Dichlorvos, an organophosphate compound commonly used as pesticide, contains xenobiotics capable of damaging aquatic ecosystems. However, there is inadequate information on its effects in aquatic vertebrates such as Heterobranchus bidorsalis. This study investigated its 96h LC50 toxicity, alterations in immunological, oxidative parameters and cytogenotoxicity in H. bidorsalis. Juvenile H. bidorsalis (n=250) were exposed to 0.00, 1.0, 2.2, 4.8 and 10 mg/l of Dichlorvos and later to sub-lethal concentrations corresponding to 1/40, 1/20 and 1/10 of the 96-h LC50 (1.16 mg/l) for 21 days. Exposure induced concentration and time-dependent suppression of immune functions in H. bidorsalis. Total immunoglobulin and serum lysozyme levels dropped significantly at 0.12 mg l-1 (0.004 g dl-1 and 0.002 g dl-1, respectively). Oxidative stress increased significantly, with lipid peroxidation rising from 0.001 to 0.011 umol mg-1 protein (P<0.05). Frequencies of MN elicited 2.2 folds increase at the highest exposure level compared to the negative control in dose and time dependent pattern (P<0.05) after 21 days. Similarly, enucleated, bi-nucleated and budded nuclei erythrocytes significantly (P<0.05) increased in 2.78, 23.6 and 10.4 folds, respectively. Results indicate that Dichlorvos weakens immune defense, disrupts oxidative balance, and induces cellular damage in fish.
Khawia species are significant pathogens causing khawiasis in cyprinids, leading to substantial economic losses in aquaculture. Current literature suggests that Khawia sinensis represents a complex of multiple distinct species. To resolve this taxonomic ambiguity, we examined 93 parasite samples from three Cyprinus carpio populations in eastern Turkiye using an integrated morphological and molecular approach. Phylogenetic relationships were inferred using Maximum Likelihood, Bayesian Inference, and species delimitation analyses based on COX1 mtDNA, NAD3, and 18S rDNA. A new species, Khawia anatolica n. sp., is described from Karakaya, Keban, and Hazar Lakes, exhibiting high phylogenetic divergence at COX1 (similar to 14-64%) compared to other Khawia species. Distinguishing morphological features, including a less wavy scolex and unique internal anatomy, separate K. anatolica n. sp. from previously described taxa. Species delimitation analyses confirmed that K. sinensis comprises multiple distinct species and that K. anatolica n. sp. forms a separate evolutionary branch. The mean abundance, intensity, and prevalence of K. anatolica n. sp. in C. carpio were 1.55 (1.1-2.4), 6.64 +/- 3.56 (2-15), and 23.33% (15-35%), respectively. This study advances understanding of parasitic diversity in Eastern Anatolian water resources and highlights the need to re-evaluate the taxonomic status of the K. sinensis complex.
Rainbow trout aquaculture is challenging due to the restricted spawning seasons. Sperm cryopreservation technology can help ensure a successful spawning season, but its effectiveness is restricted by oxidative stress during freezing and thawing, which reduces the availability of male gametes. This study aimed to evaluate the effect of several types and concentrations of antioxidants on post-cryopreservation rainbow trout sperm quality. Subsequently, a factorial completely randomized design with three replications was applied, testing four types of antioxidants Ascorbic acid, Myo-inositol, Butylated hydroxytoluene (BHT), and Alpha-tocopherol at concentrations of 0, 20, 40, and 60 mM, respectively. The evaluation parameters included motility rate, sperm lifespan, and sperm motion characteristics using the Computer Assisted Sperm Analysis system. The results showed that the type and concentration of antioxidants significantly affected sperm motility and sperm lifespan (P<0.05). The treatment method carried out using 40 mM Ascorbic acid and 20 mM BHT led to the highest sperm motility of 46.67% and sperm lifespan of 34 seconds. Although both antioxidants showed similar effectiveness, BHT at a concentration of 20 mM is more recommended due to its lower toxicity and technical as well as economic efficiency considerations.
This study analysed the length-weight relationships (LWR) and Fulton's condition factors (K) of 20 fish species inhabiting the Sapanca Lake basin (North-West Anatolia, T & uuml;rkiye). Fish specimens were collected from the lake and its streams in several times between May 2022 and December 2024 using gill nets and portable electro-shocker devices. LWR and K analyses were based on a total of 5993 specimens, ranging from five (Esox lucius) to 1674 (Rhodeus amarus). The allometric coefficient "b" estimated using a linear regression model of LWR ranged from 2.7684 (Clupeonella cultriventris) to 3.3555 (Neogobius melanostomus) and most species (12) showed positive allometric growth. The coefficient of determination (R2) values of the LWRs ranged from 0.8953 (C. cultriventris) to 0.9991 (Alosa maeotica). K values were minimum for Atherina boyeri (0.422) and maximum for Petroleuciscus borysthenicus (2.608). This study provides the first contribution to the LWR and K parameters of six species (A. pursakensis) in the Sapanca Lake Basin. The findings of this study can serve as a resource for assessing the impact of ecosystem health on fish growth in the lake basin.
This study aimed to investigate both the protective and therapeutic effects of propolis (PP) against pesticide-induced oxidative stress in aquatic environments. For this purpose, Gammarus pulex was exposed to 0.00 (control), 0.05, 0.1, and 0.2 ppm concentrations of cyfluthrin (CYF) to determine its toxic effects. To evaluate the protective effect of PP, 5 ppm of PP was added to each pesticide concentration. Samples were collected from all experimental groups after 24 and 96 hours under appropriate conditions. SOD activity decreased under CYF exposure but increased significantly after PP supplementation. Although CAT activity did not show significant changes with CYF alone, it increased in the presence of PP. GPx activity remained statistically unchanged under CYF exposure but increased following PP treatment. CYF exposure led to decreased GSH levels; however, PP did not significantly alter GSH levels. TBARS levels increased due to CYF, and this increase was alleviated by PP application.
This study aims to clarify the genetic structure and morphological differences of pikeperch (Sander lucioperca) populations in T & uuml;rkiye, focusing on both native and introduced groups. A total of 223 individuals were sampled from five lakes: four Anatolian lakes and one Thracian Lake. Thirty-four morphometric traits were assessed, and principal component analysis revealed that variation in body depth, dorsal-fin base length, and caudal peduncle length primarily drives morphological divergence among populations. Canonical analysis clearly separated native northern (Thrace and Black Sea) and introduced southern (Anatolian) populations. Genetic diversity and structure were assessed using seven microsatellite loci. Most populations were in Hardy-Weinberg equilibrium, except for NALB, which showed signs of recent bottlenecks or inbreeding. STRUCTURE analysis identified three main genetic clusters corresponding to Thrace, Black Sea, and Anatolia. Notably, 27% of genetic variation was among these groups, while over 60% was within individuals. Our findings suggest that while pikeperch is native to the Thrace and Black Sea regions, Anatolian populations -particularly those in Lake Marmara, E & gbreve;irdir, and Seyhan- display low genetic diversity, likely due to restocking activities, consistent with a founder effect. Overfishing may have also contributed to this pattern. In conclusion, the study highlights significant morphological and genetic differentiation between native and introduced pikeperch populations, emphasizing the importance of conserving native stocks and their potential as candidates for broodstock collection.
In this study, two highly active functional bacterial strains, identified as Bacillus sp. BS-K1 and Pseudomonas sp. CN-B1, were isolated and applied in combination within a perch (Maccullochella peelii) recirculating aquaculture system (RAS) to improve water quality and enhance disease resistance against pathogenic bacteria. Experimental results revealed that the combined probiotics K1+B1 achieved inhibitory rates of 65.0% and 52.3% against Staphylococcus aureus and Vibrio parahaemolyticus, respectively. Remarkably, it exhibited removal efficiencies of 81.9%, 62.4%, and 68.8% for ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen under controlled conditions. Practical application in RAS demonstrated enhanced performance with ammonia and nitrite removal rates reaching 63.8% and 60.5%, respectively, significantly higher than those observed with individual strains. Metagenomic analysis showed altered microbial community structure after K1+B1 addition, with ACE and Chao1 indices increasing by 5%, indicating higher species richness. Notably, the relative abundance of functional genera involved in nitrogen cycling (Novosphingobium and Aquabacterium) carrying nitrifying and denitrifying capabilities increased significantly. Concurrently, pathogenic Staphylococcus aureus exhibited a dramatic reduction (>98%) compared to the control group. These results suggest that the K1+B1 consortium enhances water purification efficiency through strategic modulation of microbial community structure, promoting beneficial nitrogen-cycling populations while suppressing pathogenic microorganisms.
The greater forkbeard (Phycis blennoides) is a demersal species of ecological and commercial importance along the Algerian coast, yet its stock status remains poorly understood due to limited biological and fishery data. This study represents the first application of the Length-Based Bayesian Biomass (LBB) estimator to assess the population dynamics and fisheries status of P. blennoides stocks in Algerian waters. Length frequency data from 8700 individuals collected during six scientific surveys, complemented by growth and length-weight data from 1050 individuals captured by commercial fisheries across 11 Algerian ports (i.e. Annaba, Azeffoun, Dellys, Cap Djinet, Zemmouri, Bouharoun, Algiers, La Madrague, Cherchell, Tenes and Mostaganem) between 2013 and 2017, were analyzed. Growth parameters were estimated using multiple software and empirical methods, revealing positive allometric growth and a growth performance index phi' was 3.124. Using length frequency distribution (LFD) from scientific survey and commercial fisheries as input data, the LBB estimated a length at first capture of 7.65 cm and indicated severe stock depletion, classifying the population as collapsed with a biomass ratio (B/B-msy) of 0.008 and fishing mortality greatly exceeding natural mortality (F/M= 23). The results suggest the urgent need for fisheries management interventions, including mesh size regulation and protection of juveniles, to promote stock recovery. Considering potential influences of environmental stressors and climate warming on distribution and abundance, continuous monitoring and further research are recommended. This study provides critical biological reference points and a baseline stock assessment to support sustainable management of P. blennoides in the southwestern Mediterranean.
Zebrafish (Danio rerio) are valuable model organisms for studying inflammation. This study aimed to evaluate the role of TNF-alpha and SAA in time-dependent inflammatory responses using histopathological, immunohistochemical, and ELISA techniques. Oneyear-old wild-type zebrafish were divided into five groups (n=20). Group 1 (G-1) received intraperitoneal (IP) injections of 0.9% NaCl, while Groups 2-5 were treated with Complete Freund's Adjuvant and Keyhole Limpet Hemocyanin. G-2 and G-3 received a single dose on day 0 to model peracute and acute inflammation, while G-4 and G-5 received two doses on days 0 and 14 to model subacute and chronic inflammation. Blood and spleen samples were collected for further analysis. The highest TNF-alpha and SAA immune-positivity intensity (IPI) scores were observed in G-4 and G-5, with staining in the perifollicular macrophages and lymphocytes. Plasma TNF-alpha peaked in G-4 (21.435 +/- 3.783 ng/L), and SAA in G-5 (1.657 +/- 0.218 & micro;g/ml). Significant correlations between TNF-alpha and SAA levels were found in G-2 (P<0.05). TNF-alpha and SAA levels showed statistical significance across different groups. These findings suggest that inflammatory cell accumulation via TNF-alpha and SAA plays a key role in zebrafish inflammation, providing insights into the molecular pathogenesis of time-dependent inflammatory responses.
Rainbow trout (Oncorhynchus mykiss) has become a cornerstone species in global freshwater aquaculture due to its adaptability, high nutritional value, and strong consumer demand. However, production levels differ substantially across countries, reflecting a variety of ecological, economic, and technological conditions. This study provides a quantitative, data-driven classification of worldwide rainbow trout production in order to identify common patterns and emerging trends. Using official FAO statistics covering the years 2016-2023 for 77 countries, we calculated three key indicators mean annual production, coefficient of variation (CV), and linear production trend and applied hierarchical cluster analysis based on Ward`s method with Manhattan distance. Internal validation measures confirmed the robustness of the resulting clusters, while statistical significance was assessed using non-parametric Kruskal- Wallis tests followed by Dunn`s pairwise comparisons. The analysis identified three distinct producer profiles. The first cluster, comprising 63 countries, is characterized by relatively low but stable production. The second cluster (11 countries) also represents low volume producers but exhibits high temporal variability, suggesting inconsistent or fragmented production systems. The third cluster includes only three countries Turkey, Iran, and Russia but shows markedly high production volumes with strong upward trends, positioning them as global growth leaders. By distinguishing stable, volatile and rapidly expanding producers, this study fills a gap in the literature and provides a framework for guiding aquaculture policy, investment and sustainability initiatives at the global scale.
Polysaccharides from brown algae are valuable bioactive compounds with diverse structures and antioxidant potential. Environmental factors strongly influence their properties. However, studies on how ecological conditions shape the biochemical characteristics of algal polysaccharides are limited. This study aimed to examine the structural and antioxidant properties of polysaccharides from the brown alga Colpomenia sinuosa collected from Izmir (Aegean Sea, T & uuml;rkiye) and Canakkale (Canakkale Strait, T & uuml;rkiye). FTIR, H-1 NMR, XRD, and HPLC analyses showed clear structural differences between the samples. The Izmir extract (PSI) had a branched, amorphous structure, with higher levels of D-glucose and L-fucose contents(p<0.05). The Canakkale extract (PSC) was crystalline and chain-condensed. DPPH scavenging activities were similar (20.40 +/- 0.12% in PSI and 20.10 +/- 0.31% in PSC; p>0.05). PCA and correlation heatmap analyses showed that salinity correlated positively with glucose (r=0.9988) and antioxidant activity. These results demonstrate that environmental conditions, salinity, affect the biochemical properties of C. sinuosa. Our results showed that the amorphous PSI extract may be suitable for antioxidant or pharmaceutical use, while the crystalline PSC extract can be used for structural applications. Future studies should investigate the effects of seasonal and environmental conditions on the polysaccharide composition of this species.
Algae have attracted increasing interest as feed additives in fish farming. In this study, Stypopodium schimperi, which was determined to have 81.39 +/- 0.88% ROS effect (X +/- SD) by DPPH test among representatives of three macroalgae classes, was used as a fish feed supplement. The algal extract showed 9-11 mm inhibition zones against tested pathogenic strains in disk diffusion experiments. In broth dilution tests, the highest antimicrobial efficacy was observed at a 1/16 dilution against E. coli ATCC 25922. The effects of the algae, incorporated into fish feed at a 5% concentration, on gut microbiota were assessed using 16S rRNA amplicon sequencing. Alpha diversity among groups was determined by Shannon and Simpson indices, while beta diversity was obtained by Principal Coordinate Analysis (PCoA) based on Bray-Curtis distance matrices. The PCoA1 (81.13%) and PCoA2 (18.85%) axis separates group A (experimental group) from CI (day 0 control group) and CF (day 21 control group). This indicates that the microbial community structure of sample A is fundamentally different from the other two, and the microbial profile between CI and CF is relatively close. Notably, in the Group A, Pseudomonadaceae (75.31%) and Moraxellaceae (21.57%) were the most abundant bacterial families, whereas in the CF group, Rhodobacteraceae (36.34%), Enterobacteriaceae (11.66%), and Pseudomonadaceae (6.78%) predominated. The CI group, was primarily characterized by Enterobacteriaceae (35.08%), Rhodobacteraceae (26.55%), and Pseudomonadaceae (4.8%). While algae supplementation inhibited various pathogens, a significant increase in the genus Pseudomonas was observed. Overall, the addition of S. schimperi to fish feed induced notable changes in gut microbiota composition and led to a statistically significant improvement in the fish's Specific Growth Rate.
The distribution of shelf resources is spatially heterogeneous. In this respect, understanding their spatiotemporal gradients is of fundamental importance, since it helps update models and resource management. Data from six summer expeditions carried out from 2011 to 2023 were used to estimate along-shelf and cross-shelf spatial gradients of bioluminescence intensity, phytoplankton, and zooplankton biomass in the upper mixed layer and down to the seasonal thermocline. Plankton samples were collected along transects and oceanographic station grids. The spatial gradients varied from twofold to two orders of magnitude. The ratio of scale of the cross-shelf to along-shelf gradient was a multiple of six. It indicated the cross-shelf gradient's dominant role in mediating the pelagic community's spatial structure. The ratio of scales with equal gradients should be considered when monitoring pelagic shelf ecosystems.
Data collection and field sampling for cage culture site selection at Seymareh reservoir in western Iran were conducted monthly from February 2022 at three stations and 15 depths, using 11 water quality factors. The most determinative factors were water temperature, dissolved oxygen, phosphorus, and nitrogen, respectively. The fish culture time frame is proposed to be December to April for rainbow trout and May to November for common carp. The fish weight for introduction to the cages is proposed as 100g and150g for rainbow trout and common carp, respectively. According to the acceptable dissolved phosphorus levels in the water and the predicted release of phosphorus from fish culture activities, the rainbow trout production capacity has been calculated to be 2467.44 tons/yr. The fish production strategy was proposed as the gradual increment of fish production over 4 years (25% per year) and continual assessment of the water quality to prevent any unwanted consequences on the water quality. Finally, according to the results, it was confirmed that the Seymareh reservoir is suitable for cage culture activities, and the optimum site selection was performed for fish cages and supplementary structures using available geographical raster data layers based on Boolean criteria in the GIS package.
This study examines the distribution, size-weight parameters, and feeding habits of Mediterranean horse mackerel Trachurus mediterraneus (Steindachner, 1868) during early development, along with growth, age structure, reproductive behavior, diet, and mortality rates of juveniles and adults in the northern Black Sea. Spawning peaks in July, as indicated by the gonadosomatic index dynamics. According to a logistic model, 50% of individuals reach sexual maturity at a total length of 11.09 cm at the age of one year. The highest abundance of eggs (69.9 ind./m & sup2;) and larvae (46.5 ind./m & sup2;) was recorded on July 28, 2019, in the Caucasus research area. Growth parameters estimated using the von Bertalanffy model were: asymptotic length (L-infinity) 21.8 cm, asymptotic weight (W-infinity) 77.2 g, and growth coefficient (k) 0.25 year(-)& sup1;. Mortality estimates (Z= 1.03, M= 0.49, F= 0.54 year(-)& sup1;) indicate an exploitation rate (E) of 0.53, indicating a high level of fishing pressure. This study presents the first comprehensive analysis of all ontogenetic stages of T. mediterraneus in the northern Black Sea, assesses the current population status, and provides a basis for forecasting future dynamics under climate change.
This study aims to investigate the dynamic impact of the fishing industry on marine water contamination in 27 European countries by taking into account the roles of fisheries output, the use of fossil fuels, economic development, and governance between 1990 and 2022. The results, which used a novel technique called the Method of Moments Quantile Regression (MMQR) in addition to factors that are fixed effect, demonstrated that, at most quantiles, there was a significant positive correlation between fishing production and marine water contamination. At the earliest and latest quantiles, fishery production significantly exacerbates marine water contamination, with a smaller impact at the lowest and a larger impact at the highest. Additionally, the data indicate that affluent EU14 countries produce more fish than developing EU13 countries, which has a significant and negative impact on the contamination of marine water. Marine water contamination from the usage of fossil fuels has increased significantly in the EU13 developing countries as compared to the EU14 wealthy countries. Policymakers can reduce marine water contamination in EU14 and EU13 countries by using eco-friendly fishing gear, more sustainable fishing methods, and energy technologies like wave and tidal power.
Superabsorbent polymers were synthesized from cross-linked acrylic acid using collagen and chitosan via the surface polymerization method, with N, N-methylene bis(acrylamide) as the cross-linker and ammonium persulfate as the initiator. Collagen obtained from jellyfish collected from the Sea of Marmara and marine-derived chitosan were chosen as monomers. Superabsorbent polymers were characterized using FT-IR, SEM, and DSC. The swelling capacities of superabsorbent polymers were measured and compared. The maximum water absorption capacities in saline solution were 79 and 136 g/g for chitosan-polyacrylic acid and collagen-polyacrylic acid superabsorbent polymers, respectively. The highest water retention capacities of chitosan-polyacrylic acid and collagen-polyacrylic acid superabsorbent polymers were calculated as approximately 70 times and 120 times their weight, respectively. Fickian diffusion and pseudo-second-order kinetics were applied to determine the swelling kinetics, revealing a perfect relationship. Consequently, the superabsorbent polymer synthesized with collagen obtained from jellyfish had a higher water absorption capacity. To our knowledge, no prior research has documented the production of a biobased superabsorbent derived from jellyfish (Aurelia aurita) in the Sea of Marmara. Hence, this study represents a novel and valuable contribution to the literature. Moreover, the increased use of biodegradable biobased superabsorbent polymers can help reduce the carbon footprint and mitigate environmental pollution.
In this study, Schizochytrium limacinum PA-968 and Crypthecodinium cohnii CCMP-316 were produced in the media including apple (AJ) and grape juices (GJ), which contain carbon sources that are alternatives to standard carbon containing media (SM). The S. limacinum biomass productions were 9.52 +/- 0.08 g L-1 (AJ), 8.70 +/- 0.05 g L-1 (GJ), and 8.58 +/- 0.02 g L-1 (SM). C. cohnii produced biomass as 3.45 +/- 0.06 g L-1 (GJ), 1.52 +/- 0.04 g L-1 (AJ), and 1.35 +/- 0.02 g L-1 (SM). The fruit juice-based media enhanced biomass production. It was observed that the lipid production of S. limacinum increased by 17.6% in the medium with apple juice (2.54 +/- 0.02 g L-1), while this increase was 65.3% in the grape juice-based medium (3.57 +/- 0.02 g L-1). The addition of apple juice caused an increase in the lipid amount 1.9 times higher (0.23 +/- 0.02 g L-1), while grape juice induced 5.3 times more lipid production in C. cohnii culture (0.50 +/- 0.03 g L-1). The study emphasized that these wastes or by-products can be considered as sustainable and financially supportive solutions to be alternatives to carbon sources in production with S. limacinum and C. cohnii cultures.
The popularity of artificial neural networks (ANNs) in the field of fish population management studies is increasing daily, with the potential to provide more rapid and efficient results. Length-weight relationship (LWR) and condition factor (CF) are very important in fisheries management. In addition, it enables the estimation of the amount of fish at the beginning of the fishing period by using LWR in terms of sustainable fishing. In this study, data was estimated with alternative models of ANN to calculate the classical CF used to evaluate the LWR. For the case application, whiting (Merlangius merlangus euxinus L., 1758) samples (n=1408) caught from the Black Sea coast of Giresun were used. The root mean square error (RMSE), mean absolute percent error (MAPE) and R2 of the model were 0.1674, 0.0930, and 0.99869, respectively. The results showed that the Single Multiplicative Neuron (SMN)-ANN model yielded the highest accuracy according to performance criteria. Consequently, the findings indicate that the model effectively predicts the CF, thus validating its estimation capability. This study represents the initial research in predicting the CF for whiting by the SMN-ANN model.
T & uuml;rkiye, a key biogeographic bridge between Europe and Asia, has experienced major advances in taxonomic knowledge of its freshwater fishes, but existing faunal lists lag behind recent revisions. We present a revised checklist that compiles and standardises records using the latest IUCN assessments, published descriptions and revisions (to 2026), museum collections and expert-verified data. Unestablished introductions and strictly marine visitors were excluded. We recognise 390 freshwater fish species in 37 families, including 367 native species and 23 established non-native taxa, of which 202 natives (55%) are endemic to T & uuml;rkiye. Species richness is concentrated in Leuciscidae (113 species), Nemacheilidae (59) and Cyprinidae (53), which together comprise 61.5% of the native fauna. At the catchment scale, total richness ranges from 11 species in the Van Basin to 65 in the Sakarya drainage, endemic richness was highest in Antalya (28 species) and non-native richness in the Sakarya drainage (10 species). The checklist provides updated nomenclature, distributions within T & uuml;rkiye and standardised common names, establishing an agreed taxonomic baseline for biodiversity assessment, fisheries and conservation management.
