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, 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.

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.

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.

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.

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.

Reproductive biology, age and growth of the two-banded seabream Diplodus vulgaris (Pisces: Sparidae) in the Gulf of Gabès, Tunisia

2013 ◽  
Vol 93 (5) ◽  
pp. 1415-1421 ◽  
Author(s):  
Aymen Hadj Taieb ◽  
Mohamed Ghorbel ◽  
Nader Ben Hadj Hamida ◽  
Othman Jarboui
Keyword(s):  
Growth Parameters ◽  
Age And Growth ◽  
Natural Mortality ◽  
Von Bertalanffy ◽  
Spawning Activity ◽  
Gulf Of Gabes ◽  
Instantaneous Rate ◽  
Total Length ◽  
Gulf Of Gabès ◽  
Overall Ratio

Samples of common two-banded seabream Diplodus vulgaris (N = 1097), used in this study, were caught in the Gulf of Gabès (Tunisia) from March 2008 to February 2010. Total length ranged from 7 to 25 cm. Diplodus vulgaris is a protandric hermaphrodite. The overall ratio of females to males was 1:1.66. The reproductive season extended from October to February, and the peak spawning activity occurred in December–January. The total length at which 50% of the population reached maturity was 14.14 ± 0.16 cm for females and 13.57 ± 0.01 cm for males. Parameters of the length–weight relationship (TW = aTLb) for all individuals were a = 0.0185 and b = 2.9319. The youngest specimen in this study was 0+ years, whereas the oldest one was 9 years. The von Bertalanffy growth parameters for the whole sample were: L∞ = 25.4 cm, k = 0.179 and t0 = −1.631 year. The instantaneous rate of natural mortality was: M = 0.333 year−1.

Age and growth of the sandpaper skate,Bathyraja kincaidii,using vertebral centra, with an investigation of caudal thorns

2010 ◽  
Vol 91 (6) ◽  
pp. 1149-1156 ◽  
Author(s):  
Colleena R. Perez ◽  
Gregor M. Cailliet ◽  
David A. Ebert
Keyword(s):  
Growth Parameters ◽  
Structural Similarity ◽  
Age And Growth ◽  
Von Bertalanffy ◽  
Likelihood Ratios ◽  
Band Formation ◽  
Growth Band ◽  
Vertebral Centra ◽  
Significant Difference ◽  
Age Estimates

The sandpaper skate,Bathyraja kincaidii, is one of four skate species commonly taken in trawl fisheries off central California although very little is known about its life history. In this study, age and growth were evaluated from 187 vertebrae using a common growth band counting method. An attempt to use marginal increment analysis and centrum edge analysis failed to validate the annual periodicity of growth band formation; however, it is a valid assumption based on structural similarity from other studies. Assuming annual band formation, von Bertalanffy growth parameters were determined for females (L∞ = 537.3 mm; k = 0.237; to = –1.629; N = 99) and males (L∞ = 580.2 mm; k = 0.185; to = –2.530; N = 88). Maximum likelihood ratios indicated no significant difference (P > 0.05) between male and female von Bertalanffy growth parameters, thus data were combined (L∞ = 557.8 mm; k = 0.207; to = –2.147; N = 187). Age estimates from band counts in vertebral centra indicated a minimum longevity of 17 and 18 years for female and maleB. kincaidii, respectively. Caudal thorns were also assessed for age analyses, but were deemed unreliable and could not be used to verify age estimates from vertebral centra.

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