The polychaetes used as bait for sport and commercial fishing are a natural resource exploited in many beaches in Alexandria and Suez Canal. One of the most popular species captured is
Halla parthenopeia (family: Oenonidae). Study of its reproductive biology would enable us to understand the period of growth and the spawning period, which are necessary to reach a commercially valuable size in artificial aquaculture in future. Ultra-structure of male germ cells and the character of spermatozoa of
Halla parthenopeia were investigated. Histological studies by Light, TEM and Scanning microscopes indicated that maturation was accomplished in four stages: (1) Immature stage; this was characterized by having spermatogonial cells (8-10 µm) arranged in raceme-like structures and some of them were forming nests of spermatogonia. (2) Mature or recovery stage; which displayed active spermatogenesis and the cells of all stages could be seen (spermatogonia, primary and secondary spermatocytes, spermatids including spermatozoa). Both primary and secondary spermatocytes were always grouped. Moreover, the fine structure of their nuclei were with thick clumped chromatin and a thin layer of cytoplasm. (3) Nearly ripe stage; this was characterized by the active spermiogensis process forming spermatid. (4) Ripe and spawning stage, it began by spermatid development and its metamorphosis into sperm and the appearance of the proacrosomal vesicle, then the formation of implantation fossa, finally the development of flagellum. The spermatozoon of
H. parthenopeia was morphologically simple and primitive in type. It appeared by Scanning microscope to have round nucleus, caplike round acrosom, short mid piece with 4 mitochondria and long flagellum with a basic 9 + 2 axonemes. The duration of sperm development took about 4 months. Two peaks of mature sperm appeared in late April and late December while spawning occurred in May and January. Following the classification of Jamieson and Rouse (1) sperms were of ect-aquasperm type.
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(1) Jamieson, B.G.M. and G.W. Rouse, 1989. The spermatozoa of the Polychaeta (Annelida): an ultra-structural review.
Biological Reviews (Cambridge), 64: 93-91.
