Chaetogammarus ischnus major (Stebling, 1898)

Synonyms: Ch. Ischnus Stebling 1898, Gammarus tenellus G.O. Sars 1914, Ch. Tenellus major S. Carausu 1943.

Common names: Bulg: Mamarets; Russ: Bokoplav.

Order (Scientific): AMPHIPODA.

Family (Scientific): GAMMARIDAE.

Taxonomic descriptions: Dimensions - length male 12-15 mm, female 10-13 mm. On the urosom 2-3 prickles in a group over the segments. A lot of groups of curved setae on antenna II as well as I and II pereiopodes of the male.

Chaetogammarus ischnus major arealIUCN Status:
    World level: VU
    Black Sea Regional level: VU
    Subregion level: VU

Distribution: Pontocaspian species, Bulgarian and Romanian coast.

Habitats type, Critical habitats, Limiting factors: Brackish and fresh waters, coastal lakes, swamps and rivers, salinity increase, pollution.

Biology: Inhabits brackish and fresh water lakes. It is found under stones and among water plants at a depth of up to 0.5 - 1 m. Period of breeding - from April to October.

Population trends: Decreasing trend.

Threats: Pollution caused by urbanization and uncontrolled stockfarming.

Conservation measures taken: The Shabla lake is the only stated reserve.

Conservation measures proposed: Formation of protected territories and reserves in the lakes’ surroundings and in the humid zones.


  1. Birstein, J., Vinogradova, A. Kondakova, M. Kun, V. Astahova, N. Romanova 1968. Atlas of invertebrate fauna of the Caspian Sea.
  2. Carausu, S. 1943. Amphipodes de Roumanie. I. Gammarides de types caspien. Bull. Institute de cercet. Pisc. Al Romanei.
  3. Carausu, S., E. Dobreanu, C. Manolache, 1955. Amphipoda forme solmastre si de apadulce. Fauna R.P.R. vol. IV. Fasc. 4.
  4. Kaneva-Abadjieva, V. 1972. A Contribution to the Study of the Amphipodus Fauna in the Black-Sea-Coast Lakes and River Mouths (in Bulgarian). Bulletin de l’Institut de Zoologie et Musée, vol. XXXV, pp. 164-168.
  5. Morduhaj-Boltovskoj, F. 1969. Guide book of the fauna of Black and Azov Sea. Crustacea, Amphipoda.
  6. Valkanov, A. 1957. Katalog unserer Schwarzmeerfauna. Arbeiten aus der Biologischen Meeresstation in Varna Bulgarien. Bd. XIX.

Compiled by: S.Andreev.