Persistent organochlorine pesticide residues in water and sediment samples from Lake Manyas, Turkey.

The extent of organochlorine pesticides (OCPs) contamination in Manyas Lake (Bird Lake) and its tributary rivers and streams which is situated near the South-eastern coasts of the Marmara Sea in Turkey was investigated. Residues of OCPs in surface water and sediment samples were analysed by gas chromatography equipped with electron capture detector. The total OCPs concentration (sigmaOCPs) in water and sediment samples ranged from 1.43 to 8.6 microg l(-1) and from 17.05 to 39.14 ng g(-1), respectively. According to the concentrations and detection frequencies, HCHs, DDTs, heptachlor and heptachlor epoxide were the most dominant compounds among the OCPs. The results showed that Manyas Lake was still contaminated by organochlorine pesticides and their residues despite bans on the production and usage over a long time.

Molecular phylogeny of the genus Gobio Cuvier, 1816 (Teleostei: Cyprinidae) and its contribution to taxonomy.

The phylogenetic relationships among gudgeons that represent most nominal taxa within Gobio gobio sensu lato were examined by mitochondrial and nuclear genome sequencing. The molecular analyses confirmed the separate generic status of Gobio as a monophyletic group and revealed 15 Eurasian lineages divided into two main clades, the Northern European and the Ponto-Caspian. The validity of eleven nominal taxa as distinct species was confirmed, gudgeons from the Volga River basin were described as a new species G. volgensis, and three revealed phylogenetic lineages were submitted for a comprehensive revision as "species-in-waiting". The species G. gobio showed a wide range extending from the British Isles to the Black Sea coast and overlapped the areas of several other species. Four pure lineages were detected in the middle Danube River basin. The Crimean Peninsula was found to be a region with the occurrence of individuals of hybrid origin. This region will require special investigation to define species participating in hybridization events, and to establish further steps for the conservation of endemic native gudgeon species. A simple diagnostic method, based on different lengths of the PCR products, called "S7indel diagnostics" is presented for further taxonomic investigations in the genus Gobio.

Discrimination of Cobitis simplicispina Hanko, 1925 and Cobitis turcica Hanko, 1925 populations (Pisces: Ostariophysi: Cobitidae) from Turkey.

The most significant morphometric characters differentiating the specimens of Cobitis simplicispina collected from the Sakarya-Kizilirmak river basins, Cobitis turcica collected from Bagilli and not so far recognized species from Saz Lake were investigated in this work. ANOVA (Analysis of Variance) and canonical discriminant analysis were applied to 44 variables (5 meristic and 39 metric characters derived from 24 measured variables) to show the main differences between three populations. Populations from different localities appeared to be significantly different from each other both in meristic and metric characters. The following characters: standard length/head length (sl/Hc), preorbital length/longitudinal eye diameter (PrO/Oh), standard length/interorbital width (sl/io) and head length/longitudinal eye diameter (Lc/Oh) were important in distinguishing these three populations.

Biochemical-genetic comparison of Cobitis simplicispina from Turkey, and C. taenia, C. albicoloris and C. elongata from Bulgarian freshwaters.

Taxonomic investigations of 4 species of the genus Cobitis: C. simplicispina Hanko 1925, C. taenia Linnaeus 1758, C. albicoloris Chichkoff, 1932 (= C. peshevi Sivkov & Dobrovolov, 1984) and C. elongata (Heckel & Kner 1858) from Turkey and Bulgarian freshwaters were carried out using biochemical-genetic methods. The analyses of one general muscle protein (PROT) and six enzyme systems including esterase (EST), lactate dehydrogenase (LDH), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), malic enzyme (MEP), malate dehydrogenase (MDH) and superoxide dismutase (SOD) revealed electrophoretic differences between the species examined. Fractions controlled by the LDH-B locus of C. simplicispina gave completely different electrophoretic mobility from those of the other Cobitis species. Nei's genetic distance (D(Nei)) between C. simplicispina and C. albicoloris, C. taenia and C. elongata was estimated as 1.39, 1.16 and 1.27, respectively. C. simplicispina might have diverged from the other three species 5.8 - 6.95 million years ago.

Preliminary data on growth and reproduction of Cobitis simplicispina from Turkey.

Preliminary data on growth and reproduction parameters of Cobitis simplicispina from Darýözü Creek in the Kizilimak basin in Kirsehir-Turkey were presented. The age of the specimens collected during a period between March and June 2002, ranged from 1+ to 4+. The observed maximum total length of males is 91.8 mm, and 97 mm for females. The von Bertalanffy equation for male and female specimens was found to be Lt=93.01(1-exp(-0.408(t+0.821))) and Lt=94.42(1-exp(-0.488(t+0.458))), respectively. The length-weight relationship was expressed as log W= 3.009x SL -5.171 when all specimens were taken into account. The range of absolute fecundity extended from 320 to 2141 eggs and the diameter of ripe eggs varied between 1.00 and 1.25 mm. The gonadosomatic index suggested that spawning took place in April.