Hemimysis anomala G.O. Sars, 1907

Hemimysis anomala imageSynonyms: None

Common names: Russ: Myzida anomal'naya; Ukr: Myzida anomal'na

Order: MYSIDACEA

Family: MYSIDAE

Taxonomic descriptions: One of 7 species of a genus close to Hemimysis serrata species. All ventral appendages in females are reduced, in males only the first and second pairs of pleopods are reduced. Telson with shortened apex and serrated along the whole length of side edges.

Hemimysis anomala arealIUCN Status:
    World level: Endemic of the Azov-Black Sea basin
    Black Sea Regional level: EN
    Subregion level: EN (Ukrainian sector)

Distribution: One of the few Ponto-Caspian endemics living in the sea and in freshwater bodies. Inhabits the Azov and Black seas, in the lower reaches of the Dniepr, Dniestr and Don. Encountered on the western coast of the Caspian Sea. Acclimatized in water reservoirs: Dnieprovsky, Sympheropolsky, Chernorechensky (Ukraine); Dubossarsky (Moldova) and Kaunasky (Lithuania).

Habitats type, Critical habitats, Limiting factors: Near bottom lithophile organism. Inhabits shells, rocky, rarely silty sediments; prefers firm sediments, more often rocky, rarely shells and sandy. Encounted in river estuaries in silty sinks. Leads a benthic way of life during the day, in the evening rises to the pelagic zone.

Biology: Euryhaline organism, lives in water of salinity from 0.5-18.0 ppt. Euryphagous. Duration of reproduction period is from April to October. After fertilization the female broods from 9 to 31 embryos (18 on average) in the brood pouch. Produces not less than two generations a year. In the Black Sea it reaches a length of 8-10 mm, in the Sea of Azov and freshwater areas - 6.7-8.5 mm. Bloody-red colour. The species is capable of changing colour due to chromatophores and becomes completely transparent, keeping a light colour with a touch of yellow, ivory colour.

Population trends: Low abundance. Single specimens encountered.

Threats: Pollution and silting of water bodies, reduction in river deltas, areas of seabed with hard sediments.

Conservation measures taken: Included in Red Data Books of Ukraine and the Black Sea. Acclimatizing in Dniepr and Dniestr reservoirs.

Conservation measures proposed: Recommended extension of reserve areas in the limans and deltas of rivers, conducting of regular biotechnical measures top reduce water pollution and increase river water flow.

References:

  1. Reznichenko, O.G., 1959. K ekologyi y morfologyi myzid roda Hemimysis (Crustacea, Malacostraca) (To ecology and morphology mysidas genus Hemimysis (Crustacea, Malacostraca)), In: Trudy Vsesojuz. gydrobiol. obsch., v. 9, p. 320-343 (in Russian).
  2. Bacescu, M., 1969. Order Mysidacea. In: Opredelitel fauny Chernogo i Azovskogo morey (Key of Black Sea and Sea of Azov fauna). Kiev: Naukova dumka Publ., 2, p. 363-381 (in Russian).
  3. Komarova, T.I., 1991. Vyschie rakoobraznie. Mysidae (Mysidacea) (Higher crustaceous. Mysidae (Mysidacea), In: Fauna Ukrayni, 26(7), Kiev: Naukova dumka Publ., 104 pp.
  4. Komarova, T.I., 1994. Hemimysis anomala. Chervona Knyga Ukrayiny (Red Data Book of Ukraine). Kijiv: Ukrajinska enciklopediya Publ., p. 39 (in Ukrainian).

Compiled by: B.Alexandrov