Photobacterium damselae subsp. damselae is a significant pathogen that cause severe bacterial septicemia in a broad range of hosts. This study presents the first comprehensive analysis of Photobacterium damselae subsp. damselae affecting farmed Atlantic bluefin tuna (Thunnus thynnus) stocks in Aegean Sea, Türkiye. The total mortality rate of the farm was calculated as 18% exhibiting clinical signs of the disease, characterised by lethargic swimming and loss of equilibrium in bluefin tuna cages. Although external clinical signs were not determined, hemorrhages were observed in liver, swim bladder and heart. Microbiological examinations resulted in the isolation of a total of four bacterial strains, including two isolates from the summer sampling period and two isolates from the autumn sampling period. Among these, representative strains designated as THAS1 and THAS2 were selected for further biochemical and molecular characterization, through which Photobacterium damselae subsp. damselae was identified. Histopathological examinations of liver, heart, spleen, and kidney tissues associated with the infection revealed the presence of melanomacrophage centers in histological sections of the spleen and kidney. Consequently, this study reveals the epizootic and impact of P. d. subsp. damselae infection in farmed Atlantic bluefin tuna with clinical and microbiological results associated with pathological changes. Further research on the epidemiology and epizootiology of this disease is essential for sustainable aquaculture of tuna fish stocks, especially in Mediterranean.
This study documents the occurrence of Athanas polymorphus in the Vellar estuary on the southeast coast of India, representing a distributional record that further substantiates its presence in estuarine environments. Seven specimens were examined using detailed morphological analysis and molecular confirmation based on mitochondrial 16S rRNA gene sequences. The examined material conforms closely to previously published descriptions of the species, with minor variations observed in the number of meral teeth on the major cheliped and the position of the pterygostomian tooth. Molecular analysis of a 549 bp fragment of the 16S rRNA gene showed 100% similarity with A. polymorphus sequences available in GenBank, confirming the species identity. Phylogenetic analysis further supported the placement of the Vellar specimens within the A. polymorphus clade. The occurrence of ovigerous females indicates that the species is reproducing within the estuarine environment, suggesting tolerance to fluctuating salinity conditions. This study expands the known habitat range of A. polymorphus and highlights the importance of estuarine biodiversity surveys for improving the understanding of caridean shrimp distribution in Indian coastal waters.
The Mediterranean mussel (Mytilus galloprovincialis), the only bivalve species whose production has steadily increased through aquaculture and capture in recent years, holds significant importance in T & uuml;rkiye due to its high nutritional value, economic potential, and consumer popularity. This study aims to evaluate the current status of Mediterranean mussel farming in T & uuml;rkiye. The primary data were obtained from surveys conducted between January and March 2023 with 47 certified mussel farming enterprises. The study examined farm capacities, production areas, cultivation techniques, workforce structures, marketing strategies, and challenges encountered during production. The findings indicated that mussel farming has strong development potential; however, production levels remain below capacity due to difficulties in material supply, economic fluctuations, and environmental factors such as mucilage outbreaks. In addition, deficiencies in transport and logistics infrastructure, along with insufficient technical knowledge and a lack of skilled personnel, were identified as major constraints. The results are expected to provide valuable insights for planning and policymaking to improve production design and ensure sustainability in both existing and future mussel farming facilities in T & uuml;rkiye, as well as for countries seeking to enter this emerging sector.
In recent years, one of the lessepsian migrant, Siganus luridus (Rüppell, 1829) extended its dispersal towards the Aegean Sea. Because of lacking data on the reproduction of the species along the Turkish coast, the aim of the present study was to determine some reproductive characters of dusky spinefoot Siganus luridus such as the reproductive cycle, fecundity and condition factor. A total of 181 female fish were sampled from Gökova Bay in the southern Aegean Sea using small-scale fisheries (trammel nets) and recreational fishing methods (angling and trap fisheries) between July 2019 and June 2020. Variations in the gonadosomatic index (GSI) and gonadal histological changes indicated that reproduction of S. luridus started in May, peaked in August and gradually decreased in September. Individuals ready to spawn were mostly observed between May and September, with the highest occurrence in August. The highest K value was found in April (1.67 ± 0.11) and the lowest in September (1.39 ± 0.11). Spawning females ranged from 14.8 to 25.6 cm total length. Absolute fecundity varied between 98,607 and 801,460 oocytes per female within a total length range of 12.2–25.6 cm. Relative fecundity ranged from 1,107 to 2,952 oocytes g⁻¹, with an average value of 1,734 ± 747 oocytes g⁻¹. Length at maturity value was calculated to be 16.19 cm. Findings of the present work are useful for fisheries management and may serve as the fundamental source for aquaculture of the species.
The growth response of a diatom Cylindrotheca closterium strain (DEB132303) isolated from the Golden Horn Estuary (Sea of Marmara) was investigated under different environmental conditions. C. closterium cells were grown in a silica-enriched K-medium under various temperatures (11, 18, 25 and 32°C), salinities (6, 12, 18, 24, 30 and 36 psu) and irradiances (10, 20, 50 and 65 μmol photons m⁻² s⁻¹). By the end of the acclimatization period, no viable C. closterium cells were present at temperatures of 4°C and 32°C and salinities of 6 and 36 psu, which marked the upper and lower boundaries of its environmental tolerance. The maximum specific growth rates (µmax) were 1.45 d⁻¹ at temperature of 18°C (18 psu, 50 μmol photons m⁻² s⁻¹), 1.08 d⁻¹ at salinity of 24 psu ( 18°C, 50 μmol photons m⁻² s⁻¹) and 1.80 d⁻¹ at irradiance of 65 μmol photons m⁻² s⁻¹ (18°C, 18 psu), in temperature, salinity and light experiments, respectively. The maximum cell density (Dmax) was 5×10⁵ cells mL⁻¹ at temperature of 25°C, salinity of 18 psu and irradiance of 50 μmol photons m⁻² s⁻¹. Growth rate varied significantly among different temperature, salinity and irradiance treatments (ANOVA, p<0.001) and there was a positive correlation between growth rate and irradiance (r= 0.98, p<0.01). These results demonstrate that these environmental parameters affect significantly the growth of this C. closterium strain.
In this study, the biological characteristics of the southern pond loach (Seminemacheilus ispartensis Erk'akan, Nalbant & Özeren, 2007), distributed in Lake Eğirdir and its basin, were investigated. Sampling was conducted monthly at nine stations in Lake Eğirdir between June 2010 and May 2011. A total of 315 individuals were collected during the sampling period. Of these specimens, 51.4% were identified as female, 43.2% as male, and 5.4% as immature. The total length of the specimens ranged from 3.7 to 12.2 cm, body weight from 0.43 to 18.50 g, and age from I to V years. The mean total length and mean body weight were calculated as 8.18±0.13 cm and 6.31±0.24 g, respectively. The Von Bertalanffy growth parameters of the population were estimated as L∞=17.48, k=0.22, and t₀=−0.33; the asymptotic weight (W∞) was calculated as 55.30. The length–weight relationship was determined as W=0.0067L3.15. Based on gonadosomatic index (GSI) values, the reproductive period of S. ispartensis was identified as occurring between March and May. The total fecundity of the population in Lake Eğirdir ranged from 1,440 to 16,938 eggs. The relative fecundity was determined to be 900 eggs g⁻¹. Based on the stomach content analysis, S. ispartensis was found to exhibit a predominantly carnivorous feeding habit, with its diet mainly composed of aquatic insects (Trichoptera, Ephemeroptera) and Amphipoda.
Aquaculture environments are dynamic ecosystems that may influence the evolution and adaptive potential of bacterial pathogens. In this study, a locally isolated Vibrio anguillarum strain VK1 (PRJNA1452808) from Türkiye was characterized using 16S rDNA phylogenetic analysis and whole-genome-based approaches. The high-quality draft genome (4.23 Mb; GC content 44.31%) comprised 194 contigs and 4,102 coding sequences, including 1,057 hypothetical proteins. Functional analyses revealed putative stress response mechanisms and iron acquisition systems, suggesting metabolic versatility and environmental adaptability. Genome-based screening identified 33 putative antimicrobial resistance-associated determinants, including multidrug efflux-related genes and genes linked to antibiotics commonly used in aquaculture. In addition, genes associated with Type III and Type VI secretion systems were detected, potentially indicating adaptive traits related to host interaction and environmental persistence. Overall, the findings suggest that strain VK1 possesses a flexible genomic structure that may support adaptation to fluctuating aquaculture conditions. However, further functional studies are needed to biologically validate the potential virulence and AMR related features.
This study aims to identify the non-indigenous fish species for which significant knowledge gaps persist by evaluating the existing scientific literature on their fundamental biology (age-growth and length-weight relationships). Data were synthesized descriptively following PRISMA 2020 guidelines. In the study, a list of 177 non-indigenous fish species recorded in the Mediterranean was compiled, and a systematic literature survey was conducted to identify scientific publications containing length-weight relationship (LWR) and age-growth (AG) parameters for these species. Studies outside the Mediterranean or on non-fish taxa were excluded. Databases were searched up to November 2025. Data were synthesized descriptively by species, country, and study type. Risk of bias was not formally assessed in this review. A total of 143 studies were identified. The analyses revealed an uneven geographical distribution of research, with Türkiye leading by a wide margin with 84 (58.86%) studies. Lagocephalus sceleratus with 25 studies for LWR, and Saurida lessepsianus with 11 studies for AG, stood out as the most researched species. However, it was determined that fundamental biological data are still unavailable for many non-indigenous species. These findings reveal critical knowledge gaps that need to be urgently addressed for the sustainable management of increasing non-indigenous fish populations and highlight the urgency of expanded scientific research on these species.
Morphometric approaches are widely used for stock identification in inland fisheries; however, their effectiveness may be limited in hydrologically connected systems where gene flow and environmental homogenization are high. This study evaluated the ability of landmark-based truss network morphometrics to detect phenotypic population structure in Cyprinion macrostomum inhabiting six tributaries connected to the Atatürk Reservoir in the Middle Euphrates Basin. A total of 83 specimens were analyzed using size-corrected truss measurements and multivariate statistical techniques, including Principal Component Analysis (PCA), Canonical Variate Analysis (CVA), and Linear Discriminant Analysis (LDA) with cross-validation. Most morphometric characters exhibited isometric growth, while negative allometry was observed primarily in head-related traits. Multivariate analyses revealed extensive morphological overlap among individuals from different tributaries, with no clear spatial separation. Although LDA showed relatively high classification success in the training dataset, cross-validation accuracy remained low, indicating limited predictive power for stock discrimination. The results suggest that strong hydrological connectivity within the reservoir–tributary system promotes phenotypic homogenization, thereby constraining the effectiveness of morphometric approaches. These findings highlight the limitations of relying solely on phenotype-based methods for stock identification in highly connected inland water systems. The study emphasizes the need for integrative approaches combining morphometric, genetic, and ecological data to improve the accuracy of population structure assessments and to support effective fisheries management.
Freshwater green algae, particularly Spirogyra sp., is a potential source of bioactive compounds with pharmacological relevance. This study evaluated the antioxidant and antifungal activities of Spirogyra sp. collected from Jilani Park Racecourse, Lahore, Pakistan. Methanolic and chloroform extracts were analysed using total antioxidant activity (TAA), ferric reducing antioxidant power (FRAP), total phenolic content (TPC), and metal chelating (MC) assays. Antifungal activity was assessed against Aspergillus niger Tiegh and Rhizopus stolonifer (Ehrenb.) Vuill., using fluconazole as a positive control. Methanolic extracts exhibited significantly higher TAA, TPC and MC activities compared to chloroform extracts, whereas chloroform extracts showed markedly higher FRAP values. Differences between methanolic and chloroform extracts were statistically significant (p < 0.0001). Both extracts demonstrated antifungal activity; methanolic extracts showed stronger initial inhibition, whereas chloroform extracts maintained sustained inhibitory effects over 48 h. Overall, Spirogyra sp. exhibited notable antioxidant and antifungal potential. These findings provide evidence of its solvent-dependent bioactive properties and support further in-depth investigations to explore its potential applications in pharmaceutical, nutraceutical, and biotechnological formulations.
In this study, the effects of different female / male ratios on the number of eggs, spawning frequency, and offspring production in bristlenose pleco (Ancistrus multispinis) production were investigated. Accordingly, females aged 3-4 years with a total length of around 8-10 cm and males with a total length of 9-13 cm were used as broodstock. The female/male broodstock ratios in the groups were established as follows: Group A: 1 ♀(female):1 ♂(male), Group B: 2 ♀:1 ♂, Group C: 3 ♀:1 ♂, Group D: 3 ♀:2 ♂, Group E: 4 ♀:2 ♂. A total of 60 broodstock individuals, 39 females and 21 males were utilized. A single recirculating aquaculture system (RAS) was used in the trial. In this way, the water quality parameters of all tanks were the same. The experiment lasted 120 days in total. The broodstock were fed commercial fish food twice a day and fresh red pepper once a week. After the broodstock were stocked in the tanks, spawning dates and egg numbers were recorded. At the end of the experiment, the average number of spawning in Group A was 1.67±0.67, while this number was 5.33±0.33 in Group B, 4.00±0.58 in Group C, 3.00±0.58 in Group D, and 3.67±0.88 in Group E. According to these results, the most spawning occurred in Group B. According to the results of the statistical analysis (ANOVA), the difference between the groups was found to be statistically significant (p=0.024<0.05).
Seasonal investigations were conducted on 640 Cyprinus carpio specimens obtained through commercial fishing at four different stations (Gerger, Sitilce, Hosirge, and Samsat) in the Atatürk Dam Lake. MDA (malondialdehyde) levels were measured in the liver and muscle tissues of male and female fish; the results revealed a significant increase in MDA levels at stations exposed to point-source discharge. This indicates that pollution-induced oxidative stress in fish varies significantly across seasonal and regional scales. Among the stations compared, the lowest MDA values were detected in fish tissues from the Gerger station, while the highest values were recorded at the Sitilce and Hosirge stations. Analysis of SOD, GSH-Px, and GSH values across all stations showed that these parameters fluctuated in correlation with MDA levels thereby maintaining the oxidant-antioxidant balance. This study investigated seasonal and spatial variations in oxidative stress biomarkers in common carp (Cyprinus carpio) collected from four stations in Atatürk Dam Lake. A total of 640 specimens were analyzed for malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and reduced glutathione (GSH) levels in liver and muscle tissues. Results showed that MDA levels were significantly higher in fish collected from Sitilce and Hosirge stations, indicating elevated lipid peroxidation associated with point-source pollution. In contrast, the lowest MDA levels were observed at the reference station, Gerger. Antioxidant enzyme activities (SOD, GSH-Px, and GSH) exhibited tissue-, season-, and site-dependent variations, suggesting adaptive responses to oxidative stress. Overall, the findings demonstrate that anthropogenic pressures in Atatürk Dam Lake significantly alter the oxidant–antioxidant balance in fish, highlighting the usefulness of these biomarkers for environmental monitoring.
This study investigates the effects of the fisheries and aquaculture sectors, two key components of the blue economy, on economic performance in ASEAN-5 countries over the period 2000–2023 using panel data methods. The existence of a long-run relationship among the variables is examined through the Westerlund and Edgerton panel LM bootstrap cointegration test, while long-run coefficients are estimated using the Common Correlated Effects (CCE) estimator developed by Pesaran (2006). The empirical findings reveal that fisheries production exerts a positive and statistically significant impact on economic growth. In contrast, aquaculture production does not exhibit a statistically significant effect at the panel level. Furthermore, gross fixed capital formation is identified as an important driver of long-run economic development. The results indicate that fisheries activities and capital accumulation make a substantial contribution to growth dynamics within the blue economy framework. By providing sector specific evidence for ASEAN-5 countries, the study contributes to the literature on the blue economy and offers policy-relevant insights for promoting sustainable fisheries development and regional prosperity.
This study evaluates whether otolith morphometric descriptors can reliably reflect growth patterns in the deep-sea fish Chlorophthalmus agassizi (Bonaparte, 1840) and assesses the additional explanatory value of artificial neural network (ANN) models compared with classical approaches. A total of 95 specimens were collected monthly between September 2006 and September 2008 by trawling at depths of 100–500 m in Saros Bay (North Aegean Sea). Mean total length and weight were 11.43±0.22 cm (range:7.2–17.1 cm) and 11.07±0.66 g (range:1.88–33.42 g), respectively. Otolith weight ranged from 0.0016 to 0.0067 g, while otolith length varied between 2.73 and 4.37 mm. Relationships among total length (TL), total weight (TW), otolith length (OL), and otolith weight (OW) were examined using both classical regression analyses and ANN-based predictions. Strong relationships were observed for TL–TW (R²=0.95), TL–OL (R²=0.90), TL–OW (R²=0.88), and OL–OW (R²=0.86), whereas the TW–OW relationship showed lower explanatory power (R²=0.65). These findings indicate that otolith morphometrics provide reliable proxies for growth patterns in C. agassizi, while ANN models offer complementary insights into potential nonlinear relationships.
This study examines the structural characteristics of four export‑oriented fishery processing facilities in Isparta Province using a complete enumeration method. All facilities employ permanent workers, with no seasonal labor observed, and all personnel receive hygiene and occupational safety training. Women constitute 83% of the workforce, mainly in sorting, grading, and packaging, while men account for 17%. The majority of employees are aged 36–45 (42%) and have primary (74%) or secondary (15%) education. Technical personnel remain limited, with staff consisting of 90% production workers, 4% engineers (3 fisheries engineering, 1 food engineering), and 6% administrative personnel. All facilities implement HACCP‑based food safety systems, and exports target both EU and non‑EU markets. Isparta’s location in the Lakes Region, strong production–processing linkages, and widespread female employment provide notable advantages. Enhancing R&D, diversifying products and export channels, expanding automation and traceability, and increasing qualified technical employment are essential for sectoral sustainability. The study offers an up‑to‑date, region‑specific contribution to the literature on inland fishery processing.
This study investigates the spatiotemporal dynamics of wetland ecosystems in Kars province, northeastern T & uuml;rkiye, focusing on Ayg & imath;r, & Ccedil;al & imath;, and Kuyucuk Lakes between 1990 and 2018. Land use/land cover changes were analyzed using CORINE Land Cover data in relation to climatic variables, demographic shifts, and sustainability indicators. The results revealed marked transformations in wetland extent and adjacent land uses. Around Ayg & imath;r Lake, agricultural areas expanded from 67.3% to 69%, while wetlands declined from 19.3% to 17.8%. In the & Ccedil;al & imath; Lake region, agriculture increased from 21.1% to 28%, whereas wetlands nearly disappeared (0.05%) by 2018. Kuyucuk Lake exhibited the most severe degradation, with wetlands decreasing from 11.8% in 1990 to 6.1% in 2018. Although precipitation exhibited a clear increasing trend over the study period, wetland recovery was not observed. Population decreased substantially (662,155 to 288,878), suggesting that human-induced land-use intensity rather than demographic growth is the main driver of degradation. Principal Component Analysis associated 1990 with high precipitation and population, while 2018 correlated with urbanization and agriculture. Markov Chain Analysis estimated trend-based transition probabilities indicating a high likelihood of wetland conversion to agricultural and/or urban land under the assumption that the observed land-use dynamics persist. A strong positive correlation was observed between wetland extent and precipitation (r = 0.975, p < 0.01). The findings emphasize the combined impacts of climate change, land-use intensification, and anthropogenic pressures, underscoring an urgent need for adaptive wetland management strategies in Kars province.
A new amphipod species, Niphargus hasansarii n. sp., is described based on a single female specimen collected from Homeros Valley in & Idot;zmir Province, Western T & uuml;rkiye. The species is distinguished by a unique combination of characters, specifically the high setation (>= 4) along the outer margin of dactyli on both gnathopods, a single spine on the inner margin of the dactyli of pereopods 3-7, three distal setae on the inner lobe of maxilla I, a subrounded third epimeral plate, a single robust seta at the base of uropod I, and distinct facial and lateral spines on the telson lobes. Detailed morphological examination and illustrations of the holotype's appendages were performed. The new species is compared with morphologically similar congeners, and diagnostic differences are highlighted. Although molecular data could not be obtained due to the specimen's preservation conditions and absence of additional material, the combination of unique morphological features strongly supports the species' distinct taxonomic status.
In this study, samples were taken from pikeperch (Sander lucioperca) and crayfish (Pontastacus leptodactylus) living in Egirdir, Beysehir, and Sugla lakes, which are key stopovers for migratory birds. In 2022, crayfish and pikeperch were sampled from Egirdir, Beysehir and Sugla lakes at 3 different water temperature periods (15-20 degrees C, 20-25 degrees C and 25-30 degrees C). A total of 540 samples (270 pikeperch and crayfish) were analyzed for the presence of NNV genome (RNA-1 and RNA2) by real-time RT-PCR and also inoculated in E-11 cell. No positive samples were recorded by any of the techniques. In this study, the presence of NNV was investigated for the first time in wild aquatic organisms living in freshwaters of Turkiye and NNV was not detected in the sampled pikeperch and crayfish. However, it is important to regularly examine these lakes, which are located on the migration routes of migratory birds, for NNV.
This research aimed to analyze the catch composition, CPUE (Catch per unit effort), and productivity between two bait types (small crabs and trash fish) associated with rakkang traps in Bawah Layung Village, Tanah Laut Regency, Indonesia. The method used was a field experiment with a randomized block design, and the data were analyzed using analysis of variance (ANOVA). Research activities were conducted between June and September 2025, where a total of 620 rakkang units were deployed around mangrove areas. The results showed that the rakkang captured Scylla paramamosain (77.74%) was 3.5 times higher than S. tranquebarica (22.26%), with species-specific preferences. S. paramamosain outnumbered S. tranquebarica in terms of CPUE and productivity rates (p < 0.05). The CPUE for rakkang traps baited with small crabs (0.53 ind./trap) was considerably higher than using trash fish (0.14ind./trap). Similarly, the productivity rate was much higher with small crabs (1.71 ind./h) compared to trash fish (1.05 ind./h). Small crab bait proved significantly more effective than trash fish (p < 0.05). These findings suggest that optimizing bait choice, specifically using small crabs, can contribute to more efficient and sustainable mud crab fisheries, potentially reducing bycatch and supporting conservation efforts. The capture of both legal-sized and undersized crabs emphasizes the need for species-specific management to balance market demand with sustainable fisheries.
This study examines the effects of marine non-indigenous fish species, considered invasive in the field, on ecosystems, the economy, and human security along Turkey's eastern Mediterranean coast through the lens of ecological security. A multi-stakeholder qualitative design was adopted; semistructured methods guided by purposeful and snowball sampling, focus group interviews, and participant observations were conducted in the coastal districts of Antalya, Mersin, Adana, and Hatay. Data are analyzed via thematic content analysis, and findings are cross-validated with records from municipalities, the Coast Guard, and relevant public agencies. Results are organized under ecological, economic, and human security. In shallow coastal habitats, ecosystem integrity and trophic dynamics appear weakened; in small-scale fisheries, gear damage is increasing, catch composition is shifting toward lower-value species, and income losses are rising. Health awareness is at times insufficient; public authorities intervene through monitoring, record-keeping, and incentive mechanisms. Scholars caution against demonizing species and emphasize human pressures-overfishing, pollution, and warming seas. The study underscores the need for preventive, ecosystem-based, multi-stakeholder governance supported by transboundary data sharing and attentive to nonhuman life.
