black sea red data book - Department of Biology

acteria and Infusoria. The female lays its eggs in two sacks located on the sides of
the genital segment.
Population trends. Until 1984, O. minuta was common in the mesoplankton in front
of the Bulgarian coast. After the appearance of the ctenophore M. leidyi in 1986-1991
O. minuta rapidly fell, to become almost extinct in 1991- 1994. In 1995 it reappeared
in the mesoplankton, but in modest numbers (134-152 ind.m" 3
) compared with 7,000 -
8,000 ind.m' 3
in 1970-1984.
Threats. Increased eutrophication and M. leidyi predation and competition.
Conservation measures taken. None.
Conservation measures proposed. A reduction in eutrophication, which may lead to
a drop in M. leidyi numbers.
References
Konsulov, A., 1991. Izsledvania varhu biologiata, ecologiata I znachenieto na
zooplanktona na Cherno more pred balgarskia briag. Dr. Sci. Thesis, IO, BAS, Varna,
300 pp.
Konsulov, A. & L. Kambursk,. 1997. Sensitivity to anthropogenic factors of the
plankton fauna adjacent to the Bulgarian coast of the Black Sea. In: Sensitivity to
Change: Black Sea, Baltic Sea and North Sea. NATO ASI Series 2. Environment 27:
95-104.
Opredelitel fauni Chernogo I Azovskogo morej, 1969. Kiev, Naukova Dumka 2:49-
50.
Compiled by A. Konsulov.
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