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Ultrastructure of the spermatozoa and eggs of the ocean pout ( Macrozoarces americanus L.), an internally fertilizing marine fish
Author(s) -
Yao Z.,
Emerson C. J.,
Crim L. W.
Publication year - 1995
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.1080420108
Subject(s) - biology , ultrastructure , fish <actinopterygii> , marine fish , zoology , fishery , anatomy
Abstract Ultrastructure of sperm and eggs of the ocean pout ( Macrozoarces americanus L.), an internally fertilizing marine teleost, was examined by scanning and transmission electron microscopy. The results showed that the sperm do not have an acrosome but have a very long mid‐piece (one to two times the sperm head length) containing numerous well‐developed elongated mitochondria. The sperm also have two tails (is biflagellate) each consisting of nine peripheral and one central pair (9 ± 2) of microtubules. This long mid‐piece and the biflagellate nature of the sperm appear to be associated with the long life‐span of the sperm and with sperm dispersal in the ovary to fertilize the eggs internally. The ocean pout eggs are enveloped by a porous chorionic membrane similar to that found in other teleosts but have two micropyles, a condition likely related to a mechanism of egg fertilization which increases the egg fertlity in the presence of low sperm numbers. Following insemination, some biochemically undefined excretions appeared on the surface of fertilized eggs and led to the acquisition of adherent capability of the eggs which formed a tightly associated egg mass in sea water. © 1995 wiley‐Liss, Inc.