-ecosystems. Similar to other saprophagous eristalines, the larvae of Eristalis Latreille, 1804 are characterized by an elongated anal segment and a telescopic breathing tube. These features have given them the common name of rat-tailed maggots and allow them to develop in liquid or semi-liquid media loaded with decaying organic material. This paper presents the first description of the egg and the third-instar larva of the boreal species Eristalis fratercula (Zetterstedt, 1838). Morphological studies are presented based on cryo-scanning electron microscopy (cryo-SEM). After comparison with all other known species of the genus Eristalis with described preimaginal morphology, we conclude that main diagnostic character of E. fratercula is the presence of long branched spicules located in the upper margin on the lateral lips. Finally, we provide an updated key that includes the 15 Eristalis species whose third larval stages have already been described

    Instabilities and turbulence in stellarators from the perspective of global codes

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    In this work, a comparison of the global gyrokinetic codes EUTERPE and GENE-3D in stellarator configurations of LHD and W7-X is carried out. In linear simulations with adiabatic electrons, excellent agreement is found in the mode numbers, growth rate and frequency, mode structure, and spatial localization of the most unstable mode in LHD. In W7-X, the dependence of the growth rate and frequency with the mode number is well reproduced by both codes. The codes are also compared in linear simulations with kinetic ions and electrons in W7-X using model profiles, and reasonable agreement is found in the wavenumber of the most unstable modes. A stabilization of small-scale modes in kinetic-electron simulations with respect to the adiabatic-electron case is consistently found in both codes. Nonlinear simulations using adiabatic electrons and model profiles are also studied and the heat fluxes are compared. Very good agreement is found in the turbulent ion heat fluxes in both LHD and W7-X. Two problems that cannot be properly accounted for in local flux tube codes are studied: the localization of instabilities and turbulence over the flux surface and the influence of a background long-wavelength electric field. Good agreement between codes is found with respect to the spatial localization of instabilities and turbulence over the flux surface. The localization of saturated turbulence is found in both codes to be much smaller than that of the linear instabilities and smaller than previously reported in full-surface radially-local simulations. The influence of the electric field on the localization is also found to be smaller in the developed turbulent state than in the linear phase, and smaller than in previous works. A stabilizing effect of a constant electric field on the linearly unstable modes is found in both codes. A moderate reduction of turbulent transport by the radial electric field..

    Geographic Range Expansion and Taxonomic Notes of the Shortfin Neoscopelid Neoscopelus cf. microchir (Myctophiformes: Neoscopelidae) in the North-Eastern Atlantic

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    One specimen of the shortfin neoscopelid Neoscopelus microchir Matsubara, 1943, has been recorded for the first time on the Porcupine Bank, southwestern Ireland, providing a new northern limit of distribution for the eastern Atlantic. Morphometric and meristic parameters confirm the taxonomic identification. However, DNA barcoding shows deficiencies in current taxonomy and the potential occurrence of cryptic species. On this basis, the specimen is cautiously reported as Neosopelus cf. microchir pending a taxonomic revision of the genus.Versión del edito

    Results from Bottom Trawl Survey on Flemish Cap of June-July 2017

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    A stratified random bottom trawl survey on Flemish Cap was carried out from June 16th to July 15th 2017. The area surveyed was extended up to depths of 800 fathoms (1460 meters) following the same procedures as in previous years and 181 fishing stations planned. The survey was carried out by the R/V Vizconde de Eza with the usual survey gear (Lofoten). A total of 181 valid hauls were made by the vessel R/V Vizconde de Eza, 120 up to 730 meters depth and 61 up to 1460 meters. Survey results including abundance indices of the main commercial species and age distributions for American plaice, Greenland halibut, roughhead grenadier and shrimp are presented. Cod and redfish age distributions are not available for 2017 due to administrative problems. The general indexes for this year are estimated taken into account the traditional swept area (strata 1-19, up to depths of 730 m.) and the total area surveyed (strata 1-34, up to depths of 1460 m.).Versión del editor

    Exploring Deep-Sea Biodiversity in the Porcupine Bank (NE Atlantic) through Fish Integrative Taxonomy

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    This study combined morphological and molecular approaches to the species assignment of several rare or poorly known deep-water fishes caught between 549 and 1371 m depth during a Spanish bottom trawl survey in the Porcupine Bank, west of Ireland. The following fish species were identified: Nessorhamphus ingolfianus (Schmidt, 1912), Borostomias antarcticus (Lönnberg 1905), Scopelosaurus lepidus (Krefft and Maul 1955), Bathypterois dubius Vaillant, 1888, Evermannella balbo (Risso, 1820), Antimora rostrata (Günther, 1878), Melanonus zugmayeri Norman, 1930, Lyconus brachycolus Holt and Byrne, 1906; Paraliparis hystrix Merrett, 1983, Neocyttus helgae (Holt and Byrne, 1908); Platyberyx opalescens Zugmayer, 1911; Howella atlantica Post and Quéro, 1991, Lycodes terraenovae Collett, 1896 and Pseudoscopelus altipinnis Parr, 1933. The presence of L. brachycolus, P. opalescens and P. altipinnis is reported for the first time in the Bank. The DNA barcoding results were largely consistent with morphological identification in 10 species but four did not fit the current taxonomy, indicating cases of potential cryptic speciation, misidentification, synonymy or recent diversification. Among them, the results strongly suggest that P. garmani and P. hystrix are conspecific, making P. hystrix a junior synonym of P. garmani.Versión del edito
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