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Hassen Allaya - One of the best experts on this subject based on the ideXlab platform.
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Biology of little tunny Euthynnus alletteratus in the Gulf of Gabes, Southern Tunisia (Central Mediterranean Sea) Biología de la bacoreta Euthynnus alletteratus del Golfo de Gabes, Sur de Túnez (Mar Mediterráneo Central)
2020Co-Authors: Ghailen Hajjej, Abdallah Hattour, Hassen Allaya, Othman Jarboui, Abderrahmen BouainAbstract:Biological features known as sex-ratio, Gonad-Somatic Index (GSI), Hepatic-Somatic Index (HSI) and size at first sexual maturity, and the length-weight relationships (LWR) were studied in little tunny, Euthynnus alletteratus, caught in the Gulf of Gabes (Southern Tunisia). A total of 397 little tunny (244 females and 153 males) were analysed. Fish length ranged between 36.7 and 97.8 cm, average 52.29 ± 5.87 cm. Samples were monthly fished from January 2008 to December 2009. Sixty one percent of the specimens caught were females. The high GSI suggest that the spawning period runs from June to September. Fish in spawning condition are to be observed in August since GSI reaches the peak in July. Negative allometry was found in little tunny. Fork length at first sexual maturity in males (42.8 cm) was smaller than in females (44.8 cm).
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Disparate past demographic histories of three small Scombridae (Actinopterygii) species in Tunisian waters
Hydrobiologia, 2015Co-Authors: Hassen Allaya, Abdallah Hattour, Abderraouf Ben Faleh, Monia Trabelsi, Jordi ViñasAbstract:The bullet tuna Auxis rochei , the little tunny Euthynnus alletteratus , and the Atlantic Chub mackerel Scomber colias are three small Scombridae with similar life-history traits such as overlapping epipelagic distribution and a shared spawning area in Tunisian waters. In this study, we compared the phylogeography and demographic histories of these species by analyzing the sequence variability of the mitochondrial DNA control region. None of the species showed genetic differentiation in their Tunisian distribution; however, we inferred three completely different population histories. E. alletteratus showed a demographic history of a very recent bottleneck followed by sudden population expansion probably consequence of a population decline in the Last Glacial Maximum. S. colias also presented a population expansion after collapse but in this case about ten-fold older than that observed in E. alletteratus . Finally, A. rochei presented a history of demographic stability. These contrasting population histories were discussed based on their possible differences in life-history traits, but the hypothesis of stochastic factors affecting the demography of these species was also invoked.
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biology of little tunny Euthynnus alletteratus in the gulf of gabes southern tunisia central mediterranean sea
Revista De Biologia Marina Y Oceanografia, 2010Co-Authors: Ghailen Hajjej, Abdallah Hattour, Hassen Allaya, Othman Jarboui, Abderrahmen BouainAbstract:Se describen algunos parametros biologicos de la bacoreta Euthynnus alletteratus en el Golfo de Gabes (sur de Tunez), tales como la proporcion de sexos, el Indice Gonado-Somatico (IGS), el Indice Hepato-Somatico (IHS), la longitud de primera madurez sexual, y la relacion longitud-peso. Se analizo un total de 397 specimenes (244 hembras y 153 machos) entre los 36,7 y 97,8 cm de longitud, con un promedio 52,29 ± 5,87 cm. Las muestras se recolectaron mensualmente, entre enero de 2008 y diciembre de 2009. El 61% de los ejemplares fueron hembras. El periodo de desove se extiende de junio a septiembre, calculado a partir de los altos valores de IGS. Las relaciones longitud-peso revelaron que la bacoreta presenta una alometria negativa. La longitud promedio de primera madurez de las muestras tomadas en el Golfo de Gabes fue de 44,8 cm de longitud de horquilla para las hembras y 42,8 cm para los machos.
Isik K Oray - One of the best experts on this subject based on the ideXlab platform.
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Morphometric differentiation between two juvenile tuna species [Thunnus thynnus (Linnaeus, 1758) and Euthynnus alletteratus (Rafinesque, 1810)] from the Eastern Mediterranean Sea
Journal of Applied Ichthyology, 2016Co-Authors: F S Karakulak, Isik K Oray, Piero Addis, Taner Yildiz, Uğur UzerAbstract:Summary The main objective of this study was to analyse the differences in morphometric characteristics among specimens of Atlantic juvenile bluefin tuna Thunnus thynnus [12.2–46.5 cm fork length (FL)] and juvenile little tuna Euthynnus alletteratus (14.1–26.4 cm FL). A total of 353 bluefin tuna (young of the year) and 288 little tuna (young of the year) were collected from the commercial hand line fisheries in the eastern Mediterranean Sea between July and October of 2011–2013 with three round-bent hook sizes (numbers 10, 12 and 14; Mustad 2315S). By using univariate and multivariate analysis, 11 morphometric characters were investigated. anova revealed highly significant differences (P
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reproductive biology of little tunny Euthynnus alletteratus rafinesque from the north eastern mediterranean sea
Journal of Applied Ichthyology, 2008Co-Authors: Abdullah Ekrem Kahraman, Tugrul Zahit Alicli, Tulay Akayli, Isik K OrayAbstract:Summary The study aimed at identifying spawning season and potential year classes reaching maturity in the north-eastern Mediterranean, an area where little information on tuna spawning is available. Gonads (60 ovaries and 36 testis) were obtained from little tunny, Euthynnus alletteratus. The fish were caught between November 2002 and May 2005 in the north-eastern Mediterranean Sea. The ovaries were histologically examined to determine the reproductive conditions and developmental stages of oocytes. Seven females sampled in May, July, and August were sexually mature (stage III or IV). The gonado-somatic index (GSI) indicated that spawning generally occurred between May and September. The most intensive spawning period was observed between July and August. The sex ratio was calculated as 1 : 1.7 M ⁄ F (total n = 96). The length and weight relationship was calculated with W = 0.038 L 2.77 , ages from year I to IV being included in
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further evidence of spawning of bluefin tuna thunnus thynnus l 1758 and the tuna species auxis rochei ris 1810 Euthynnus alletteratus raf 1810 in the eastern mediterranean sea preliminary results of tunalev larval survey in 2004
Journal of Applied Ichthyology, 2005Co-Authors: Isik K Oray, F S KarakulakAbstract:Summary A tuna larval survey (TUNALEV) in the Northern Levantine Basin (Cilician Basin) was conducted onboard a trawler from 5 to 18 June 2004. To determine the spatial distribution and abundance of tuna larvae, Bongo 60 and Bongo 90 nets were used. Ichtyoplankton samples from 104 stations were taken. In total, 121 bluefin tuna (Thunnus thynnus), 94 bullet tuna (Auxis rochei) and 22 Atlantic black skipjack (Euthynnus alletteratus) larvae were collected. In comparison with the other tuna larvae, the concentration of bluefin tuna larvae was highest in the Bay of Mersin. The collected larvae in this area were composed mainly of 5–9 mm size specimens.
Somayeh Frokhzad - One of the best experts on this subject based on the ideXlab platform.
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Human health risk assessment of heavy metals via consumption of commercial marine fish (Thunnus albacares, Euthynnus affinis, and Katsuwonus pelamis) in Oman Sea
Environmental Science and Pollution Research, 2020Co-Authors: Parvin Sadeghi, Mehran Loghmani, Somayeh FrokhzadAbstract:This study was performed to determine the concentrations of copper (Cu), zinc (Zn), and lead (Pb) in the gill, liver, muscle, and tail fin tissues of Euthynnus affinis , Katsuwonus pelamis , and Thunnus albacares from Oman Sea. All samples were analyzed using a flame atomic absorption spectrophotometer and the results were expressed as μg g^−1 dry weight. Metal concentrations were significantly higher in the liver than other tissues in three species (with some exceptions) ( p Cu > Pb. Correlation matrix and principal component analysis (PCA) revealed that Zn and Pb have anthropogenic sources. Estimated daily intake (EDI) in three tuna species for heavy metals were below the tolerable daily intake (TDI). Also, the mean target hazard quotient (THQ) based on studied metals in three tuna species was below 1, which suggests that consumption of these fish can be safe for human health in the Oman Sea. Graphical Abstract .
Abdallah Hattour - One of the best experts on this subject based on the ideXlab platform.
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Biology of little tunny Euthynnus alletteratus in the Gulf of Gabes, Southern Tunisia (Central Mediterranean Sea) Biología de la bacoreta Euthynnus alletteratus del Golfo de Gabes, Sur de Túnez (Mar Mediterráneo Central)
2020Co-Authors: Ghailen Hajjej, Abdallah Hattour, Hassen Allaya, Othman Jarboui, Abderrahmen BouainAbstract:Biological features known as sex-ratio, Gonad-Somatic Index (GSI), Hepatic-Somatic Index (HSI) and size at first sexual maturity, and the length-weight relationships (LWR) were studied in little tunny, Euthynnus alletteratus, caught in the Gulf of Gabes (Southern Tunisia). A total of 397 little tunny (244 females and 153 males) were analysed. Fish length ranged between 36.7 and 97.8 cm, average 52.29 ± 5.87 cm. Samples were monthly fished from January 2008 to December 2009. Sixty one percent of the specimens caught were females. The high GSI suggest that the spawning period runs from June to September. Fish in spawning condition are to be observed in August since GSI reaches the peak in July. Negative allometry was found in little tunny. Fork length at first sexual maturity in males (42.8 cm) was smaller than in females (44.8 cm).
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Disparate past demographic histories of three small Scombridae (Actinopterygii) species in Tunisian waters
Hydrobiologia, 2015Co-Authors: Hassen Allaya, Abdallah Hattour, Abderraouf Ben Faleh, Monia Trabelsi, Jordi ViñasAbstract:The bullet tuna Auxis rochei , the little tunny Euthynnus alletteratus , and the Atlantic Chub mackerel Scomber colias are three small Scombridae with similar life-history traits such as overlapping epipelagic distribution and a shared spawning area in Tunisian waters. In this study, we compared the phylogeography and demographic histories of these species by analyzing the sequence variability of the mitochondrial DNA control region. None of the species showed genetic differentiation in their Tunisian distribution; however, we inferred three completely different population histories. E. alletteratus showed a demographic history of a very recent bottleneck followed by sudden population expansion probably consequence of a population decline in the Last Glacial Maximum. S. colias also presented a population expansion after collapse but in this case about ten-fold older than that observed in E. alletteratus . Finally, A. rochei presented a history of demographic stability. These contrasting population histories were discussed based on their possible differences in life-history traits, but the hypothesis of stochastic factors affecting the demography of these species was also invoked.
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biology of little tunny Euthynnus alletteratus in the gulf of gabes southern tunisia central mediterranean sea
Revista De Biologia Marina Y Oceanografia, 2010Co-Authors: Ghailen Hajjej, Abdallah Hattour, Hassen Allaya, Othman Jarboui, Abderrahmen BouainAbstract:Se describen algunos parametros biologicos de la bacoreta Euthynnus alletteratus en el Golfo de Gabes (sur de Tunez), tales como la proporcion de sexos, el Indice Gonado-Somatico (IGS), el Indice Hepato-Somatico (IHS), la longitud de primera madurez sexual, y la relacion longitud-peso. Se analizo un total de 397 specimenes (244 hembras y 153 machos) entre los 36,7 y 97,8 cm de longitud, con un promedio 52,29 ± 5,87 cm. Las muestras se recolectaron mensualmente, entre enero de 2008 y diciembre de 2009. El 61% de los ejemplares fueron hembras. El periodo de desove se extiende de junio a septiembre, calculado a partir de los altos valores de IGS. Las relaciones longitud-peso revelaron que la bacoreta presenta una alometria negativa. La longitud promedio de primera madurez de las muestras tomadas en el Golfo de Gabes fue de 44,8 cm de longitud de horquilla para las hembras y 42,8 cm para los machos.
Rita Hayati - One of the best experts on this subject based on the ideXlab platform.
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Kesan Suhu Pengeringan dan Penggaraman Terhadap Kualiti Ikan Tongkol Kering (Euthynnus Affinis) (Effect of Drying and Salting on the Quality of Dried Fish (Euthynnus affinis))
2020Co-Authors: Rita Hayati, Aminah Abdullah, Mohd. Khan Ayob, Soewarno T. SorkartoAbstract:A study was carried out to study the effect of drying temperature (50, 60, 70°C) and salt concentration (3, 5, 7%) on quality of dried Euthynnus affinis (tongkol). The proximate analysis showed significant different (p
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kesan suhu pengeringan dan penggaraman terhadap kualiti ikan tongkol kering Euthynnus affinis
Sains Malaysiana, 2006Co-Authors: Rita Hayati, Aminah Abdullah, Mohd. Khan Ayob, Soewarno T SoekartoAbstract:Kajian terhadap kesan suhu pengeringan (50, 60, 70oC) dan kepekatan garam (3, 5, 7%) terhadap kualiti ikan tongkol (Euthynnus affinis) telah dilakukan. Analisis kandungan proksimat menunjukkan nilai yang berbeza secara bererti (p<0.05), terutama kandungan protein (76.66%) ikan yang dikering pada suhu 50°C. Pengeringan pada suhu dan kepekatan garam yang tinggi cenderung untuk menghasilkan ikan tongkol kering dengan wama yang agak gelap (72.39). Ikon tongkol kering memiliki keupayaan memegang air yang rendah iaitu antara 3.43-3.66 ml/g sampel. Aktiviti air (aw) ikon tongkol yang hanya mencapai 0.76 atau kurang, merupakan tahap yang paling baik untuk tujuan penyimpanan, dan dapat mengawal pertumbuhan mikroorganisma, merencat aktiviti enzim dan memenuhi keperluan pembungkusan.
