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...
Local Ecological Knowledge of 92 professional fishers from Tunisia and Libya was used to investig... more Local Ecological Knowledge of 92 professional fishers from Tunisia and Libya was used to investigate on the occurrence and establishment of the exotic Hemiramphus far and Saurida undosquamis along the southern Mediterranean coasts. According to fisherman’s knowledge, H. far and S. undosquamis appeared in Libya, in 1980 and 1989 respectively. In Tunisia these species were observed afterwards, in 2004 and 2007. Currently both H. far and S. undosquamis result to be well distributed and established, along the entire surveyed area, from Tubrouk (eastern Libya) to Tabarka (western Tunisia). A statistical analysis of the qualitative trends in abundance perceived by the respondents show that both species have significantly increased in abundance in Tunisia. In Libya an increase of the abundance of H. far was also apparent during the first decade of the 21st century but the current abundance of S. undosquamis resulted to be stable at the level of occasional captures. Given the lack of regula...
Surveys recently conducted throughout the Tunisian coast allow to record, for the first time, the... more Surveys recently conducted throughout the Tunisian coast allow to record, for the first time, the indo pacific mantis shrimp Erugosquilla massavensis (Kossmann, 1880) in the area. Of the 11 specimens observed, 8 were collected in the Gulf of Gabes and 3 in Tunis Southern Lagoon. These new records point out an extension range of the species in the Mediterranean Sea, which could be explained by the pelagic life of larvae which enhances its expansion throughout the Mediterranean Sea. However, global warming and increasing of shipping traffic cannot be totally ruled out. Additionally these new Tunisian findings do not constitute a sufficient support to state that a sustainable population is at present established in the area.
Ce travail traite de l’eco biologie de F. Fragilis (Forskal in Niehbur, 1775), bivalve lessepsien... more Ce travail traite de l’eco biologie de F. Fragilis (Forskal in Niehbur, 1775), bivalve lessepsien, signale en Tunisie depuis 1996. La biologie de la reproduction a ete etudiee et un suivi la croissance relative et absolue a ete effectue, a deux biotopes differents (la baie de Tunis et la lagune de Bizerte). Le statut de F. Fragilis en Tunisie a ete etabli. Les etudes histologiques ont revele que c’est une espece hermaphrodite simultanee. L’echelle de maturation sexuelle a ete dressee. La fecondation interne et l’auto fecondation sont possibles chez cette espece. La ponte est continue sur toute l’annee. Ce mode de reproduction optimise le succes de l’installation de l’espece mais est couteux en energie. D’ailleurs, des mortalites estivales ont ete notees et une deficience du cycle de reproduction chez F. Fragilis de la lagune de Bizerte, site fortement pollue, a ete observee. Le suivi de la cinetique du diametre ovocytaire a permis la validation de l’echelle de maturation sexuelle. L’indice de condition constitue un bon indicateur de l’etat physiologique de F. Fragilis. L’etude de la croissance relative de F. Fragilis, aux deux sites de collecte, revele des differences majeures. La coque presente une forme plus allongee a la baie de Tunis. La croissance ponderale de ce bivalve invasif est generalement defavorisee par rapport a celle de la longueur coquilliere, a Tunis, inversement a la population de Bizerte. Au second site, la croissance coquilliere pourrait etre affectee par la pollution. Le suivi de la croissance absolue dans les deux sites atteste que le recrutement de ce bivalve serait etale dans le temps a Tunis et tres faible a Bizerte.
Journal of the Marine Biological Association of the United Kingdom, 2011
This study is the first work on the reproductive biology of lessepsian bivalve Fulvia fragilis. M... more This study is the first work on the reproductive biology of lessepsian bivalve Fulvia fragilis. Monthly and bimonthly samplings were made in the period from April 2006 to October 2007, at the Bay of Tunis (northern Tunisia). From histological preparations of gonad, a gametogenic scale was drawn up based on eight stages: sexual rest; initiation of gametogenesis; advanced gametogenesis; ripe; partial spawning; advanced spawning; restoration; and spent. After examination of gonad preparations, F. fragilis appeared to be a simultaneous hermaphrodite species. Spawning was continuous all along the year, scarce in winter and with peaks during the rest of the year. The spawning peaks were positively correlated with the rise of the sea surface temperature and the nutrient availability. Furthermore, the presence of oocytes surrounded by spermatozoa in female and male follicles and in male gonoducts was observed. Self-fertilization may occur in this species. High summer mortalities probably du...
Regular surveys, conducted in the Tunis Southern Lagoon from June 2014 to May 2015 in 10 stations... more Regular surveys, conducted in the Tunis Southern Lagoon from June 2014 to May 2015 in 10 stations, allowed us to sample 44 crustacean species: 31 are autochthonous and 13 allochthonous. These new settlements are the consequences of the successfully environmental restoration of the area, which enhanced the presence of species locally unknown. The canonical correspondence analysis (CCA) highlighted the concomitant influence of several environmental factors. The Shannon-Weaver diversity index indicates that the lagoon is a good-moderate ecosystem and the evenness (J') tends towards 1 reflecting an almost equal distribution of individuals in the species.
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, brackish area located in northern Tunisia. This species was mainly recorded in the Atlantic Ocean and recently extended its natural range toward 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 occurs and 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 female co...
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...
Local Ecological Knowledge of 92 professional fishers from Tunisia and Libya was used to investig... more Local Ecological Knowledge of 92 professional fishers from Tunisia and Libya was used to investigate on the occurrence and establishment of the exotic Hemiramphus far and Saurida undosquamis along the southern Mediterranean coasts. According to fisherman’s knowledge, H. far and S. undosquamis appeared in Libya, in 1980 and 1989 respectively. In Tunisia these species were observed afterwards, in 2004 and 2007. Currently both H. far and S. undosquamis result to be well distributed and established, along the entire surveyed area, from Tubrouk (eastern Libya) to Tabarka (western Tunisia). A statistical analysis of the qualitative trends in abundance perceived by the respondents show that both species have significantly increased in abundance in Tunisia. In Libya an increase of the abundance of H. far was also apparent during the first decade of the 21st century but the current abundance of S. undosquamis resulted to be stable at the level of occasional captures. Given the lack of regula...
Surveys recently conducted throughout the Tunisian coast allow to record, for the first time, the... more Surveys recently conducted throughout the Tunisian coast allow to record, for the first time, the indo pacific mantis shrimp Erugosquilla massavensis (Kossmann, 1880) in the area. Of the 11 specimens observed, 8 were collected in the Gulf of Gabes and 3 in Tunis Southern Lagoon. These new records point out an extension range of the species in the Mediterranean Sea, which could be explained by the pelagic life of larvae which enhances its expansion throughout the Mediterranean Sea. However, global warming and increasing of shipping traffic cannot be totally ruled out. Additionally these new Tunisian findings do not constitute a sufficient support to state that a sustainable population is at present established in the area.
Ce travail traite de l’eco biologie de F. Fragilis (Forskal in Niehbur, 1775), bivalve lessepsien... more Ce travail traite de l’eco biologie de F. Fragilis (Forskal in Niehbur, 1775), bivalve lessepsien, signale en Tunisie depuis 1996. La biologie de la reproduction a ete etudiee et un suivi la croissance relative et absolue a ete effectue, a deux biotopes differents (la baie de Tunis et la lagune de Bizerte). Le statut de F. Fragilis en Tunisie a ete etabli. Les etudes histologiques ont revele que c’est une espece hermaphrodite simultanee. L’echelle de maturation sexuelle a ete dressee. La fecondation interne et l’auto fecondation sont possibles chez cette espece. La ponte est continue sur toute l’annee. Ce mode de reproduction optimise le succes de l’installation de l’espece mais est couteux en energie. D’ailleurs, des mortalites estivales ont ete notees et une deficience du cycle de reproduction chez F. Fragilis de la lagune de Bizerte, site fortement pollue, a ete observee. Le suivi de la cinetique du diametre ovocytaire a permis la validation de l’echelle de maturation sexuelle. L’indice de condition constitue un bon indicateur de l’etat physiologique de F. Fragilis. L’etude de la croissance relative de F. Fragilis, aux deux sites de collecte, revele des differences majeures. La coque presente une forme plus allongee a la baie de Tunis. La croissance ponderale de ce bivalve invasif est generalement defavorisee par rapport a celle de la longueur coquilliere, a Tunis, inversement a la population de Bizerte. Au second site, la croissance coquilliere pourrait etre affectee par la pollution. Le suivi de la croissance absolue dans les deux sites atteste que le recrutement de ce bivalve serait etale dans le temps a Tunis et tres faible a Bizerte.
Journal of the Marine Biological Association of the United Kingdom, 2011
This study is the first work on the reproductive biology of lessepsian bivalve Fulvia fragilis. M... more This study is the first work on the reproductive biology of lessepsian bivalve Fulvia fragilis. Monthly and bimonthly samplings were made in the period from April 2006 to October 2007, at the Bay of Tunis (northern Tunisia). From histological preparations of gonad, a gametogenic scale was drawn up based on eight stages: sexual rest; initiation of gametogenesis; advanced gametogenesis; ripe; partial spawning; advanced spawning; restoration; and spent. After examination of gonad preparations, F. fragilis appeared to be a simultaneous hermaphrodite species. Spawning was continuous all along the year, scarce in winter and with peaks during the rest of the year. The spawning peaks were positively correlated with the rise of the sea surface temperature and the nutrient availability. Furthermore, the presence of oocytes surrounded by spermatozoa in female and male follicles and in male gonoducts was observed. Self-fertilization may occur in this species. High summer mortalities probably du...
Regular surveys, conducted in the Tunis Southern Lagoon from June 2014 to May 2015 in 10 stations... more Regular surveys, conducted in the Tunis Southern Lagoon from June 2014 to May 2015 in 10 stations, allowed us to sample 44 crustacean species: 31 are autochthonous and 13 allochthonous. These new settlements are the consequences of the successfully environmental restoration of the area, which enhanced the presence of species locally unknown. The canonical correspondence analysis (CCA) highlighted the concomitant influence of several environmental factors. The Shannon-Weaver diversity index indicates that the lagoon is a good-moderate ecosystem and the evenness (J') tends towards 1 reflecting an almost equal distribution of individuals in the species.
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, brackish area located in northern Tunisia. This species was mainly recorded in the Atlantic Ocean and recently extended its natural range toward 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 occurs and 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 female co...
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...
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