Annual reproductive cycle of the female brown banded bamboo shark

Annual reproductive cycle of the female brown banded bamboo shark, Chiloscyllium punctatum (Elasmobranchii: Hemiscylliidae) from the Persian Gulf: Morphological and endocrine correlation of reproduction

Nadieh Falahiehzadeh, Negin Salamat

ABSTRACT:

The present study aimed to assess the annual reproductive cycle of female brown banded bamboo shark, Chiloscyllium punctatum , from the Persian Gulf using macroscopic and microscopic evaluation of reproductive tract. The annual cycle of gonadal steroids (17b‐estradiol (E2), progesterone (P4) and testosterone (T)) was also assessed in this shark. Totally, 130 female C. punctatum were collected from the Bahrakan Creek (located at the northwest of the Persian Gulf) between January 2018 and March 2019. Females were oviparous with an external‐type ovary and only one functional ovary. Five sexual maturity stages were recognized based on macroscopic and microscopic evaluation including Immature I (August–October), Immature II (November–January), Mature (February–March), Pregnant (April–May), and Spent (Jun‐July). The structural changes in the oviducts, oviducal glands and uterus throughout the annual reproductive cycle were consistent with their roles in the egg movement, the egg capsule production, and sperm storage. The plasma levels of the gonadal steroids were associated with morphological changes in the reproductive tract. 17b‐estradiol showed two detectable peaks during March (close to ovulation) and June (just before mating). Progesterone and testosterone displayed a peak just before ovulation.

Journal of Fish Biology, DOI 10.1111/jfb.14419

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