1063-0740/03/2903- $25.00 © 2003
Russian Journal of Marine Biology, Vol. 29, No. 3, 2003, pp. 144–149.
Original Russian Text Copyright © 2003 by Biologiya Morya, Kasatkina, Selivanova.
This paper presents results of the analysis of sea-
sonal plankton samples collected in Kievka Bay, Sea of
Japan, during 2000 and 2001. According to numerous
investigations performed from 1937 to 1982 [1–3, 5–7],
most phyto- and zooplankton species inhabiting the
waters of the northwestern Sea of Japan were character-
ized as high-boreal; no low-boreal species of arrow-
worms have been registered in this area. The genus
has never been encountered north of Pos’eta
Bay, while the genera
comprised only high-boreal species there,
, respectively. Studies of arrowworm
fauna in the northwestern Sea of Japan initiated in the
mid-1980s have demonstrated signiﬁcant changes in
the composition of the fauna. The high-boreal species
has disappeared, but species of low-boreal
genesis appeared instead, like
Additionally, some new species of arrow-
worms have been discovered . The appearance of
new species can probably be explained by their drift
with a cross-vortex current from the coast of Japan. The
changes in the hydrological regime registered since
1995 [8, 9] caused changes in the fauna of the north-
western Sea of Japan. In this paper we note the occur-
rence of the genus
in the northwestern
Sea of Japan. Earlier on, this genus had been described,
but it had been observed only in the southernmost part
of Peter the Great Bay. We also present here descrip-
tions of some species new either for science or for the
fauna of the surveyed region.
The holotype is deposited in the Paciﬁc Institute of
Oceanology FEB RAS, Vladivostok, under reference
number OLR-2/1. It was collected in Kievka Bay, Sea
of Japan, on November 24, 2001, during a total sam-
pling through the layer of 13–0 m deep, using a Juday
net (with a ring diameter of 37 cm). The temperature of
the surface water and the near-bottom water layer was
C, respectively. Coll. E.N. Selivanova.
More than 100 specimens of
found in samples from the open part of the bay. The
paratypes were collected from the same sample as the
holotype, their reference numbers are OLR-2/2 and
Description of the holotype.
Body is rather
“ﬂabby”; longitudinal muscle bands are wide, clearly
visible. Head is wider than the trunk; genital septum
has no constriction. The specimen is at the 3rd stage of
The body is 7.45 mm long. Tail region and suben-
teric ganglion are 27% and about 11% as long as the
entire body. Intestinal diverticula on midgut are small,
closely applied to the gut. The midgut is not vacuolated.
Short ciliary loop appears beyond the level of eyes and
is rounded on head; it has only one pair of poorly pro-
nounced medial protuberances. The anterior margin of
the ﬁns of the ﬁrst pair is located behind the level of the
posterior margin of the subenteric ganglion, at a dis-
tance of one-quarter of the length of the subenteric gan-
glion, and is 2.7% of the entire body length. The ﬁns of
the second pair are 1.4 times longer than the ﬁns of the
ﬁrst pair, which are 17.5% of the entire body length.
The anterior margin of the ﬁns of the second pair is sep-
arated from the posterior margin of the ﬁns of the ﬁrst
pair by a gap, which is 6% of the entire body length.
This distance is about 2.3 times as great as that between
the subenteric ganglion and the ﬁns of the ﬁrst pair. The
New Species of Arrowworms (Chaetognatha) Belonging
from Kievka Bay, Sea of Japan
A. P. Kasatkina
and E. N. Selivanova
Paciﬁc Institute of Oceanology, Far East Division, Russian Academy of Sciences, Vladivostok, 690041 Russia
Far Eastern State University, Vladivostok, 690600 Russia
Received December 6, 2002
—The paper presents descriptions and illustrations for several species of the genera
, either new for science or encountered for the ﬁrst time in the surveyed area. The
occurrence of one species of the genus
and two species of the genus
from the south-
ern part of Peter the Great Bay has been registered in the northwestern part of the Sea of Japan.
Chaetognatha, Sea of Japan.