25 research outputs found

    Patrón de abundancia espacio-temporal de la gamba de altura, Parapenaeus longirostris, y de la cigala, Nephrops norvegicus, en las aguas mediterráneas europeas

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    The main characteristics concerning the distribution of two of the most important decapod crustaceans of commercial interest in the Mediterranean Sea, the deep-water rose shrimp, Parapenaeus longirostris, and the Norway lobster, Nephrops norvegicus, are studied in the European Mediterranean waters. The study is based on data collected under the MEDITS trawl surveys from 1994 to 2015 from the Gibraltar Straits to the northeastern Levantine Basin (Cyprus waters). The observed differences can be interpreted as different responses to environmental drivers related to the differing life history traits of the two species. In fact, N. norvegicus is a long-living, benthic burrowing species with low growth and mortality rates, while P. longirostris is an epibenthic, short-living species characterized by higher rates of growth and mortality.Se investigaron las características de la distribución de dos de los crustáceos decápodos más importantes a nivel comercial del mar Mediterráneo, la gamba de altura, Parapenaeus longirostris y la cigala, Nephrops norvegicus, en aguas mediterráneas europeas. El presente estudio se basa en datos recopilados en las campañas de pesca experimental de arrastre MEDITS, relizadas de 1994 a 2015 desde el estrecho de Gibraltar hasta la cuenca levantina nororiental (aguas de Chipre). Las diferencias observadas en el patrón de distribución se pueden interpretar como distintas respuestas a factores ambientales relacionados con los diferentes rasgos del ciclo vital de las dos especies. De hecho, N. norvegicus es una especie bentónica de vida larga, con bajas tasas de crecimiento y mortalidad, mientras que P. longirostris es una especie epibentónica de vida corta, caracterizada por tasas más altas de crecimiento y de mortalidad

    Estabilidad de las relaciones entre las agrupaciones de peces demersales y los factores ambientales-actividad pesquera a gran escala espacio-temporal en el norte del mar Mediterráneo

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    Trawling pressure and environmental changes may affect the composition of fish assemblages. Our knowledge on large spatio-temporal patterns of demersal fish composition remains incomplete for the Mediterranean Sea. We investigated (1) the spatio-temporal stability of demersal assemblages, (2) the relationships between these assemblages and potential structuring factors (trawling pressure and environmental conditions) in order to assess the dynamic of the assemblage structure at the scale of the northern Mediterranean Sea. We analysed a dataset of 18062 hauls from 10 to 800 m depth performed annually during the last two decades across 17 Geographical Sub-Areas (GSAs) (MEDITS program). A multi-table analysis (STATICO-CoA) evidenced a strong inter-GSAs stability in the organization of assemblages, with specificities for some GSAs. The most stable structuring factors were linked to combined gradients of chlorophyll a, phytoplancton carbon biomass and temperature, inversely correlated with depth, salinity and nutrient gradients (axis 1 of the STATICO-CoA compromise, 93.74% of the total variability). A common pattern linking the distribution of species to these environmental gradients was evidenced for most of the 17 GSAs. Estimate of trawling pressure showed a minor role in the organization of the assemblages for the spatial scale and years investigated (axis 2, 4.67%).La presión pesquera y los cambios ambientales pueden afectar a la composición de las agrupaciones de peces. En el Mediterráneo, nuestro conocimiento a gran escala sobre los patrones espacio-temporales de la composición de especies de peces demersales sigue siendo incompleto. Investigamos (1) la estabilidad espacio-temporal de las agrupaciones demersales (2) las relaciones entre dichas agrupaciones y los posibles factores estructurantes (presión pesquera de arrastre y condiciones ambientales) para evaluar la dinámica de la estructura de las agrupaciones en el norte del mar Mediterráneo. Analizamos un conjunto de 18062 lances entre 10 y 800 m. de profundidad realizados anualmente, durante las últimas dos décadas, en 17 sub-áreas geográficas (GSAs) (Proyecto MEDITS). El análisis multi-tablas (STATICO-CoA) evidenció una fuerte estabilidad inter-GSAs en la organización de agrupaciones, con especificidades para algunas GSAs. Los factores estructurantes más estables se relacionaron con los gradientes combinados de clorofila a, fitoplancton, carbono y temperatura, correlacionados inversamente con los gradientes de profundidad, salinidad y nutrientes (eje 1 del STATICO-CoA, 93.74% de la variabilidad total). En la mayoría de las GSAs encontramos un patrón común que vincula la distribución de las especies a estos gradientes ambientales. La estimación de la presión pesquera de arrastre mostró un papel menor en la organización de las agrupaciones para la escala espacial y los años investigados (eje 2, 4.67%)

    ClimateFish: A Collaborative Database to Track the Abundance of Selected Coastal Fish Species as Candidate Indicators of Climate Change in the Mediterranean Sea

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    Under the effects of global warming, many animals and plants are undergoing rapid distribution shifts. These changes can be particularly rapid in marine fishes, and many species have responded markedly to recent increases in sea temperature. ClimateFish is an open-access database, which collates abundance data for 7 Mediterranean indigenous and 8 non-indigenous fishes, proposed as candidate indicators of climate change. These species have been selected by a network of Mediterranean scientists based on their wide distribution, responsiveness to temperature conditions and easy identification. Data are periodically collected according to a standard visual census protocol in four different depth layers. At present, the database collates data on a total number of 101'771 observed individuals belonging to the 15 target species. Counts were realized along 3142 transects carried out in 7 Mediterranean countries between 2009 and 2021. This database, associated with climate data, offers new opportunities to investigate spatiotemporal effects of climate change and to test the effectiveness of each selected indicator. Data are available at https://doi.org/10.17882/86784.The Mediterranean ClimateFish initiative was initially conceived by the international basin wide monitoring program CIESM Tropical Signals (funded by the Albert II of Monaco Foundation) and subsequently supported by the Interreg Med Programme (Projects: MPA-ADAPT, grant number 1MED15_3.2_M2_337 and MPA Engage, grant number 5MED18_3.2_M23_007), 85% co funded by the European Regional Development Fund

    Large-Scale Spatio-Temporal Patterns of Mediterranean Cephalopod Diversity

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    Species diversity is widely recognized as an important trait of ecosystems’ functioning and resilience. Understanding the causes of diversity patterns and their interaction with the environmental conditions is essential in order to effectively assess and preserve existing diversity. While diversity patterns of most recurrent groups such as fish are commonly studied, other important taxa such as cephalopods have received less attention. In this work we present spatio-temporal trends of cephalopod diversity across the entire Mediterranean Sea during the last 19 years, analysing data from the annual bottom trawl survey MEDITS conducted by 5 different Mediterranean countries using standardized gears and sampling protocols. The influence of local and regional environmental variability in different Mediterranean regions is analysed applying generalized additive models, using species richness and the Shannon Wiener index as diversity descriptors. While the western basin showed a high diversity, our analyses do not support a steady eastward decrease of diversity as proposed in some previous studies. Instead, high Shannon diversity was also found in the Adriatic and Aegean Seas, and high species richness in the eastern Ionian Sea. Overall diversity did not show any consistent trend over the last two decades. Except in the Adriatic Sea, diversity showed a hump-shaped trend with depth in all regions, being highest between 200–400 m depth. Our results indicate that high Chlorophyll a concentrations and warmer temperatures seem to enhance species diversity, and the influence of these parameters is stronger for richness than for Shannon diversityVersión del editor4,411

    Sunetti ta’ William Shakespeare

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    Ġabra ta’ poeżiji u proża li tinkludi: Grand Prix ta’ Carmel Azzopardi – Pizza marinara ta’ Carmel Azzopardi – Ħajku ta’ Kit Azzopardi – Ix-xemgħa qiegħda ta’ Charles Bezzina – U taħti ramel, ramel ta’ Charles Bezzina – Vażett ta’ Ġorġ Borg – Bniedem li mhux ta’ Ġorġ Borg – Il-ħajbu ta’ Antoine Cassar – Il-mistoħbija ta’ Manwel Cassar – Għasel ta’ Carmel G. Cauchi – Dgħajsa ta’ Carmel G. Cauchi – Ħitan ta’ Alfred Degabriele – Skeletru silwett...f’realtà moħbija ta’ Stefano Farrugia – Minjatura tal-enimmi ta’ Stefano Farrugia – Mnejn jgħaddi Kristu ta’ Joe Friggieri – Rebbiegħa ta’ Reno Fenech – Blogger ta’ Charles Flores – Veġeterjana ta’ Charles Flores – Mejju ta’ Joe P. Galea – Kien hemm lejla u tmien nisa ta’ Claudia Gauci – Ħobbni ta’ Sergio Grech – Mitlufin ta’ Maria Grech Ganado – Moħħi ta’ Maria Grech Ganado – Viżjoni ta’ Maria Grech Ganado – Inkontinenza ta’ Adrian Grima – Andrew jħebb in-nar ta’ Adrian Grima – It-Tlieta, 20 ta’ Lulju 2004 ta’ Alfred Massa – Fuq l-għolja tal- Verdala ta’ Jane Micallef – Imm’issa ta’ Jane Micallef – Baby blues ta’ Immanuel Mifsud – Ġo dar sawra ta’ Immanuel Mifsud – Lil Dun Karm ta’ Maurice Mifsud Bonnici – Il-fuklar ta’ Achille Mizzi – Ut videam ta’ Achille Mizzi – Karnival solitarju ta’ Patrick Sammut – Mill-baħħ etern ta’ Joe Zammit Tabona – ...fil-ħmieġ ta’ ftit blatiet... ta’ Paul P. Borg – Bħall-qasab ta’ Steve Borg – L-aħħar żjara ta’ Victor Fenech – Ħelwa.morra 18 ta’ Ann Marie Schembri – Jack & Jill ta’ Trevor Żahra – Għadbilura ta’ Russell Davis, traduzzjoni ta’ Toni Aquilina – Sunetti ta’ William Shakespeare, traduzzjoni ta’ Oliver Friggieri.peer-reviewe

    Sea trials datasets for the evaluation of trawl selectivity in the multispecific Maltese fisheries case

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    The current study aims to improve the trawl gear selectivity from the 40 mm square-mesh size currently in use by the Mediterranean demersal trawling fleet so as to reduce discards of hake (Merluccius merluccius), deep-water rose shrimp (Parapenaeus longirostris), and red mullet (Mullus spp) while retaining as much as possible of the legally sized catch. This study targeted the development of four different methods; two of them relied on the codend mesh size and its configuration. The other two assessed the implementation of side escape panels (SEPs) in the trawl body in order to get the fish leaving the trawl net before entering the codend. The new selection system included a V-shaped guiding device to enhance fish contact with the SEPs. For all the investigated species, the good selective properties of the 40-mm square-mesh codend have been confirmed, which were further improved in combination with the 50-mm SEPs. Trawling gears could be made more selective also by using larger mesh sizes in the codend or in the escape panels. Nevertheless, this solution may be difficult to apply in Mediterranean waters for social and political reasons, while the development and compulsory use of square-mesh panels in the trawl body deserve attention

    Summary for sea trials datasets for the evaluation of trawl selectivity in the multispecific Maltese fisheries case

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    The current study aims to improve the trawl gear selectivity from the 40 mm square-mesh size currently in use by the Mediterranean demersal trawling fleet so as to reduce discards of hake (Merluccius merluccius), deep-water rose shrimp (Parapenaeus longirostris), and red mullet (Mullus spp) while retaining as much as possible of the legally sized catch. This study targeted the development of four different methods; two of them relied on the codend mesh size and its configuration. The other two assessed the implementation of side escape panels (SEPs) in the trawl body in order to get the fish leaving the trawl net before entering the codend. The new selection system included a V-shaped guiding device to enhance fish contact with the SEPs. For all the investigated species, the good selective properties of the 40-mm square-mesh codend have been confirmed, which were further improved in combination with the 50-mm SEPs. Trawling gears could be made more selective also by using larger mesh sizes in the codend or in the escape panels. Nevertheless, this solution may be difficult to apply in Mediterranean waters for social and political reasons, while the development and compulsory use of square-mesh panels in the trawl body deserve attention

    Spatial and temporal patterns in the Mediterranean populations of Aristaeomorpha foliacea and Aristeus antennatus (Crustacea: Decapoda: Aristeidae) based on the MEDITS surveys

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    The aristeids Aristaeomorpha foliacea and Aristeus antennatus are two species of great economic importance in the Mediterranean Sea, where they are exploited almost exclusively by bottom trawlers. We analysed their geographical and inter-annual patterns using data collected, following a standardized protocol, during the MEDITS international experimental bottom trawl surveys. The data used consisted of standardized abundance and biomass indices, size structure and individual biological information collected in the northern Mediterranean for more than two decades. Several univariate and multivariate methodologies were used to analyse the data. The current study confirms previous findings, such as the longitudinal gradient in the relative presence of the aristeids, but also offers additional information for a better understanding of the intrinsic variability of the data over the years and between areas. Moreover, geographical variability in the somatic condition index is discussed, taking into account the role of environmental conditions and fishing pressure. The large geographical variability found for both species in this regional approach reflects the importance of additional studies at a small-scale geographical level. Such studies could be particularly important for managing and ensuring the stability of these species, for which large regional approaches may be inadequate.JRC.D.2-Water and Marine Resource

    Spatial and temporal trend in the abundance and distribution of gurnards (Pisces: Triglidae) in the northern Mediterranean Sea

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    In this study we investigated the spatio-temporal distribution of gurnards (8 species of Triglidae and one species of Peristediidae) in the northern Mediterranean Sea using 22 years of MEDITS bottom trawl survey data (1994-2015). Gurnards showed significant differences in terms of abundance, dominance and composition among geographical sub-areas and ecoregions, with the highest relative biomass (BIy) being found in Malta, eastern Corsica, the Balearic Islands and the eastern Ionian Sea. The lowest gurnards BIy were observed in the highly exploited areas of the western Mediterranean and the Adriatic Sea, where the largest number of species with a negative linear trend in BIy was also found. The temporal trends in species abundances highlighted a general decrease for the coastal species (C. lucerna, C. lastoviza, C. obscurus) as compared with the species inhabiting the deep continental shelf and slope (T. lyra, P. cataphractum). The results provide for the first time an overview of the spatiotemporal trend in the abundance of gurnards over the wide spatial scale of the northern Mediterranean Sea, also suggesting the possible use of these species as indicators for monitoring the impact of fishing pressure on demersal fish assemblages.  En este estudio hemos investigado la distribución espacio-temporal de los gurnardos (8 especies de Triglidae y 1 especie de Peristediidae) en el norte del Mediterráneo usando 22 años de datos de la campaña de pesca de arrastre MEDITS (1994-2015). Los gurnardos mostraron diferencias significativas en la abundancia, dominancia y composición entre las distintas sub-areas geográficas (GSAs) y las ecoregiones, encontrándose las mayores biomasas relativas (BIy) en Malta, el este de Córcega, las Islas Baleares y el oeste del mar Jónico. Por otro lado, los menores valores de BIy fueron observados en las áreas más explotadas del oeste del Mediterráneo y del Mar Adriático, donde también se observó el mayor número de especies con una tendencia lineal negativa en relación a BIy. La tendencia temporal en la abundancia de especies evidenció una disminución general en las especies costeras (C. lucerna, C. lastoviza, C. obscurus) respecto a las especies que habitan la profunda plataforma y pendiente continentales (T. lyra, P. cataphractum). Los resultados proporcionan por primera vez una visión general de las tendencias espacio-temporales en la abundancia de los gurnardos en la amplia escala espacial del norte del Mediterráneo, sugiriendo también la posibilidad de usar estas especies como indicadores para monitorear el impacto de la presión de pesca sobre los ensamblajes de peces demersales
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