Hesionides arenarius (Friedrich, 1936)
Common names: None.
Order (Scientific): NEREIMORPHA.
Family (Scientific): HESIONIDAE.
Taxonomic descriptions: One of three species of Hesionidae family in the Black Sea. Length from 1.7 to 3.0 mm, brownish pigmentation, having up to 19-25 segments, eyes are absent. Pygidium with two distinctly separated anal lamellae, which do not overlap, but distally broadened and fan-shaped. Two long, threadlike anal cirri.
Black Sea Regional level:
Subregion level: EN (Ukrainian shelf and Romanian sector), VU (Romanian sector)
Distribution: Hesionides arenarius are known to have a wordwide distribution in tropical and subtropical beaches, also inhabits boreal regions. In the Black Sea it was reported on the Bulgaria, Romania and Ukraine shelves. This species belongs to the characteristic forms of the interstitial meiofauna of ware-washed sandy beaches.
Limiting factors: Sandy bottom mediolittoral stripe. Limiting factors are size of grains of sand, the pollution of sand of the sea's edge, man-made changes in the granulometric composition of sand.
Biology: Species of the genus Hesionides formed a common element in the interstitial animal community. Its preferred habitat is coarse sand free of mud.
Population trends: A sharp decline in population numbers since 1983s. A reduction of 80-90%.
Threats: Pollution of the mediolittoral and supralittoral zones stripe changes in the granulometric composition of sand.
Conservation measures taken: None.
Conservation measures proposed: Entry in the Black Sea Red Data Book.
Compiled by: C.Dumitrache, L.Vorobyova.