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Öğe Analysis of the economic performance of salmon farming in submerged and surface cages in the Black Sea(Springer Science and Business Media Deutschland GmbH, 2023) Yiğit, Umut; Yiğit, Murat; Ergün, Sebahattin; Kuşku, Halit; Ek, Hüseyin; Maita, MasashiThe production period for salmon farming in the Black Sea comprises the winter period and is limited to seven months, due to high water temperatures during the summer time. As an alternative strategy, temporary cage submersion during the summer season might be a solution for salmon grow-out throughout the year. Therefore, this study was conducted for comparative evaluation of economic performance of submerged and surface cages, by analyzing structural costs and returns for Turkish salmon farming in the Black Sea. As a result of the temporary cage submersion strategy, economic profits increased by nearly 70%, granting higher values of financial indicators with increased net profit (685,652.5 $ year−1) and margin of safety (89.6%), compared to the traditional surface cage (397,058.5 $ year−1 net profit and 88.4% margin of safety). The “What-if” analysis showed that profits from both cage systems were sensitive to variations in sale price, and the simulation by 10% reduced export market value may decrease revenues, with less financial profit loss for the submerged cage over the surface once. Hence, temporary cage submersion seems to be an alternative farm management strategy with extended production cycle and higher profits for the sustainable development of Turkish salmon farming in the Black Sea.Öğe Bioaccumulation of trace metals in Mediterranean mussels (Mytilus galloprovincialis) from a fish farm with copper-alloy mesh pens and potential risk assessment(Taylor & Francis Inc, 2018) Yigit, Murat; Celikkol, Barbaros; Yılmaz, Sevdan; Bulut, Musa; Ozalp, Baris; Dwyer, Robert L.; Maita, MasashiConcentrations of trace metals were determined in the muscle tissue, digestive gland and gills of Mediterranean mussels (Mytilus galloprovincialis) collected from different locations around an offshore copper alloy fish farm. Levels of copper (Cu), zinc (Zn), manganese (Mn) and iron (Fe) as mg/kg wet weight in the edible part of the mussels collected from distant zone (upstream Zn7.33 > Fe2.8 > Cu0.13 > Mn0.07 and downstream Zn9.9 > Fe5.67 > Cu0.18 > Mn0.17) were significantly lower (p < 0.05) than those sampled from the cage zone (bottom panel Zn22.25 > Fe13.75 > Cu2.39 > Mn0.85 and cage frame Zn17.1 > Fe8.74 > Cu1.39 > Mn0.26). Trace metal concentrations in mussels were significantly higher (p < 0.05) in the samples from the frame and bottom panel of the copper alloy mesh pen, compared to those from distant areas, namely the farm affected downstream - and non-affected upstream locations. However, the rates of target hazard quotients (THQ) for all tested trace metals from all locations in the present study were smaller than one (THQ < 1), indicating that the consumption of mussels grown around a cage farm with copper alloy mesh pens were within safe limits and did not exceed maximum levels suggested by the US Food and Drug Administration (USFDA) and European Union (EU) regulations for seafood consumption.Öğe Comparision of copper alloy mesh with conventional nylon nets in offshore cage farming of gilthead seabream (Sparus aurata)(Central Fisheries Research Institute, 2018) Yigit, Murat; Celikkol, Barbaros; Ozalp, Baris; Bulut, Musa; Dwyer, Robert L.; Yılmaz, Sevdan; Maita, MasashiIn the present study, a new net technology of copper alloy mesh (CAM) was tested and compared with traditional nylon nets either with (TNN+AF)-or without antifouling coats (TNN–AF) in a long-term growth experiment on gilthead seabream (Sparus aurata). Fish performed better growth and feed utilization in the CAM pen over the TNN+AF and TNN–AF, with a survival rate over 85% in all cage environments after the 7 months growth period. Relative wet weight gain of seabream in the CAM and TNN+AF pens were 25% and 15% higher compared to the TNN–AF cage, respectively. Surface of the TNN–AF mesh remained clean for two months after sea water deployment, while the mesh size in the TNN+AF pen remained effective for four months, and shrinking in mesh size thereafter. Dissolved oxygen was highest inside the CAM followed by the TNN+AF and TNN–AF cages, respectively. The results of the present study demonstrate that CAM might be beneficial for cage farming in offshore conditions, however further studies are encouraged to evaluate leaching of metals into the marine environment as well as toxic influences on fish tissues and health risks to human consumers. © 2018, Central Fisheries Research Institute. All rights reserved.Öğe Health Risk Assessment of Metals via Consumption of Rapa Whelk (Rapana venosa) from the Black Sea(Ankara Univ, Fac Agriculture, 2024) Bayrakli, Baris; Yigit, Murat; Altuntas, Mutlu; Maita, MasashiThe present study investigated the bioaccumulation of metals in raw, heat treated-and sterilized Rapa whelk, and evaluated the consumer risks for human consumption. All of the metals, with the exception of Mn, were found to be lower than the permissible FAO standards. A remarkable amount of metal was released into the boiling water (Al, Cr, Cu, Fe, Hg, Pb, Sb, Se, Zn) after heat treatment and hypochlorite solution (Al, As, Cu, Hg, Mn, Pb, Se, Zn). After sterilization, the levels for As, Mo, Cd, Sb, Cr, Zn, Se, Cu, and Hg in Rapa whelk were reduced by 47.4%, 40.1%, 24.9%, 20.3%, 17.5%, 4.5%, 3.6%, 0.93%, and 0.68%, respectively. The metals in Rapa whelk exposed to hypochlorite immersion were found to be below permissible upper limits. The target hazard quotients for the non- carcinogenic risks of consuming sterilized Rapa whelk were below 1 (THQ<1), showing no potential health risks for adult men, women and children when consuming sterilized Rapa whelk. Indeed, Rapa whelk could be a good source of Cr, Cu, Fe, Mn, Mo, Se, and Zn to meet the daily recommended quantities in food, when consumed regularly. However, the cancer risks of As, Cd, Ni, and Pb proved to be over acceptable levels; hence, the safe consumption limits determined in this study are advisable when consuming Rapa whelk.
