New data on the reproductive biology of the common guitarfish of the Gulf of Gabès (southern Tunisia, central Mediterranean)

2008 ◽  
Vol 88 (5) ◽  
pp. 1063-1068 ◽  
Author(s):  
Samira Enajjar ◽  
Mohamed Nejmeddine Bradai ◽  
Abderrahmen Bouain
Keyword(s):  
Sexual Maturity ◽  
Gravid Female ◽  
Central Mediterranean ◽  
Gulf Of Gabes ◽  
Chemical Balance ◽  
Gulf Of Gabès ◽  
Southern Tunisia ◽  
The Common ◽  
Males And Females ◽  
Size At Birth

The common guitarfish Rhinobatos rhinobatos is abundanly captured along the coast of the Gulf of Gabès (southern Tunisia). The sizes at the first sexual maturity of females and males are 790 and 700 mm total length (TL) respectively. Females are larger than males; the maximum TL for males and females is 1000 and 1200 mm respectively. The smallest gravid female observed is 750 mm TL. Rhinobatos rhinobatos is an aplacental viviparous species. The two ovaries and the two uteri are functional. Mature oocytes and foetuses are symmetrically distributed respectively in ovaries and uteri. Vitellogenesis and gestation occur simultaneously. Gestation lasts 10 to 12 months; parturition occurs from the end of summer to the beginning of autumn. Mating and ovulation take place after parturition. Ovarian fecundity is higher than uterine fecundity; means of 8.95 and 5.34 young per year are respectively calculated. There is a positive relationship between the two categories of fecundity and size of females. The size at birth ranges from 250 to 290 mm TL. The common guitarfish is purely a lecithotrophic species. The chemical balance of development is estimated at 1.02.

Age, growth, longevity, mortality and reproductive biology of Dipturus oxyrinchus, (Chondrichthyes: Rajidae) off the Gulf of Gabès (Southern Tunisia, central Mediterranean)

2014 ◽  
Vol 95 (3) ◽  
pp. 569-577 ◽  
Author(s):  
Hasna Kadri ◽  
Sondes Marouani ◽  
Mahamed Nejmeddine Bradai ◽  
Abderrahmen Bouaïn ◽  
Eric Morize
Keyword(s):  
Additional Data ◽  
Growth Parameters ◽  
Age And Growth ◽  
Central Mediterranean ◽  
Gulf Of Gabes ◽  
Gulf Of Gabès ◽  
Southern Tunisia ◽  
Marginal Increment ◽  
Males And Females ◽  
Annual Deposition

The age, growth, longevity, mortality and reproductive parameters were estimated for Dipturus oxyrinchus from the Gulf of Gabès (Southern Tunisia, central Mediterranean Sea), collected monthly during 2007 from commercial fisheries. The present study provides the first data on age and growth of this species in Tunisian waters, as well as additional data on its reproduction. A total of 240 females (16.5–105 cm total length (TL)) and 280 males (15.5–95 cm TL) were examined to study the reproductive cycle. A subsample of 285 specimens (175 females and 110 males, ranging from 15.5 to 105 cm TL) were analysed to study the age and growth. The oldest female in this study was 25 yr and 105 cm TL, whereas the oldest male was 22 yr and 95 cm. The annual deposition of growth bands was verified by marginal increment and edge analysis. The von Bertalanffy growth parameters were L∞ = 123.9 ± 2.56 cm, K = 0.08 ± 0.004 yr−1 and t0 =  −1.26 ± 0.04 10−1 yr for females and L∞ = 102.1 ± 3.23 cm, K = 0.12 ± 0.007 10−3 yr−1 and t0 = −1.18 ± 0.03 10−1 yr for males. Growth was not significantly different between sexes. The maturity size was 72.05 cm for males and 82.1 cm for females. The maturity age was estimated to be 11.95 and 13.96 years, respectively, for males and females. Size and age at maturity were not significantly different between sexes. The estimated longevity was 26.18 and 38.84 yr for males and females, respectively. Based on life history parameters, natural mortality was estimated at 0.53 yr−1 for females and 0.41 yr−1 for males.

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.

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

Age, growth and longevity of the grey triggerfish, Balistes capriscus Gmelin, 1789 (Teleostei, Balistidae) in the Gulf of Gabès, southern Tunisia, Mediterranean Sea

2015 ◽  
Vol 95 (5) ◽  
pp. 1061-1067 ◽  
Author(s):  
Hichem Kacem ◽  
Lobna Boudaya ◽  
Lassâd Neifar
Keyword(s):  
Mediterranean Sea ◽  
Growth Parameters ◽  
Fork Length ◽  
Growth Zone ◽  
Age And Growth ◽  
Gulf Of Gabes ◽  
Gulf Of Gabès ◽  
Southern Tunisia ◽  
Balistes Capriscus ◽  
Males And Females

The age and growth parameters of grey triggerfish, Balistes capriscus from the Gulf of Gabès, southern Tunisia, Mediterranean Sea, were estimated from the first dorsal spine sections of 463 specimens (206 males and 257 females), whose fork length was between 139 and 427 mm and the total weight ranged from 90.04 to 1967.41 g. The monthly percentage of specimens having a terminal translucent zone has indicated that the growth zone is formed once a year, during the cold season (February). The von Bertalanffy growth equations were: FL = 420.7 [1 − e−0.233(t + 0.123)] and FL = 417.0 [1 − e−0.238(t + 0.074)], for males and females, respectively. The longevity estimated was 13 years old for both sexes. The instantaneous mortality rates were estimated to 0.23 for males and 0.24 for females. The weight–length relationships of the grey triggerfish were Wt = 21.510−3 LF3.046 and Wt = 41.010−3 LF2.835, for males and females, respectively.

Distribution and reproductive biology of the blackchin guitarfish, Rhinobatos cemiculus (Pisces: Rhinobatidae), in Tunisian waters (central Mediterranean)

1994 ◽  
Vol 45 (4) ◽  
pp. 551 ◽  
Author(s):  
C Capape ◽  
J Zaouali
Keyword(s):  
Reproductive Biology ◽  
Gravid Female ◽  
Total Sample ◽  
High Rate ◽  
Adult Males ◽  
Central Mediterranean ◽  
Chemical Balance ◽  
Adult Females ◽  
Males And Females ◽  
The Mean

Aspects of the reproductive biology of Rhinobatos cemiculus are described from specimens collected in Tunisian waters. Sizes at first sexual maturity of males and females are 1000 mm and 1100 mm total length (TL), respectively. Adult females are generally larger than adult males, the maximum TL for males and females being 1920 mm and 2300 mm, respectively. The smallest gravid female observed was 1220 mm TL. R. cemiculus is an aplacental viviparous species, with each female having two ovaries and two uteri, both functional. Ripe oocytes in the ovaries, ova, embryos and fully developed fetuses in the uteri are symmetrically distributed. The gestation period could last for a maximum of eight months. Vitellogenesis proceeds in parallel with gestation, and at the time of parturition a crop of ripe oocytes is ready to be ovulated. Ovulation and parturition occur during winter and summer, respectively. There is probably one litter per year. The mean TL and mean weight of fully developed fetuses are 39.6 mm and 115.1 g, respectively. A computed chemical balance of development, based on the mean dry weights of fully developed fetuses and ripe oocytes, is 1.01. This low value is due to the fact that R. cemiculus is purely a lecithotrophic species. Fecundity ranges from 5 to 12 young per litter. Ovarian fecundity and uterine fecundity are slightly correlated with the size of females. Females are more numerous than males in the total sample, as well as in utero and at the juvenile stage; however, this is not the case for subadults and adults. This phenomenon is probably due to segregation of the sexes at different depths during certain stages of the reproductive cycle rather than to a high rate of mortality among subadult and adult females.

scholarly journals Biology of little tunny Euthynnus alletteratus in the Gulf of Gabes, Southern Tunisia (Central Mediterranean Sea)

2010 ◽  
Vol 45 (3) ◽  
pp. 399-406 ◽  
Author(s):  
Ghailen Hajjej ◽  
Abdallah Hattour ◽  
Hassen Allaya ◽  
Othman Jarboui ◽  
Abderrahmen Bouain
Keyword(s):  
Mediterranean Sea ◽  
Central Mediterranean ◽  
Gulf Of Gabes ◽  
Gulf Of Gabès ◽  
Southern Tunisia ◽  
Central Mediterranean Sea
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