MARINE REPORTS (MAREP)

Interactive governance of fisheries and aquaculture: Transdisciplinary challenges and stakeholder involvement in coastal zone management

Mbachi Ruth MSOMPHORA — 2024-12-28

This paper examines the interactions between fisheries and aquaculture in Northern Norway, with a particular focus on environmental impacts and governance frameworks. The increasing overlap between aquaculture facilities and critical fisheries, such as cod spawning grounds, has raised concerns regarding habitat degradation and ecosystem sustainability. This study evaluates stakeholder perspectives through a 2020 survey, exploring the challenges of governance, stakeholder engagement, and compliance with environmental regulations. We analyzed how national, regional, and local governance structures interact and how these multi-layered frameworks are crucial for mitigating conflicts between aquaculture and fisheries. The findings underscore the need for enhanced monitoring systems, more transparent decision-making processes, and an integrated governance approach that incorporates both scientific knowledge and local insights to ensure the sustainable development of coastal zones.

Reducing phosphorus and nitrogen excretion in Yellowtail (Seriola quinqueradiata) nutrition: II. Effects of dietary fishmeal replacement and increasing energy level

Orhan UYAN — 2024-12-28

Defatted soybean meal was replaced with fishmeal to evaluate its effect on growth and phosphorus/nitrogen excretion for young yellowtail (Seriola quinqueradiata). Soybean meal was replaced by fishmeal with the levels of 4 and 16% at 10, 16 and 20% dietary lipid level. The feeding trial continued for 80 days. Weight gain of fish significantly increased with increasing dietary lipid. Fishmeal (FM) replacement did not cause any negative effect on growth at any level of dietary lipid. Feed and protein efficiencies slightly decreased with increased level of FM replacement. Both parameters significantly (P<0.05) improved with increasing dietary lipid. No significant interaction was determined between dietary lipid and SBM level on the any measured parameter. P and N excretion significantly (P<0.05) decreased with increasing dietary lipid. In conclusion, based on growth and P/N excretion data, 10% FM replacement by defatted soybean meal with 20% lipid from the diet containing 43% protein could be recommended to obtain superior results considering decreasing detrimental effect of P and N to the environment in yellowtail nutrition weighing from ~420 g to ~900 g.

Antioxidant potential of Citrus aurantium essential oil in mitigating fish oil oxidation

Osman Sabri KESBİÇ — 2024-12-28

This study evaluated the antioxidant potential of Citrus aurantium flowers essential oil (neroli oil), in protecting fish oil, a lipid source highly susceptible to oxidation. Fish oil samples were supplemented with neroli oil (NEO) at concentrations ranging from 10 to 1500 ppm and subjected to rapid oxidation conditions (50°C for 48 hours with 70% humidity). Peroxide values (PV) were measured to assess oxidative stability, and significant differences were observed across treatment groups (p < 0.05). The lowest PV (7.65±0.28 meq O₂/kg) was recorded in the 1500 ppm NEO group, while the control group without supplementation had the highest PV (29.54±1.02 meq O₂/kg). NEO demonstrated comparable effectiveness to the commercial antioxidant Butylated Hydroxytoluene (BHT, 200 mg/kg). Gas chromatography-mass spectrometry (GC-MS) analysis identified linalool (25.2%) and linalyl acetate (42.77%) as the major volatile components of NEO. The study highlights that NEO effectively suppresses lipid oxidation without exhibiting toxicity, making it a viable natural alternative for fish feed applications. Further investigations are recommended to explore the potential pro-oxidant effects at higher concentrations and the long-term implications of secondary oxidation products.

Differential alterations in physiological and biochemical traits of rohu (Labeo rohita) exposed to experimental doses of carbofuran pesticide

Ayesha Akter MITU — 2024-12-28

Carbofuran is a common and widely used pesticide for agriculture (growing different types of crops) across Bangladesh. The ultimate destination of pesticides is aquatic environments through run-off, having a long-term adverse effect ecosystem and aquatic biodiversity. The present study was conducted to determine the effects of different doses of carbofuran on a major carp fish, Rohu (Labeo rohita). Four different doses of carbofuran were maintained including: 0 mg/L (control), 0.5 mg/L (T1), 1 mg/L (T2) and 2 mg/L (T3) to investigate the biological changes in Rohu for 60 days. Carbofuran treatments resulted in 20 – 30% lower growth, 20 – 48% lower survival rate and 10 – 20% lower blood cell counts compared to the control. In contrast, 30 – 60% higher oxygen consumption rate, 15 – 50% higher blood cortisol and 20 – 80% higher blood glucose levels were obtained for the three carbofuran treatments. Significantly higher (P < 0.05) growth, survival and blood cell counts in contrast to lower levels of O₂ consumption, blood glucose and cortisol levels indicate no imposed stress on Rohu at the control condition. Large scale changes in growth, survival, O₂consumption, blood cell counts, blood cortisol and glucose levels are indicative of the intensity of stress imposed on the experimental fishes. Types and number of deformed blood cells were also found to vary significantly (P < 0.05) among the treatments. Gill ultra-structural view also exhibited considerable damage in gill lamellae and filaments with increasing pesticide concentrations. Overall, findings of this study imply that lower carbofuran dose (T1 = 0.5 mg/L) initiate the slight damage in different biological traits of Rohu while higher doses (T1 = 1 mg/L and T2 = 2 mg/L) cause severe damage. Thus, pesticide pollution is a severe threat to aquatic biodiversity and appropriate measures must be taken to control the excessive use of this chemical to protect the entire aquatic ecosystem as well as biodiversity.

Effect of morphometric variables and natural microbial load on the survival time of live Mytilus galloprovincialis during postharvest cold storage

İbrahim Ender KÜNİLİ — 2024-12-28

This study investigated the relationships between morphometric characteristics, microbiological parameters, pH changes, and survival rates of Mediterranean mussels (Mytilus galloprovincialis) during post-harvest storage at +4°C. Mussels were categorized into three size groups based on shell length: large (63.92-80.19 mm), medium (48.51-62.63 mm), and small (30.08-47.75 mm). Total heterotrophic aerobic bacteria (THAB), Enterobacteriaceae, and Vibrio sp. counts were monitored over a 16-day storage period, along with pH changes and survival rates. Results demonstrated significant size-dependent variations in survival, with larger specimens showing superior viability throughout storage. THAB counts increased continuously across all groups, while Enterobacteriaceae levels remained relatively stable in medium and small groups. Vibrio sp. counts decreased in large specimens but remained stable in other groups. Strong negative correlations were observed between survival rates and both THAB (r: -0.854, p<0.001) and Enterobacteriaceae (r: -0.777, p<0.001) counts. Principal component analysis revealed that the first two components explained 83% of total variance, with physical dimensions primarily influencing PC1 (56.5%) and yield-related traits, pH, and THAB characterizing PC2 (26.5%). By day 16, medium and small groups reached 0% survival, while large specimens maintained partial survival. These findings suggest that mussel size significantly influences post-harvest survival and should be considered when developing storage protocols. Future research should focus on optimizing storage conditions through combined approaches of temperature control, modified atmospheres, and periodic water exposure, particularly considering morphometric variables.

Management and determination of hazardous occupational health and safety risks in recirculating aquaculture systems (RAS)

Mustafa KARGA — 2024-12-28

Responding to the increasing demand for protein consumption globally, the aquaculture sector continues to grow exponentially every day. Recirculating Aquaculture Systems (RAS) are advanced technology systems that provide sustainable fish farming opportunities by ensuring the efficient use of water resources. In addition, ornamental aquarium fish farming is also intensively carried out in RAS. There is a need for manpower to meet the increasing workload in RAS as well as in offshore aquaculture facilities. However, the working environment in RAS also brings with it various occupational health and safety (OHS) risks. The main hazards affecting occupational safety in these systems can be listed as chemical substance use, biological risks, electrical hazards, physical ergonomic difficulties and psychosocial working conditions. The aim of this study is to determine the OHS risks encountered in the RAS environment in Türkiye, based on 3 different enterprises, and to evaluate solution strategies for these risks and methods for creating a safe working environment. In the study, 3 different RAS were examined (A, B, C) and as a result of our study, it was seen that the risk assessment, emergency planning and employee training criteria were fully met in RAS workplaces where occupational health and safety specialist services were provided. Accordingly, it was determined that risk scores decreased in businesses employing occupational safety specialists. In addition, the total percentage risk score was calculated and it was shown that the total percentage risk score was lower in RAS with occupational safety specialists compared to the others.

Influence of IMEAK maritime chamber of commerce towards policies and the development of the maritime sector

Kenan AKPINAR — 2024-12-28

Around 85% of the world’s trade is carried out through the maritime sector, which reveals the importance of the logistics sector based on shipping. The sector moves along with the course of international trade. The importance of the sector for Türkiye, which is surrounded by seas on three sides, is an undeniable fact. Many global and national actors play a role in the policies developed for the maritime sector. The organization that has an important position among these actors in Türkiye is the Istanbul and Marmara, Aegean, Mediterranean, Black Sea Regions Chamber of Shipping (IMEAK DTO). The aim of this study is to examine the role of IMEAK DTO, the umbrella organization of the sector, in the policies developed for the maritime sector since its establishment. In order to gain a deeper perspective, the research involved consulting and interpreting the views of sector professionals. The interpretation and evaluation of the information obtained through a standardized open-ended interview forms have been evaluated. The main mass of the research consists of individuals, institutions and organizations involved in the formulation of maritime policies and/or affected by these policies. A sample of 30 people was selected. The sample consisted of experts, senior managers, academicians, employers and professionals working in the maritime sector who are directly or indirectly involved in the formation of maritime policies. The main findings of the research are as follows: The establishment of an independent maritime chamber of commerce has made significant contributions to the Turkish maritime sector. IMEAK DTO has been found to be the most important actor in the development of maritime policies and has provided significant advantages to the sector. It has been determined that the lack of a ‘Ministry of Maritime’ in Türkiye slows down the capacity and growth rate of the maritime sector.