MARINE REPORTS (MAREP)

Automatic detection of eddies and influence of warm eddy on sound propagation in the Persian Gulf

Omid MAHPEYKAR, Amir ASHTARI LARKI, Mohammad AKBARINASAB — Tue, 25 Jun 2024 00:00:00 +0300

Eddies are among the most complex phenomena in marine environments, with significant impacts on hydrodynamic parameters. Various intelligent algorithms are utilized to identify and analyze these eddies. In this study, a vector geometry algorithm based on the rotation of velocity vectors was employed to detect and extract eddies in the Persian Gulf. The algorithm utilizes horizontal velocity components from numerical modeling as inputs. Following eddy extraction, their characteristics were thoroughly examined. A total of 4308 cyclonic and 2860 anticyclonic eddies were identified at the surface, with 617 cyclonic and 329 anticyclonic eddies detected at a depth of 50 meters for daily data over one year. Additionally, an investigation into the impact of eddies on sound propagation revealed that warm eddies create areas of severe transmission loss at their centers, leading to divergence in sound rays.

Reassessment of Rapa whelk shells and an innovative roadmap for industrial applications

Baris BAYRAKLI, Harun YILDIZ, Serdar BEKTAŞ, Bayram KIZILKAYA — Tue, 25 Jun 2024 00:00:00 +0300

This study aims to determine the industrial and economic potential of Rapa whelk (Rapana venosa) shells as an economic product using characterization methods. Methods such as Zero Charge Point (pH_PZC), FT-IR analysis, scanning electron microscopy (SEM) images, EDS analysis, and X-ray diffraction analyses were employed. The results indicate that the pH_PZC of Rapa whelk shells is 8.35, suggesting their surfaces will be electrically neutral at pH 8.35. X-ray diffraction analyses revealed that the main building material of the shells is aragonite-structured calcium carbonate (CaCO₃). SEM and EDS analyses demonstrated that the main components of the shells are carbon (C), calcium (Ca), and oxygen (O), with low levels of protein. FT-IR analyses confirmed the presence of CO₃^-2 vibration bands at 1407 cm-1, indicating that the shells are primarily composed of CaCO₃. These characterization methods provide essential information for evaluating the potential of Rapa whelk shells as an economic product. This study will significantly contribute to the sustainable utilization and industrial valorization of marine resources by understanding material's surface chemistry and interaction mechanisms.

Effect of arsenic on the biological traits of the Major carp, Rohu (Labeo rohita)

Tue, 25 Jun 2024 00:00:00 +0300

Arsenic is a highly toxic metalloid that can have detrimental effects on farmed aquatic species, negatively impacting growth, metabolism, immunity and overall wellbeing of fish. The Indian major carp, Rohu (Labeo rohita) is a major freshwater aquaculture species that faces various production related issues associated with water quality parameters. The current study was designed to elucidate the effects of three different doses of arsenic (As) (T₁ = 1 µg/L, T₂ = 2 µg/L, and T₃ = 3 µg/L) on the physiological (growth and O₂ consumption), biochemical (blood cell counts), and genetic (expression levels of three selected genes) responses of Rohu. This study revealed significant (P<0.05) biologicl abnormalities and deformities in arsenic-exposed Rohu carp. The growth rate of fish decreased with increasing arsenic concentrations. O₂consumption rates of fish were increased (1.6 – 2 fold) with increasing experimental arsenic concentrations but blood cell counts were in a declining trend. Expression levels of the three selected genes showed arsenic dose specific differential changes; higher expression at control condition (1.5 – 2.1 fold) while lower expression at the treatment conditions. Results of this study clearly point out that different doses of arsenic impose stress at different orders of magnitude on the experimental Rohu individuals. The findings of the present study suggest that arsenic pollution significantly impacts the physiological (growth, development, metabolism and survivability), biochemical (hematological parameters) and molecular mechanisms of this economically important fish (L. rohita). Therefore, it is an imperative to maintain the optimum water quality (pollutant free) in the farming environments.

Studies on reducing of phosphorus and nitrogen excretion in Yellowtail (Seriola quinqueradiata) nutrition: I. Effects of dietary protein and energy level

Orhan UYAN, Shunsuke KOSHIO, Manabu ISHIKAWA, Saichiro YOKOYAMA — Tue, 25 Jun 2024 00:00:00 +0300

The objective of the present study was to investigate the effect of increasing dietary energy at varying dietary protein levels on reducing phosphorus and nitrogen excretion in young yellowtail (Seriola quinqueradiata) in a 55-day growth trial by using 180g of fish. Three levels of dietary protein (46%, 50% and 54%) and two levels of dietary energy were tested in a complete randomized design with a 3 x 2 factorial arrangement. Dietary protein and energy levels did not cause any significant difference in final weight, weight gain, feed intake or survival. However, feed and protein efficiencies significantly (P < 0.05) improved with increasing dietary energy in each respective dietary protein levels. Phosphorus and nitrogen excretion rates were significantly (P < 0.05) reduced with increasing dietary energy at all dietary protein level. There was no interaction between dietary protein and energy level on the parameters measured. In conclusion, the diet containing 46% protein and 19.5% lipid with the total energy content of 5.2 kcal / g was recommended for yellowtail growing from 180 g to 460 g to obtain the lowest phosphorus and nitrogen excretion values without reduction of growth performances under the present experimental conditions.

Analysis of the causes of loss of life as a result of the sinking of the M/V Batuhan-A, using the fishbone method

Burhan TAŞLI — Tue, 25 Jun 2024 00:00:00 +0300

There are many large -or small-scale accidents in world maritime history. In addition to the fact that maritime is a dangerous profession, when the human factor is added, accidents become an inevitable reality. Maritime accidents have various consequences, such as pollution, injury and loss of life and others. Precautions are taken to prevent accidents and consequences occuring as a result of accidents. Despite all precautions, maritime accidents occur and many seafarers are injured or even loss their life. Six personnel lost their lives in the accident that resulted in the ship named Batuhan-A, sinking in the Sea of Marmara on 15 February 2024. The fact that all personnel lost their lives in the accident that took place 4 nm away from the shore is an issue that should be particularly examined. In this study, the fishbone method, also known as the Ishikawa diagram, was used to seek an answer to the question of why there was loss of life in the accident. As a result of the analysis, it was revealed that there was a delay of order to abandon the ship and that the emergency procedure was not operated correctly.

Effects of humic acid supplemented feeds on growth performance, hematological parameters and antioxıdant capacity on common carp (Cyprinus carpio)

Tue, 25 Jun 2024 00:00:00 +0300

The present study investigated the impact of humic acid on the growth, blood parameters, and antioxidant capacity of common carp (Cyprinus carpio). Fish were fed twice a day until saturation with increasing doses of humic acid at 0.0, 0.2, 0.4 and 0.8%. In a 60-day feeding treatment, FW, WG and SGR values (41.37±0.87, 23.26±1.01, 1.37±0.05 respectively) of the group with 0.4% humic acid had statistically greater values compared to the control group (p<0.05). RBC (red blood cell), WBC (white blood cell) and Hct (haematocrit) parameters were evaluated for haematological analyses, the WBC value of the group fed 0.2% and 0.4% humic acid (20.62±3.74, 21.43±1.50 respectively) increased significantly (p<0.05). However, serum biochemistry parameters did not show any statistical difference (p>0.05). The SOD analysis evaluated to determine the antioxidant capacity showed that the group fed 0.4% and 0.8% humic acid had higher values than the control (72.78±3.38, 71.63±5.01 respectively). Our results indicate that 0.4% humic acid as a feed additive for carp can improve growth parameters, antioxidant capacity, and general health.

An evaluation on the applications of some marine biopolymers

Bayram KIZILKAYA, Dilek ŞENOL BAHÇECI — Tue, 25 Jun 2024 00:00:00 +0300

The environmental pollution caused by plastic waste is increasingly becoming a significant concern. As a result, the use of biodegradable plastics is gaining more importance. This study provides a detailed review of the applications of marine-sourced biodegradable plastics based on chitosan, gelatin, and alginate. Chitosan, a polysaccharide found in the shells of crustaceans, possesses properties that allow it to biologically degrade without harming the environment. These biodegradable characteristics make chitosan an eco-friendly alternative to traditional plastics. Chitosan is used in various fields such as food packaging, drug delivery systems, and wound healing materials. Gelatin is a protein derivative obtained from animal bones and skins. This material also possesses properties that allow it to biodegrade without harming the environment. Gelatin flexible nature makes it suitable for various applications in the plastic industry. It is used in areas such as food packaging, pharmaceutical capsules, and phototherapy devices. Alginate, derived from seaweed, is another polysaccharide that is biodegradable and environmentally friendly. Its high water-absorption capacity makes it an ideal material for applications such as food packaging and drug delivery systems. Marine-sourced chitosan, gelatin, and alginate-based biodegradable plastics stand out as eco-friendly plastic alternatives. The use of these materials can help reduce the environmental damage caused by plastic waste and contribute to a sustainable future. However, further research and development are needed on the industrial-scale use and recycling of these materials. In conclusion, marine-sourced biodegradable plastics have various applications and hold significant potential as environmentally friendly plastic alternatives. More efforts should be made in the future to increase the use of these materials and reduce plastic waste.