scholarly journals Spatial distribution of tuna larvae in the Gulf of Gabes (Eastern Mediterranean) in relation with environmental parameters

2013 ◽  
Vol 14 (1) ◽  
pp. 5 ◽  
Author(s):  
W. KOCHED ◽  
A. HATTOUR ◽  
F. ALEMANY ◽  
A. GARCIA ◽  
K. SAID
Keyword(s):  
Spatial Distribution ◽  
Eastern Mediterranean ◽  
Environmental Parameters ◽  
Physical Parameters ◽  
Gulf Of Gabes ◽  
Atlantic Bluefin Tuna ◽  
Gulf Of Gabès ◽  
Moderate Salinity ◽  
Regular Sampling ◽  
Distribution And Ecology

Spatial distribution and ecology of the larvae of three tuna species (Thunnus thynnus, Auxis rochei and Euthynnus alletteratus) were studied during an ichthyoplankton survey carried out in the Gulf of Gabes (Tunisia) in June and July 2009. A total of 80 stations, distributed on a regular sampling grid, were sampled. The main objectives of this survey were to provide information on tuna larvae distribution in the Gulf of Gabes in relation to the environmental parameters. Regarding small tunas, larvae of A. rochei (bullet tuna) showed the more widespread distribution, being found at both inshore and offshore stations. E. alletteratus (Atlantic black skipjack) larvae were mainly found at the inshore stations covering the wide continental shelf of this region. On the other hand, larvae of the large migratory tuna T. Thynnus (Atlantic bluefin tuna), were mainly recorded at offshore stations, suggesting that spawning possibly takes place mainly near the shelf break. Regarding the biological and physical parameters examined, our results indicate that tuna larvae were mainly collected in oligotrophic and mixed waters resulting from the confluence of surface water of recent Atlantic origin and resident surface Mediterranean waters, as shown by their preference for lower chlorophyll a concentrations (from 1.4 to 2.5 mg m-3) and moderate salinity values (between 37.35 and 37.75). Significantly, tuna larvae seemed to avoid the more eutrophic and saltier waters of the gulf situated very close to the coast and around Kerkennah and Djerba islands.

scholarly journals High diversified benthic habitats in a tidal Mediterranean sub-tropical environment: the case of the Gulf of Gabès (Tunisia)

2018 ◽  
Author(s):  
Abir Fersi ◽  
Nawfel Mosbahi ◽  
Ali Bakalem ◽  
Jean-Philippe Pezy ◽  
Alexandrine Baffreau ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Tropical Environment ◽  
Gulf Of Gabes ◽  
Annual Cycles ◽  
Gulf Of Gabès ◽  
Zostera Noltei ◽  
Sediment Types ◽  
The Mediterranean ◽  
The Impact

The Gulf of Gabès on the southern coasts of Tunisia in the central part of the Mediterranean is a very shallow basin, characterized by semidiurnal tides, attaining a range of 2.3 m during spring tides. The intertidal zone was covered by extended Zostera (Zosterella) noltei Hornemann, 1832 beds mainly developed around the Kneiss Islands while tidal channels ensured the water circulation in this sub-tropical environment with very low freshwater input and high summer temperature. In spite of protected conventions, the area remained under high human pressures: overfishing, and the impact of the pollution of the phosphate industry. Intensive sampling in both intertidal and shallow subtidal zones during annual cycles permitted to identify a rich macrofauna which increase considerably the species known in this eastern part of the Mediterranean Sea. More than 50 species are added for the Tunisian fauna. Moreover, patterns of diversity are analysed with the sediment types, presence or absence of Zostera noltei seagrass bed, and human pressures. The list of the collected species are compared with those of surrounding areas in both Western and Eastern Mediterranean Sea.

scholarly journals High diversified benthic habitats in a tidal Mediterranean sub-tropical environment: the case of the Gulf of Gabès (Tunisia)

2018 ◽  
Author(s):  
Abir Fersi ◽  
Nawfel Mosbahi ◽  
Ali Bakalem ◽  
Jean-Philippe Pezy ◽  
Alexandrine Baffreau ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Tropical Environment ◽  
Gulf Of Gabes ◽  
Annual Cycles ◽  
Gulf Of Gabès ◽  
Zostera Noltei ◽  
Sediment Types ◽  
The Mediterranean ◽  
The Impact

The Gulf of Gabès on the southern coasts of Tunisia in the central part of the Mediterranean is a very shallow basin, characterized by semidiurnal tides, attaining a range of 2.3 m during spring tides. The intertidal zone was covered by extended Zostera (Zosterella) noltei Hornemann, 1832 beds mainly developed around the Kneiss Islands while tidal channels ensured the water circulation in this sub-tropical environment with very low freshwater input and high summer temperature. In spite of protected conventions, the area remained under high human pressures: overfishing, and the impact of the pollution of the phosphate industry. Intensive sampling in both intertidal and shallow subtidal zones during annual cycles permitted to identify a rich macrofauna which increase considerably the species known in this eastern part of the Mediterranean Sea. More than 50 species are added for the Tunisian fauna. Moreover, patterns of diversity are analysed with the sediment types, presence or absence of Zostera noltei seagrass bed, and human pressures. The list of the collected species are compared with those of surrounding areas in both Western and Eastern Mediterranean Sea.

High-resolution numerical modelling of the barotropic tides in the Gulf of Gabes, eastern Mediterranean Sea (Tunisia)

2017 ◽  
Vol 129 ◽  
pp. 224-232 ◽  
Author(s):  
Achref Othmani ◽  
Béchir Béjaoui ◽  
Cristèle Chevalier ◽  
Dalila Elhmaidi ◽  
Jean-Luc Devenon ◽  
...  
Keyword(s):  
High Resolution ◽  
Numerical Modelling ◽  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Gulf Of Gabes ◽  
Eastern Mediterranean Sea ◽  
Gulf Of Gabès

scholarly journals Synthesis review of the Gulf of Gabes (eastern Mediterranean Sea, Tunisia): Morphological, climatic, physical oceanographic, biogeochemical and fisheries features

2019 ◽  
Vol 219 ◽  
pp. 395-408 ◽  
Author(s):  
Béchir Béjaoui ◽  
Sana Ben Ismail ◽  
Achref Othmani ◽  
Olfa Ben Abdallah-Ben Hadj Hamida ◽  
Cristèle Chevalier ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Gulf Of Gabes ◽  
Eastern Mediterranean Sea ◽  
Gulf Of Gabès

Copepod community structure related to environmental factors from a summer cruise in the Gulf of Gabès (Tunisia, eastern Mediterranean Sea)

2009 ◽  
Vol 90 (1) ◽  
pp. 145-157 ◽  
Author(s):  
Zaher Drira ◽  
Malika Belhassen ◽  
Habib Ayadi ◽  
Asma Hamza ◽  
Rafik Zarrad ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Sampling Period ◽  
Trophic Levels ◽  
Copepod Community ◽  
Gulf Of Gabes ◽  
Small Copepod ◽  
Eastern Mediterranean Sea ◽  
Gulf Of Gabès

We studied the summer spatial distribution of the copepod community in both the neritic and oceanic areas of the Gulf of Gabès (Tunisia, eastern Mediterranean Sea) coupled with environmental factors. Copepods were the most abundant zooplankton throughout the sampling period, contributing 78% of the total zooplankton. A total of 14 copepod families were identified in all stations, with an overwhelming abundance of Acartiidae and Oithonidae (39.05 and 39.09% of total abundance, respectively). Abundance of Acartia clausi and chlorophyll-a concentrations were negatively correlated with salinity, suggesting that this species probably escaped the high coastal salinity (38 psu). Significant correlation determined between A. clausi and tintinnids at 50 m isobaths indicates that these planktonic ciliates probably served as a substantial food link towards higher trophic levels of this area. Conversely, Oithona nana which was well adapted to high chlorophyll-a concentrations and high salinity along the coast, showed significant correlations with Dictyochophyceae, Dinophyceae, Bacillariophyceae and Euglenophyceae, suggesting that this small copepod was capable of feeding on a wide selection of phytoplankton preys.

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