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Population Dynamics and Exploitation Status of Merlangius merlangus (Linnaeus, 1758) in the Sea of Marmara
(Springer Int Publ Ag, 2025) Arslan İhsanoğlu, Mukadder; Daban, İsmail Burak; İşmen, Ali; Yığın, Cahide Çiğdem; Şirin, Murat
Merlangius merlangus is a species of notable economic significance. In this study, its population parameters—including length–weight relationships, age structure, growth patterns, and mortality rates—were assessed in the Sea of Marmara. Samples were collected using trawl nets at 34 stations between March 2017 and December 2018. A total of 4,978 specimens were analyzed, with total lengths ranging from 5.0 to 26.7 cm and weights from 2.03 to 167.3 g. The length–weight relationship indicated isometric growth across the population. The length distribution of age-determined individuals were 6.4–24.2 cm in total length. These data were used in the calculation of growth parameters. The estimated asymptotic length (L∞) was 24.65 cm, the growth coefficient (K) was 0.34 year⁻¹, and the theoretical age at zero length (t₀) was − 1.27 years. Individuals were aged between 0 and 4 years, and the maximum estimated lifespan (tmax) was 5.5 years. Mortality parameters were also calculated, revealing an exploitation rate (E) of 0.55 per year, suggesting considerable fishing pressure on the stock.
Integrated analysis of trophic structure and feeding dynamics of invasive Callinectes sapidus Rathbun, 1896 in a Mediterranean coastal lagoon using stable isotopes and digestive enzyme activity
(Elsevier Science Ltd, 2025) Acar, Seçil; Ertürk Gürkan, Selin; Ateş, A. Suat; Yalçın Özdilek, Şükran
The objective of this study is to examine the invasive characteristics of the blue crab (Callinectes sapidus Rathbun, 1896) and its potential impact on lagoon ecosystems. A total of 90 individuals were collected from the & Ccedil;anakkale Strait. A comprehensive suite of analytical techniques was employed, encompassing stomach content analysis, stable isotope analysis, and digestive enzyme profiling. The resulting data set was then subjected to rigorous statistical and bioinformatic analysis, with a particular focus on elucidating its correlation with morphometric characteristics. Stomach content analysis revealed that algae (47.19 %) and fish (25.37 %) constituted the primary dietary components. Isotope data further confirmed the species' omnivorous feeding strategy, with Ruditapes decussatus emerging as a dominant dietary component in isotopic signatures, although it was not directly observed in stomach contents. Adult male specimens exhibited a propensity for carnivorous feeding behaviour, as evidenced by isotopic patterns, which may be indicative of vestiges of their pelagic larval phase. A dietary niche overlap was identified between C. sapidus and the native green crab (Carcinus aestuarii) in the lagoon, with the former exhibiting a broader niche width. Despite the limited sample size, these findings contribute valuable preliminary insights into the feeding ecology and ecological interactions of C. sapidus in Mediterranean transitional waters, highlighting its potential invasive impact.
A new member of an entirely Anatolian clade of the Horatiinae DW Taylor, 1966, Hydrobiidae W. Stimpson, 1865
(Taylor & Francis Ltd, 2025) Odabaşı, Deniz Anıl; Falniowski, Andrzej; Hofman, Sebastian; Jaszczynska, Aleksandra
A species new to science, representing the family Horatiinae, is described from Dağılcak Spring in Dağılcak Nature Park in the Seyhan River Basin. This is a minute snail characterised by a broad low-spired shell with broad parietal lip, radula with median cusp of the central tooth twice longer than the adjacent ones, bursa copulatrix large and spherical, one distal receptaculum seminis long and sac-shaped, penis broad and gradually tapering with pointed tip, and vas deferens well visible, running in zigzags. The new species forms the sister lineage of Anadoludamnicola Şahin, Koca & Yıldırım, 2012 and an undetermined representative of the genus Sheitanok Schütt & Şeşen, 1991 in a mitochondrial phylogeny based on partial sequences of the cytochrome c oxidase subunit I (COI) gene. These three taxa form an entirely Anatolian clade.
Reproduction of the narrow-clawed crayfish, Pontastacus leptodactylus (Eschscholtz, 1823) (Decapoda: Astacidea: Astacidae), in western Turkey
(Oxford Univ Press, 2025) Berber, Selçuk; Kale, Semih; Acarlı, Deniz; Demirci, Aydın
Monthly collections using fyke nets between July 2020 and June 2021 (2,606 females, 3,864 males) in Atikhisar Reservoir, & Ccedil;anakkale, Turkey allowed us to investigate the reproduction of the narrow-clawed crayfish (Pontastacus leptodactylus ). The smallest female with visibly developed and quantifiable oocytes in the ovaries had a carapace length (CL) of 38.46 mm and a weight of 12.44 g among 568 individuals. The smallest male carrying spermatophores measured 25.06 mm in CL and weighed 18.96 g. Oocytes were observed from August to December, with enhanced development and darker colors noted from October to December. Density of female sexual maturity increased from October, reaching its peak in December. The length at first maturity (L50) for females and males was determined as 10.91 cm and 6.75 cm, respectively. Analysis of 493 pleopodal females revealed a mean of 145 fertilized eggs. The mean pleopodal egg weight was 1.47 g and ellipsoidal egg volumes varied 1.25-17.6 mm3. Samples from January 2021 exhibited the highest average egg number (190), whereas those from April 2021 had the largest mean egg size. Our results support the legal regulation of a minimum catch length of 10 cm for female crayfish in Turkey. Our research is the first comprehensive exploration of the reproductive characteristics of male and female narrow-clawed crayfish in Atikhisar Reservoir, providing valuable insights for decision-makers and fisheries managers to ensure stock sustainability. The findings furnish valuable insights for optimizing crayfish broodstock management within aquaculture systems.
Reproductive Biology of Bogue, Boops boops Linneaus, 1758 in the Aegean Sea and Sea of Marmara, Türkiye
(Istanbul Univ Press, 2025) Şen, Yusuf; Daban, İsmail Burak; Arslan İhsanoğlu, Mukadder; Ayaz, Oğuzhan; Özekinci, Uğur
Bogue (Boops boops Linnaeus, 1758) is one of the most economic and common species in Türkiye. The bogue individuals were obtained monthly from the commercial catches of gillnet fisheries from May to August 2024 and purse seine fisheries from September 2024 to April 2024 around the Northern Aegean Sea and Southwest Sea of Marmara, Türkiye. The 378 total individuals consisted of 176 females, 201 males and 1 unspecified in the Aegean Sea. The 370 total individuals consisted of 214 females, 154 males and 2 individuals unspecified in the Sea of Marmara. The female:male ratio was calculated as 0.9:1.0 in the Aegean Sea and 1.4:1.0 in the Sea of Marmara. The total length and weight of individuals varied from 10.6 to 28.6 cm (17.52±0.15) and 8.1 to 236.86 g (54.20±2.43) in the Aegean Sea, respectively, and the total length was 10.8 to 28.5 cm (17.92±0.18) and the weight was 13.08 to 399.88 g (76.54±3.14) in the Sea of Marmara. The positive allometric growth was found for females, males and all sexes in both seas. The first maturity length was determined as 12.2 cm TL for females, 15.8 cm TL for males in the Aegean Sea, whereas it was 12.8 cm TL for females, 15.1 cm TL for males in the Sea of Marmara. The reproductive period is estimated between January and May in the Aegean Sea, while February to May in the Sea of Marmara. The total fecundity varied between 2770-85112 (mean:20021±2027) in the Sea of Marmara, while it was 2740-309457 (mean:42834±9194) in the Aegean Sea. As results of this study, some differences were determined in sex ratio, spawning period, and fecundity from the reproductive characteristics between the Sea of Marmara and Aegean Sea. Due to the limited scientific data on the reproductive biology of B.boops in Türkiye, the results of the present study should contribute to the strategic assessment, management, and sustainability of B.boops.
Entirely Anatolian Hydrobiid (Caenogastropoda-Truncatelloidea-Hydrobiidae) Clade Revisited: Two More New Genera and Six New Species
(Mdpi, 2025) Jaszczynska, Aleksandra; Hofman, Sebastian; Odabaşı, Deniz Anıl; Ekin, İhsan; Sirbu, Ioan; Falniowski, Andrzej
Previous studies identified a clade of the Hydrobiidae endemic to Anatolia, with no closer relationships with the European snails, despite close relations between the fauna of these two regions. Three genera—each monotypic: Sheitanok Schütt et Şeşen, 1991, Anadoludamnicola Şahin, Koca et Yıldırım, 2012, and Kozanium Odabaşı et Falniowski, 2025—belonged to this clade. Our study describes the Hydrobiidae collected at five springs in Anatolia. Shell morphology and biometry, radulae, soft parts pigmentation, female reproductive organs, and penes are described and illustrated. Cytochrome oxidase subunit I (COI) sequences have been used to infer phylogenetic relationships and species distinctness of these snails. An integrative taxonomic approach resulted in the distinction of six species new to science. One of them belonged to the genus Sheitanok, another one to Anadoludamnicola. The other four species are clustered into two genera not described thus far, and the offered names are Dicle and Adaniya. It is noteworthy that three species recognized within one of these genera were clearly demarcated both molecularly and morphologically (morphological differences were higher than typical of the hydrobiid congeners). However, two of the three techniques of species delimitation based on the molecular sequences did not confirm their distinctness. This stresses the necessity of a holistic approach in the truncatelloid taxonomy.
Phenotypic plasticity in Mediterranean gorgonians Eunicella singularis and Paramuricea clavata at high temperature and low pH
(Elsevier B.V., 2025) Belivermiş, Murat; Kılıç, Önder; Özalp, Hasan Barış; Demiralp, Selcan; Gezginci-Oktayoğlu, Selda; Eldem, Vahap; Şahin, Berna
The Mediterranean gorgonian octocorals are threatened by acidification, warming and marine heat waves. Phenotypic plasticity is critical for slow-growing gorgonians, as adaptation through natural selection might not be fast enough to cope with rapid environmental changes. DNA methylation (DNAm) is a type of (trans)generational phenotypic plasticity mechanism that may help slow-growing corals better withstand the effects of environmental changes by adjusting gene expression. This study aimed to assess the physiological responses and epigenetic modifications associated with phenotypic plasticity in the Mediterranean gorgonians Eunicella singularis and Paramuricea clavata exposed to warming (+4 °C), acidification (?0.35 pHT units) and their combination over two weeks. In addition, RNA-Seq-based differential gene expression analysis was performed for E. singularis. High temperature, low pH and their combination did not cause tissue death or necrosis in the corals. Polyp activity in E. singularis increased at high temperatures. Warming increased oxygen consumption in both species. Energy reserves (protein, lipid, carbohydrate contents) were not affected by temperature, pH or their interaction in either species. The global DNA methylation (gDNAm) rate was ten times higher in P. clavata than in E. singularis. There was no effect of temperature, pH or their interaction on gDNAm in E. singularis. gDNAm in P. clavata decreased at high temperatures and low pH. Differential gene expression analysis indicated that high temperature induced the most extensive transcriptional changes in E. singularis, while low pH alone had the least impact. The combined stress of high temperature and low pH also led to notable up- and downregulation of gene expression. Heat stress in E. singularis caused widespread downregulation of transcription factors (TFs), particularly those in the zf-C2H2, AP-2, and HMG families. Conversely, the IRF, RFX, P53, and NRF1 families were upregulated, highlighting the complex transcriptional response to thermal stress. Overall, these physiological, transcriptomic and epigenetic alterations have the potential to negatively impact the fitness of these emblematic species and their associated ecosystems.
Temporal and spatial status of environmental variables and pollutants in Çardak Lagoon (Çanakkale Strait)
(2025) Ateş, Abdullah Suat; Büyükateş, Yeşim; Acar, Secil
The objective of this study was to analyse the correlation between domestic pollutants, specifically organic matter, anionic detergent, and suspended solids, and environmental variables such as temperature, salinity, and sediment grain size in Çardak Lagoon on a seasonal basis. Samples were obtained using 5 L Nansen bottles at a depth of 1 m from the surface waters across 6 stations within the lagoon, as well as from 1 station situated on the seaward side. The collection period for the latter was from October 28, 2018, to June 28, 2019. The study demonstrated that the primary indicators of water pollution, namely NH+4 and anionic detergents, were consistently found at very low levels throughout the year in the study area.
Morphometric assessment of plastic deposition in a wind-driven marine corridor under bidirectional forces
(2025) Gürses, Rıdvan Kaan; Maghuyop, Ashley Lyle; Roa, Nerissa; Büyükateş, Yeşim; Ergün, Sebahattin; Yiğit, Murat; Erenoğlu, Ramazan Cüneyt
Plastic pollution poses a growing threat to coastal and marine ecosystems. This study examines the spatial dynamics of plastic accumulation in the coastal area of Kepez Cape, located within the Çanakkale Strait (Türkiye), a bidirectional marine corridor connecting the Black Sea and the Sea of Marmara to the Aegean and the Mediterranean. Due to its exposure to dominant wind regimes (NNE, NE, SW), Kepez Cape offers a valuable natural setting for investigating the interaction between wind and currents in shaping the deposition of plastic debris. Departing from traditional particle count metrics, the study introduces morphometric parameters, surface area and volume, as more ecologically relevant indicators of pollution load. Plastic debris was sampled from three shoreline sectors using standardised transects, and particle dimensions were analysed. Results revealed substantial spatial variability in plastic accumulation, with larger particles found in regions influenced by Black Sea surface currents. These findings highlight the importance of physical forces in shaping deposition patterns and advocate for incorporating surface area-based metrics into coastal plastic monitoring. The study contributes to the development of wind-informed, regionally coordinated monitoring strategies, offering a refined framework for assessing and ultimately reducing plastic pollution in dynamic marine corridors worldwide.
Physicochemical characterization of porang tubers (Amorphophallus muelleri) analog rice with the addition of Spirulina platensis
(IPB University Department of Aquatic Product Technology, 2025) Juno, Bintang Diva; Setyaningsih, Iriani; Büyükateş, Yeşim; Tarman, Kustiariyah
Analog rice is a functional food designed to resemble conventional rice but is produced from non-rice sources. This study developed porang analog rice enriched with Spirulina platensis to improve its nutritional and antioxidant properties. The variation of four concentrations of S. platensis (0, 1.5, 3, and 4.5%) was evaluated using a completely randomized design. Sensory evaluation indicated that the 1.5% formulation was significantly preferred (p < 0.05) and selected for further analysis. On a dry basis, the optimized product contained 92.2% carbohydrates, 2.73% protein, and 57% of dietary fiber. Its cooking time was 7.53 min, with 129.2% water absorption and a bulk density of 0.47 g/mL. Phytochemical screening confirmed the presence of flavonoids, phenolic compounds, and saponins. The antioxidant activity was classified as very strong, with an IC₅₀ of 47.10 ppm, demonstrating significant radical scavenging potential. The novelty of this research lies in the unique combination of porang, potato, and Spirulina, which has not been previously applied in the development of analog rice. This formulation integrates the high dietary fiber content of porang, the starch functionality of potato, and the bioactive compounds of Spirulina, resulting in a product with enhanced nutritional quality and functional properties. Overall, porang analog rice with spirulina showed strong consumer acceptance and bioactivity, highlighting its potential as a promising functional food.
Ulusal Sualtı Bilimsel Araştırma ve Değerleri Sempozyumu (USUBADES) Özet Kitabı
(Çanakkale Onsekiz Mart Üniversitesi, 2023) Çelik, Ekrem Şanver; Kuşku, Halit; Ayaz, Adnan; Altınağaç, Uğur; Özekinci, Uğur; Öztekin, Alkan; Çelik, Ekrem Şanver; Kuşku, Halit; Ayaz, Adnan; Altınağaç, Uğur; Özekinci, Uğur; Öztekin, Alkan
[No Abstract Available]
Restricted effects of climate change on annual streamflow of Sarıçay stream (Çanakkale, Turkey)
(2016) Kale, Semih; Ejder, Tuba; Acar, Seçil; Hisar, Olcay; Mutlu, Fatih
The global warming and the associated climate change lead to significant problems related to sustainability of natural resources. The observations and research on this issue have shown that most of the water resources have been affected by this phenomenon. These effects of global warming on water resources can be listed as decreased amount of water and droughts in mid-latitude belt. In the current study the changes in the flows of Sarıçay stream in Çanakkale and the time series of the climate parameters related to the region were determined and trends of these variations were estimated. A 34-years data set regarding the river flows between 1978 and 2011 as well as some annual climate parameters such as temperature, evaporation and precipitation have been collected by three meteorological observation stations (Bozcaada, Gökçeada, Çanakkale) for 43 years were used. Pettitt change-point analysis was used to determine the change points for streamflow and climatic parameters. Box-Jenkins method and the ARIMA model were used for trend analyses. Results showed that there was a decrease in precipitation and streamflow on the contrary an increase in evaporation and temperature. However, these changes were statistically insignificant (P > 0.05). In conclusion, climate change effects on river streamflow could be unstable and many factors such as latitudinal location, anthropogenic effects, agricultural activities, population density and residential areas could affect the streamflow.
Gene expression responses unveil the negative effects of Olive Mill Wastewater on Gammarus komareki (Amphipoda: Gammaridae)
(Springer, 2025) Yılmaz, Sevdan; Odabaşı, Deniz Anıl; Zilifli, Aytuğ; Banni, Mohammed; Abdel-Latif, Hany M. R.
Olive Mill Wastewater (OMW) is a major organic pollutant, particularly in Mediterranean countries with intensive olive oil production. In this study, the toxic effects of OMW were tested on a freshwater macroinvertebrate, Gammarus komareki. Animals were exposed to different concentrations of 1/5, 1/10, and 1/20 of the previously calculated 72-h LC50 (LC50 = 3.65%) and was applied as high (0.73%), medium (0.365%) and low (0.1825%) levels, respectively for 20 days. At exposure, female and male individuals from each group were sampled separately. Samples were analyzed for the expression levels of antioxidant defences (cat, gst, se-gpx, and mn-sod), reproduction (vitellogenin-like protein, vtg), respiration (hemocyanin, hc), antitoxic defences (heat shock protein 70, hsp70), and molting (molt-inhibiting hormone, mih) related genes. Results revealed that the expression levels of vtg gene in females exposed to low doses were increased significantly compared to other groups; however, its levels were decreased in group exposed to high doses compared to the control and other groups. The mRNA expression levels of mn-sod and se-gpx genes of males and female individuals exposed to low OMW doses increased significantly compared to other doses. The mRNA expression levels of gst gene increased in males and females exposed to moderate doses and only in males exposed to low doses compared to other groups. The mRNA expression levels of cat gene of females were similar in all groups, while their levels were higher in males exposed to OMW than in the control group. The expression values of hsp70 gene were significantly decreased in females and all males exposed to high doses of OMW. On the other hand, the mih gene expression in females was increased at low doses of OMW, while decreased in the groups exposed to high doses compared to the control group. In male individuals, the mih expression levels significantly increased in all experimental groups. The expression of the hc gene was decreased in male and female individuals exposed to all doses of OMW compared to the control group. To put it briefly, the great variations in the gene expression levels in groups exposed to OMW underlines the toxic effects of this effluent and its negative impacts on the aquatic organisms.
Controlled Ghost Fishing: Effects of Soaking Times and Mesh Sizes on Catchability in Trammel Net Fisheries
(Wiley, 2025) Şen, Yusuf; Özekinci, Uğur
Trammel nets are used with extended soaking times to increase the catching efficiency for demersal fish in commercial fishing. Long soaking time causes deterioration or damage to species caught in the first days. Effects of soaking time were investigated with 36-mm, 42-mm, and 46-mm mesh sizes soaked over 1, 3, 5, and 7 days on target, non-target, and other species. Only 26.3% (293 individual fish) of 1113 individual fish were not damaged of the target species. Total weight of non-damaged individuals was 247.6 kg, of which 150.6 kg (60.8%) was the target species. Critically endangered and endangered Chondrichthyes species were negatively affected by soaking time and mesh size. Current and previous regulations did not restrict soaking time or mesh size of trammel-net fisheries in T & uuml;rkiye. Extended soaking times of trammel nets may cause more negative ecosystem effects than ghost fishing. Consequently, 42-mm mesh-size trammel nets soaked for 1 day should be used by fishers. If used for more than 1 day, 42-mm or 46-mm mesh sizes should be used.
Prevalence, molecular identification and genotyping of the crayfish plague pathogen, Aphanomyces astaci in major narrow-clawed crayfish (Pontastacus leptodactylus Eschscholtz, 1823) populations from Türkiye
(Sciendo, 2024) Akhan, Süleyman; Çağatay, İfakat Tülay; Berber, Selçuk; Taştan, Büşra; Taştan, Yiğit; Dalar, Tuba
Introduction: Crayfish plague is considered the most important crayfish disease globally. It is caused by the fungus-like agent, Aphanomyces astaci. This study aimed to identify and determine the prevalence of A. astaci using PCR in narrow-clawed crayfish (Pontastacus leptodactylus) populations from across Turkiye. Material and Methods: A PCR was carried out with primers specific to the internal transcribed spacer region of the A. astaci pathogen on both telson and abdominal cuticle tissues from crayfish individuals from 41 different locations. Results: Aphanomyces astaci was detected in the crayfish from 34 of the locations. Molecular diagnosis showed the prevalence rates of A. astaci to be between 0% and 68.2%. For 7 of the 34 locations, the strain of A. astaci was determined. Microsatellite analysis of tissue from individuals with positive PCR results revealed the A. astaci genotypes in seven populations. Genotype B was found to be the predominant genotype responsible for crayfish plague in Turkish crayfish populations. The Psl genotype (genotype B) was determined in six of the populations, and the As genotype (genotype A) was detected in only one. Conclusion: Crayfish plague poses a significant threat to crayfish populations, necessitating the development of rapid, highly sensitive diagnostic methods. An understanding of the sensitivity of the PCR detection method and of the prevalence and genotyping of A. astaci in Turkish crayfish populations has been gained from this study.
Phenotypic and Genotypic Antibiotic Resistance of Bacteria Isolated from Ready-to-eat Salted Seafood
(Istanbul Univ Press, Fac Aquatic Sciences, 2025) Kahraman Yılmaz, Dilek; Berik, Nermin
Safe food production faces significant challenges from both disease-causing bacteria and antibioticresistant bacteria, as both pose serious risks to public health and food safety. This study investigated the presence of antibiotic-resistant bacteria in salted seafood (lakerda) samples obtained from fishermen and fish markets. Phenotypic analysis revealed that lakerda samples collected from fishermen contained bacteria with multi-antibiotic resistance, including Pseudomonas fluorescens, Staphylococcus haemolyticus, and Staphylococcus equorum. Carnobacterium maltaromaticum, Carnobacterium mobile, and Vibrio hibernica species were isolated in larkerda samples sold by fish markets. It was determined that among isolated bacteria, V. rumoiensis did not contain any of the genotypically tested genes. However, P. fluorescens carried blaTEM, qnrB, qnrS, blaZ, and msrA; S. haemolyticus harbored blaTEM, tetK, dfrD, blaZ, msrA, msrB, and mecA; C. maltaromaticum possessed blaTEM, qnrA, qnrB, qnrS, strA-strB, aphAI-IAB, and mecA; C. mobile included blaTEM, blaZ, msrA, dfrD, and mecA; and V. hibernica carried blaTEM, blaZ, mecA, and VanA. In addition, S. pasteuri and S. equorum had the mecA resistance gene. In conclusion, public health needs to provide hygiene conditions in the preparation of lakerda, determine the ways of transmission, take precautions, and raise awareness of producers and consumers.
Developing an Artificial Neural Network (ANN) to Estimate Growth Model of Narrow-Clawed Crayfish (Pontastacus leptodactylus) in Yenice Reservoir (Çanakkale, Turkiye)
(Mekelle Univ, Coll Natural & Computational Sciences, 2025) Kale, Semih; Berber, Selçuk
This study aims to develop an artificial neural network (ANN) to estimate the growth model of the narrow-clawed crayfish (Pontastacus leptodactylus). A total of 546 (255 males and 291 females) narrow-clawed crayfish individuals were collected monthly between July 2007 and June 2008 by using fyke nets (34 mm mesh size) from Yenice Reservoir, & Ccedil;anakkale, T & uuml;rkiye. Total length (TL) and total weight (TW) were measured, and the relationship between TL and TW was modeled using both the traditional length-weight relationship (LWR) and ANN approaches. The performance of both models was evaluated, and the ANN developed in this study yielded superior results when compared to the traditional LWR method. The R-value was found 0.95077. This value indicates that the model developed using ANN provides better results than traditional growth forecasting models. The present study demonstrates that ANNs can be used as a novel and effective approach to estimating the growth of narrow-clawed crayfish. The ANN approach can provide useful information for sustainable and successful fisheries management.
The impact of acute cold water stress on blood parameters, mortality rate and stress-related genes in Oreochromis niloticus, Oreochromis mossambicus and their hybrids
(Elsevier Ltd, 2021) Yılmaz, Sevdan; Ergün, Sebahattin; Çelik, Ekrem Şanver; Banni, Mohamed; Ahmadifar, Ehsan; Dawood, Mahmoud A. O.
This study aims to evaluated the response of Oreochromissp. to cold stress. Two experiments were conducted involving a total of 1080 juvenile Oreochromis niloticus, O. mossambicus, O. niloticus♂ × O.mossambicus♀=F1♂ × O.mossambicus ♀ (Hybrid 1; H1) and O. mossambicus♂ × O. niloticus♀ (Hybrid 2; H2). In the 1st experiment, fish were exposed to cold water (12 °C) for 24 h and then hematological parameters, serum biochemical variables, innate immune responses, antioxidant status, and liver gene expression responses (hsp70, hsp27, hsp90, hsp40, cat, sod, eef1a1 and calreticulin) were analyzed. Hematological and serum biochemical responses involved species-specific differences. At optimal temperatures (28 °C), respiratory burts activity (RBA) and myeloperoxidase (MPO) values of H1, H2 and O. mossambicus were significantly higher than O. niloticus (p< 0.05). While the RBAvalue of O. mossambicus decreased after exposure to cold water (p< 0.05), lysozyme activities of O. niloticus and H2 and MPO activities of all experimental fish increased significantly (p< 0.05). At control conditions (28 °C), cortisol levels were found to be higher in O. mossambicus than in H1 and O. niloticus (p< 0.05). A significant increase in cat and sod transcripts was observed in liver of fish being very pronounced in O. mossambicus and H2. The highest up-regulation was observed for hsp70 target where the lowest but significant up-regulation was observed for hsp90 gene. In 2nd experiment, water temperature was gradually decrease from 28 °C to 12 °C (average, 1 °C/1 h).Survival rates of H1 and H2 were found to be different compared to O. mossambicus and O. niloticus (p< 0.05) after 20 days of cold water challenge.O. mossambicus was the most cold-sensitive group, followed by the H2, H1 and O. niloticus. Our data should be carfully considered in view of the possible physiological and anti-stressor responses being species-specific in fish.
Understanding the public attitude towards sharks for improving their conservation
(Elsevier Ltd, 2021) Giovos, Ioannis; Barash, Adi; Barone, Monica; Borme, Diego; Tunçer, Sezginer
Sharks are among the oldest residents of the planet, they possess a unique value as top predators and constitute irreplaceable elements of marine ecosystems. Unfortunately, contemporary narratives widely presented in popular mainstream media have attached an utterly negative connotation to sharks, propagating an unsubstantiated and fabricated image of them as implacable and voracious predators. Recently a lot of attention is devoted to understanding the public perception towards sharks in order to promote their conservation given that a quarter of all shark species are facing extinction. This work assessed the current attitude of the public towards sharks on a global scale, utilizing modern technology through a single protocol that explored the importance of factors like culture, history, or educational level in shaping attitudes. We collected 13,800 questionnaires from 137 countries, with 25 countries presenting more than 100 answers each, representing in total 92% of the filled questionnaires. A generally positive attitude towards sharks emerged from our study, influenced significantly by several factors including knowledge and participation in marine conservation projects. Interestingly, shark attacks emerged as an important factor, with countries having high numbers of shark attacks exhibiting a highly positive attitude towards sharks, potentially because their citizens are more aware of the issue and the importance of sharks for the marine ecosystems. Guidelines for shifting public attitude towards sharks and consequently advancing shark conservation were also drawn.
Age, Growth and Some Biological Characteristics of White Bream (Blicca bjoerkna L., 1758) in Uluabat Lake, in Northwestern of Anatolia
(Academic Journals Inc, 2012) Sasi, Hüseyin; Berber, Selçuk
In this research, age, sex compositions, mortality, age-length, age-weight, length-weight relations, condition factors of white bream, Blicca bjoerkna (L., 1758), were determined from 183 specimens between April 2002 and March 2003 caught in Uluabat lake, in the northwest of Turkey. The age compositions of specimens were between 1-7 years and sex percentages were found as 50.27% for females and 49.73% for males. The mean forked length varied between 8.35 and 17.85 cm while mean weight ranged from 9.56 to 122.68 g. Growth of population was the most rapid at the first years of life afterwards growth ratio was slower. The weight of white bream increased allometrically for all sexes as seen b = 2.58. It was determined that the average condition factor of ages was between 1.62 and 2.51. The population has shown better growth performance than other habitats because the lake is low in latitude. We have given some of the population parameters and characters from Uluabat lake in northwestern part of Anatolia.

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