49 results on '"Politou, Chrissi-Yianna"'
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2. Identification of deep-water pink shrimp abundance distribution patterns and nursery grounds in the eastern Mediterranean by means of generalized additive modelling
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Politou, Chrissi-Yianna, Tserpes, George, Dokos, John, Martens, K., editor, and Valavanis, Vasilis D., editor
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- 2008
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3. Identification of hake distribution pattern and nursery grounds in the Hellenic seas by means of generalized additive models
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Tserpes, George, Politou, Chrissi-Yianna, Peristeraki, Panagiota, Kallianiotis, Argyris, Papaconstantinou, Costas, Martens, K., editor, and Valavanis, Vasilis D., editor
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- 2008
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4. Reproducibility of the multi-component aspect of species diversity across different areas and scales: towards the constitution of a shortlist of complementary indices for monitoring fish diversity?
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Gaertner, Jean-Claude, Mérigot, Bastien, Rélini, Giulio, Bertrand, Jacques A., Mazouni, Nabila, Politou, Chrissi-Yianna, de Sola, Luis Gil, Kallianiotis, Argyris, Carpentieri, Paolo, Murenu, Matteo, Durbec, Jean-Pierre, Vrgoc, Nedo, and Ungaro, Nicola
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- 2010
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5. Do changes in environmental and fishing pressures impact marine communities? An empirical assessment
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Rochet, Marie-Joëlle, Trenkel, Verena M., Carpentier, André, Coppin, Franck, de Sola, Luis Gil, Léauté, Jean-Pierre, Mahé, Jean-Claude, Maiorano, Porzia, Mannini, Alessandro, Murenu, Matteo, Piet, GerJan, Politou, Chrissi-Yianna, Reale, Bruno, Spedicato, Maria-Teresa, Tserpes, George, and Bertrand, Jacques A.
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- 2010
6. A Review of the Biology and Fisheries of the Genus Plesionika Bate, 1888 (Decapoda, Caridea, Pandalidae) in European Waters
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Vafidis, Dimitris, Politou, Chrissi-Yianna, Carbonell, Aina, and Company, Joan B.
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- 2005
7. Correction: Large-Scale Diversity of Slope Fishes: Pattern Inconsistency between Multiple Diversity Indices
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Gaertner, Jean-Claude, primary, Maiorano, Porzia, additional, Mérigot, Bastien, additional, Colloca, Francesco, additional, Politou, Chrissi-Yianna, additional, De Sola, Luis Gil, additional, Bertrand, Jacques A., additional, Murenu, Matteo, additional, Durbec, Jean-Pierre, additional, Kallianiotis, Argyris, additional, and Mannini, Alessandro, additional
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- 2018
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8. DEEPFISHMAN: management and monitoring of deep-sea fisheries and stocks
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Lorance, Pascal, Arnason, Ragnar, Cloete, Rudi, Diez, Guzman, Dransfeld, Leonie, Failler, Pierre, Figueiredo, Ivone, Gil, Juan, González-Costas, Fernando, Hillary, Richard, Jacobdóttir, Klara, Large, Phil A., Planque, Benjamin, and Politou, Chrissi-Yianna
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fisheries ,VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Resource biology: 921 ,fiskerier - Abstract
Deepwater fisheries pose particular difficulties for management. Target species are difficult to assess with adequate levels of certainty, they are slow growing and generally vulnerable to overfishing and many of these fisheries reside outside EEZs and are, therefore, not subject to national jurisdictions. The EU project DEEPFISHMAN will develop a range of strategy options for the management of deepwater fisheries in the NE Atlantic that will take account of these factors. The primary objective of the project is to identify and develop new and more effective assessment methods, reference points, control rules and management strategies to be used in the short term. The second objective is to develop a long-term research and management framework in which additional data needs will be specified in order to fill current information gaps to achieve reliable long-term management requirements. This research effort will be supported by a range of case studies selected to reflect the characteristics of the different types of deepwater fisheries found in the NE Atlantic. In addition, two case studies outside the NE Atlantic are selected to give a wider perception of the management and monitoring of deepwater fisheries in the world. Case studies will collate, store, combine and raise data to appropriate fisheries/stocks levels. The socio-economic aspect of the fisheries and the expected impact of the management strategy options will be examined. The project outputs will aim to provide robust guidelines for deepwater fisheries management suitable for adoption within the Common Fishery policy. Keywords: Deep-water fisheries, EU project
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- 2009
9. Demersal faunal assemblages in the deep waters of the eastern Ionian Sea
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Politou, Chrissi-Yianna, Mytilineou, Chryssi, D, Gianfranco, Onghia, and Dokos, John
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Biodiversity ,Taxonomy - Abstract
Politou, Chrissi-Yianna, Mytilineou, Chryssi, D, Gianfranco, Onghia, Dokos, John (2008): Demersal faunal assemblages in the deep waters of the eastern Ionian Sea. Journal of Natural History 42 (5-8): 661-672, DOI: 10.1080/00222930701835613, URL: http://dx.doi.org/10.1080/00222930701835613
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- 2008
10. International bottom trawl survey in the Mediterranean (Medits), Instruction manual - Version 5
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Bertrand, Jacques, Souplet, Arnauld, Gil De Sola, Luis, Relini, Giulio, and Politou, Chrissi-yianna
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This document is the fifth version of a manual elaborated in the frame of an international project to harmonise the samplings by bottom trawling of the demersal resources in the Mediterranean Sea (MEDITS program). It is the reference document for the surveys to be conducted from 2007 onwards by the research institutes contributing in the Medits surveys on the continental shelves and slopes in the Mediterranean (Fig. 1). The manual describes the sampling gear characteristics, the sampling methodology and the treatment of the samples. Finally it gives the specifications of the data files for data storage and exchange.
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- 2007
11. Do population and community metrics tell the same story about recent changes in Northern Mediterranean fish communities?
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Rochet, Marie-joelle, Trenkel, Verena, Gil De Sola, Luis, Politou, Chrissi-yianna, Tserpes, George, and Bertrand, Jacques
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Community metrics ,ecosystem approach to fisheries ,length-based metrics ,Mediterranean ,fish community ,survey data - Abstract
This document presents a comparative study of human impacts on the length-structure of fish communities across North-Mediterranean ecosystems. We use survey data to examine trends in length-based metrics and their consistency within and among the two levels of organisation populations and communities, and to suggest interpretations of observed trend combinations. We start from a set of population processes potentially affected by human pressures: fishing will induce mortality especially in target species, whereas the hydrological environment and eutrophication potentially affect recruitment and individual growth. How population changes will be reflected at the community level is expected to depend on community evenness. Based on this expectation, a tentative theory for predicting the joint response of a suite of population and community length-based metrics to potential changes in the environment is proposed. The trends in these metrics from survey data are then examined, focusing on the consistency with the above predictions. The potential causes suggested for the observed trends are then checked against independent evidence of environmental and human pressures on these communities. The approach is applied to the MEDITS survey data, which cover a series of neighbouring fish communities undergoing various human pressures, including fishing, coastal pollution and eutrophication, and a possible change in temperature and hydrology over the last decade.
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- 2007
12. Distribución profunda, aspectos biológicos y ecológicos de Aristeus antennatus (Risso, 1816) en el Mediterráneo occidental y central
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Sardà, Francisco, D'Onghia, Gianfranco, Politou, Chrissi Yianna, Company, Joan Baptista, Maiorano, Porzia, and Kapiris, Konstantinos
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Aristeus ,Mediterranean ,deep-sea ,shrimp ,crustaceans ,Mediterráneo ,mar profundo ,gamba ,crustáceos - Abstract
The object of the DESEAS Project, funded by the EC, was to gather preliminary data on the abundance and maximum depth distribution of the rose shrimp Aristeusantennatus in the Mediterranean Sea. An exploratory survey was therefore designed with that goal in mind and conducted on the R/V García del Cid, sampling the maximum depths in three specific areas in the central and western Mediterranean, one off Ibiza (Balearic Islands), one off Calabria (western Ionian Sea), and one off the southern Peloponnesian Peninsula (Gulf of Kalamata, eastern Ionian Sea). The depths sampled ranged from 600 to 4000 m, with specimens of A. antennatus being collected down to 3300 m. There were three distinct boundaries marking the abundance of this species: < 1000 m, relatively high abundance (up to 1000 ind km-2); 1000-1500 m, relatively moderate abundance (up to 300 ind km-2); and > 1500 m, relatively low abundance (, El objetivo del proyecto DESEAS, financiado por la CE, fue obtener datos preliminares de abundancia y distribución de profundidad máxima de la gamba rosada Aristeus antennatus en el Mar Mediterráneo. El diseño de la campaña exploratoria fue realizado con este propósito y se desarrolló a bordo del B/O García del Cid. Se realizaron muestreos en las máximas profundidades de tres áreas específicas en el Mediterráneo occidental y central: una cerca de Menorca (Islas Baleares), otra frente a las costas de Calabria (Iónico occidental) y la última al sur de la península del Peloponeso (en el Golfo de Kalamata, Iónico oriental). Las profundidades muestreadas fueron las comprendidas entre 600 y 4000 m, obteniendo individuos de A. antennatus hasta 3300 m. Se detectaron tres niveles de abundancias diferenciados en esta especie: < 1000 m, relativamente muy abundante (hasta 1000 ind km-2); 1000-1500 m, abundancia relativamente moderada (hasta 300 ind km-2); > 1500 m, relativamente poco abundante (< 100 ind km-2). En las tres áreas estudiadas se confirmó la estructura de la población conocida hasta el momento, es decir, aumento de la proporción de machos y juveniles con la profundidad. No se encontraron evidencias de diferencias en el desarrollo gonadal o en la presencia de espermatóforos de las hembras entre áreas. Finalmente se observó la existencia de una tendencia en el aumento de la proporción de juveniles con la profundidad.
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- 2004
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13. Biología del Mediterráneo profundo: el caso de Aristaeomorpha foliacea (Risso,1827) (Crustacea: Decapoda: Aristeidae)
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Politou, Chrissi-Yianna, Kapiris, Konstantinos, Maiorano, Plorzia, Capezzuto, Francesca, and Dokos, John
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Aristaeomorpha foliacea ,distribución ,biología ,aguas profundas ,Mediterráneo ,distribution ,biology, deep waters ,Mediterranean - Abstract
Data on the distribution, abundance and biological parameters of the giant red shrimp Aristaeomorphafoliacea were collected during a research survey in deep waters (600-4000 m) of the Mediterranean Sea at three locations: the Balearic Sea, the western Ionian and the eastern Ionian in early summer 2001. The shrimp was mainly found in the shallower zone (< 1000 m) of the eastern Ionian Sea. Few specimens were caught in the deeper waters of this region, with 1100 m being the lower limit of its distribution. This is the maximum depth reported for the species in the Mediterranean. At the other two locations, the species was scarcely caught and only in the shallowest zone (< 1000 m). In the area and depth zone of high abundance, 5 modal groups for females and 3 for males were distinguished using the Bhattacharya method. The recruitment seems to take place at the shallowest stations (600 m). More than 50% of adult females were in advanced maturity stages. The striking abundance differences of the species between the western and eastern locations may be explained by the different exploitation level of the deep waters (almost null in the eastern Ionian Sea and extensive more westwards). However, the distribution and biological characteristics of A.foliacea indicate a higher vulnerability to over-fishing comparing to the other commercial co-occurring deep-water shrimp Aristeusantennatus., Se obtuvieron datos sobre distribución, abundancia y parámetros biológicos de la gamba gigante Aristaeomorpha foliacea durante una campaña de investigación en aguas profundas (600-4000 m) en tres localidades a lo largo del Mediterráneo: región Balear, Iónico occidental y Iónico oriental, que tuvo lugar en verano de 2004. Esta gamba fue encontrada mayoritariamente en la zona menos profunda (< 1000m) del Iónico oriental. En aguas más profundas de esta región (1100 m) se encontraron menos ejemplares, pero determinó el límite inferior de su distribución. Esta es la máxima profundidad registrada en el Mediterráneo para esta especie. En las otras dos localidades, esta especie fue escasa y solo se encontró en la zona menos profunda (< 1000 m). En el área y en la profundidad de máxima abundancia, se observaron 5 grupos modales de hembras y 3 de machos mediante el método de Battacharya. El reclutamiento parece que tiene lugar en aguas menos profundas (600 m). Más del 50% de las hembras adultas se encontraron en avanzado estado de madurez gonadal. Esta curiosa diferencia entre la parte más occidental y las localidades más orientales puede explicarse por el diferente nivel de explotación en las aguas profundas (casi nulo en el Iónico oriental e intensivo más al oeste). Sin embargo, la distribución y características biológicas de A. foliacea indican una vulnerabilidad alta a la sobre-explotación pesquera si la comparamos con otras especies de gambas comerciales profundas como Aristeus antennatus.
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- 2004
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14. Nuevas citas de peces teleósteos de aguas profundas en los mares Balear y Iónico (Mar Mediterráneo)
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d'Onghia, Gianfranco, Lloris, Domingo, Politou, Chrissi-Yianna, Sion, Letizia, and Dokos, John
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nuevas citas ,distribución batimétrica ,distribución geográfica ,teleósteos ,peces ,Mediterráneo ,new records ,bathymetric distribution ,geographic distribution ,teleost ,fish ,Mediterranean Sea - Abstract
During an EC-funded research carried out in the Mediterranean Sea deep-water fish (600-4000 m) were collected in the Balearic Sea as well as the western and eastern Ionian Sea. Caelorhynchusmediterraneus is a new record for the Balearic Sea, Cyclothone braueri, Hygophum benoiti, Paralepis speciosa, Chalinura mediterranea, Coryphaenoides guentheri, C. mediterraneus, Lepidion lepidion and Cataetyx laticeps for the western Ionian Sea, and Polyacanthonotus rissoanus, C. guentheri, C. mediterraneus, L. lepidion and C. laticeps for the eastern Ionian Sea. The bathymetric distribution of other species has been updated. Species richness decreased with depth in the three surveyed areas, showing a significant shift below 1500 m. At depths greater than 1000 m macrourid and morid species were dominant except in the Balearic Sea, where Alepocephalus rostratus was found to be very abundant as deep as 1500 m. At depths greater than 1500 m the dominant species were Bathypterois mediterraneus, C. mediterranea and C. guentheri. The results of this research confirm the scarcity of deep fish fauna in the Mediterranean compared to the Atlantic. For the greatest depths are concerned, the faunistic difference between the western and eastern Mediterranean seems to be most probably due to a lesser number of investigations on the eastern side rather than any real paucity of ichthyofauna., Se recolectaron especies de peces en el mar Balear y en el Iónico oriental y occidental, gracias a una investigación subvencionada por la CE en aguas profundas del Mediterráneo (600-4000 m). Caelorhynchus mediterraneus es una nueva cita para el mar Balear, Cyclothone braueri, Hygophum benoiti, Paralepis speciosa, Chalinura mediterranea, Coryphaenoides guentheri, C. mediterraneus, Lepidion lepidion y Cataetyx laticeps lo son para el mar Iónico occidental, Polyacanthonotus rissoanus, C. guentheri, C. mediterraneus, L. lepidion y C. laticeps para el mar Iónico oriental. También se ha puesto al día la distribución batimétrica de otras especies. En las tres áreas muestreadas se ha observado que la riqueza específica desciende con la profundidad, marcándose un cambio significativo por debajo de los 1500 m. A profundidades superiores a 1000 m las especies de macrúridos y móridos fueron dominantes excepto para el mar Balear donde Alepocephalus rostratus fue la especie más abundante hasta 1500 m. A profundidades superiores a los 1500 m las especies dominantes fueron Bathypterois mediterraneus, C. mediterranea y C. guentheri. Los resultados confirman la escasez de ictiofauna profunda en el Mediterráneo comparada con la del Atlántico. Hasta las máximas profundidades muestradas, la diferencia faunística entre el Mediterráneo occidental y oriental parece ser debida, más al menor número de investigaciones llevados a cabo en el Mediterráneo oriental, que no a unas determinadas pautas en la distribución y abundancia dicha ictiofauna.
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- 2004
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15. Crustáceos decápodos de profundidad del Mediterráneo occidental y central: aspectos preliminares sobre la distribución de especies, la biomasa y la estructura de población
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Company, Joan B., Maiorano, Porzia, Tselepides, Anastasios, Politou, Chrissi Yianna, Plaity, Wanda, Rotllant, Guiomar, and Sardá, Francisco
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Mar profundo ,Mediterráneo ,crustáceos decápodos ,distribución de especies ,estructura de la población ,deep-sea ,Mediterranean ,decapod crustaceans ,species distribution ,population structure - Abstract
Three deep-sea areas in the Mediterranean Sea were sampled using a bottom otter trawl during the DESEAS oceanographic survey carried out from early June to early July 2001, covering an area in the western Mediterranean from 600 to 2800 m in depth and two areas in the central Mediterranean, the western and eastern Ionian Sea from 600 to 4000 m in depth. Decapod crustaceans were one of the dominant megafaunal groups, together with fishes, in terms of both biomass and abundance. A total of 2799 decapod specimens belonging to 32 species were collected. Abundance and biomass of the decapod crustaceans decreased with depth. For depths below 1000 m, a decrease in total decapod biomass was recorded from west to east. From the data reported in this study and data from the available literature, decapod crustaceans display differential depth distributions in the different areas. For the most abundant species, size and sex distributions versus depth gradient were examined to compare intraspecific population structures between the sampling areas. Despite differences, among areas, in the species biomass compositions by depth strata and differences in their overall bathymetric ranges of distribution, intraspecific population structures of the most abundant species seem to follow similar trends for size and sex distribution versus depth gradient between the western and central areas. This might be an indication that the individual species structure their populations according to a similar basic pattern regardless of differences in local environmental features. The results have been discussed in the general context of the environmental features encountered by the species in each of the sampling areas., Se muestrearon tres áreas del Mediterráneo profundo con una red de arrastre bentónica durante la campaña oceanográfica DESEAS, desde principios de junio hasta principios de julio de 2001. El rango batimétrico muestreado en el Mediterráneo occidental fue entre los 600 y los 2800 m de profundidad. Se muestraron dos áreas del Mediterráneo central, una situada en la parte occidental del Mar Iónico y la otra situada en la parte más oriental del mismo, cubriendo un rango batimétrico entre los 600 y 4000 m de profundidad. Los crustáceos decápodos fueron uno de los grupos, junto con los peces, dominantes de la megafauna en términos de biomasa y abundancia. Se capturaron en total de 2799 individuos de decápodos pertenecientes a 32 especies. La abundancia y biomasa de los crústaceos decápodos disminuyó con la profundiad. Teniendo en cuenta únicamente las muestras tomadas a profundidades superiores a los 100 m, se detectó una disminución de la biomasa total de los crustáceos decápodos en el área de muestreo más oriental (parte oriental del mar Jónico con respecto al mediterráneo occidental (mar Balear). Los datos aportados en este estudio junto con los datos disponibles en la literatura, indican que los cruatáceos decápodos se distribuyen en rangos batimétricos diferentes en cada una de las áreas de estudio. Aunque se encontraron diferencias entre las áreas de estudio, en la distribución de biomasa con respecto a la profundidad y en los rangos batimétricos de cada especie, la estructura de población de las especies mas abundantes para seguir la msima tendencia por lo que respecta a la distribución batimétrica de sexos y tamaño de sus individuos en toda el área geográfica muestreada. Este último aspecto podría ser una indicación de que las especies estructuran sus poblaciones de acuerdo a un patrón similar, independientemente de las diferencias locales del ambiente. Los resultados se han discutido bajo el contexto general de las características ambientales encontradas por cada especie en cada una de las áreas de muestreo.
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- 2004
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16. Deep-sea distribution, biological and ecological aspects of Aristeus antennatus (Risso, 1816) in the western and central Mediterranean Sea
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Sardà, Francisco, Maiorano, Porzia, Company, Joan B., D´Onghia, Gianfranco, and Politou, Chrissi-Yianna
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Shrimp ,Deep-sea ,Aristeus ,Mediterranean ,Mar profundo ,Mediterráneo ,Gamba ,Crustáceos ,Crustaceans - Abstract
[EN] The object of the DESEAS Project, funded by the EC, was to gather preliminary data on the abundance and maximum depth distribution of the rose shrimp Aristeusantennatus in the Mediterranean Sea. An exploratory survey was therefore designed with that goal in mind and conducted on the R/V García del Cid, sampling the maximum depths in three specific areas in the central and western Mediterranean, one off Ibiza (Balearic Islands), one off Calabria (western Ionian Sea), and one off the southern Peloponnesian Peninsula (Gulf of Kalamata, eastern Ionian Sea). The depths sampled ranged from 600 to 4000 m, with specimens of A. antennatus being collected down to 3300 m. There were three distinct boundaries marking the abundance of this species: < 1000 m, relatively high abundance (up to 1000 ind km-2); 1000-1500 m, relatively moderate abundance (up to 300 ind km-2); and > 1500 m, relatively low abundance (, [ES] El objetivo del proyecto DESEAS, financiado por la CE, fue obtener datos preliminares de abundancia y distribución de profundidad máxima de la gamba rosada Aristeus antennatus en el Mar Mediterráneo. El diseño de la campaña exploratoria fue realizado con este propósito y se desarrolló a bordo del B/O García del Cid. Se realizaron muestreos en las máximas profundidades de tres áreas específicas en el Mediterráneo occidental y central: una cerca de Menorca (Islas Baleares), otra frente a las costas de Calabria (Iónico occidental) y la última al sur de la península del Peloponeso (en el Golfo de Kalamata, Iónico oriental). Las profundidades muestreadas fueron las comprendidas entre 600 y 4000 m, obteniendo individuos de A. antennatus hasta 3300 m. Se detectaron tres niveles de abundancias diferenciados en esta especie: < 1000 m, relativamente muy abundante (hasta 1000 ind km-2); 1000-1500 m, abundancia relativamente moderada (hasta 300 ind km-2); > 1500 m, relativamente poco abundante (< 100 ind km-2). En las tres áreas estudiadas se confirmó la estructura de la población conocida hasta el momento, es decir, aumento de la proporción de machos y juveniles con la profundidad. No se encontraron evidencias de diferencias en el desarrollo gonadal o en la presencia de espermatóforos de las hembras entre áreas. Finalmente se observó la existencia de una tendencia en el aumento de la proporción de juveniles con la profundidad, This work was financially supported by the Directorate General Fisheries of the EC as part of the DESEAS survey programme (DGXIV, Study Contract, 2000/39)
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- 2004
17. Large-Scale Diversity of Slope Fishes: Pattern Inconsistency between Multiple Diversity Indices
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Gaertner, Jean-claude, Maiorano, Porza, Merigot, Bastien, Colloca, Francesco, Politou, Chrissi-yianna, Gil De Sola, Luis, Bertrand, Jacques, Murenu, Matteo, Durbec, Jean-pierre, Kallianiotis, Argyris, Mannini, Alessandro, Gaertner, Jean-claude, Maiorano, Porza, Merigot, Bastien, Colloca, Francesco, Politou, Chrissi-yianna, Gil De Sola, Luis, Bertrand, Jacques, Murenu, Matteo, Durbec, Jean-pierre, Kallianiotis, Argyris, and Mannini, Alessandro
- Abstract
Large-scale studies focused on the diversity of continental slope ecosystems are still rare, usually restricted to a limited number of diversity indices and mainly based on the empirical comparison of heterogeneous local data sets. In contrast, we investigate large-scale fish diversity on the basis of multiple diversity indices and using 1454 standardized trawl hauls collected throughout the upper and middle slope of the whole northern Mediterranean Sea (36 degrees 3' - 45 degrees 7' N; 5 degrees 3'W - 28 degrees E). We have analyzed (1) the empirical relationships between a set of 11 diversity indices in order to assess their degree of complementarity/redundancy and (2) the consistency of spatial patterns exhibited by each of the complementary groups of indices. Regarding species richness, our results contrasted both the traditional view based on the hump-shaped theory for bathymetric pattern and the commonly-admitted hypothesis of a large-scale decreasing trend correlated with a similar gradient of primary production in the Mediterranean Sea. More generally, we found that the components of slope fish diversity we analyzed did not always show a consistent pattern of distribution according either to depth or to spatial areas, suggesting that they are not driven by the same factors. These results, which stress the need to extend the number of indices traditionally considered in diversity monitoring networks, could provide a basis for rethinking not only the methodological approach used in monitoring systems, but also the definition of priority zones for protection. Finally, our results call into question the feasibility of properly investigating large-scale diversity patterns using a widespread approach in ecology, which is based on the compilation of pre-existing heterogeneous and disparate data sets, in particular when focusing on indices that are very sensitive to sampling design standardization, such as species richness.
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- 2013
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18. Mesoscale spatio-temporal dynamics of demersal assemblages of the Eastern Ionian Sea in relationship with natural and fisheries factors
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Tsagarakis, Konstantinos, Mytilineou, Chryssi, Haralabous, John, Lorance, Pascal, Politou, Chrissi-yianna, Dokos, John, Tsagarakis, Konstantinos, Mytilineou, Chryssi, Haralabous, John, Lorance, Pascal, Politou, Chrissi-yianna, and Dokos, John
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Data from the MEDITS bottom trawl surveys in the Eastern Ionian Sea, covering a depth range of 28 to 845 m were analysed for the period 1998-2008. For each trawling location, environmental and geographical parameters were recorded, while biomass, abundance, biodiversity and size-based metrics were estimated for the total megafaunal community, as well as for four taxonomic sub-communities (Osteichthyes, Chondrichthyes, Crustacea and Cephalopoda) which were expected to respond differently to environmental changes and fishing. In addition, biomass and abundance of ten species selected based on commercial interest, depth range and life history traits were explored, with particular emphasis on deep-sea species. Fishing effort data collected during the study period were analysed and showed a decreasing trend, mainly due to a decrease in the activity of static nets. The relation between the estimated parameters and environmental and spatial factors, as well as temporal (interannual) effects and the effect of fishing effort were explored using generalized additive models (GAMs). Results of GAMs showed that depth and location explained much of the variation in community metrics, probably reflecting mesoscale spatial features and species/communities requirements. Even though the different communities and species exhibited variant patterns in bathymetric and spatial distribution, some common aggregation patterns in productive areas were identified. Despite the relatively short time series, GAMs were effective in detecting increasing trends for several metrics; taking into account spatial factors further contributed to attributing the remaining deviance to temporal effects. These trends were partly explained by the observed decline of fishing effort, which is further supported by the fact that negative relations between several metrics and fishing effort were identified, for some of the selected communities and populations. Abundance, species richness and maximum length proved
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- 2013
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19. Strengths and Weaknesses of the Management and Monitoring of Deep-Water Stocks, Fisheries, and Ecosystems in Various Areas of the World-A Roadmap Toward Sustainable Deep-Water Fisheries in the Northeast Atlantic?
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Large, Philip A., Agnew, David J., Alvarez Perez, Jose Angel, Barrio Frojan, Christopher, Cloete, Rudi, Damalas, Dimitrios, Dransfeld, Leonie, Edwards, Charles T. T., Feist, Stephen, Figueiredo, Ivone, Gonzalez, Fernando, Gil Herrera, Juan, Kenny, Andrew, Jakobsdottir, Klara, Longshaw, Matt, Lorance, Pascal, Marchal, Paul, Mytilineou, Chryssi, Planque, Benjamin, Politou, Chrissi-yianna, Large, Philip A., Agnew, David J., Alvarez Perez, Jose Angel, Barrio Frojan, Christopher, Cloete, Rudi, Damalas, Dimitrios, Dransfeld, Leonie, Edwards, Charles T. T., Feist, Stephen, Figueiredo, Ivone, Gonzalez, Fernando, Gil Herrera, Juan, Kenny, Andrew, Jakobsdottir, Klara, Longshaw, Matt, Lorance, Pascal, Marchal, Paul, Mytilineou, Chryssi, Planque, Benjamin, and Politou, Chrissi-yianna
- Abstract
Scientific interest in deep-water marine resources has increased dramatically over the last 10-20 years as management bodies have sought advice on how to manage deep-water fisheries and protect deep-water ecosystems. The strengths and weaknesses of the management and monitoring of deep-water stocks, fisheries, and ecosystems in various areas of the world are described, with the objective of informing the EU FP7 DEEPFISHMAN project so that it can fulfill its primary aim, which is to develop strategic options for a short-and long-term management and monitoring ecosystem-based framework for the northeast Atlantic. To provide a baseline, the current monitoring and management regime in the northeast Atlantic is reviewed, followed by a brief description of the regimes applying to deep-water fisheries in the northwest Atlantic, the southeast Atlantic, off Brazil, in the Antarctic, off Australia and New Zealand, and in the Mediterranean. The strengths and weaknesses of these are discussed, taking into account additional information available from DEEPFISHMAN case study stocks, outcomes from consultations with stakeholders in the deep-water fishing industry in the northeast Atlantic, and the requirements of EU regulations and developing policy that will likely impact deep-water fisheries in the northeast Atlantic.
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- 2013
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20. Strengths and Weaknesses of the Management and Monitoring of Deep-Water Stocks, Fisheries, and Ecosystems in Various Areas of the World-A Roadmap Toward Sustainable Deep-Water Fisheries in the Northeast Atlantic?
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Large, Phil, Agnew, D.J., Álvarez-Pérez, J.A., Barrio Froján, Christopher, Cloete, R., Damalas, Dimitrios, Dransfeld, Leonie, Edwards, C.T.T., Feist, S., Figueiredo, Ivone, González-Costas, Fernando, Gil-Herrera, Juan, Kenny, A., Jakobsdottir, Klara, Longshaw, M., Lorance, Pascal, Marchal, Paul, Mytilineou, Chryssi, Planque, Benjamín, Politou, Chrissi-Yianna, Large, Phil, Agnew, D.J., Álvarez-Pérez, J.A., Barrio Froján, Christopher, Cloete, R., Damalas, Dimitrios, Dransfeld, Leonie, Edwards, C.T.T., Feist, S., Figueiredo, Ivone, González-Costas, Fernando, Gil-Herrera, Juan, Kenny, A., Jakobsdottir, Klara, Longshaw, M., Lorance, Pascal, Marchal, Paul, Mytilineou, Chryssi, Planque, Benjamín, and Politou, Chrissi-Yianna
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- 2013
21. MEDITS-based information on the deep water red shrimps Aristaeomorpha foliacea and Aristeus antennatus (Crustacea: Decapoda: Aristeidae)
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Cau, Angelo, Carbonell, Aina, Follesa, Maria Cristina, Mannini, Alessandro, Orsi Relini, Lidia, Politou, Chrissi Yianna, Ragonese, Sergio, and Rinelli, Paola
- Subjects
lcsh:SH1-691 ,biology ,Aristaeomorpha foliacea ,aristeus antennatus ,mediterranean ,SH1-691 ,red shrimps ,Mediterranean ,lcsh:Aquaculture. Fisheries. Angling ,Aristeus antennatus ,Aquaculture. Fisheries. Angling ,bottom trawls ,distribution ,aristaeomorpha foliacea - Abstract
The application of statistical models on a time series of data arising from the MEDITS International Trawl Survey, an experimental demersal resources survey carried out during six years (1994-1999) in the same season of the year (late spring - early summer) using the same fishing gear in a large part of the Mediterranean, has allowed for a study to compare, for the first time, the space-time distribution, abundance, and size structure of the two Aristeids Aristaeomorpha foliacea and Aristeus antennatus throughout most of the Mediterranean Sea. This research has shown a large variability among the six reference areas, that were arbitrarily defined within the basin. In particular the two shrimps do not seem to present any correlation or yield continuity in the years. The same lack of homogeneity was also observed in the time trend of the abundances and frequencies of each of the two species. These data seem to confirm the intrinsic variability of the species, the cause of which is still unknown and undocumented. Nevertheless, a longitudinal gradient of catches has been observed where A. antennatus is more abundant in the west and A. foliacea in the east of the basin., No disponible
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- 2002
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22. Notes on the distribution and biology of the deep-sea crab Bathynectes maravigna (Brachyura: Portunidae) in the Mediterranean Sea
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Abelló, Pere, Ungaro, Nicola, Politou, Chrissi-Yianna, Torres, P., Román-Marcote, Esther, Rinelli, R., Maiorano, Porzia, and Norrito, G.
- Subjects
Centro Oceanográfico de Vigo ,Mediterranean Sea ,Bathynectes maravigna ,Pesquerías ,Distribution ,Biology - Abstract
Data on the distribution and biology of the deep-sea portunid crab Bathynectes maravigna are reported for the Mediterranean Sea, based on several fisheries research surveys. Densities are low and, therefore, biological data are scarce. In the western Mediterranean, the species is much commoner in Alborán Sea than in the Catalano-Balearic Sea. Occurrences are also scarce in the southern Adriatic and northwestern Thyrrenian Sea, as well as in the Ionian Sea. The Alborán Sea and the seas surrounding the southern Italian peninsula are the areas where densities are the highest. The occurrence depth range was found to be 245–786 m, but most of the occurrences took place deeper than 500 m. Sizes ranged between 9 and 51 mm carapace length in males and between 12 and 51 mm in females. Ovigerous females have been only reported in October–December and March–May. Eighty three percent of both males and females are right-handed. Sexual dimorphism was present in cheliped length with males having longer chelae than females. The species appears to be much commoner in those areas where Atlantic influence is the highest, We wish to thank all participants in the EU MEDITS trawl surveys for their help and collaboration in the acquisition of the data
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- 2001
23. Notes on Brachioteuthis riisei (Steenstrup, 1882) and Onychoteuthis banksi (Leach, 1817)(Cephalopoda: Teuthoidea) found in the Aegean Sea
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Lefkaditou, Eugenia, Politou, Chrissi-Yianna, and Papaconstantinou, Costas
- Abstract
The occurrence of Brachioteuthis riisei and Onychoteuthis banksi in the region of Argosaronikos (Aegean Sea) is reported in this note. Both species were collected by the experimental bottom trawl net used in the framework of the International Bottom Trawl Survey in the Mediterranean (MEDITS). A single individual of Brachioteuthis riisei was caught in June 1997, between 380-418 m of depth. It was a fully mature female with a mantle length of 66 mm, representing the largest individual ever caught in the Mediterranean and the first one recorded in the Aegean Sea. Five specimens of Onychoteuthis banksi were found in June 1997 and June 1998 at depths ranging between 685 and 760 m. All specimens were immature their size ranging from 55 to 107 mm DML. This is the first finding of the species in the Aegean Sea and the Eastern Mediterranean (east of 23¡ E).
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- 2000
24. Using the ALADYM simulation model for exploring the effects of management scenarios on fish population metrics
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Spedicato, Maria Teresa, Poulard, Jean-charles, Politou, Chrissi-yianna, Radtke, Krzysztof, Lembo, Giuseppe, Petitgas, Pierre, Spedicato, Maria Teresa, Poulard, Jean-charles, Politou, Chrissi-yianna, Radtke, Krzysztof, Lembo, Giuseppe, and Petitgas, Pierre
- Abstract
Simulation of fisheries systems is a widely used approach that integrates monitoring and assessment tools. We applied the ALADYM (age-length based dynamic model) simulation model to three different studies aimed at investigating correlations between pressure and population metrics, exploring the viability of different mortality levels in long-term scenarios and predicting the effects of combined management measures. Uncertainty was incorporated into the simulations following the Monte Carlo paradigm. Three stocks were used for these exercises: red mullet in the central-southern Tyrrhenian Sea and European hake in both the Bay of Biscay and the Aegean Sea. The analysis of the relationships between total mortality and indicators highlighted significant pairwise negative correlations for red mullet. These signals of decline were supported by the spawning potential ratio indicator (mean exploited to mean unexploited spawning-stock biomass ESSB/USSB), which was low compared to target levels. It only remained within safe bounds ( > 0.2; probability: 0.90-0.95) at total mortality levels lower than 1.6. The simulation results for European hake in the Bay of Biscay showed that a sustainable exploitation rate might range from 0.87 to 1.04. The benefits of combined management measures were demonstrated for European hake in the Aegean Sea, and with a further dataset on the Eastern cod stock in the Baltic Sea.
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- 2010
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25. Towards an ecosystem approach to fisheries management (EAFM) when trawl surveys provide the main source of information
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Cotter, John, Petitgas, Pierre, Abella, Alvaro, Apostolaki, Panayiota, Mesnil, Benoit, Politou, Chrissi-yianna, Rivoirard, Jacques, Rochet, Marie-joelle, Spedicato, Maria Teresa, Trenkel, Verena, Woillez, Mathieu, Cotter, John, Petitgas, Pierre, Abella, Alvaro, Apostolaki, Panayiota, Mesnil, Benoit, Politou, Chrissi-yianna, Rivoirard, Jacques, Rochet, Marie-joelle, Spedicato, Maria Teresa, Trenkel, Verena, and Woillez, Mathieu
- Abstract
Ideas and considerations are put forward for managing fisheries and marine populations using primarily trawl surveys to supply biological and spatial indicators of the state of stocks, and to permit catch per unit effort (CPUE)-based assessments. Trawl surveys seldom allow absolute estimates of fish population sizes but, if appropriately located, timed, and designed, can provide a broad range of information about catchable fish species and the ecosystem that supports them. This information may be more conducive to sustainable management of fisheries than the traditional focus on the abundances of selected stocks. The paper first briefly proposes how survey-based methods might supplement existing fishery-dependent stock assessments, as would be necessary during a transition phase to a more ecosystem-orientated system of management. Full survey-based management is then considered in relation to management objectives, the selection of indicators, survey design, reference periods, levels and directions, statistical aspects, CPUE-based assessments, and management responses to good and bad signals from the ecosystem. We argue that existing fishery-dependent stock assessments cannot be claimed to produce absolute estimates of stock abundance and fishing mortality because natural mortality (M) is seldom known accurately and, therefore, that they should not be presumed superior to the relative information from surveys, and an agreeable form of adaptive management.
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- 2009
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26. DEEPFISHMAN: management and monitoring of deep-sea fisheries and stocks
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Pascal, L., Arnason, R., Cloete, R., Dransfeld, Leonie, Figueiredo, Ivone, Gil, Juan, Díez, Guzmán, Failler, P., González-Costas, Fernando, Jakobsdottir, Klara, Large, Phil, Hillary, R., Planque, Benjamín, Politou, Chrissi-Yianna, Pascal, L., Arnason, R., Cloete, R., Dransfeld, Leonie, Figueiredo, Ivone, Gil, Juan, Díez, Guzmán, Failler, P., González-Costas, Fernando, Jakobsdottir, Klara, Large, Phil, Hillary, R., Planque, Benjamín, and Politou, Chrissi-Yianna
- Published
- 2009
27. Trawl selectivity studies on Nephrops norvegicus (L.) in the Eastern Mediterranean Sea
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Mytilineou, Chryssi, Fourtouni, Anna, and Politou, Chrissi Yianna
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Selectivity ,trawl ,mesh size ,Crustacea ,Nephrops norvegicus ,Norway lobster ,Eastern Mediterranean ,Greece ,Selectividad ,arrastre ,luz de malla ,cigala ,Mediterráneo oriental ,Grecia - Abstract
The trawl codend selectivity on Nephrops norvegicus was studied using diamond meshes of 16 mm, 20 mm, 24 mm and 26 mm nominal side mesh size. The cover codend method was applied for the sampling. The logistic function for the probability of retention by the codend was used for the estimation of selectivity parameters from all data combined. The results indicated that the 16 mm mesh size was not selective and that almost all individuals were retained. The 24 mm and 26 mm mesh size showed quite similar results and were a little more selective than the 20 mm mesh size. None of the experimental mesh sizes proved to be adequate for N. norvegicus, since all estimated values of length of 50% retention (L50) were lower than the length at first maturity and those of length of 25% retention (L25) were lower than the legislated minimum landing size. It is suggested that mesh size should be much larger than 20 mm, the size legislated by E.U. for the Mediterranean., La selectividad de Nephrops norvegicus para el copo de arrastre se ha analizado utilizando mallas de 16 mm, 20 mm, 24 mm and 26 mm (de lado). Para el estudio de la selectividad se utilizó el método del sobrecopo. Se utilizó la ecuación logística para conocer la probabilidad de retención del copo y los parámetros de selectividad. Los resultados indican que la malla de 16 mm no es selectiva y que no deja escapar casi ningún ejemplar. Las mallas de 24 mm y de 26 mm presentan resultados parecidos entre sí y son un poco más selectivas que la malla de 20 mm. Aunque la proporción de individuos retenidos aumenta con la luz de malla, ninguna de las mallas utilizadas se considera adecuada para N. norvegicus, ya que todos los valores estimados de L50 fueron menores que la talla de primera madurez y, que todos los valores de L25 fueron menores que la talla mínima de captura legislada. Se recomienda que la malla del copo debe ser mucho más que 20 mm, la cual es la malla legislada por la EU para el Mediterráneo.
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- 1998
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28. Mesoscale spatio-temporal dynamics of demersal assemblages of the Eastern Ionian Sea in relationship with natural and fisheries factors
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Tsagarakis, Konstantinos, primary, Mytilineou, Chryssi, additional, Haralabous, John, additional, Lorance, Pascal, additional, Politou, Chrissi-Yianna, additional, and Dokos, John, additional
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- 2013
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29. Large-Scale Diversity of Slope Fishes: Pattern Inconsistency between Multiple Diversity Indices
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Gaertner, Jean-Claude, primary, Maiorano, Porza, additional, Mérigot, Bastien, additional, Colloca, Francesco, additional, Politou, Chrissi-Yianna, additional, Gil De Sola, Luis, additional, Bertrand, Jacques A., additional, Murenu, Matteo, additional, Durbec, Jean-Pierre, additional, Kallianiotis, Argyris, additional, and Mannini, Alessandro, additional
- Published
- 2013
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30. Strengths and Weaknesses of the Management and Monitoring of Deep-Water Stocks, Fisheries, and Ecosystems in Various Areas of the World—A Roadmap Toward Sustainable Deep-Water Fisheries in the Northeast Atlantic?
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Large, Philip A., primary, Agnew, David J., additional, Álvarez Pérez, José Ángel, additional, Barrio Froján, Christopher, additional, Cloete, Rudi, additional, Damalas, Dimitrios, additional, Dransfeld, Leonie, additional, Edwards, Charles T. T., additional, Feist, Stephen, additional, Figueiredo, Ivone, additional, González, Fernando, additional, Herrera, Juan Gil, additional, Kenny, Andrew, additional, Jakobsdóttir, Klara, additional, Longshaw, Matt, additional, Lorance, Pascal, additional, Marchal, Paul, additional, Mytilineou, Chryssi, additional, Planque, Benjamin, additional, and Politou, Chrissi-Yianna, additional
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- 2013
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31. Relationships between population spatial occupation and population dynamics
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Woillez, Mathieu, Petitgas, Pierre, Rivoirard, Jacques, Fernandes, Paul, Hoftstede, Remment Ter, Korsbrekke, Knut, Orlowski, Andrzej, Spedicato, Maria-teresa, Politou, Chrissi-yianna, Woillez, Mathieu, Petitgas, Pierre, Rivoirard, Jacques, Fernandes, Paul, Hoftstede, Remment Ter, Korsbrekke, Knut, Orlowski, Andrzej, Spedicato, Maria-teresa, and Politou, Chrissi-yianna
- Abstract
Population dynamics is commonly described non-spatially using parameters of population demography and vital traits. Population spatial organisation is therefore considered implicit and its importance in the population dynamics ignored. The present study evidences on a variety of stocks correlation between population spatial distribution indices, population abundance, recruitment and mortality. Series of research fisheries monitoring surveys were considered for a range of different stocks (cod, herring, anchovy, hake, mullet) in different regions of the North East Atlantic and Mediterranean (North Sea, Barents Sea, Baltic Sea, Bay of Biscay, Tyrrhenian Sea, Ionian Sea and Aegean Sea). For each population, each age and each year, 9 spatial indices were computed that characterised the spatial distribution in their centre of gravity, inertia, anisotropy, extension areas, number of patches and microscale structure. For each population and age, spatial indices were linearly regressed on the abundance, on the following recruitment, and on the mortality residuals (as a constant mortality has been fitted on cohort curves). A metaanalysis table was constructed that showed the number of times that correlations were significant. The result is that spatial indices provide additional indicators for assessing population status and could be helpful in the context of stock decline and habitat loss.
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- 2006
32. New records of deep-water teleost fish in the Balearic Sea and Ionian Sea (Mediterranean Sea)
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D´Onghia, Gianfranco, Lloris, Domingo, Sion, Letizia, Politou, Chrissi-Yianna, Dokos, John, D´Onghia, Gianfranco, Lloris, Domingo, Sion, Letizia, Politou, Chrissi-Yianna, and Dokos, John
- Abstract
[EN] During an EC-funded research carried out in the Mediterranean Sea deep-water fish (600-4000 m) were collected in the Balearic Sea as well as the western and eastern Ionian Sea. Caelorhynchusmediterraneus is a new record for the Balearic Sea, Cyclothone braueri, Hygophum benoiti, Paralepis speciosa, Chalinura mediterranea, Coryphaenoides guentheri, C. mediterraneus, Lepidion lepidion and Cataetyx laticeps for the western Ionian Sea, and Polyacanthonotus rissoanus, C. guentheri, C. mediterraneus, L. lepidion and C. laticeps for the eastern Ionian Sea. The bathymetric distribution of other species has been updated. Species richness decreased with depth in the three surveyed areas, showing a significant shift below 1500 m. At depths greater than 1000 m macrourid and morid species were dominant except in the Balearic Sea, where Alepocephalus rostratus was found to be very abundant as deep as 1500 m. At depths greater than 1500 m the dominant species were Bathypterois mediterraneus, C. mediterranea and C. guentheri. The results of this research confirm the scarcity of deep fish fauna in the Mediterranean compared to the Atlantic. For the greatest depths are concerned, the faunistic difference between the western and eastern Mediterranean seems to be most probably due to a lesser number of investigations on the eastern side rather than any real paucity of ichthyofauna, [ES] Se recolectaron especies de peces en el mar Balear y en el Iónico oriental y occidental, gracias a una investigación subvencionada por la CE en aguas profundas del Mediterráneo (600-4000 m). Caelorhynchus mediterraneus es una nueva cita para el mar Balear, Cyclothone braueri, Hygophum benoiti, Paralepis speciosa, Chalinura mediterranea, Coryphaenoides guentheri, C. mediterraneus, Lepidion lepidion y Cataetyx laticeps lo son para el mar Iónico occidental, Polyacanthonotus rissoanus, C. guentheri, C. mediterraneus, L. lepidion y C. laticeps para el mar Iónico oriental. También se ha puesto al día la distribución batimétrica de otras especies. En las tres áreas muestreadas se ha observado que la riqueza específica desciende con la profundidad, marcándose un cambio significativo por debajo de los 1500 m. A profundidades superiores a 1000 m las especies de macrúridos y móridos fueron dominantes excepto para el mar Balear donde Alepocephalus rostratus fue la especie más abundante hasta 1500 m. A profundidades superiores a los 1500 m las especies dominantes fueron Bathypterois mediterraneus, C. mediterranea y C. guentheri. Los resultados confirman la escasez de ictiofauna profunda en el Mediterráneo comparada con la del Atlántico. Hasta las máximas profundidades muestradas, la diferencia faunística entre el Mediterráneo occidental y oriental parece ser debida, más al menor número de investigaciones llevados a cabo en el Mediterráneo oriental, que no a unas determinadas pautas en la distribución y abundancia dicha ictiofauna
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- 2004
33. Deep-water fish assemblages in the Mediterranean Sea
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D´Onghia, Gianfranco, Politou, Chrissi-Yianna, Bozzano, Anna, Lloris, Domingo, Rotllant, Guiomar, Sion, Letizia, Mastrototaro, Francesco, D´Onghia, Gianfranco, Politou, Chrissi-Yianna, Bozzano, Anna, Lloris, Domingo, Rotllant, Guiomar, Sion, Letizia, and Mastrototaro, Francesco
- Abstract
[EN] Data collected during the DESEAS survey carried out in three areas of the Mediterranean Sea (Balearic Sea, western and eastern Ionian Sea) were used to describe the structure and spatial distribution of the fish assemblages at depths between 600 and 4000 m. A total of 55 species (8 chondrichthyes and 47 teleost fish) were sampled, 38 of them in the Balearic Sea, 30 in the western Ionian and 37 in the eastern Ionian. Multivariate analysis showed a clear pattern of zonation with depth and geographic area. Three main assemblages were identified across the vertical gradient investigated: on the upper slope around a depth of 600 m, on the middle slope between 800 and 1300 m, and on the lower slope below 1300 m. The geographic characterisation of the ichthyofauna structure was mainly observed on the upper and middle slope. The highest abundance and biomass values were found at depths of 1000-1200 m due to the presence of larger species with high energy requirements, such as Alepocephalusrostratus, Mora moro and Galeus melastomus. On the middle slope, significant differences in the abundance, biomass and mean fish weight were detected between the three areas. Significant differences for these parameters were also shown between the middle and lower slope assemblages. A significant decrease in species richness and diversity was shown with increasing depth, indicating an impoverishment of the megafauna with depth and a higher similarity between the Balearic Sea and the Ionian Sea with regard to the greatest depths. The dominant species on the deepest bottoms were Bathypteroismediterraneus, Chalinura mediterranea and Coryphaenoides guentheri. On the lower slope, the shark Centroscymnuscoelolepis was also found to be relatively abundant off the Balearic Islands, Etmopterusspinax in the eastern Ionian Sea and the teleost fish Cataetyx laticeps throughout the three study areas. The deepest bottoms of the Mediterranean Sea shelter an ichthyofauna dominated by small-medium spe, [ES] A partir de datos recolectados durante la campaña DESEAS, llevada a cabo en tres áreas del mar Mediterráneo (Mar Balear y Iónico occidental y oriental), se describe la estructura y la distribución espacial de las asociaciones de peces entre 600 y 4000 m de profundidad. Se obtuvieron un total de 55 especies (8 condrictrios y 47 peces teleósteos), 38 de los cuales procedían del mar Balear, 30 del Iónico occidental y 37 del oriental. El análisis multivariante de los datos nos muestra un claro patrón en zonación tanto en profundidad como por área geográfica. Se identificaron tres asociaciones principales a través del gradiente batimétrico estudiado: en el talud superior a profundidades alrededor de los 600 m, en el talud medio entre 800 y 1300 m, y en el talud inferior por debajo de los 1300 m. La caracterización geográfica de la estructura de la ictiofauna se observó principalmente en el talud superior y medio. A profundidades comprendidas entre 1000 y 1200 m fue donde se encontraron los mayores valores de biomasa, debido a la presencia de especies más grandes y con mayores requerimientos energéticos como Alepocephalus rostratus, Mora moro y Galeus melastomus. En el talud medio se detectaron diferencias significativas en abundancia, biomasa y peso medio de los peces entre las tres áreas. También se encontraron en las asociaciones de peces diferencias significativas en estos parámetros en el talud superior e inferior. Con el aumento de profundidad se detecta una disminución de la riqueza específica y la diversidad, indicando un empobrecimiento de la magafauna con la profundidad. Sin embargo se observa alta similaridad entre las áreas de estudio y en las máximas profundidades alcanzadas. Las especies dominantes en los fondos más profundos fueron: Bathypterois mediterraneus, Chalinura mediterranea y Coryphaenoides guentheri. En el talud inferior del mar Balear, el tiburón Centroscymnus coelolepis fue también relativamente abundante. Etmopterus spinax en el Iónico ori
- Published
- 2004
34. Deep-sea decapod crustaceans in the western and central Mediterranean Sea: preliminary aspects of species distribution, biomass and population structure
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Company, Joan B., Maiorano, Porzia, Tselepides, Anastasios, Plaity, Wanda, Politou, Chrissi-Yianna, Sardà, Francisco, Rotllant, Guiomar, Company, Joan B., Maiorano, Porzia, Tselepides, Anastasios, Plaity, Wanda, Politou, Chrissi-Yianna, Sardà, Francisco, and Rotllant, Guiomar
- Abstract
[EN] Three deep-sea areas in the Mediterranean Sea were sampled using a bottom otter trawl during the DESEAS oceanographic survey carried out from early June to early July 2001, covering an area in the western Mediterranean from 600 to 2800 m in depth and two areas in the central Mediterranean, the western and eastern Ionian Sea from 600 to 4000 m in depth. Decapod crustaceans were one of the dominant megafaunal groups, together with fishes, in terms of both biomass and abundance. A total of 2799 decapod specimens belonging to 32 species were collected. Abundance and biomass of the decapod crustaceans decreased with depth. For depths below 1000 m, a decrease in total decapod biomass was recorded from west to east. From the data reported in this study and data from the available literature, decapod crustaceans display differential depth distributions in the different areas. For the most abundant species, size and sex distributions versus depth gradient were examined to compare intraspecific population structures between the sampling areas. Despite differences, among areas, in the species biomass compositions by depth strata and differences in their overall bathymetric ranges of distribution, intraspecific population structures of the most abundant species seem to follow similar trends for size and sex distribution versus depth gradient between the western and central areas. This might be an indication that the individual species structure their populations according to a similar basic pattern regardless of differences in local environmental features. The results have been discussed in the general context of the environmental features encountered by the species in each of the sampling areas, [ES] Se muestrearon tres áreas del mediterráneo profundo con una red de arrastre bentónica durante la campaña oceanográfica DESEAS, desde principios de junio hasta principios de julio de 2001. El rango batimétrico muestreado en el Mediterráneo occidental fue entre los 600 y los 2800 m de profundidad. El rango batimétrico muestreado en el Mediterráneo occidental fue entre los 600 y los 2800 m de profundidad. Se muestrearon dos áreas del Mediterráneo central, una situada en la parte occidental del Mar Iónico y la otra situada en la parte más oriental del mismo, cubriendo un rango batimétrico entre los 600 y 4000 m de pro- fundidad. Los crustáceos decápodos fueron uno de los grupos, junto con los peces, dominantes de la megafauna en términos de biomasa y abundancia. Se capturaron un total de 2799 individuos de decápodos pertenecientes a 32 especies. La abundancia y biomasa de los crustáceos decápodos disminuyó con la profundidad. Teniendo en cuenta únicamente las muestras tomadas a profundidades superiores a los 1000 m, se detectó una disminución de la biomasa total de los crustáceos decápodos en el área de muestreo más oriental (parte oriental del Mar Iónico) con respecto al Mediterráneo occidental (Mar Balear). Los datos aportados en este estudio junto con los datos disponibles en la literatura, indican que los crustáceos decápodos se distribuyen en rangos batimétricos diferentes en cada una de las áreas de estudio. Aunque se encontraron diferencias entre las áreas de estudio, en la distribución de biomasa con respecto a la profundidad y en los rangos batimétricos de cada especie, la estructura de población de las especies más abundantes parece seguir la misma tendencia por lo respecta la distribución batimétrica de sexos y tamaño de sus individuos en toda el área geográfica muestreada. Este último aspecto podría ser una indicación de que las especies estructuran sus poblaciones de acuerdo a un patrón similar, independientemente de las diferencias locales del ambient
- Published
- 2004
35. Using the ALADYM simulation model for exploring the effects of management scenarios on fish population metrics
- Author
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Spedicato, Maria Teresa, primary, Poulard, Jean-Charles, additional, Politou, Chrissi-Yianna, additional, Radtke, Krzysztof, additional, Lembo, Giuseppe, additional, and Petitgas, Pierre, additional
- Published
- 2010
- Full Text
- View/download PDF
36. MEDITS-based information on the deep water red shrimps Aristaeomorpha foliacea and Aristeus antennatus (Crustacea: Decapoda: Aristeidae)
- Author
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Abelló, P. (Pere), Bertrand, J.A. (Jacques A.), Gil-de-Sola-Simarro, L. (Luis), Papaconstantinou, C. (Costas), Relini, G. (Giulio), Souplet, A. (Arnauld), Cau, Angelo, Carbonell, Ana, Follesa, Maria Cristina, Mannini, Alessandro, Norrito, Giacomo, Orsi-Relini, Lidia, Politou, Chrissi-Yianna, Ragonese, Sergio, Rinelli, Paola, Abelló, P. (Pere), Bertrand, J.A. (Jacques A.), Gil-de-Sola-Simarro, L. (Luis), Papaconstantinou, C. (Costas), Relini, G. (Giulio), Souplet, A. (Arnauld), Cau, Angelo, Carbonell, Ana, Follesa, Maria Cristina, Mannini, Alessandro, Norrito, Giacomo, Orsi-Relini, Lidia, Politou, Chrissi-Yianna, Ragonese, Sergio, and Rinelli, Paola
- Abstract
The application of statistical models on a time series of data arising from the MEDITS International Trawl Survey, an experimental demersal resources survey carried out during six years (1994-1999) in the same season of the year (late spring - early summer) using the same fishing gear in a large part of the Mediterranean, has allowed for a study to compare, for the first time, the space-time distribution, abundance, and size structure of the two Aristeids Aristaeomorpha foliacea and Aristeus antennatus throughout most of the Mediterranean Sea. This research has shown a large variability among the six reference areas, that were arbitrarily defined within the basin. In particular the two shrimps do not seem to present any correlation or yield continuity in the years. The same lack of homogeneity was also observed in the time trend of the abundances and frequencies of each of the two species. These data seem to confirm the intrinsic variability of the species, the cause of which is still unknown and undocumented. Nevertheless, a longitudinal gradient of catches has been observed where A. antennatus is more abundant in the west and A. foliacea in the east of the basin
- Published
- 2002
37. Towards an ecosystem approach to fisheries management (EAFM) when trawl surveys provide the main source of information
- Author
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Cotter, John, primary, Petitgas, Pierre, additional, Abella, Alvaro, additional, Apostolaki, Panayiota, additional, Mesnil, Benoit, additional, Politou, Chrissi-Yianna, additional, Rivoirard, Jacques, additional, Rochet, Marie-Joëlle, additional, Spedicato, Maria Teresa, additional, Trenkel, Verena M., additional, and Woillez, Mathieu, additional
- Published
- 2009
- Full Text
- View/download PDF
38. Identification of hake distribution pattern and nursery grounds in the Hellenic seas by means of generalized additive models
- Author
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Tserpes, George, primary, Politou, Chrissi-Yianna, additional, Peristeraki, Panagiota, additional, Kallianiotis, Argyris, additional, and Papaconstantinou, Costas, additional
- Published
- 2008
- Full Text
- View/download PDF
39. Identification of deep-water pink shrimp abundance distribution patterns and nursery grounds in the eastern Mediterranean by means of generalized additive modelling
- Author
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Politou, Chrissi-Yianna, primary, Tserpes, George, additional, and Dokos, John, additional
- Published
- 2008
- Full Text
- View/download PDF
40. Influences of environmental variability on the population structure and distribution patterns of the short-fin squid Illex coindetii (Cephalopoda: Ommastrephidae) in the Eastern Ionian Sea
- Author
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Lefkaditou, Eugenia, primary, Politou, Chrissi-Yianna, additional, Palialexis, Andreas, additional, Dokos, John, additional, Cosmopoulos, Panayota, additional, and Valavanis, Vasilis D., additional
- Published
- 2008
- Full Text
- View/download PDF
41. Demersal faunal assemblages in the deep waters of the eastern Ionian Sea
- Author
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Politou, Chrissi‐Yianna, primary, Mytilineou, Chryssi, additional, D'Onghia, Gianfranco, additional, and Dokos, John, additional
- Published
- 2008
- Full Text
- View/download PDF
42. Deep-sea decapod crustaceans in the western and central Mediterranean Sea: preliminary aspects of species distribution, biomass and population structure
- Author
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Company, Joan B., primary, Maiorano, Porzia, additional, Tselepides, Anastasios, additional, Politou, Chrissi Yianna, additional, Plaity, Wanda, additional, Rotllant, Guiomar, additional, and Sardá, Francisco, additional
- Published
- 2004
- Full Text
- View/download PDF
43. Deep-water fish assemblages in the Mediterranean Sea
- Author
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D'Onghia, Gianfranco, primary, Politou, Chrissi Yianna, additional, Bozzano, Anna, additional, Lloris, Domingo, additional, Rotllant, Guiomar, additional, Sión, Letizia, additional, and Mastrototaro, Francesco, additional
- Published
- 2004
- Full Text
- View/download PDF
44. New records of deep-water teleost fish in the Balearic Sea and Ionian Sea (Mediterranean Sea)
- Author
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D'Onghia, Gianfranco, primary, Lloris, Domingo, additional, Politou, Chrissi-Yianna, additional, Sion, Letizia, additional, and Dokos, John, additional
- Published
- 2004
- Full Text
- View/download PDF
45. Deep-sea distribution, biological and ecological aspects of Aristeus antennatus ( Risso, 1816) in the western and central Mediterranean Sea
- Author
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Sardà, Francisco, primary, D'Onghia, Gianfranco, additional, Politou, Chrissi Yianna, additional, Company, Joan Baptista, additional, Maiorano, Porzia, additional, and Kapiris, Konstantinos, additional
- Published
- 2004
- Full Text
- View/download PDF
46. Deep-sea Mediterranean biology: the case of Aristaeomorpha foliacea (Risso, 1827) (Crustacea: Decapoda: Aristeidae)
- Author
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Kapiris, Konstantinos, primary, Politou, Chrissi-Yianna, additional, Maiorano, Plorzia, additional, Capezzuto, Francesca, additional, and Dokos, John, additional
- Published
- 2004
- Full Text
- View/download PDF
47. Estudio de la selectividad de Nephrops norvegicus (L.) para el arte de arrastre en el Mediterráneo Oriental
- Author
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Mytilineou, Chryssi, primary, Fourtouni, Anna, additional, and Politou, Chrissi Yianna, additional
- Published
- 1998
- Full Text
- View/download PDF
48. Deep-water decapod crustacean fauna of the Eastern Ionian Sea.
- Author
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Politou, Chrissi-Yianna, Maiorano, Porzia, D'Onghia, Gianfranco, and Mytilineou, Chryssi
- Published
- 2005
49. Deep-water fish fauna in the Eastern Ionian Sea.
- Author
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Mytilineou, Chryssi, Politou, Chrissi-Yianna, Papaconstantinou, Costas, Kavadas, Stefanos, D'Onghia, Gianfranco, and Sion, Leticia
- Published
- 2005
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