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  • 1
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    Variations saisonnières de la taille et du poids sec chez les principaux copépodes pélagiques de la mer de Bou Grara (Tunisie). (2016)
    Details
    Publication Date: 2021-05-19
    Description: Les principaux copepodes pelagiques de la lagune de Bougrara sont representes par ordre d'abondance decroissante par Oithona nana, Paracalanus parvus, Euterpina acutifrons, Centropages kroyeri, Acartia latisetosa. Des mesures de tailles et de poids secs de copepodes adultes ont ete effectuees sur des echantillons preleves au cours de l'annee 92-93. L'etude des variations saisonnieres de la taille nous ont permis de rappeler le role du phytoplancton mais aussi de mettre en evidence la relation inverse existant entre la taille des copepodes et la temperature moyenne des eaux : des correlations negatives tres significatives ont ete observees. L'etude du poids sec nous a permis de correler ce facteur a la taille des copepodes : des equations de regression reliant la taille au poids sec ont ainsi pu etre reduites.
    Description: The major pelagic copepods of Bou Grara lagoon (Tunisia) are respectively represented by Oithona nana, Paracalanus parvus, Euterpina acutifrons, Centropages kroyeri, Acartia latisetosa. Length and dry weight measurement of adult copepods are taken on samples dated from year 92-93. The study of length variation during the year allowed us to confirm the role of phytoplankton and inverted relation between length and seawater temperature. Dry weight measurement had been correlated with length of copepods: regressions lines between those parameters had been developed
    Description: Published
    Keywords: Copépodes pélagiques ; Weight ; Length ; Abundance ; Phytoplankton ; Shellfish ; Water temperature ; Paracalanus parvus ; Acartia latisetosa ; Oithona nana ; Centropages kroyeri ; Euterpina acutifrons ; Marine
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp. 41-47
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  • 2
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    Discrimination de trois populations d’anchois du genre Engraulis (Clupeiforme, Engraulidae) des côtes Tunisiennes par analyse de forme des otolithes (2013)
    Details
    Publication Date: 2021-05-19
    Description: En Janvier 2008, trois lots d’anchois ont été capturés dans les eaux tunisiennes : un lot dans la lagune de Bizerte, un lot dans le littoral de Korba et un lot prés de l’ile Zembra (les trois sites dans la Tunisie septentrionale). Une étude otolithometrique a été appliquée afin d’étudier l’hétérogénéité des stocks d’anchois colonisant les eaux tunisiennes. En effet, l’étude de la forme des otolithes basée sur l’analyse elliptique de Fourier, est une nouvelle et puissante technique. Les descripteurs de Fourier sont caractérisés par des harmoniques que chacune est représentée par quatre coefficients. L’analyse statistique de ces coefficients permet la séparation des individus étudiés. L’application de cette technique nous a permis de séparer par une analyse canonique discriminante trois populations d’anchois récoltés dans les eaux tunisiennes.
    Description: Recently it has been confirmed genetically, the heterogeneity of anchovy colonizing the Mediterranean. In this work, we became interested in the study of this heterogeneity in Tunisian waters, through analysis and comparison of shapes of otoliths. Indeed, this method based on elliptic Fourier analysis is a powerful new technique. The Fourier descriptors are characterized by harmonics that each is represented by four coefficients. Statistical analysis of these factors allows the separation of specimens studied. Applying this technique allowed us to separate three populations of anchovies catched in Tunisian waters.
    Description: Published
    Description: Anchovy, otolith, shape, elliptic Fourier analysis
    Keywords: Anchovy fisheries
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed , Article
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  • 3
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    Dynamique trophique du zooplancton et relation phytoplancton-zooplancton au sein de l'écosystème de la mer de Bou Grara. (2016)
    Details
    Publication Date: 2021-05-19
    Description: L'etude de la dynamique trophique du zooplancton nous a permis de mettre en evidence son role essentiel dans l'elaboration et la transformation de la matiere organique aux premiers echelons de la chaine alimentaire marine. Le zooplancton conduit la matiere organique du phytoplancton vers les carnivores superieurs( poissons planctonophages, especes benthiques). Son etude est un caractere essentiel pour la comprehension des relations trophiques au sein du zooplancton, mais aussi entre phytoplancton et zooplancton. Les nauplii de copepodes et les tintinnides constituent les deux groupes les plus importants du microzooplancton (40,46). Les copepodes pelagiques, principal representant du mesozooplancton, constituent durant l'annee d'etude (Avril 92-Mars 93) 34,25% du zooplancton total. Les carnivores eux sont essentiellement representes par Oithona nana, Podon polyphemoides et Sagitta inflata.
    Description: Study of the trophic dynamics of the zooplankton in Bou Grara Lagoon, Tunisia confirmed its essential role in the production and transformation of organic matter into the first steps of the marine food chain, leading it to the upper carnivores (planktonophagic fish, benthic species). Phytoplankton trophic dynamics is an important characteristic in the understanding of trophic relationships both within zooplankton, and also between phytoplankton and zooplankton. Copepod nauplii and tintinnids comprise the 2 most important groups of microzooplankton (40.46%). Pelagic copepods, the major group representing the mesozooplankton, comprise 34.25% of the total zooplankton during the year studied (April 1992-March 1993). The carnivores are mainly represented by Oithona nana, Podon polyphemoides and Sagitta inflate.
    Description: Published
    Keywords: Gyrodinium favella ; Organic matter ; Zooplankton ; Phytoplankton ; Trophic relationships ; Trophodynamic cycle ; Transformation ; Food chains ; Carnivores ; Lagoons ; Podon polyphemoides ; Oithona nana ; Sagitta ; Sagitta inflate ; Marine
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp. 48-65
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  • 4
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    Etat environnemental de la lagune de Boughrara et ses alentours deux ans après les travaux d'aménagement et d'élargissement du pont d'el Kantara (2014)
    Details
    Publication Date: 2021-05-19
    Description: L’étude de l’état environnemental de la lagune de Boughrara a été réalisée deux ans après la mise en service du nouveau pont El Kantara. Les paramètres étudiés dans l’eau (nitrites, nitrates, ammonium, azote, phosphore total, chlorophylle a) et le sédiment (matière organique, faciès sédimentaire) ont été analysés dans trois zones de la lagune appartenants à divers contextes géographiques et environnementaux. Les résultats obtenus ont montré d’évidents signes d’amélioration des conditions générales de cet écosystème. Les distributions spatiotemporelles et saisonnières des paramètres étudiés indiquent que les teneurs trouvées atteignent le seuil d’eutrophisation pas mal de fois mais restent toujours inférieurs à ceux mentionnés par la DGPA en 2000 avant les travaux d’aménagement. L’analyse granulométrique des sédiments superficiels reflète un fond à sables moyens à fins à des proportions différentes en matière organique selon les zones.
    Description: The present study aims to characterize water quality and sediment in Boughrara lagoon and its surrounding two years after the construction of new bridge. Abiotic parameters (water and sediment) are calculated in three areas with different geographical and environmental contexts. The results have shown clear signs of improvement in terms of the ecosystem. The spatiotemporal distributions of physicochemical parameters of water indicate that the levels found below the threshold of eutrophication quite a few times but are still lower than those reported by DGPA (2000). The size analysis of surface sediments shows that the bottom of the three underwater zones explored is covered mainly by medium to fine sand rich in organic matter.
    Description: Published
    Keywords: Coastal lagoons ; Environmental assessment ; Water quality ; Coastal lagoons ; Sediments ; Abiotic factors
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed , Article
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  • 5
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    Reproductive traits of two calanoid copepods: Centropages ponticus and Temora stylifera, in autumn in Bizerte Channel (2012)
    Oxford University Press
    Details
    Publication Date: 2012-12-28
    Description: The in situ reproductive activity of the copepods Centropages ponticus and Temora stylifera was investigated in autumn 2006 in the Bizerte Channel in relation to abiotic factors and phytoplankton composition. Egg production rate (EPR), hatching success (HS) and nauplii survival rate of both species were measured from samples taken daily over 45 days from September 28 to November 11 and then weekly over 8 supplementary weeks. Over this period, C. ponticus and T. stylifera had mean EPRs of 13.7 ± 0.3 and 35.2 ± 3.8 eggs f –1 day –1 , and mean HS of 24.4 ± 1.6 and 50.4 ± 5.5%, respectively. EPR and HS remained fairly stable for C. ponticus throughout the study period compared with T. stylifera in which reproductive traits fluctuated considerably. Changes in EPR and HS for both species resulted from environmental parameter variations and in particular, from phytoplankton composition, with slight decreasing EPR and HS observed after the important phytoplankton blooms. Centropages ponticus , a lagoon species, was able to withstand high turbidity, whereas T. stylifera , a marine species, had low EPR and HS under turbid conditions. The low HS recorded for C. ponticus , in particular in December, may be due to production of resting eggs.
    Print ISSN: 0142-7873
    Electronic ISSN: 1464-3774
    Topics: Biology
    Published by Oxford University Press
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  • 6
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    Cetacean occurrence and spatial distribution in the central Mediterranean Sea using ferries as platform of observation (2015)
    Springer
    Details
    Publication Date: 2015-09-01
    Print ISSN: 1063-0740
    Electronic ISSN: 1608-3377
    Topics: Biology
    Published by Springer
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  • 7
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    FOREWORD (2007)
    Oxford University Press
    Details
    Publication Date: 2007-01-01
    Print ISSN: 0142-7873
    Electronic ISSN: 1464-3774
    Topics: Biology
    Published by Oxford University Press
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  • 8
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    A blooming jellyfish in the northeast Atlantic and Mediterranean (2010)
    The Royal Society
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    Publication Date: 2010-04-07
    Description: A long-term time series of plankton records collected by the continuous plankton recorder (CPR) Survey in the northeast Atlantic indicates an increased occurrence of Cnidaria since 2002. In the years 2007 and 2008, outbreaks of the warm-temperate scyphomedusa, Pelagia noctiluca , appeared in CPR samples between 45° N to 58° N and 1° W to 26° W. Knowing the biology of this species and its occurrence in the adjacent Mediterranean Sea, we suggest that P. noctiluca may be exploiting recent hydroclimatic changes in the northeast Atlantic to increase its extent and intensity of outbreaks. In pelagic ecosystems, Cnidaria can affect fish recruitment negatively. Since P. noctiluca is a highly venomous species, outbreaks can also be detrimental to aquaculture and make bathing waters unusable, thus having profound ecological and socio-economic consequences.
    Print ISSN: 1744-9561
    Electronic ISSN: 1744-957X
    Topics: Biology
    Published by The Royal Society
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