The venerid clam Chamelea gallina is a popular and economic foodstuff around the Mediterranean countries especially in Italy, Spain, and France. The aim of this study is to evaluate the nutritional quality of striped venus of Southern Marmara. Samples were harvested seasonally at five stations and analyzed to determine meat yield, proximate, and elemental composition. According to the results, meat yield ranged from 20.24% to 29.94%. Means of water, protein, lipid, and ash content were 67%, 10.12%, 2.57%, and 1.66%, respectively. The mean concentrations (mg/kg wet weight) of elements in tissues are as follows: B: 2.37-4.24; Cr: 0-0.76; Co: 0-0.43; Cu: 0.71-5.30; Mn: 0.30-5.94; Zn: 13.08-77.76; Ni: 0-1.22; Fe: 2.46-114.22; Al: 1.23-75.49; Pb: 0.18-3.24; Ba: 0.66-15.97; Cd: 0.04-0.69. Among the reported metal levels, only Pb and Zn in two stations exceeded the maximum critical concentrations enforced by Turkish legislation and European Commission. Therefore, we report that striped venus from Southern Marmara Sea, in general, are safe for human consumption; nonetheless, Pb and Zn levels should be closely monitored in the future.

Ruditapes philippinarum, a venerid clam, is a dominant species in the sandy and muddy areas in the coastal waters of the Marmara Sea. Intensive commercial harvesting of this species is conducted in these regions. We studied the population dynamics of R. philippinarum on the southern coast of the Marmara Sea (Bandırma). Samples were collected on a monthly basis between September 2012 and August 2013. Seasonal von Bertalanffy growth parameters using the length-frequency distribution of R. philippinarum were estimated at L ? = 67.50 mm and K = 0.33 year -1 , and the seasonal oscillation in growth rate was 0.53. The slowest growth period was in January. The growth performance index and potential lifespan were 3.182 and 8.06 years, respectively. The growth relationship was confirmed to have a positive allometric pattern. The average total mortality rate was estimated to be 0.777 year -1 , whereas the natural and fishing mortality rates were 0.539 and 0.238 year -1 , respectively. The current exploitation rate of R. philippinarum was 0.306. The recruitment pattern peaked during June-August, and spawning occurred between May and August. The results of this study provide valuable information on the status of R. philippinarum stocks.

Öz:Araştırmada, Marmara Denizi'nin batısında doğal stokların bulunduğu alanlardan örneklenen beyaz kum midyesi (Chamelea gallina) ve kum şırlanının (Donax trunculus) büyüme özellikleri tahmin edilmiştir. Numuneler, ticari avcılığa kapalı bölgelerden 24 ay süre ile aylık olarak dreç yardımıyla toplanmıştır. C. gallina populasyonunda bireylerin, boy dağılımı 7-39 mm, ağırlığı 0.3-21.05 g olarak belirlenmiş, D. trunculus'un ise boyu 11.5-42 mm ve ağırlığı 0.26-17.22 g arasında değişmiştir. Her iki türün de negatif allometrik büyüme gösterdiği tespit edilmiştir. C. gallina bireylerinin ortalama et verimi %19.10; D. trunculus'un ise %19.45 olarak belirlenmiştir. Abstract: Properties Growth of Populations The Striped Venus (Chamelea gallina L., 1758) and The Wedge Clam (Donax trunculus L., 1758) in The West Marmara SeaIn this study, of individuals the striped venus (Chamelea gallina) and the wedge clam (Donax trunculus) sampled from the natural stock in west of the Marmara Sea were estimated properties growth. Samples were collected for a period of 24 consecutive months in zones off commercial fishing by dredging. The distribution length of individuals in populations C. gallina and D. trunculus were 7-39 mm and 11.5-42 between, weight 0.3-21.05 g and 0.26 -17.22 g between, respectively. Both species showed negative allometric growth. The average meat yield of C. gallina and D. trunculus were about %19.10 and %19.45, respectively.

Arcobacter cryaerophilus was isolated from naturally infected rainbow trout ( Oncorhynchus mykiss Walbaum), and its pathogenicity was tested by intramuscular injection using healthy 1-year-old rainbow trout under cold-water conditions (at 5 °C). The lethal dosage of 50% end point (LD 50 ) for A. cryaerophilus was calculated as 7.79 × 10 5 viable cells. Experimental infection caused gross clinical abnormalities such as fallen scales, exophthalmia, oedema in injection region and at the base of fins, pale gills, kidney necrosis, hyperaemic areas in pale liver, haemorrhagic spots in heart, elongated spleen and swollen gallbladder. Activities of aspartate aminotransferase and alkaline phosphatase, and concentrations of glucose, total protein, albumin, cholesterol, triglyceride and calcium in the serum of the experimentally infected rainbow trout were significantly decreased compared with the healthy fish. Positive correlations were observed among blood parameters. Total lipid weights increased in the brain, muscle and liver tissues of infected fish and dropped in the gill and spleen tissues. Lipid peroxide contents in the brain, liver, kidney, spleen, muscle and gill tissues of infected rainbow trout were significantly higher than in healthy animals. The present work shows that A. cryaerophilus can be moderately virulent for rainbow trout at low water temperature, and changes in lipid and lipid peroxide contents of tissues and blood indices can highlight barely detectable effects of A. cryaerophilus infection in rainbow trout under laboratory conditions. However, the application of these indices in farm biomonitoring using rainbow trout will need more detailed studies and a careful consideration of the environmental parameters.

Mytilus galloprovincialis, the Mediterranean mussel, is an important shellfish species that constitutes the majority of production and consumption among bivalve mollusks in Turkey. Since shellfish can accumulate toxic chemicals from seawater, it is important to monitor bioaccumulation from their natural beds. For this reason, in this study, the aim was to monitor the levels of dioxins and dioxin-like polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and toxic metals (Pb, Cd, and Hg) in M. galloprovincialis collected from the southern coast of the Marmara Sea from 2014 to 2017. According to the results, the maximum levels of dioxins, PAHs, and toxic metals during the monitoring period were determined as 0.30 pg/g, 2.52 mg/kg, and 0.43-0.34-0.76 (Pb-Cd-Hg) mg/kg, respectively. Dioxin, PAHs, and toxic metal amounts in mussel samples were determined to be below the threshold levels enforced by the European Commission. The highest benzo(a)pyrene and total PAHs were determined in winter 2015, while toxic metals, dioxins, and dioxin-like PCBs (WHO/PCDD/F-PCB-TEQ) were higher in autumn 2014 than the rest of the sampling period. In conclusion, toxic chemicals monitored in M. galloprovincialis were found at low concentrations from the point of view of food safety. However, monitoring of these or other toxic chemicals should be repetitively performed in the future to ensure food safety in aquatic animals.

Concentrations of eight heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) were determined in economically important bivalve species: oyster (Ostrea edulis), wedge clam (Donax trunculus), manila clam (Ruditapes philippinarium) and warty clam (Venus verrucosa) from the Marmara and Aegean seas. Samples were collected seasonally between 2008 and 2009. Metal levels of bivalves were found in the following ranges: As 0.02-3.40, Cd 0.02-2.80, Cr 0.19-0.82, Cu 0.82-25.06, Hg < LOD-0.12, Ni 0.09-0.73, Pb 0.05-4.16 and Zn 6.85-899 mg kg(-1). The most abundant elements were Zn > Cu > As. In addition, the results showed that oysters had the highest concentrations of Zn in all seasons. The next abundant heavy metal detected was Cu in oyster and other clam species. It was concluded that in the future, these metals should be monitored regularly.

No abstract

The present study was performed to determine the depuration time and ability of Donax trunculus (Wedge Clam) and Tapes decussatus (Carpet Shell) contaminated with Escherichia coli, Salmonella enterica subsp. enterica serovar Typhimurium and Vibrio parahaemolyticus. Clams were contaminated with each bacterium at the level of 7.0 – 8.0 Log10 cfu/g. After contamination, clams were analyzed every 3 h in the first 24 h time period and every 6 h until the 72nd hour. During the depuration process of both clams, the level of bacteria decreased quickly to 40% of initial load in the first 12 h. The results of this study indicate that the depuration time of carpet shells for all bacteria is 66 h. The depuration process of the wedge clam was different from the carpet shell; S. typhimurium and E. coli can be depurated in 66 and 78 h, respectively, while V. parahaemolyticus was present after 72 h at the level of 1.7 Log10 cfu/g.