Vol 49, No 3 (2011)
Original paper
Published online: 2011-10-28
Reproductive biology of the endangered percid Zingel asper in captivity: a histological description of the male reproductive cycle
DOI: 10.5603/FHC.2011.0069
Folia Histochem Cytobiol 2011;49(3):486-496.
Abstract
The endemic Rhodanian percid Zingel asper (Linnaeus, 1758), is usually found throughout the Rhône
basin, but this fish is now in sharp decline. Understanding its reproductive physiology is important so as to be able
to artificially control its reproduction with a view to re-introducing it. This study was carried out on a population
obtained by artificial fertilization and bred in external tanks. Fishes were observed from the juvenile stages through
to adulthood. Patterns of testicular development were defined from histological observations. Testes of Z. asper
were paired, elongated and fusiform dorsocaudal organs. The two lobes of each gonad joined together to form
a duct that extended to the urogenital papillae. They showed a lobular structure. The testicular lobules were of the
unrestricted spermatogonial type. Up to 10 months-old, most of the males were immature: their testes showed only
type A spermatogonia. The appearance of type B spermatogonia in the lobules of a testis indicated the beginning
of spermatogenesis in 10 months-old fish. Spermiogenesis occurred 24 months after the fertilization and, in 26
months-old fish, the cyst opened and released spermatozoa into the lumen of lobules. The spermiation belonged to
a cystic type. During the third year, histological observations pointed to the same evolution of adult gonads as
during the second year. Sexual maturity was reached in captive Z. asper after two years. The spawning occurred in
May in the breeding conditions. (Folia Histochemica et Cytobiologica 2011, Vol. 49, No. 3, 486–496)
Keywords: Zingel aspertestis developmentsexual maturityreproductive cyclehistology
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