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Abstract
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The present study aimed to assess the ovarian tissue structure and plasma levels of the hypophysial-gonadal hormones, including 17-β estradiol, progesterone, GTH-I and GTH-II of the Arabian carpet shark, Chiloscyllium arabicum inhabiting the Persian Gulf in spring (April to July) and autumn (August to December). In this regards, a total of 60 C. arabicum female specimens were collected from the Bahrakan Port, in the north of the Persian Gulf. Fish were bleed after euthanization and biometrical characters and levels of 17-β estradiol, progesterone, GTH-I and GTH-II were measured. Fish were then dissected and samples were taken from the ovary and fixed in Bruin’s solution for 48 hrs. Histological sections were prepared using routine histological techniques and stained with hematoxylin and eosin. Based on the results, four different developmental stages were observed in the ovary in spring, including stage I, stage II (primary oogenesis), stage III (mediate oogenesis), and stage IV (final oogenesis). However, only three first stages were detected in autumn samples. The plasma levels of the studied hormones were higher in spring. Based on the results, spring (especially mid-April to mid-July) is the reproduction season of C. arabicum in the Persian Gulf.
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