Histological assessment of seasonal gonad maturation of red mullet (Mullus barbatus L., 1758) in Antalya Bay of Mediterranean in Turkey

Abstract

In this study, gonadal changes of red mullet (Mullus barbatus L., 1758) were investigated by histologically in Antalya Bay of Eastern Mediterranean in Turkey. A total of 890 specimens were collected monthly between May 2015 and October 2016 from fishing boats. The age of 890 red mullets was found to range from 0+ to VI+. Their gonads were dissected and fixed in 10% neutral buffered formaldehyde. They were embedded in paraffin blocks after histochemical processes. The sectioned tissue samples were stained with Haematoxylin-Eosin and Masson Trichrome. Two different stages in females and in males were observed according to gonadal development. Histologically, female individuals had in immature female (66 fish, 0+-IV+ ages), chromatin-nucleolus (67 fish, I+-VI+ ages), perinucleolus (63 fish, I+-IV+ ages), cortical alveoli (55 fish, I+-V+ ages), vitellogenesis (50 fish, I+-V+ ages), maturity (39 fish, I+-VI+ ages) and post-ovulation stages (59 fish, I+-VI+ ages). Male individuals had in spermatogenesis (96 fish, 0+-VI+ ages), spermiogenesis (97 fish, I+-IV+ ages), spermiation (85 fish, I+-VI+ ages), sperm release (84 fish, I+-VI+ ages) and resting stages (116 fish, I+-VI+ ages). Results show that the spawning season of M. barbatus is between May and September, and that egg diameters range from 31.00 ± 15 to 428.00 ± 40 µm.

Keywords

• gonadal development
• histological assessment
• mullus barbatus
• eastern mediterranean
• antalya bay