black sea red data book - Department of Biology

Synonym: Oithona nana Giesbr., 1892.
Common names: None.
Oithona minuta (Kriczagin, 1873)
Order CYCLOPOIDA
Family OITHONIDAE
Taxonomic description. Céphalothorax with enlarged middle part. In the
Zonguldak and Akçakoça areas, rostrum absent in both sexes. Anal segment shorter
than preceding one. Female's first antennae extending to end of third thorax segment
Fifth pair of legs bears two setae. Egg sacs ciniform. Length of female 0.5-0.7 mm,
of male 0.4-0.6 mm.
IUCN Status
World level:
Black Sea Regional level:
Subregion level: EN
Distribution, Habitat type, Critical habitats, Limiting factors. An euryhaline
species which mainly inhibits the surface of the Black Sea. The high degree of
eutrophication and feeding competition with larval Mnemiopsis leidyi in the last ten
years was an important limiting factor. Another factor is that adult M. leidyi feed on
0. minuta. The elimination of O. minuta is mostly due to the fact that its eggs are
carried in egg-sacks. Together with the mother these fall prey to the ctenophore and
are effectively eliminated.
Biology. Mainly in the upper water layers. Performs diurnal migrations with a wide
vertical range. Observed during the whole year. Feeds on tiny phytoplankton,
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