Sex steroids, gonadal histology and biological indices of fall and spring Caspian lamprey (Caspiomyzon wagneri) spawning migrants in the Shirud River, Southern Caspian Sea

• Published in: Environmental biology of fishes Vol. 92; no. 2; pp. 229 - 235
• Main Authors: Ahmadi, Mohammad, Amiri, Bagher Mojazi, Abdoli, Asghar, Fakharzade, Seyed Mohammad Esmael, Hoseinifar, Seyed Hossein
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-10-2011; Springer; Springer Nature B.V
• Subjects: Agnatha. Pisces; Animal and plant ecology; Animal populations; Animal reproduction; Animal Systematics/Taxonomy/Biogeography; Animal, plant and microbial ecology; Animals; Autoecology; Biological and medical sciences; Biomedical and Life Sciences; Caspiomyzon wagneri; Environment; Fecundity; Fish; Fish migration; Fresh water ecosystems; Freshwater & Marine Ecology; Fundamental and applied biological sciences. Psychology; Gonads; Histology; Life Sciences; Migrants; Nature Conservation; Petromyzontidae; Seasons; Spawning; Spring; Steroids; Synecology; Vertebrata; Zoology; Caspian Sea; Eurasia, Caspian Sea; Gonads histology; Caspian lamprey; Sex steroids; Migration; Steroid; Spawning; Genital system; Sex; Histology; Rivers; Vertebrata; Migratory; Gonad; Pisces; Stream
• ISSN: 0378-1909; 1573-5133
• DOI: 10.1007/s10641-011-9836-9

This study investigates sex steroids, gonadal histology and some biological indices of fall and spring spawning migrants of Caspian lamprey
Caspiomyzon wagneri
(Kessler, 1870). Blood and gonad samples were collected from 15 migrants during fall and spring. Serum sex steroid levels including testosterone (T), 17β-estradiol (E
2
) and progesterone (P) were determined with ELISA and gonadal development was studied using conventional histological methods. Our results showed serum E
2
level in females were similar in the two seasons but in males, fall migrants had higher serum E
2
concentrations. No differences were found in T levels in fall and spring migrants. Serum P concentration in fall migrant males were significantly higher than spring migrant males while spring migrant females had higher serum P levels compare to fall migrant females. Gonads in both fall and spring migrants were in the final stage of maturity. Fall and spring migrant males had similar HSI and GSI; fall migratory female had significantly higher HSI and GSI. Sex ratios were close to 1:1 in both seasons. There was a significant relationship between fecundity and length in both seasons. Comparison of fecundity and egg diameter between fall and spring seasons showed no significant difference. These results indicate that both fall and spring migrants Caspian lamprey were ready for spawning. Further studies are needed to clarify when spawning occurs in Caspian lamprey.