Lessepsian fishes, entering the Mediterranean through the Suez Canal, have showed so far little g... more Lessepsian fishes, entering the Mediterranean through the Suez Canal, have showed so far little genetic structure, but notable exceptions suggest the importance of life-history factors that may influence their patterns of spatial genetic variation. In this study, by sampling two invasive fishes with different life histories (the rabbitfish Siganus rivulatus and the filefish Stephanolepis diaspros ), we looked at evidence of population structure and selection at the boundary between the Red Sea and the Mediterranean (the Suez Canal), using thousands of molecular markers. Results illustrate two divergent patterns of genetic patterns, with little genetic structure in S. rivulatus and strong population structure in S. diaspros, even at such small spatial scale. We discuss differences in ecological characteristics between the two species to account for such differences. In addition, we report that in the face of both high ( S. rivulatus ) and low ( S. diaspros ) gene flow, loci under sel...
The Strait of Sicily is a major hydrodynamic, biogeographical and geological transition zone with... more The Strait of Sicily is a major hydrodynamic, biogeographical and geological transition zone within the Mediterranean Sea, considered as the boundary between the Western and Eastern sub-basins. During the last few decades, an increasing number of marine species native of either the Atlantic or the Indo-Pacific Oceans have been recorded in this area by researchers from Malta, Italy and Tunisia. Here we list recently recorded fish from the Strait of Sicily, illustrating suitable methodologies for their detection, and advocating the need of transnational monitoring networks. Introduction-The Strait of Sicily represents the major West-East transition zone within the Mediterranean, both from a hydrodynamic and biogeographical perspective. This area is considered as a strategic observation outpost within the Central Mediterranean for the monitoring of marine non-indigenous species (NIS) and the range extension of those entering the Mediterranean through the Gibraltar Strait. The objective...
Un specimen du cordonnier bossu, Alectis alexandrinus (E. Geoffroy Saint-Hilaire, 1817) (Carangid... more Un specimen du cordonnier bossu, Alectis alexandrinus (E. Geoffroy Saint-Hilaire, 1817) (Carangidae) est signale pour la premiere fois au large de la cote algerienne, pres d'Annaba par 50-100 m de fond environ. Une description succincte de l'espece est presentee ainsi que des caracteres biometriques et meristiques. La repartition de A. alexandrinus en Mediterranee est commentee.
In January 2021 during a scientific survey to assess the economic impacts of a Mass Mortality Eve... more In January 2021 during a scientific survey to assess the economic impacts of a Mass Mortality Event, a single individual of the Gracile lizardfish Saurida gracilis (Quoy & Gaimard, 1824) was caught out of Korbous (Northern Tunisia). This observation, confirmed by genetic analysis, provides evidence on the occurrence of a new non-indigenous species in Mediterranean waters. The relevance of this finding for the current monitoring strategies implemented at the regional level are briefly raised and discussed.
... des ressources animales, halieutiques et des technologies agro-alimentaires, institut nationa... more ... des ressources animales, halieutiques et des technologies agro-alimentaires, institut national agronomique de Tunisie, 43 avenue Charles Nicolle, Cité ... species which lives in shallow waters (ivant-soff and Crowley, 1991) and reaches 150 mm total length (Kuiter and Tonozuka ...
Des observations récentes faites au cours de campagnes de prélèvements médio et infralittoraux d’... more Des observations récentes faites au cours de campagnes de prélèvements médio et infralittoraux d’organismes benthiques dans des lagunes côtières tunisiennes nous ont permis de mettre en évidence l’installation de 4 crustacés d’origine lessepsienne signalés pour la première fois en Tunisie et sur la rive Sud de la M éditerranée (amphipode Caprella scaura) et en Méditerranée centrale (amphipodes Maera hamigera, Gammaropsis togoensis et l’isopode parasite Anilocra pilchardi).
The dataset was collected with the the Mediterranean LEK initiative. The initiative was initially... more The dataset was collected with the the Mediterranean LEK initiative. The initiative was initially conceived by the international basin-wide monitoring program <em>CIESM Tropical Signals</em> (funded by the Albert II of Monaco Foundation) and subsequently adopted by the projects BALMAS (Ballast Water Management System for Adriatic Sea Protection, IPA Adriatic Cross-Border Cooperation Programme; <em>FAO-AdriaMed</em> and <em>FAO-MedSudMed</em>. This action was recently supported by the Interreg Med Programme (Grant number Pr MPA-Adapt 1MED15_3.2_M2_337) 85% co-funded by the European Regional Development Fund, which implemented the use of standard LEK protocols for Marine Protected areas and partially supported the writing of this publication. Data refers to self-reported trends of various fish species, which were regarded as increaseing by a sample of fishermen from various Mediterranean countries. Interviews were elicited from fishermen through sem...
A total of 4665 specimens of Sphaeroma venustissimum Monod, 1931 were collected between February ... more A total of 4665 specimens of Sphaeroma venustissimum Monod, 1931 were collected between February 2012 and January 2013, in Tunis Southern Lagoon, a brackish area located in northern Tunisia. This species was mainly recorded in the Atlantic Ocean and recently extended its natural range toward the southern Mediterranean Sea. Biological and ecological traits were not available to date with special regard to its native and recipient habitat. S. venustissimum isopoda inhabits area below stones covered by biofouling and empty nests of barnacles. The species occursand reproduces in Tunis Southern Lagoon throughout the year with a peak in early spring and late summer. Males significantly outnumbered females during high reproductive activity period (May - July). The first gravid female was observed at 7 mm and the fecundity ranged between 6 and 17 eggs. Among the gravid females, a significant relationship was noted between the importance of brood versus total body length for all ovigerous fe...
An updated inventory of alien marine fauna in coastal and offshore Tunisian waters is presented. ... more An updated inventory of alien marine fauna in coastal and offshore Tunisian waters is presented. Records were compiled from scientific and ‘grey’ publications, presentations at scientific meetings, theses presented in fulfillment of requirements towards MSc and PhD degrees, websites and personal observations. 136 alien species were recorded in Tunisian waters, 60 records in northern coasts, West Mediterranean and 76 in central and southern coasts, Central Mediterranean. Nearly half of the first sightings in Tunisian waters took place in the Gulf of Gabès. The dominant taxa are Crustancean (24%), Molluscs (23%), Fishes (19%) and Annelida (13%). Twenty one species previously reported as aliens, were upon consideration, reclassified as range-expanding Atlantic species. Amathia verticillata, previously considered native to the Mediterranean, is reclassified as pseudoindigenous. Twenty one alien species are newly recorded from Tunisia, including 5 fish species, 5 polychaetes, 4 crustacea...
Mediterranean fauna is undergoing drastic modifications as a result of anthropogenic activities a... more Mediterranean fauna is undergoing drastic modifications as a result of anthropogenic activities and global warming. The most important of these is the colonization of the Mediterranean Sea by alien species, many of them entering through the Suez Canal. While many of them are still confined to the Levant Basin, several have extended their distribution westwards to Tunisian waters. The presence of the Indo-west Pacific hymenosomatid crab Elamena mathoei on a rocky shore at Sidi Daoud, Cape Bon Peninsula, Tunisia, is the first Mediterranean record of this species. It is a testimony to the changes in the patterns of invasion in the Mediterranean Sea.
Reproduction of the sawback angelshark Squatina aculeata is presented with specimens captured off... more Reproduction of the sawback angelshark Squatina aculeata is presented with specimens captured off Tunisia (central Mediterranean) and off Senegal (eastern tropical Atlantic). The smallest adult male and adult female were 120 and 137 cm total length (TL), respectively, and weighed 12.7 and 22.0 kg, respectively. Above 122 cm TL for males and 143 cm TL for females, all the observed specimens were adult. The largest male and the largest female were 152 and 175 cm TL and weighed 24.0 kg and 32.0 kg, respectively. Males and females presented similar total length versus total mass relationships, although the latter were considerably heavier than the former. Size at birth was between 30.3 and 35.0 cm TL and mass at birth between 276 and 325 g. The two ovaries and the two uteri were functional. Ripe ovarian follicles ready to be ovulated ranged between 76 and 85 mm in diameter and weighed between 200 and 237.6 g. Gestation lasted one year approximately, but ovarian follicles growth blocked ...
During the last decades, 4 alien isopods have been reported from harbours and nearby lagoons in T... more During the last decades, 4 alien isopods have been reported from harbours and nearby lagoons in Tunisia. The intensification of shipping activities and the significant increase in the average water temperature has been enhanced the introduction and the establishment of non indigenous species. Since its occurrence Sphaeroma walkeri was studied. A brief description and some ecological main features are given and discussed.
La reproduction de l'ange de mer epineux Squatina aculeata est decrite a partir de specimens ... more La reproduction de l'ange de mer epineux Squatina aculeata est decrite a partir de specimens captures au large du Senegal (Atlantique oriental tropical) et de la Tunisie (Mediterranee centrale). Le plus petit mâle adulte et la plus petite femelle adulte mesuraient 120 et 137 cm de longueur totale (LT) et pesaient 12,7 et 22,0 kg, respectivement, tous les individus observes etaient adultes, au-dessus de 122 cm LT pour les mâles et de 143 cm LT pour les femelles. Dans notre echantillon, le plus grand mâle et la plus grande femelle avaient une LT de 152 et 175 cm et pesaient respectivement 24 kg et 32 kg. Les relations taille-masse sont semblables chez les mâles et les femelles, bien que ces dernieres soient plus lourdes. La taille a la naissance se situait entre 30,3 et 35,0 cm LT et la masse entre 276 et 345 g. Les deux ovaires et les deux uterus sont fonctionnels. Les follicules ovariens murs, prets a etre pondus, avaient un diametre compris entre 76 et 85 mm et une masse compri...
Adult bluntnose sixgill shark (Hexanchus griseus) males and females from the Mediterranean were o... more Adult bluntnose sixgill shark (Hexanchus griseus) males and females from the Mediterranean were over 3000 mm TL and 3940 mm. Size at birth was 556-680 mm TL. Ripe oocytes ranged between 68 and 75 mm TL (mean 71.71′2.6) indiameter and 127-147 g (mean 134′8.4) in weight. The reproductive cycle lasted at least one year, but probably more. The chemical balance of development (dry weight of newborn pup/dry weight of ripe oocyte) was 3. One adult female contained 57 ripe oocytes; a second contained 100. Hexanchus griseus is probably able to live and reproduce in the Mediterranean Sea, however, further observations are needed to confirm that a sustainable bluntnose sixgill shark population has been established here, especially off the Maghrebin coast.
Feeding habits of the invasive spider crab Libinia dubia from the Mediterranean Sea were studied ... more Feeding habits of the invasive spider crab Libinia dubia from the Mediterranean Sea were studied in the Gulf of Gabès (Tunisia) using the frequency of occurrence and points methods. The population was sampled at least monthly between November 2015 and October 2016. Stomach contents of 384 specimens were analysed. Results indicate that L. dubia is an herbivorous species exhibiting clear preferences for algae (ALG) and Magnoliophyta (MAG) (62.03%, 7.13 points and 59.36%, 5.3 points respectively) although Echinodermata (ECH), Porifera (POR), Cnidaria (CNI), Mollusca (MOL), Polychaeta (POL), Crustacea (CRU) and fish (FIS) were accidentally consumed along with Bryozoa (BRY), sediment (SED), and unidentifiable materials (UNM). The diversity of ALG ingested was studied in detail: Chlorophyceae were found in 87.93% of stomachs containing ALG and contributed most of points to the stomach contents (4.18 points) followed respectively by Phaeophyceae (81.03%, 2.27 points) and Rhodophyceae (40.9...
Lessepsian fishes, entering the Mediterranean through the Suez Canal, have showed so far little g... more Lessepsian fishes, entering the Mediterranean through the Suez Canal, have showed so far little genetic structure, but notable exceptions suggest the importance of life-history factors that may influence their patterns of spatial genetic variation. In this study, by sampling two invasive fishes with different life histories (the rabbitfish Siganus rivulatus and the filefish Stephanolepis diaspros ), we looked at evidence of population structure and selection at the boundary between the Red Sea and the Mediterranean (the Suez Canal), using thousands of molecular markers. Results illustrate two divergent patterns of genetic patterns, with little genetic structure in S. rivulatus and strong population structure in S. diaspros, even at such small spatial scale. We discuss differences in ecological characteristics between the two species to account for such differences. In addition, we report that in the face of both high ( S. rivulatus ) and low ( S. diaspros ) gene flow, loci under sel...
The Strait of Sicily is a major hydrodynamic, biogeographical and geological transition zone with... more The Strait of Sicily is a major hydrodynamic, biogeographical and geological transition zone within the Mediterranean Sea, considered as the boundary between the Western and Eastern sub-basins. During the last few decades, an increasing number of marine species native of either the Atlantic or the Indo-Pacific Oceans have been recorded in this area by researchers from Malta, Italy and Tunisia. Here we list recently recorded fish from the Strait of Sicily, illustrating suitable methodologies for their detection, and advocating the need of transnational monitoring networks. Introduction-The Strait of Sicily represents the major West-East transition zone within the Mediterranean, both from a hydrodynamic and biogeographical perspective. This area is considered as a strategic observation outpost within the Central Mediterranean for the monitoring of marine non-indigenous species (NIS) and the range extension of those entering the Mediterranean through the Gibraltar Strait. The objective...
Un specimen du cordonnier bossu, Alectis alexandrinus (E. Geoffroy Saint-Hilaire, 1817) (Carangid... more Un specimen du cordonnier bossu, Alectis alexandrinus (E. Geoffroy Saint-Hilaire, 1817) (Carangidae) est signale pour la premiere fois au large de la cote algerienne, pres d'Annaba par 50-100 m de fond environ. Une description succincte de l'espece est presentee ainsi que des caracteres biometriques et meristiques. La repartition de A. alexandrinus en Mediterranee est commentee.
In January 2021 during a scientific survey to assess the economic impacts of a Mass Mortality Eve... more In January 2021 during a scientific survey to assess the economic impacts of a Mass Mortality Event, a single individual of the Gracile lizardfish Saurida gracilis (Quoy & Gaimard, 1824) was caught out of Korbous (Northern Tunisia). This observation, confirmed by genetic analysis, provides evidence on the occurrence of a new non-indigenous species in Mediterranean waters. The relevance of this finding for the current monitoring strategies implemented at the regional level are briefly raised and discussed.
... des ressources animales, halieutiques et des technologies agro-alimentaires, institut nationa... more ... des ressources animales, halieutiques et des technologies agro-alimentaires, institut national agronomique de Tunisie, 43 avenue Charles Nicolle, Cité ... species which lives in shallow waters (ivant-soff and Crowley, 1991) and reaches 150 mm total length (Kuiter and Tonozuka ...
Des observations récentes faites au cours de campagnes de prélèvements médio et infralittoraux d’... more Des observations récentes faites au cours de campagnes de prélèvements médio et infralittoraux d’organismes benthiques dans des lagunes côtières tunisiennes nous ont permis de mettre en évidence l’installation de 4 crustacés d’origine lessepsienne signalés pour la première fois en Tunisie et sur la rive Sud de la M éditerranée (amphipode Caprella scaura) et en Méditerranée centrale (amphipodes Maera hamigera, Gammaropsis togoensis et l’isopode parasite Anilocra pilchardi).
The dataset was collected with the the Mediterranean LEK initiative. The initiative was initially... more The dataset was collected with the the Mediterranean LEK initiative. The initiative was initially conceived by the international basin-wide monitoring program <em>CIESM Tropical Signals</em> (funded by the Albert II of Monaco Foundation) and subsequently adopted by the projects BALMAS (Ballast Water Management System for Adriatic Sea Protection, IPA Adriatic Cross-Border Cooperation Programme; <em>FAO-AdriaMed</em> and <em>FAO-MedSudMed</em>. This action was recently supported by the Interreg Med Programme (Grant number Pr MPA-Adapt 1MED15_3.2_M2_337) 85% co-funded by the European Regional Development Fund, which implemented the use of standard LEK protocols for Marine Protected areas and partially supported the writing of this publication. Data refers to self-reported trends of various fish species, which were regarded as increaseing by a sample of fishermen from various Mediterranean countries. Interviews were elicited from fishermen through sem...
A total of 4665 specimens of Sphaeroma venustissimum Monod, 1931 were collected between February ... more A total of 4665 specimens of Sphaeroma venustissimum Monod, 1931 were collected between February 2012 and January 2013, in Tunis Southern Lagoon, a brackish area located in northern Tunisia. This species was mainly recorded in the Atlantic Ocean and recently extended its natural range toward the southern Mediterranean Sea. Biological and ecological traits were not available to date with special regard to its native and recipient habitat. S. venustissimum isopoda inhabits area below stones covered by biofouling and empty nests of barnacles. The species occursand reproduces in Tunis Southern Lagoon throughout the year with a peak in early spring and late summer. Males significantly outnumbered females during high reproductive activity period (May - July). The first gravid female was observed at 7 mm and the fecundity ranged between 6 and 17 eggs. Among the gravid females, a significant relationship was noted between the importance of brood versus total body length for all ovigerous fe...
An updated inventory of alien marine fauna in coastal and offshore Tunisian waters is presented. ... more An updated inventory of alien marine fauna in coastal and offshore Tunisian waters is presented. Records were compiled from scientific and ‘grey’ publications, presentations at scientific meetings, theses presented in fulfillment of requirements towards MSc and PhD degrees, websites and personal observations. 136 alien species were recorded in Tunisian waters, 60 records in northern coasts, West Mediterranean and 76 in central and southern coasts, Central Mediterranean. Nearly half of the first sightings in Tunisian waters took place in the Gulf of Gabès. The dominant taxa are Crustancean (24%), Molluscs (23%), Fishes (19%) and Annelida (13%). Twenty one species previously reported as aliens, were upon consideration, reclassified as range-expanding Atlantic species. Amathia verticillata, previously considered native to the Mediterranean, is reclassified as pseudoindigenous. Twenty one alien species are newly recorded from Tunisia, including 5 fish species, 5 polychaetes, 4 crustacea...
Mediterranean fauna is undergoing drastic modifications as a result of anthropogenic activities a... more Mediterranean fauna is undergoing drastic modifications as a result of anthropogenic activities and global warming. The most important of these is the colonization of the Mediterranean Sea by alien species, many of them entering through the Suez Canal. While many of them are still confined to the Levant Basin, several have extended their distribution westwards to Tunisian waters. The presence of the Indo-west Pacific hymenosomatid crab Elamena mathoei on a rocky shore at Sidi Daoud, Cape Bon Peninsula, Tunisia, is the first Mediterranean record of this species. It is a testimony to the changes in the patterns of invasion in the Mediterranean Sea.
Reproduction of the sawback angelshark Squatina aculeata is presented with specimens captured off... more Reproduction of the sawback angelshark Squatina aculeata is presented with specimens captured off Tunisia (central Mediterranean) and off Senegal (eastern tropical Atlantic). The smallest adult male and adult female were 120 and 137 cm total length (TL), respectively, and weighed 12.7 and 22.0 kg, respectively. Above 122 cm TL for males and 143 cm TL for females, all the observed specimens were adult. The largest male and the largest female were 152 and 175 cm TL and weighed 24.0 kg and 32.0 kg, respectively. Males and females presented similar total length versus total mass relationships, although the latter were considerably heavier than the former. Size at birth was between 30.3 and 35.0 cm TL and mass at birth between 276 and 325 g. The two ovaries and the two uteri were functional. Ripe ovarian follicles ready to be ovulated ranged between 76 and 85 mm in diameter and weighed between 200 and 237.6 g. Gestation lasted one year approximately, but ovarian follicles growth blocked ...
During the last decades, 4 alien isopods have been reported from harbours and nearby lagoons in T... more During the last decades, 4 alien isopods have been reported from harbours and nearby lagoons in Tunisia. The intensification of shipping activities and the significant increase in the average water temperature has been enhanced the introduction and the establishment of non indigenous species. Since its occurrence Sphaeroma walkeri was studied. A brief description and some ecological main features are given and discussed.
La reproduction de l'ange de mer epineux Squatina aculeata est decrite a partir de specimens ... more La reproduction de l'ange de mer epineux Squatina aculeata est decrite a partir de specimens captures au large du Senegal (Atlantique oriental tropical) et de la Tunisie (Mediterranee centrale). Le plus petit mâle adulte et la plus petite femelle adulte mesuraient 120 et 137 cm de longueur totale (LT) et pesaient 12,7 et 22,0 kg, respectivement, tous les individus observes etaient adultes, au-dessus de 122 cm LT pour les mâles et de 143 cm LT pour les femelles. Dans notre echantillon, le plus grand mâle et la plus grande femelle avaient une LT de 152 et 175 cm et pesaient respectivement 24 kg et 32 kg. Les relations taille-masse sont semblables chez les mâles et les femelles, bien que ces dernieres soient plus lourdes. La taille a la naissance se situait entre 30,3 et 35,0 cm LT et la masse entre 276 et 345 g. Les deux ovaires et les deux uterus sont fonctionnels. Les follicules ovariens murs, prets a etre pondus, avaient un diametre compris entre 76 et 85 mm et une masse compri...
Adult bluntnose sixgill shark (Hexanchus griseus) males and females from the Mediterranean were o... more Adult bluntnose sixgill shark (Hexanchus griseus) males and females from the Mediterranean were over 3000 mm TL and 3940 mm. Size at birth was 556-680 mm TL. Ripe oocytes ranged between 68 and 75 mm TL (mean 71.71′2.6) indiameter and 127-147 g (mean 134′8.4) in weight. The reproductive cycle lasted at least one year, but probably more. The chemical balance of development (dry weight of newborn pup/dry weight of ripe oocyte) was 3. One adult female contained 57 ripe oocytes; a second contained 100. Hexanchus griseus is probably able to live and reproduce in the Mediterranean Sea, however, further observations are needed to confirm that a sustainable bluntnose sixgill shark population has been established here, especially off the Maghrebin coast.
Feeding habits of the invasive spider crab Libinia dubia from the Mediterranean Sea were studied ... more Feeding habits of the invasive spider crab Libinia dubia from the Mediterranean Sea were studied in the Gulf of Gabès (Tunisia) using the frequency of occurrence and points methods. The population was sampled at least monthly between November 2015 and October 2016. Stomach contents of 384 specimens were analysed. Results indicate that L. dubia is an herbivorous species exhibiting clear preferences for algae (ALG) and Magnoliophyta (MAG) (62.03%, 7.13 points and 59.36%, 5.3 points respectively) although Echinodermata (ECH), Porifera (POR), Cnidaria (CNI), Mollusca (MOL), Polychaeta (POL), Crustacea (CRU) and fish (FIS) were accidentally consumed along with Bryozoa (BRY), sediment (SED), and unidentifiable materials (UNM). The diversity of ALG ingested was studied in detail: Chlorophyceae were found in 87.93% of stomachs containing ALG and contributed most of points to the stomach contents (4.18 points) followed respectively by Phaeophyceae (81.03%, 2.27 points) and Rhodophyceae (40.9...
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