scholarly journals Reproductive biology of the Golden grey mullet Liza aurata, in the Gulf of Gabes (central Mediterranean, Tunisia) in the Gulf of Gabes (central Mediterranean, Tunisia)

2013 ◽  
Vol 14 (2) ◽  
pp. 409 ◽  
Author(s):  
C. ABDALLAH ◽  
M. GHORBEL ◽  
O. JARBOUI
Keyword(s):  
Condition Factor ◽  
Mean Value ◽  
Grey Mullet ◽  
Central Mediterranean ◽  
Gulf Of Gabes ◽  
Liza Aurata ◽  
Gulf Of Gabès ◽  
Large Size ◽  
Sexually Mature ◽  
Somatic Index

In spite of its high commercial value, very few information are available on the biological feature of the Golden grey mullet in Tunisian waters (central Mediterranean). These data would be of great help in identifying the current stock state. In this study, Gonado Somatic Index (GSI), Hepato Somatic Index (HSI), condition factor (K), Length at first sexual maturity TL50 was calculated and the fecundity was estimated using the volumetric method. The Gonado Somatic Index (GSI) indicated that the spawning season of the Golden grey mullet extends from October to December. The monthly variation of Hepato-Somatic Index (HSI) indicates that L. aurata saves lipid reserves in liver. The species is sexually mature at 23.73, 23.84 and 23.79 cm TL respectively for female, male and combined sexes. In the present study the sex-ratio was unbalanced, with females dominating among large size individuals (TL > 24 cm). Absolute fecundity with a mean value of 286564 varied from a minimum of 210400 eggs for age 4 and a maximum of 533600 for age 7+.

scholarly journals Allometry, condition factor and growth of the swimming blue crab Portunus segnis in the Gulf of Gabes, Southeastern Tunisia (Central Mediterranean)

2019 ◽  
Vol 20 (3) ◽  
pp. 566
Author(s):  
OLFA BEN ABDALLAH-BEN HADJ HAMIDA ◽  
NADER BEN HADJ HAMIDA ◽  
HOUDA CHAOUCH ◽  
HECHMI MISSAOUI
Keyword(s):  
Carapace Length ◽  
Condition Factor ◽  
Growth Parameters ◽  
Carapace Width ◽  
Central Mediterranean ◽  
Gulf Of Gabes ◽  
Gulf Of Gabès ◽  
Significant Difference ◽  
The Mediterranean ◽  
Portunus Segnis

The blue swimming crab Portunus segnis (Forskål, 1775) is one of the earliest Lessepsian invaders of the Mediterranean Sea, and is recorded since decades in various areas of the Mediterranean. Its presence in the southeastern Tunisian coasts (Gulf of Gabes) is, however, very recent. Allometry, condition factor and growth of P. segnis were studied along the Gulf of Gabes coasts. Sampling was performed by artisanal fishing gears as well as trawl net during a one-year period (October 2015 to September 2016) as processed 4971 crabs were collected. The crab carapace width (CW) ranged from 45 to 168 mm for males and 50 to 159 mm for females. The crab carapace length (CL) was 22.02-89.20 mm and 38.70-85.28 mm, respectively for males and females. The carapace width-carapace length, carapace width- front, carapace width-carapace height and carapace width-weight relationships were studied in separate sexes of crab. The covariance analysis indicates a significant difference between the two sexes with respect to the carapace width-carapace length and the carapace width-weight relationships. The condition factor ranged between 0.0042 and 0.0118 with a mean of 0.0078. The condition factor decreased with increasing crab size. The Von Bertalanffy growth parameters CW∞, K and t0 were estimated on the basis of Length-frequency modal progression analysis methods. The mean values of L∞ (mm), K (year-1) and t0 would be, respectively, 206.48 mm, 1.34 and -0.130 for males; 183.89 mm, 1.42 and -0.127 for females and, 190.60 mm, 1.02 and -0.177 for combined sexes.

First data on the age, growth and sexual maturity of the piked spurdog, Squalus megalops (Chondrichthyes: Squalidae), in the Gulf of Gabès (central Mediterranean Sea)

2016 ◽  
Vol 67 (5) ◽  
pp. 578 ◽  
Author(s):  
Sondes Marouani ◽  
Hasna Kadri ◽  
Mohamed Nejmeddine Bradai
Keyword(s):  
Mediterranean Sea ◽  
Growth Parameters ◽  
Natural Mortality ◽  
Central Mediterranean ◽  
Gulf Of Gabes ◽  
Band Formation ◽  
Mortality Estimation ◽  
Gulf Of Gabès ◽  
Central Mediterranean Sea ◽  
Males And Females

The occurrence of the piked spurdog (Squalus megalops) in the Gulf of Gabès (Tunisia, central Mediterranean Sea) was recently confirmed. The present study is the first to report the age, growth, longevity, natural mortality and size and age at maturity of this species in the Mediterranean Sea, precisely in the Gulf of Gabès. Marginal increment and edge analysis suggested annual band formation. Age estimates ranged from 0 to 26 and from 0 to 29 years for males and females respectively. Von Bertalanffy growth parameters derived from length-at-age data were: the theoretical asymptotic length L∞=82.31±1.55cm, the growth-rate coefficient k=0.06±0.003 years–1, the theoretical age at length zero t0=–3.89±0.25 years for females; and L∞=68.55±0.98cm, k=0.08±0.003 years–1, t0=–4.65±0.25 years for males. Males and females reached maturity at 44.36- and 56.41-cm total length, corresponding to 8.39 and 15.38 years respectively. Longevity estimates were 32.85 and 46.11 years for males and females respectively. On the basis of life-history parameters, natural mortality estimation M ranged from 0.14 to 0.17.

Diet and feeding strategy of thornback ray, Raja clavata (Chondrichthyes: Rajidae) from the Gulf of Gabes (Tunisia—Central Mediterranean Sea)

2014 ◽  
Vol 94 (7) ◽  
pp. 1509-1516 ◽  
Author(s):  
Hasna Kadri ◽  
Sondes Marouani ◽  
Mohamed Nejmeddine Bradai ◽  
Abderrahmen Bouaïn
Keyword(s):  
Feeding Strategy ◽  
Stomach Contents ◽  
Ontogenetic Changes ◽  
Central Mediterranean ◽  
Gulf Of Gabes ◽  
Gulf Of Gabès ◽  
Thornback Ray ◽  
Raja Clavata ◽  
Food And Feeding ◽  
Quantitative Analyses

Food and feeding strategy of the thornback ray, Raja clavata, were studied from stomach contents analysis of specimens caught monthly in the Gulf of Gabes. The data were analysed according to sex, size and season. At total of 1280 stomachs was examined, from specimens ranging from 14 to 110 cm total length (TL), of which 1076 (83.98%) contained food. Thornback ray feed mainly on teleosts, crustaceans and cephalopods, whereas gastropods and polychaetes are occasionally consumed. Significant differences were found between the diets of males and females; however, ontogenetic changes were also detected, with crustaceans constituting the greatest proportion of the diet of smaller rays. Both teleosts and cephalopods increased in importance with growth of the skates. Prey diversity increased with size; large and mobile prey species were more commonly found in the diet of larger skates. Diet composition showed seasonal variations. Quantitative analyses and graphical methods indicate that the thornback ray is a generalist feeder.

Diet composition and food habits of Diplodus puntazzo (Sparidae) from the Gulf of Gabès (Central Mediterranean)

2013 ◽  
Vol 93 (8) ◽  
pp. 2257-2264 ◽  
Author(s):  
Houda Chaouch ◽  
Olfa Ben Abdallah-Ben Hadj Hamida ◽  
Mohamed Ghorbel ◽  
Othman Jarboui
Keyword(s):  
Food Source ◽  
Feeding Habits ◽  
Feeding Strategy ◽  
Stomach Contents ◽  
Important Food ◽  
Central Mediterranean ◽  
Gulf Of Gabes ◽  
Diplodus Puntazzo ◽  
Gulf Of Gabès ◽  
Important Food Source

The diet and feeding habits of the sharpsnout seabream, Diplodus puntazzo, from the Gulf of Gabès were investigated using stomach contents of 490 specimens ranging from 12.6 cm to 26.1 cm total length in size and from 29.95 g to 230.83 g in weight collected from commercial catches between April 2008 and March 2009. Of the total number of examined stomachs, 279 were empty (%VI = 56.94). This percentage varied significantly with months, attaining a maximum in spring (74.88%) and a minimum in autumn (37.38%). Eight major taxa were identified (Plantae, Spongia, Tunicata, Echinodermata, Crustacea, Annelida, Mollusca and Teleostei) in stomach contents of D. puntazzo. Plants were the most important food source, constituting 89.88% of the total Index of relative importance. The other groups, such as teleosts, molluscs, crustaceans and annelids represented accessory food. Significant differences in diet were observed in relation to season. Plants were the most important food source item in all seasons, especially during the autumn. The estimation of trophic level gave an average of 2.57 ± 0.2 for the whole population of D. puntazzo in the Gulf of Gabès. Based on the composition of its diet, this species may be considered as an omnivorous fish with a preference for vegetable material, and showing specialist feeding strategy.

Feeding behaviour of greater amberjackSeriola dumerili(Risso, 1810) from Central Mediterranean (Gulf of Gabes, Tunisia)

2016 ◽  
Vol 96 (6) ◽  
pp. 1229-1234 ◽  
Author(s):  
Ayda Sley ◽  
Aymen Hadj Taieb ◽  
Othman Jarboui ◽  
Mohamed Ghorbel ◽  
Abderrahmen Bouain
Keyword(s):  
Stomach Contents ◽  
Frequency Of Occurrence ◽  
Central Mediterranean ◽  
Gulf Of Gabes ◽  
Seriola Dumerili ◽  
Gulf Of Gabès ◽  
Important Prey ◽  
Significant Difference ◽  
Opportunistic Predator ◽  
Greater Amberjack

The diet of greater amberjackSeriola dumerili(Carangidae) in the Gulf of Gabes (Tunisia, Mediterranean) was described from analysis of stomach contents of 290 specimens fished between June 2004 and May 2006. The index of vacuity (%VI) was relatively low (37.9%) and differed significantly across size classes.Seriola dumeriliis an opportunistic predator that consumes mostly pelagic organisms; benthic prey were also examined in small proportion. The diet was quantified using the frequency of occurrence (%O), numerical abundance (%N), weight (%W) and the index of relative importance (IRI and %IRI) for each prey taxa. The most important prey were teleosts (%IRI = 99.61); molluscs and crustaceans were found occasionally (%IRI, 0.38 and 0.01%, respectively). Among teleosts, Clupeidae were also the dominant food items in number (%N = 36.06%) and then in frequency of occurrence (%O = 36.7%). In term of weight, Sparidae were the most abundant prey (%W = 36.5%). There is no significant difference between male and female diets. Seasonal differences in the diet components were observed.

Age, growth and reproductive biology of the rough skate, Raja radula (Chondrichthyes: Rajidae), off the Gulf of Gabes (southern Tunisia, central Mediterranean)

2013 ◽  
Vol 64 (6) ◽  
pp. 540 ◽  
Author(s):  
Hasna Kadri ◽  
Sondes Marouani ◽  
Mohamed Nejmeddine Bradai ◽  
Abderrahmen Bouaïn
Keyword(s):  
Reproductive Cycle ◽  
Growth Parameters ◽  
Age And Growth ◽  
Age At Maturity ◽  
Central Mediterranean ◽  
Gulf Of Gabes ◽  
Vertebral Centra ◽  
Gulf Of Gabès ◽  
Southern Tunisia ◽  
Significant Difference

Age, growth and reproductive parameters were estimated for Raja radula from the Gulf of Gabes (southern Tunisia, central Mediterranean Sea), collected monthly during 2007 from commercial fisheries. In total, 550 females (18.5–80.0 cm TL) and 400 males (13.4–65 cm TL) were examined to study the reproductive cycle. A subsample of 272 specimens (140 females and 132 males, ranging from 15.5 to 80 cm in total length, TL) was used for age and growth estimation derived from vertebral centra. The marginal-increment and edge analysis showed annual deposition of growth bands. The oldest female in the study was 12 years old and 80 cm in TL, whereas the oldest male was 9 years old and 65 cm in TL. The von Bertalanffy growth parameters were L∞ = 76.36 cm, K = 0.22 year–1 and t0 = –0.16 years for males. There was no significant difference in growth between the sexes. The size-at-maturity was 47.05 cm for males and 56.48 cm for females. The age-at-maturity was estimated to be 4.47 and 5.89 years, respectively, for males and females. There was no significant difference of size- and age-at-maturity between the sexes. Females carrying egg cases occurred throughout the year. Variations in the gonadosomatic and hepatosomatic indices showed a continuous reproductive cycle throughout the year.

Age, growth, sexual maturity and reproduction of the thornback ray,Raja clavata(L.), of the Gulf of Gabès (south-central Mediterranean Sea)

2013 ◽  
Vol 10 (4) ◽  
pp. 416-425 ◽  
Author(s):  
Hasna Kadri ◽  
Sondes Marouani ◽  
Bechir Saïdi ◽  
Mohamed Nejmeddine Bradai ◽  
Abderrahmen Bouaïn ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Sexual Maturity ◽  
Central Mediterranean ◽  
Gulf Of Gabes ◽  
Gulf Of Gabès ◽  
South Central ◽  
Thornback Ray ◽  
Raja Clavata ◽  
Central Mediterranean Sea
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