Chryssa Anastasiadou

Karyological Analysis of the Freshwater Shrimp Atyaephyra desmarestii (Decapoda: Caridea: Atyidae)

Abstract The karyotype of Atyaephyra desmarestii, the European freshwater shrimp, from Louros River (NW Greece) was studied through the examination of metaphase chromosome spreads from the first zoeal stage larval tissues. A total of 42 mitotic metaphases were examined and the diploid chromosome number was determined to 2n  =  32. The karyotype consisted of 22 metacentric and 10 submetacentric chromosomes. Atyaephyra desmarestii karyotype is reported here for the first time providing a basis for further cytogenetic comparative study of the species populations.

Shrimps of an ancient Balkan lake: Bionomy and conservation

In order to have a comprehensive evaluation and classification of the natural biota of Lake Pamvotis, the present study aims at investigating shrimps’ bionomic traits. Information on shrimps’ habitat preferences, abundances, and syntopic species in relation to the physicochemical profile of the lake’s water are investigated for the first time. The study was carried out on a bi-monthly base, at six littoral sites of the lake. Samples’ study from different habitats and seasons revealed that the freshwater shrimp Atyaephyra thyamisensis was the most abundant species, accounting for 44.76% of the total taxa catch, while the grass shrimp Palaemonetes antennarius was less abundant (7.54%). Syntopic fish species in the littoral zone of Lake Pamvotis such as Economidichthys pygmaeus, Gambusia holbrooki, Knipowitschia caucasica and Rutillus panosi showed interannual differences with abundances of 24.12%, 19.13%, 4.26% and 0.20%, respectively. Correspondence analysis revealed clear patterns between species and stations. A. thyamisensis was predominant in shallow, well oxygenated water bodies rich with aquatic vegetation, but it was absent from deeper habitats. P. antennarius was found mainly in lentic water bodies, rocky substratum and deeper habitats. Taking into account the high ecological importance of the freshwater shrimps in ecosystems’ energy flow, ecological and biological data of lake’s shrimps are discussed and presented thoroughly. Threats and conservation measures for both shrimp species are debated also in detail.

Length–weight relations of seven native fish species (Actinopterygii) from the Louros River, Greece

Length–weight relations were estimated for 7 native fish species of the Louros River in north-western Greece, 6 of them being endemic to the Ionian Sea ecoregion. The b values ranged from 3.05 to 3.21. Five species, namely Cobitis hellenica Economidis et Nalbant, 1996; Pelasgus thesproticus (Stephanidis, 1939); Gasterosteus gymnurus Cuvier, 1829; Economidichthys pygmaeus (Holly, 1929); and Valencia letourneuxi (Sauvage, 1880) displayed an isometric growth pattern (b = 3) while the remaining two species—Salmo lourosensis Delling, 2011 and Telestes pleurobipunctatus (Stephanidis, 1939)—showed a positive allometric growth (b > 3). New maximum lengths are given for three species. Moreover, this study constitutes the first world report on the length–weight relations for 5 species and the first report for the Ionian Sea ecoregion for two other species.