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Abstract

Analysis of gonad organization and development revealed that Serranus atricauda is a functional simultaneous hermaphrodite. The ovary is classified as asynchronous. Oocyte growth is divided into five stages: stage I (primary growth stage), stage II (yolk vesicle formation), stage III (vitellogenesis), stage IV (oocyte maturation) and stage V (mature egg). The testis is of the unrestricted or lobular spermatogonial type. Spermatogenic cells include spermatogonia, primary and second-Aquatic Sciences ary spermatocytes, spermatids (which form cysts in the seminiferous tubules) and spermatozoa (free in the lumen). The histological structure of the gonad and sperm morphology would seem to indicate that this species is an externally fertilizing teleost. The observation of several spermatozoa on a hydrated oocyte within the ovarian lumen suggests, for the first time in this genus, that 'internal gametic association' may occur.

Reproductive strategies of the marine fishes from the southwest Atlantic Ocean: an application of histological and image processing techniques

“…Moreover, the spermatogonia were found throughout the testicular tissues; according to Grier (1981) this distribution is typical of species with unrestricted spermatogonial testicular type. In general, this type of spermatogenesis and testes organisation occur in the most teleosts, and they have been also reported by several authors for other hermaphrodite fishes (GÁRCIA-DÍAZ et al, 2002;TUSET et al, 2005;ALONSO-FERNÁNDEZ et al, 2011).…”