ISSN 1063-0740, Russian Journal of Marine Biology, 2006, Vol. 32, No. 1, pp. 64–67. © Pleiades Publishing, Inc., 2006.
Original Russian Text © V.B. Durkina, 2006, published in Biologiya Morya.
The resorption of vitellogenous oocytes has been
studied well in ﬁshes. In general, it is speciﬁed by
destruction of the nucleus and radial coating of
gametes, and by utilization of the yolk material. In var-
ious ﬁsh species, the cells of the follicular epithelium,
blood, and connective tissue can participate in the latter
process [3, 5, 6,]. An unusual, collating with other ﬁsh
species, pattern of the degeneration of ovarial follicles
was observed in the spawning season in the striped
from Amur Bay,
Sea of Japan . It was not entailed by destruction of
the radial coating of oocytes, and the cells of the follic-
ular epithelium did not manifested any apparent phago-
cytic activity concerning the trophic material, despite
the fact that it gradually passed away from the gametes.
To ﬁnd out what cellular elements of the gonad of the
striped ﬂounder participated in utilization of the oocyte
yolk, the ovaries of this ﬂounder species were studied
in the spawning, prespawning, and postspawning sea-
sons, i.e., the times when a portion of the gametes was
being resorbed in ﬁshes, according to the literature .
MATERIAL AND METHODS
Females of the striped ﬂounder
(body length of 27–30 cm) were ﬁshed in the
suburb zone of Vladivostok City in Amur Bay, Peter the
Great Bay, in January (V SGM), February (VI SGM),
and March (II SGM) and in October and November (IV
stage of gonad maturity, SGM) in the years 2000–2002.
Pieces of gonads were ﬁxed in a mix of formalin, etha-
nol, and acetic acid. The material was embedded in par-
afﬁn by the standard technique. Sections 7
were stained by hematoxylin and eosin. The maturity of
ﬂounder gonads was deﬁned applying the scale sug-
gested by Sakun and Butskaya . Ovaries of 15–
20 females were examined at all stages of maturation.
The resorbing of gametes at maturity stage IV
occurred seldom in the ovaries of the striped ﬂounder.
The nuclei of these gametes were deformed; their
nucleoplasm became like a granular structure and was
intensely stained by hematoxylin (Fig. 1a). The radial
coating was disrupted, and its fragments were observed
among the yolk granules (Fig. 1b). The follicular epi-
thelium was not preserved as a complete layer, and its
cells were not always identiﬁed on the background of
ﬁne-grained sites of the oocyte cytoplasm and yolk
granules (Fig. 1b).
Unlike the previous stage, mass resorption of the
vitellogenous oocytes occurred in the striped ﬂounder
in maturity stage V (Fig. 1c) and the principle feature of
this process was accretion of the follicle wall. Protru-
sions formed by the wall were directed to the ovary
lumen, and they greatly increased in size and were
speciﬁed by rugosity (Figs. 2a–2c). During resorption,
the homogenized trophic material was gradually
released from the oocytes through the radial coating to
the follicular wall. The initial stage of resorption was
bound to homogenization of part of the yolk granules
located at the plasma membrane (Fig. 2d); the release
of the yolk from sex cells was still poorly manifested
that season. It is interesting that the radial coating did
not degrade in oocytes in spite of some defects that it
Patterns of Resorption of Vitellogenous Oocytes
in the Striped Flounder
V. B. Durkina
Institute of Marine Biology, Far East Division, Russian Academy of Sciences, Vladivostok, 690041
Received June 16, 2005
—Two patterns of resorption of vitellogenous oocytes with the participation of follicular cells, differ-
ing in their morphological features, were revealed in the striped ﬂounder
. In the
prespawning season, the resorption affected a small number of oocytes with yolk granules and resembled in
some features (destruction of the nucleus and radial coating) the atresia of ovarian follicles in many ﬁsh species
previously studied. In the spawning season, resorption was speciﬁed by accretion of the follicular epithelium
and release of the homogenized yolk from the oocytes to the follicular wall. No destruction of the radial coating
was observed in that case, and the trophic material was utilized in protrusions of the follicular wall.
, resorption, vitellogenous oocytes.