An investigation on systematic history and distribution areas of tarek (Alburnus tarichi (Güldenstädt, 1814)) / Uma investigação sobre a história sistemática e as áreas de distribuição de tarek (Alburnus tarichi (Güldenstädt, 1814))

Abstract This study aimed to determine the distribution area of tarek (Alburnus tarichi (Güldenstädt, 1814)) and to define how it must be called according to the scientific name by evaluating its previous studies made by various systematisers and their reports on its distribution, and by comparing literature knowledge. The taxonomic characteristics of the collected samples were evaluated and several measurements and counts were taken on the samples; analfin origin 0-4 scales behind dorsal fin-base; 72-91 lateral line scales; 21-29 gill rakers; 7½-10 branched dorsal-fin rays and 10-12½ branched anal-fin rays. Body and caudal peduncle was moderately compressed. Body was covered by overlapping scales. Tarek has five different populations in the Basin. They are Van, Erçek, Nazik and Aygır Lakes and Koçköprü Dam Lake populations. The main living area of the tarek population is Lake Van; however, between May and June, mature individuals of tarek enter to tributaries of Van Lake. Some of them are Karasu, Bendimahi, Deliçay, Zilan, Karmuç, Sapur, Yanıkçay, Gevaş, Engil, Kurubaş and Akköprü Streams. At the end of study, it was concluded that tarek should be called as Alburnus tarichi (Güldenstädt, 1814) and it is an endemic fish species distributed only in Van Lake Basin.

Resumo Este estudo teve como objetivo determinar a área de distribuição de tarek (Alburnus tarichi) (Güldenstädt, 1814) e definir como deve ser chamado de acordo com o nome científico, avaliando estudos anteriores feitos por vários sistematizadores e seus relatórios sobre sua distribuição, e comparando o conhecimento da literatura. As características taxonômicas das amostras coletadas foram avaliadas e várias medições e contagens foram realizadas nas amostras, como origem analfin 0-4 escalas atrás da base da barbatana dorsal; 72-91 escalas de linha lateral; 21-29 rakers branquiais; 7½-10 raios da nadadeira dorsal ramificada, e 10-12½ raios da nadadeira anal ramificados. Pedúnculo caudal e corporal foram moderadamente comprimidos. O corpo estava coberto por escamas sobrepostas. Tarek tem cinco populações diferentes na bacia estudada. São as populações dos lagos Van, Erçek, Nazik e Aygır, e Koçköprü barragem. A principal área de presença da população tarek é o Lago Van; no entanto, entre maio e junho, indivíduos maduros de tarek entram nos afluentes do lago Van. Alguns deles são os fluxos Karasu, Bendimahi, Deliçay, Zilan, Karmuç, Sapur, Yanıkçay, Gevaş, Engil, Kurubaş e Akköprü. No final do estudo, concluiu-se que tarek deveria ser chamado Alburnus tarichi (Güldenstädt, 1814) e que é uma espécie de peixe endêmica distribuída apenas na Bacia do Lago Van.

An investigation on systematic history and distribution areas of tarek (Alburnus tarichi (Güldenstädt, 1814)).

This study aimed to determine the distribution area of tarek (Alburnus tarichi (Güldenstädt, 1814)) and to define how it must be called according to the scientific name by evaluating its previous studies made by various systematisers and their reports on its distribution, and by comparing literature knowledge. The taxonomic characteristics of the collected samples were evaluated and several measurements and counts were taken on the samples; analfin origin 0-4 scales behind dorsal fin-base; 72-91 lateral line scales; 21-29 gill rakers; 7½-10 branched dorsal-fin rays and 10-12½ branched anal-fin rays. Body and caudal peduncle was moderately compressed. Body was covered by overlapping scales. Tarek has five different populations in the Basin. They are Van, Erçek, Nazik and Aygir Lakes and Koçköprü Dam Lake populations. The main living area of the tarek population is Lake Van; however, between May and June, mature individuals of tarek enter to tributaries of Van Lake. Some of them are Karasu, Bendimahi, Deliçay, Zilan, Karmuç, Sapur, Yanikçay, Gevas, Engil, Kurubas and Akköprü Streams. At the end of study, it was concluded that tarek should be called as Alburnus tarichi (Güldenstädt, 1814) and it is an endemic fish species distributed only in Van Lake Basin.

An investigation on systematic history and distribution areas of tarek (Alburnus tarichi (Güldenstädt, 1814))

Abstract This study aimed to determine the distribution area of tarek (Alburnus tarichi (Güldenstädt, 1814)) and to define how it must be called according to the scientific name by evaluating its previous studies made by various systematisers and their reports on its distribution, and by comparing literature knowledge. The taxonomic characteristics of the collected samples were evaluated and several measurements and counts were taken on the samples; analfin origin 0-4 scales behind dorsal fin-base; 72-91 lateral line scales; 21-29 gill rakers; 7½-10 branched dorsal-fin rays and 10-12½ branched anal-fin rays. Body and caudal peduncle was moderately compressed. Body was covered by overlapping scales. Tarek has five different populations in the Basin. They are Van, Erçek, Nazik and Aygr Lakes and Koçköprü Dam Lake populations. The main living area of the tarek population is Lake Van; however, between May and June, mature individuals of tarek enter to tributaries of Van Lake. Some of them are Karasu, Bendimahi, Deliçay, Zilan, Karmuç, Sapur, Yankçay, Geva, Engil, Kuruba and Akköprü Streams. At the end of study, it was concluded that tarek should be called as Alburnus tarichi (Güldenstädt, 1814) and it is an endemic fish species distributed only in Van Lake Basin.

Resumo Este estudo teve como objetivo determinar a área de distribuição de tarek (Alburnus tarichi) (Güldenstädt, 1814) e definir como deve ser chamado de acordo com o nome científico, avaliando estudos anteriores feitos por vários sistematizadores e seus relatórios sobre sua distribuição, e comparando o conhecimento da literatura. As características taxonômicas das amostras coletadas foram avaliadas e várias medições e contagens foram realizadas nas amostras, como origem analfin 0-4 escalas atrás da base da barbatana dorsal; 72-91 escalas de linha lateral; 21-29 rakers branquiais; 7½-10 raios da nadadeira dorsal ramificada, e 10-12½ raios da nadadeira anal ramificados. Pedúnculo caudal e corporal foram moderadamente comprimidos. O corpo estava coberto por escamas sobrepostas. Tarek tem cinco populações diferentes na bacia estudada. São as populações dos lagos Van, Erçek, Nazik e Aygr, e Koçköprü barragem. A principal área de presença da população tarek é o Lago Van; no entanto, entre maio e junho, indivíduos maduros de tarek entram nos afluentes do lago Van. Alguns deles são os fluxos Karasu, Bendimahi, Deliçay, Zilan, Karmuç, Sapur, Yankçay, Geva, Engil, Kuruba e Akköprü. No final do estudo, concluiu-se que tarek deveria ser chamado Alburnus tarichi (Güldenstädt, 1814) e que é uma espécie de peixe endêmica distribuída apenas na Bacia do Lago Van.

Determination of hormones inducing oocyte maturation in Chalcalburnus tarichi (Pallas, 1811).

Chalcalburnus tarichi is an endemic cyprinid species living in the Lake Van basin, in eastern Anatolia, Turkey. The present study was undertaken to determine which hormones induce oocyte maturation in C. tarichi. The levels of 17alpha,20beta,21-trihydroxyprogesterone (20beta-S), progesterone (P), 17alpha-hydroxyprogesterone (17alpha-HOP), 11-deoxycortisol (11-DOC), and 17alpha-hydroxy-20beta-dihydroprogesterone (17,20beta-P) were measured in fish caught from Lake Van and the Karasu River, and injected with human chorionic hormone (hCG) (1,000 and 1,500 IU/kg). Oocytes of fish caught from the lake were also incubated in vitro with different doses (50, 200, and 1,000 ng/ml) of 20beta-S, 17alpha-HOP, 11-DOC, and 17,20beta-P. 11-DOC was found to be the most effective hormone among those measured for inducing oocyte maturation in vivo and in vitro. 17,20beta-P could not be determined in the plasma of any fish in vivo (P < 0.05). 1,000 IU/kg dose of hCG given by injection caused a statistically significant increase in all plasma hormone levels (P < 0.05). It was found that there was a significant decrease in the P level only at 1,500 IU/kg dose of hCG injected (P < 0.05), while the level of other hormones increased at this dose (P < 0.05). It was also determined that all the hormones were effective in germinal vesicle breakdown (GVBD) in in vitro oocyte culture (P < 0.05). However, 11-DOC was found to be the most effective hormone in GVBD at a dose of 200 ng/ml (70% GVBD). In conclusion, 11-DOC synthesized during final oocyte maturation in C. tarichi was found to be a potent inducer of GVBD, which shows that 11-DOC may be described as an oocyte maturation steroid in this species.