Molecular identification of Hysterothylacium aduncum specimens isolated from commercially important fish species of Eastern Mediterranean Sea using mtDNA cox1 and ITS rDNA gene sequences.

The presence of a Raphidascarid parasitic nematode Hysterothylacium aduncum (Rudolphi, 1802) in two sparid fish (Sparus aurata and Diplodus vulgaris) and one soleid fish (Solea solea) was investigated in this study. A total of 868 individuals; 385 S. aurata, 437 D. vulgaris and 46 S. solea were collected from the Mersin Bay between February 2013 and January 2014 and examined. Variations in the prevalence, mean intensity, and mean abundance of the parasite were 14.55%, 2.05, and 0.30 for S. aurata, 4.12%, 2.44, and 0.10 for D. vulgaris, and 15.22%, 3.29, and 0.50 for S. sole respectively. Nucleotide sequences of 1398 base pair long fragment of 18S rRNA-ITS1-5.8S rRNA-ITS2-28S rRNA region and 641 base pair long fragment of mtDNA cytochrome c oxidase I (cox1) gene were used in molecular identification of isolated parasites at species level. All the parasite samples were identified as H. aduncum based on nucleotide sequence comparisons. Both ITS rDNA and mtDNA cox1 sequences revealed a genetic variation among H. aduncum specimens isolated from different fish species, while only mtDNA cox1 sequences were indicating a mean genetic distance of 0.010 among H. aduncum specimens of the same host species.

Assessment of heavy metal contamination in various tissues of six ray species from Iskenderun Bay, northeastern Mediterranean Sea.

This study was performed to investigate the heavy metal concentrations in muscle, liver, gill and intestine of six ray species from Iskenderun Bay. The present study is the first for rays in Iskenderun Bay, providing valuable preliminary information about heavy metal contents in different tissues of the examined ray species from the bay, and indirectly, indicating the environmental contamination of Iskenderun Bay. Heavy metal levels in intestines were generally higher than those in other tissues for all species. Metal levels in ray muscle tissue were below the international maximum allowable levels for fish and fishery products, as well as Turkish national guidelines, with the exception of the highest value for Cd in Dasyatis pastinaca.

The evaluation of gnathiid (Crustacea: Isopoda: Gnathidae) parasitism in goldblotch grouper (Epinephelus costae Staindahner, 1878) in the northeastern Mediterranean Sea using the self-organizing map (SOM).

The self-organizing map (SOM), which is widely used in economics and engineering applications, is a type of artificial neural network trained without supervision. SOM is used to represent multidimensional data in much lower dimensional spaces-usually in two dimensions (2D)-while preserving the topological properties of the input space. In this study, 2D maps were produced by using SOM to display the relationship between seasons, length, weight, and isopod infestation of goldblotch grouper (Epinephelus costae Staindahner, 1878). This is first study of gnathiid isopod praniza larvae infesting goldblotch grouper (E. costae Staindahner, 1878) in the northeast Mediterranean Sea (36°36' N-36°07' E, 35°52' N-36°25' E) in Iskenderun Bay. Fish were sampled monthly from Iskenderun Bay for a period of 12 months from 2006 May to 2007 April (Nt=331, Wt+/-SD (range)=392.92+/-72.76 g (169-927 g) TLt+/-SD (range)=30.85+/-3.88 cm)). Gnathia sp. was only extracted from the epithelium of the buccal cavity and internal side of the gills arch. The monthly patterns in infested fish samples (Np=109, Wp+/-SD (range)=349.25+/-182.79 g (169-853 g) TLt+/-SD (range)=26.05+/-12.68 cm (18.2-45.0 cm)) infestation rates (mean prevalence, P=28.12% (0-60) and mean intensity (MI+/-SD=23.69+/-14.78 (4-82), the relationship between length-weight and infested/non-infested fish were calculated. Although the gnathiid parasite high intensities were observed in fish, there was no significant effect on the growth and general health condition of infested fish.

Accumulation of some heavy metals in Hysterothylacium aduncum (Nematoda) and its host sea bream, Sparus aurata (Sparidae) from North-Eastern Mediterranean Sea (Iskenderun Bay).

The sea bream's nematode and Sparus aurata, sampled from the Iskenderun Bay, Mediterranean, in March 2008 were analyzed by inductively coupled plasma-atomic emission spectrometry for their some heavy metal (Cd, Cr, Cu, Fe, Hg, Mn, Mg, Pb, and Zn) levels. The metal concentrations of the parasites were compared to different organs (liver, muscle, gill, intestine, and skin) of the fish hosts. There were significant differences in Cd, Cr, Cu, Fe, Mn, Zn, Hg, Mg, and Pb concentrations in tissues of fish and its parasite. The parasite Cd, Cu, and Pb concentration was higher than the other tissues. Furthermore, significant differences were detected in the heavy metal accumulations between the parasitized and unparasitized fish tissues in Cd, Cu, Hg, and Pb concentrations. The Cd, Hg, and Pb concentrations were found in fish muscle at mean concentrations over the permissible limits proposed by the Food and Agriculture Organization.

Accumulation of some heavy metals seasonally in Hysterotylacium aduncum (Nematoda) and its host Red Sea Bream, Pagellus erythrinus (Sparidae) from Gulf of Iskenderun (North-eastern Mediterranean).

The Red Sea Bream's nematode and Sparus aurata, sampled from the Iskenderun Bay, North-eastern Mediterranean in March 2008 were analysed by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) for their some heavy metal (Cd, Cr, Cu, Fe, Hg, Mn, Mg, Pb and Zn) levels. The metal concentrations of the parasites were compared to different organs (liver, muscle, swimbladder, intestine and skin) of the fish hosts. The highest Cd (0.303 mg/kgg ww) concentrations were found in the muscle, highest Cr (4.932 mg/kg ww), Hg (2.350 mg/kg ww) Pb (22.82 mg/kg ww) concentrations were found in the parasite, highest Cu (7.608 mg/kg ww) and Fe (176.7 mg/kg ww) concentrations were found in the liver, highest Mn (31.24 mg/kg ww) Zn (78.51 mg/kg ww) concentrations were found in the swimbladder for parasitized fish. The highest Cd (0.612 mg/kg ww), Cu (8.261 mg/kg ww) Fe (261.1 mg/kg ww) concentrations were found in the liver, highest Cr (6.123 mg/kg ww) and Pb (9.125 mg/kg ww) concentrations were found in the intestine, highest Hg (2.013 mg/kg ww) Zn (83.30 mg/kg ww) and Mn (41.24 mg/kg ww) concentrations were found in the swimbladder for un-parasitized fish.

Element concentrations in the swimbladder parasite Anguillicola crassus (nematoda) and its host the European eel, Anguilla anguilla from Asi River (Hatay-Turkey).

The European eel's swimbladder nematode, Anguillicola crassus, sampled from the Asi River (Orontes River) in Antakya (Hatay, Turkey) in May 2006 were analysed by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) for their some heavy metal (Cd, Cr, Cu, Fe, Hg, Mn, Pb and Zn) levels. The metal concentrations of the parasites were compared to different organs (swimbladder, liver, muscle and skin) of the fish hosts. The parasite contained statistically highly significantly amounts of Fe (P < 0.05). The iron level of nematode was up to 25.52 times than the muscle of its host, Anguilla anguilla. However, bioconcentration of Cd, Cr, Cu, Hg, Mn, Pb, Zn were detected in the A. crassus and it contained no statistically differences with the other tissues of its host, the eel (P > 0.05). Furthermore, no significant differences were detected in the heavy metal accumulations between the parasitized and un-parasitized fish tissues. The analysed metals (Cd, Cr, Cu, Fe, Mn, Pb and Zn) were found in fish muscle at mean concentrations under the permissible limits proposed by FAO.

Infestation status of gnathiid isopod juveniles parasitic on Dusky grouper (Epinephelus marginatus) from the northeast Mediterranean Sea.

This is the first detailed documented record of Gnathiid isopod praniza larvae infestating dusky grouper, (Epinephelus marginatus Lowe 1834) in the northeast Mediterranean Sea (36 degrees 36'N-36 degrees 07'E, 35 degrees 52'N-36 degrees 25'E). Fish were sampled monthly from Iskenderun Bay during a 3-year period from 2000 to 2003 [N = 468, W+/-SD (range) = 503.69+/-342.35 g (177-2,832 g), TL+/-SD (range) = 32.39+/-9.22 cm (16.1-67.0 cm), W (total) = 0.213L (total) (2.19), r (total) (2) = 0.85]. Juveniles of the Gnathia sp. were only extracted from the epithelium of the buccal cavity. The monthly and seasonal patterns in infestation rates (mean prevalence, P = 27.35% and mean intensity, MI+/-SD = 21.35+/-16.19), and the relationship between length-weight and infested/non-infested fish were calculated. This study suggests that gnathiid parasite has no effect on the growth and general health condition of infested fish, although high intensities were observed in fish.