Reproductive biology of the annular seabream, Diplodus annularis (Linnaeus, 1758), in the Gulf of Gabes (Central Mediterranean) (original) (raw)
Related papers
Turkish Journal of Fisheries and Aquatic Sciences, 2021
This work provides useful knowledge on the reproductive traits and somatic growth of the white seabream (Diplodus sargus sargus Linnaeus, 1758) of the central sector of the Algerian coast. It aimed to estimate the maximum yield size of this sparid and evaluate its reproductive potential, by presenting the first results on its global fecundity. A total of 497 specimens, ranging in size from 12.4 to 40.3 cm, were monthly and randomly sampled from the artisanal fishery fleet, between January and December 2017. The obtained length-weight relationships indicated negative allometry for males (TW=0.024 TL2.842) and isometry for females (TW=0.016 TL3.013). The white seabream is a digynic protandrous hermaphrodite species. Sex reversal was observed with a large size overlap of 12 to 32 cm with a median of 23.5 cm. The reproductive season was observed from January to May and spawning occurred in spring. The size at first sexual maturity (TL50) was 20.55 cm for both sexes. Based on these resul...
2013
The reproduction of the common-two banded seabream (N=916), Diplodus vulgaris, was studied in the Gulf of Gabes (Tunisia). The length at the first maturity averages 13.64 ± 0.18 cm for males and 13.84 ± 0.17 cm for females. Macroscopic examination of gonads and gonad-somatic index indicated that spawning occurs once a year between November and February with peak activity in November and December. Fecundity estimates ranged from 8 400 to 30 800 oocytes. ISSN: 0001-5113 AADRAY ACTA ADRIAT., 53(3): 437 446, 2012
Study of fecundity for Diplodus vulgaris in Gulf of Gabes
The study of the general biology of species requires a full treatment of reproduction and its features via the determination of sex with different stages of maturity, duration of the spawning season, size at first sexual maturity, strategy of reproduction and the estimation of fecundity. Absolute fecundity, fertility or on individual as well as reproductive capacity have been the subject of this study, based on a sample of 67 females in advanced stage of maturity of two banded seabream, Diplodus vulgaris (E. Geoffroy St. Hilaire, 1817) collected on the southern Tunisian coasts sizes (LT) between 14.2 and 25.4 cm. We measured the diameter of oocytes in order to study the distribution of their size frequency in the ovary. The number of oocytes per ovary was then determined to calculate the relative fertility per gram of fish gonads. D. vulgaris has an average absolute fecundity of 15437 ± 1126 eggs, a relative fecundity of 162 eggs per gram of fresh fish and 3441 eggs per gram of gonads.
Acta Adriatica
The reproduction of the common-two banded seabream (N=916), Diplodus vulgaris, was studied in the Gulf of Gabes (Tunisia). The length at the first maturity averages 13.64 ± 0.18 cm for males and 13.84 ± 0.17 cm for females. Macroscopic examination of gonads and gonad-somatic index indicated that spawning occurs once a year between November and February with peak activity in November and December. Fecundity estimates ranged from 8 400 to 30 800 oocytes.
Sinai Journal of Applied Sciences, 2015
White seabream D. sargus (n = 991) were caught along the Eastern Mediterranean between September 2010 and April 2012. Total length ranged from 11 to 38 cm, represented age classes between 1 and 5 years. Total weight ranged from 12 to 840 gm. The scales were used to estimate the age. Age group (I) is dominant in the catch of D. sargus. Growth was supported using the back-calculation method. The growth performance index (Φ) showed a relatively high growth. Length at first maturity (L m) was 21.27 cm corresponding age (t m) 2.68 years. Length at first capture (L c) was 18.1 cm corresponding age (t c) 2.08 years. So we have to increase the length at first capture to the length at first maturity in order to give fishes opportunity to spawn at first time at least.
Age estimation and growth pattern of two-banded seabream Diplodus vulgaris in Tunisian south coast
Bulletin de la Societe Zoologique de France
Samples (N=1097) of common two-banded seabream, Diplodus vulgaris, were caught in the Gulf of Gabes (Tunisia) from June 2006 to May 2007. Total length ranged from 7 to 25 cm. The length-weight relationship for all individuals is described by the following parameters: a = 0.0185 and b = 2.9319. Fish were found from 0-7 years of age. The Von Bertalanffy growth parameters for both sexes were: L∞ = 24.14 cm, k = 0.163 and t0 = -2.33 years.
Journal of the Marine Biological Association of the United Kingdom, 2013
Reproductive biology, age and growth of the two-banded seabream Diplodus vulgaris (Pisces: Sparidae) in the Gulf of Gabès, Tunisia aymen hadj taieb, mohamed ghorbel, nader ben hadj hamida and othman jarboui Samples of common two-banded seabream Diplodus vulgaris (N ¼ 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 ¼ aTL b ) for all individuals were a ¼ 0.0185 and b ¼ 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 1 ¼ 25.4 cm, k ¼ 0.179 and t 0 ¼ 21.631 year. The instantaneous rate of natural mortality was: M ¼ 0.333 year 21 .
Thalassas: An International Journal of Marine Sciences, 2019
The present study aims to describe population dynamics (age, growth, mortality and fecundity) of common two-banded seabream. Sampled individuals were obtained monthly between November 2017 and October 2018 directly from commercial fisherman in the Northern Aegean Sea. Ages were estimated from 327 otolith readings; the minimum and maximum ages observed were 1 and 8 years, respectively, corresponding to 13 and 29 cm total length (TL). The length-weight relationship was W = 0.0156*L 2.97 (R 2 = 0.92) for the whole population and isometric growth was detected. The growth parameters of Von Bertalanffy fitted to back-calculated size for age data were: L∞ = 30.69 cm, K = 0.20 and t 0 = −2.64 per year. The instantaneous rates of total mortality (Z) and natural mortality (M) were 0.86 and 0.47 per year, respectively. Rates of fishing mortality F and exploitation E were 0.39 and 0.35 per year, respectively. The spawning season extended from September to March and peaked in December. Total lengths at 50% maturity were 18.32 cm for males and 20.37 cm for females. Mean absolute fecundity (F) was 73,154 ± 10,271 oocytes, ranging from 10,727 to 316,730.
Journal of the Marine Biological Association of the UK, 2008
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.
Oceanological and Hydrobiological Studies, 2020
This study determines the length distribution, length– weight relationship, age, growth parameters, mortality rate, sex ratios, length at first maturity and reproduction of saddled seabream (Oblada melanura) collected monthly by fishermen around the Northern Aegean Sea between November 2017 and October 2018. The length–weight relationship was calculated as W=0.0091×L 3.11 (R 2=0.95) and positive allometric growth was found. The condition factor and GSI varied between 0.81–1.58 and 0.01–9.61, respectively. The spawning season extended from May to July and peaked in June. Total lengths at 50% maturity were 18.97 cm for males and 18.83 cm for females. Parameters of the von Bertalanffy growth equation were: L∞ =29.91 cm, K =0.27 per year, t 0 =−0.82 year and age varied between 1 and 8. The instantaneous rates of total mortality (Z) and natural mortality (M) were 1.36 and 0.58 per year, respectively. Rates for fishing mortality F and exploitation E were 0.78 and 0.57 per year, respective...