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Öğe ACOUSTIC NOISE POLLUTION FROM MARINE INDUSTRIAL ACTIVITIES: EXPOSURE AND IMPACTS(2018) Kuşku, Halit; Yiğit, Murat; Ergün, Sebahattin; Yiğit, Ümüt; Taylor, NicThe improvements in marine technological developments propagate urbanization in the ocean environment. The construction or operational activities of marine structures such as energy plants,oil platforms, pipe-lines, sea-tunnel passages, or cable-stayed suspension bridges, and vessel traffic are sources of underwater noise pollution. How underwater sounds such as piling, pole drilling,or machinery noises may affect the marine live is mostly ignored in marine construction, and thereis lack of information regarding underwater sound effects on marine live in the oceans. Recently,a remarkable interest is developing concerning underwater sound effects, especially in aquaculturefacilities, with experimentation of musical stimuli or various noises caused by pumps or filter systems on behavior and stress responses of fish in culture conditions. With the increase of urbanization and progressive development of marine industries, more and more pressure from human-generated (anthropogenic) underwater sound pollution may threaten marine mammals, fish speciesand invertebrates from underwater noises that in terms might be called as “Underwater Noise Pollution”. The future of marine life and that of human being, and the dramatic increase of underwatersound pollution is a new debate that needs to be controlled in a sustainable way with environmentsound approaches. Therefore the potential effects of various sound sources derived from marineindustrial activities have been reviewed in this study.Öğe Ağ kafes sistemlerinde bakır alaşım ağların kullanılması ve ekonomik verimliliğinin değerlendirilmesi(Çanakkale Onsekiz Mart Üniversitesi, Lisansüstü Eğitim Enstitüsü, 2018) Yiğit, Ümüt; Ergün, SebahattinBu çalışmada, yenilikçi ve çevre dostu bakır alaşım ağ teknolojisinden yararlanılarak oluşturulan ağ kafes üretim sistemlerinin geleneksel ağ malzemeleriyle kıyaslanması, levrek balıklarının (Dicentrarchus labrax) bir yıllık üretim döngüsünde büyüme performans değerleri ve yem verimliliğine etkileri ekonomik göstergeler ile ele alınmış ve yatırım maliyeti ölçeğinde biyo-ekonomik verimliliğin belirlenmesi amaçlanmıştır. Tesisin kurulum ve denize yerleştirme gibi yatırım maliyeti belirlendikten sonra, ağ değiştirme veya antifouling uygulamaları gibi işletim maliyetleri belirlenmiştir. Çalışma sonunda elde edilen verilere göre, bakır alaşım ağ kafeste yetiştirilen levrek balıklarında büyüme performansı ve ekonomik verimlilik indeksleri geleneksel naylon ağ kafesteki balıklara göre daha yüksek kaydedilmiştir. Elde edilen sonuçlar doğrultusunda, kafes balıkçılığında bakır alaşım ağların kullanılabilir olduğu ve yüksek dayanımı sayesinde uzun süreli kullanıma elverişli görüldüğü, sıklıkla ağ değiştirme gereksiniminin ortadan kalkmasıyla antifouling boya kullanımına da ihtiyaç duyulmamasından dolayı, ekonomikliğinin yanısıra aynı zamanda çevre dostu bir malzeme olduğu sonucuna varılmıştır. Bu çalışma kapsamında elde edilen bilgilere göre, bakır alaşım ağların çevre dostu olması ve uzun vadede ekonomik yönden avantaj sağlaması nedeniyle sürdürülebilir su ürünleri üretim endüstrisinde kullanılabileceği düşünülmektedir.Öğe An extensive review of human health benefits from consuming farmed or wild fish with special reference to gilthead seabream (Sparus aurata)(2024) Yiğit, Ümüt; Ergün, Sebahattin; Yiğit, MuratIn public, there is a significant concern regarding the safety and quality of farmed fish that poses problems for fish farmers in marketing. There is widespread recognition that farmed fish are less healthy than their wild equivalent, mostly attributed to unhealthy farm conditions or the ingredients used in artificial diets for aquaculture. However, the nutritional quality of farmed -or wild-caught fish may differ based on regional variation or a cultural environment's complex aspects. Whether farmed or wild fish provide better product quality is a long-standing matter for consumer preferences and marketing. Information was collected from a wide range of references through an extensive literature review, and detailed evaluations were made on the health levels of cultured fish and natural fish in human consumption. Therefore, the present study provides an extensive review to address the differences in the nutritional contribution of farmed and wild fish for human consumers. Addressing the questions arising from consumers’ concerns will undoubtedly support farmers in their challenging marketing efforts.Öğe Assessment of initial investment strategies for different farm-scale scenarios with economic cost analyses in offshore salmon farming(Walter De Gruyter Gmbh, 2024) Yiğit, ÜmütThe simulation of investment strategies with different farm-scale scenarios has been evaluated for best management plan in cage farming business for the establishment of a salmon production with either full capacity - or progressive investment. Economical revenues were analyzed with business risk assessment based on operating-and fixed costs for each of the four scenarios. In the theoretical model projected for the stimulation of best management plans, structural elements for the construction of an offshore Turkish salmon farm in the Black Sea were designed and investment costs for an annual production capacity of 4,000 tons were re-scaled by 25, 50 and 75% reduction, corresponding to 3,000, 2,000 and 1,000 tons per year, respectively. Economic variables of operational costs were comparatively evaluated with the revenues and annual profit conditions by sales of harvested fish. The break-even points for all investment strategies with different farm-scale scenarios were remarkably lower (on average 302,574.7 kg/year) than the harvest yields from the farms (on average 3,702,857.1 kg/year). Based on break-even points and margin of safety (MOS over 85%), all farms gained net profits with low risks in the first year, whether the farm received full investment, or initiated business with reduced investment expenditures for a gradual and progressive expansion plan. Findings of this study exhibit useful indications for farm management in understanding conditions of a step-wise establishment of business plans for salmon farming in offshore conditions.Öğe Impacts of Brent Crude Oil Price Fluctuations on Global Aquaculture Production During World Economic Crises(2024) Yiğit, ÜmütThis study evaluates the linkage between brent crude oil prices and volatility spillover on the global aquaculture volume -and values during world economic crises. Besides the main variable costs comprising feed expenses with over the half of total costs in aquaculture facilities, the energy expenditures are among the important operational costs that influence farm profits through feed costs overall, but also with direct effects in recirculating systems as electricity use. Findings in this study evidenced that global aquaculture volume and value is closely related to global brent crude oil price variations during the periods of crises, as a result of increase in production costs. The correlations between brent crude oil prices and percent changes in volume -or values of farmed fish covering the crises periods between 2008 and 2021 were highest as 0.798 (R=0.798134676) and 0.716 (R=0.715832960), respectively, which are close to zero “0”, showing strong correlations between the investigated structures. However, no correlation was found between the investigated structures during the pre-crisis, post-crisis or inter-crisis periods. Over the last ten years, there were three periods when brent oil prices dropped remarkably, with interrelated effects on world aquaculture production volume or values with severe price dip following the brent oil trends. Hence, the results from this study reveal that any severe change in the energy sector will in turn hit the aquaculture industry with significant influences on both production volume -and values. Therefore, information regarding the interrelation of brent crude oil price variations and global aquaculture production provided in this study, may support building management strategies for sustainable fish farming business with foresights to world economic crises.Öğe Multiple exposure to thunderstorm-sound in Nile tilapia (Oreochromis niloticus): physiological response and stress recovery(Sciendo, 2023) Kuşku, Halit; Yiğit, Murat; Yılmaz, Sevdan; Yiğit, Ümüt; Ergün, SebahattinThe present study investigated the impacts of multiple thunderstorm-sound exposures on growth and respiratory parameters in Nile tilapia (Oreochromis niloticus) in order to evaluate the acoustic stress response. Thunderstorm-sound exposure for 3 hours triggered respiration speed with an alarm reflex and rapid elevation of opercula beat rate (OBR) and pectoral wing rate (PWR), which increased two-fold over the control with no sound treatment, and peaked (OBR, 71.33±5.86 beat/min; PWR, 75.00±3.61 beat/min) in 10 hours after initiation of sound. Thereafter, respiration rates declined over the following days and returned to near-initial levels (45.33±4.04 beat/min OBR and 43.00±1.00 beat/min PWR) by day 3, an indication that fish recovered from thunderstorm-sound stress after 3 days of exposure. However, the same reaction course was observed each time of multiple sound exposures, repeated 20 times in a row with 4-day intervals, underlining that fish could not attune to repeated thunderstorm sound. Reduced voluntary feed intake as a result of anxiety and appetite loss was recorded in fish exposed to multiple thunderstorm sound, resulting in 50% less growth compared to those without sound treatment by the end of the 80-day experimentation. Therefore, it is advisable to monitor fish behavior during the 3-day stress period after a thunderstorm event in order to prevent waste from excess feeding, that in turn may contribute environment-friendly aquaculture for the future and sustainability of the oceans.Öğe Temporal Volatility of Brent Oil Prices and Interrelation With Maritime Traffic Density in the Turkish Straits During COVID-19 Crisis(2024) Yiğit, ÜmütThis research evaluated variations in Brent oil prices and the interrelation with maritime traffic density in the Turkish Straits during the COVID-19 pandemic. The number of commercial ships that made non-stop over passage through the Turkish Straits in the last 5 years, covering the COVID-19 -and post-pandemic periods with economic instabilities was investigated along with variables of vessel characteristics such as; gross tonnage, size and type of vessel loads. Results of the present study reveal that the maritime traffic density between 2019 and 2023, was influenced by the pandemic crisis, when harsh quarantine measures of lockdown and curfews in the first shock wave. In the aftermath, conflicts between Ukraine and Russia led to economic recession or upheaval with instabilities in Brent oil prices. For the period examined in this study, the number of non-stop over passage vessels and gross tonnages used the Turkish Straits were affected by the pandemic outbreak and Brent oil price variations. The number of vessels decreased by 5.22% from 84,871 to 80,440 during the epidemic in 2020, and by 5.38% from 43.342 to 42.340 during the global recession in 2022. Overall, the number of non-stop over passage vessels using the Turkish Straits between 2019 and 2023 declined by 1.15%, while the gross tonnage and ship length increased by 3.44% and 13.24%, respectively. In total, the number of non-specific tankers (TTA) and those carrying chemicals (TCH) increased by 2.92% and 10.97%, respectively, but a 13.25% decrease was noted for the liquefied petroleum gas (LPG) tankers over the 5 years. Considering that the world trade network is largely dependent on maritime transportation, identifying the changes in maritime transportation with the interrelation of Brent oil during global crises may provide important data for strategy building of best trade management with foresights to world economic crises.
