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  • 1
    Publication Date: 2021-05-19
    Description: The results are given of a study of the dolphinfish Coryphaena hippurus fishery production in coastal waters of Tunisia; catches were caught during a survey which lasted 3-4 months. Spatio-temporal fluctuations of the production were analyzed with respect to physico-chemical parameters (temperature and salinity) and exploitation data (recording of contributions, increase of landing sites). Details are given of the catching techniques using fish aggregating devices. The total size at recruitment was estimated at 15 cm. The average sizes were determined throughout the duration of the survey.
    Description: Published
    Keywords: Marine fisheries ; Fishery surveys ; Catching methods ; Exploitation ; Coryphaena hippurus ; Marine
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp. 1-14
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  • 2
    Publication Date: 2021-05-19
    Description: L’étude histologique chez la carpe (Cyprinus carpio communis) de la retenue du barrage Sidi Saâd a pour objectifs l'identification des différentes phases du développement ovocytaire, la description de la cinétique de l'ovogenèse et la stratégie de ponte de cette espèce. Cette étude a été réalisée sur les ovaires de 150 femelles de la carpe commune pêchées dans le barrage. Les follicules post-ovulatoires et les ovocytes atrétiques ont été utilisés comme indicateurs d’une activité de ponte antérieure. Chaque phase histologique a été corrélée au stade macroscopique de maturité et au rapport gonado-somatique des individus étudiés et ceci afin de valider les différentes phases du cycle de reproduction chez la carpe. L’analyse des coupes histologiques des ovaires a permis de diviser l’ovogenèse en 4 phases : la vitellogenèse, la ponte partielle, la fin de ponte et le repos sexuel. Le cycle sexuel des femelles de la carpe peut être composé de 6 étapes : juvéniles, repos sexuel, début de la vitellogenèse, vitellogenèse, ponte, post-ponte et récupération. La présence des follicules post ovulatoires et des ovocytes à différents stades de développement permettent d’affirmer que la carpe commune est une espèce à ponte sériée. L’estimation de la fécondité chez la carpe a indiqué que cette espèce porte environ 102000 oeufs par kg du poids corporel.
    Description: Published
    Keywords: Cyprinus carpio communis ; Stratégie de ponte ; Cinétique de l’ovogenèse ; Histologie ; Fécondité ; Cyprinus carpio communis ; Spawning strategy ; kinetics of oogenesis ; Histology ; Fertility ; Reproductive biology
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp.57-69
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  • 3
    Publication Date: 2021-05-19
    Description: In Tunisia, the small pelagic species (Sardina pilchardus, Engraulis encrasicolus, sardinella aurita, Boops boops, Trachurus sp and Scomber sp.) account for 40% of the total national landings. Thus, since 1996, INSTM has developed a multidisciplinary and long-term research program, dedicated to this group of fish, based on direct method. Thus, the INSTM organizes OASIS surveys (Operations Anchovy and Sardine of the Institute of Salammbô),) for stock assessment of small pelagic species by acoustic techniques based on échointégration and coupled to experimental fishing hauls. The last survey, OASIS_16, was carried out during autumn season of 2018. The biomasses estimated to 50 thousand tons are at their lowest levels since 1998. The largest decreases are observed in the Gulf of Gabes. However, specific and regional fluctuations are observed. Also, the most abundant species (Trachurus sp et sardina pilchardus), have, in their majorities, sizes smaller than the size of first sexual maturity.
    Description: Published
    Keywords: Acoustique ; Petits pélagiques ; Répartition géographiaque ; Biomasse ; Acoustics ; Small pelagic ; Geographical distribution ; Biomass estimation
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp.15 -31
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  • 4
    Publication Date: 2021-05-19
    Description: Des donnees de production et d'effort de peche ont ete recueillies aupres des services de la Direction Generale de la Peche et de l'Aquaculture (DGPA). Ces donnees s'etendent sur onze ans (1987-1997). L'unite d'effort selectionnee est le produit du nombre de jours en mer et de la jauge brute (JM*JB). L'application des modeles de production (Fox et Shaefer) a ces donnees montre que les stocks de chevrette actuellement exploites sont proches de leur optimum d'exploitation. Ainsi, un leger accroissement d'effort pourrait etre envisage mais le developpement de la peche de la chevrette passe, inevitablement, par l'exploration de nouvelles zones de peche
    Description: Production and fishing effort data have been collected at services of the Tunisian Fisheries and Aquaculture General Direction DGPA. These data concern eleven years (1987-1997). The selected effort unit is the fishing days and gauge tonnage (FD*GT), which combine fishing days and stored capacity of boat. The application of production models (Fox and Shaefer) to these data shows that stocks of deep-water pink-shrimps P. longirostris currently exploited are close to their optimum exploitation. Thus, a light increase of effort should be envisaged but the development of the fishing stocks of this species must be passing by the exploration of new fishing zones
    Description: Published
    Keywords: Evaluation des stocks ; Fishing vessels ; Shrimp culture ; Shrimp fisheries ; Abundance ; Stock assessment ; Marine aquaculture ; Fishing effort ; Biomass ; Parapenaeus longirostris ; Marine
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp. 5-16
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  • 5
    Publication Date: 2021-05-19
    Description: En vue de realiser une premiere evaluation du stock des especes halieutiques benthiques exploitees dans le golfe de Gabes, des donnees de production et d'effort de peche ont ete recueillies et analysees. Ces donnees s'etendant sur une periode de 9 annees (1980-1988) concernant les differents types de flottilles operant dans cette region. De nombreuses correlations ont ete testees afin de selectionner l'unite d'effort adequate a employer dans la presente etude. L'ajustement des modeles synthetiques (SCHAEFER et FOX) aux donnees de production et d'effort a montre que la situation d'exploitation optimale est depasee, depuis 1988, d'environ 20 p. 100.
    Description: In order to realize a first assessment of exploited stock of benthic species in the gulf of Gabes, data on production and fishing effort have been collected and analysed. These data cover a period of 9 years (1980-1988) for differents types of the fleets operating in the region. A number of correlations were tested in order to select the adequate fishing effort unit to use in this evaluation. The ajustment of synthetic models (Schaefer and Fox) to the data on production and fishing effort unit emonstrated that optimal exploitation has been passed since 1988 by 20%
    Description: Published
    Keywords: Stock benthique ; Marine fisheries ; Overexploitation ; Stock assessment ; Statistical analysis ; Fishing effort ; Fishery resources ; Benthos ; Marine
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp. 23-38
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  • 6
    Publication Date: 2021-05-19
    Description: Notre étude s’est intéressée à l’état du stock de la carpe commune Cyprinus carpio communis (L., 1758) dans la retenue du barrage de Sidi Saâd (Centre de la Tunisie) durant l’année 2014. Cette espèce est présente dans la plupart des barrages et des lacs artificiels en Tunisie. Elle constitue l’une des principales espèces exploitées dans les barrages tunisiens. Les bases de données collectées ont fait l’objet d’une analyse de pseudo-cohortes, conformément aux exigences du programme VIT. Le stock réel de la carpe dans la retenue du barrage a été caractérisé par des individus ayant une longueur moyenne totale de 26,45 cm, une taille qui est supérieure que celle de la première maturité sexuelle. Les résultats de l’analyse de la pseudo-cohorte de cette espèce estime la biomasse exploitée à 143 tonnes. Ceci indique que cette espèce est en état de sous exploitation et qu’un effort de pêche supplémentaire pourrait être envisagé.
    Description: Published
    Keywords: Carpe commune ; Evaluation des stocks ; Programme VIT ; Common carp ; Stock assessment ; VIT program ; CYPRINUS CARPIO COMMUNIS
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp.51-56
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  • 7
    Publication Date: 2021-10-28
    Description: Metals in sediment constitute a significant source of environmental pollution. Trace metals and oligo-elements in surface sediments from Hammamet gulf (Tunisia) were assessed in order to evaluate their levels and spatial distribution due to urbanization, economic and touristic development of this region. Twenty stations were prospected and the collected sediment samples were analyzed by Atomic Absorption Spectrophotometry. The ranges of the measured concentrations in the sediments were as follows: 0.19-1.86 mg.kg-1 for Cd, 47.6-150.2 mg.kg-1 for Pb, 0.23-0.46 mg.kg-1 for Hg, 1.80-30.42 mg.kg-1 for Cu, 287-713 mgkg-1 for Zn, 3-26 gkg-1 for Fe, 86-374 mgkg-1 for Mn, 11-18 gkg-1 for Mg, 61-160 g.kg-1 for Na, 8-109 g.kg-1 for Ca, 4-19 g.kg-1 for K. The results showed significant correlation between Cu, Pb and Zn, indicating that they have common anthropogenic 160 and natural sources. The spatial distribution of metals in sediments of Hammamet gulf shows that the level of metals in the central and south eastern parts of the gulf is relatively high by some metals (i.e. Pb, Zn) This contamination is depending mainly on anthropogenic sources and petrochemical activities. Concentrations of trace metals in the studied area was comparable to the levels recorded in different other Mediterranean ecosystems. A constant monitoring should be conducted since the level of heavy metals may increase as industries are established in Hammamet Gulf.
    Description: Les métaux dans les sédiments constituent une source importante de pollution de l'environnement marin. Les métaux traces et les oligo-éléments dans les sédiments de surface du golfe de Hammamet (Tunisie) ont été évalués afin de déterminer leurs niveaux et leur distribution spatiale en raison de l'urbanisation, du développement économique et touristique de cette région.Vingt stations ont été prospectées et les échantillons de sédiments recueillis ont été analysés par Spectrophotométrie d'Absorption Atomique (SAA). Les fourchettes des concentrations mesurées dans les sédiments étaient les suivantes: 0,19-1,86 mgkg-1 pour le cadmium, 47,6-150,2 mg.kg-1 pour le plomb, 0,23-0,46 mg.kg-1 pour le mercure, 1,80-30,42 mg.kg-1 pour le cuivre, 287 -713 mg.kg-1 pour Zn, 3-26 g.kg-1 pour Fe, 86-374 mg.kg-1 pour Mn, 11-18 g.kg-1 pour Mg, 61-160 g.kg-1 pour Na, 8-109 g.kg-1 pour le Ca, 4-19 g.kg-1 pour K. Les résultats ont montré une corrélation significative entre Cu, Pb et Zn, indiquant qu'ils y avaient des sourcesanthropiques et naturelles communes. La distribution spatiale des métaux dans les sédiments du golfe deHammamet montre que le niveau de métaux dans les parties centrale et sud-est du golfe est relativement élevépour certains métaux (à savoir le Pb, le Zn). Cette contamination dépend principalement de sources anthropiqueset d'activités pétrochimiques. . Les concentrations de métaux en traces dans la zone étudiée étaient comparablesaux niveaux enregistrés dans différents autres écosystèmes méditerranéens. Une surveillance constante doit êtremenée car le niveau de métaux lourds peut augmenter avec l’implantation d’industries dans le golfe deHammamet
    Description: Published
    Description: Refereed
    Keywords: Contaminant ; Marine Sediments ; Heavy metals ; trace elements ; pollution
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: 159-170
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  • 8
    Publication Date: 2021-10-29
    Description: Un spécimen mâle de la crevette royale grise Penaeus aztecus Ives, 1891, une espèce de l’Atlantique Ouest, a été capturé par chalut de fond le long de la côte Nord de la Tunisie (Méditerranée centrale). Ce spécimen a été observé au niveau des captures de la chevrette Parapenaeus longirostris à la fin du mois de juillet 2020. En se basant sur la revue de la littérature et les informations récentes, l’aire de répartition de la crevette royale grise exotique Penaeus aztecus en mer Méditerranée a été ainsi présentée.
    Description: A male of the northern brown shrimp Penaeus aztecus Ives, 1891, a West Atlantic species, were unexpectedly caught by bottom trawler along the northern coast of Tunisia (Central Mediterranean). This atlantic species was landed during a fishing survey of Deep water rose shrimp Parapenaeus longirostris, later July 2020. Based on the literature review and recent information, the range of the exotic brown shrimp Penaeus aztecus in the Mediterranean Sea was thus presented.
    Description: Published
    Description: Refereed
    Keywords: Première signalisation ; crevette ; Penaeus aztecus
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: 29-36
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  • 9
    Publication Date: 2023-03-02
    Description: A new esseous part, the opercula bone, is used to estimate age of 2009 round sardine (Sardinella aurita Valenciennes, 1847) captured in the Cap Bon area. The period of sampling with a monthly rhythm, is spread out June 1994 at December 1995 and from June to September 1996. Th relation between the length of fish (LF) and the ray of opercula (RT) is LF= 22,25 RT 0,994 . The validation of age estimate method is carried out directly by the monthly follow-up of overage marginal lengthening and the percentage of individuals with marginal hyaline zone. This study showed that the round sardine has a double cycle of growth of the age-length shows that the females dominate in the majority of age groups the parameter of growth in length according to the model of Von Bertalanffy are estimated by direct enumeration of the hyaline zone and retrocalcul. The curves of growth obtained by employ retrocalculed data describe better the growth of the round sardine in Cap Bon area.
    Description: Published
    Description: Refereed
    Keywords: Sardinella aurita ; round sardine ; Opercula bone ; Age ; Gowth ; Validation
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: 9-22 pp
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  • 10
    Publication Date: 2024-01-10
    Description: Sandy barriers are coastal features formed and reworked by terrestrial and marine-induced processes along decadal to millenary scale periods. In the semi-arid areas along the extended North African coast, these coastal landscapes are undergoing accelerated morphodynamical changes induced by intensifying anthropogenic and climate drivers in the last century. To quantify the latter, we assess the changes in sediment dynamics of the Ghar El Melh sandy barrier extended over the northern part of the Gulf of Tunis in Tunisia using sedimentological analysis and quantification of the aeolian flux. A total of 37 subsurface samples and 30 surface aeolian trapped ones were collected at the coastal dunes of Ghar El Melh. Our sedimentological analysis reveals a distribution of 97% of sandy sediments and 3% of silty facies. The modal statistical analysis suggests that there are three distinguishable sediment types with 87% of samples formed by fine sands with modal value of 0.16 mm. The mixture of these indicates mixed terrigenous and marine sources redistributed by the hydrodynamic processes. The measurement of the aeolian flow suggests a maximum value of 0.0022 kg.m.-1min-1 which occurs in dust storms. This study reveals the low detrital sand supplies to the lagoon-sea barrier of Ghar El Melh, results in its gradual submersion, further exposing the coastal lagoon and engendering severe ecological degradations.
    Description: Published
    Description: Refereed
    Keywords: Mediterranean ; Sand banks ; Sedimentation ; Coastal erosion ; Eolian dust ; submerged shorelines
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: 37-48 pp
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