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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.
Karagöz istavrit (Trachurus trachurus) balığının hematolojik parametrelerine su sıcaklığı, tuzluluk, mevsim, üreme, cinsiyet, balık büyüklüğü ve yaşın etkisi
(Kafkas Üniv. Veteriner Fak., 2012) Çelik, Ekrem Şanver; Kaya, Hasan; Yılmaz, Sevdan; Çakıcı, Hasan
In order to determine some hematological parameters of horse mackerel, Trachurus trachurus, sampling was conducted between April 2005 and March 2007 at the Dardanelles. Moreover, the effects of season, reproduction, sex, size, age, water temperature, and salinity on the horse mackerel hematologic parameters were investigated. The following annual averages were obtained for the hematological parameters: hematocrit ratio (Hct), females 38.0 +/- 0.32%, males 37.3 +/- 0.36%; hemoglobin level (Hb), females 12.8 +/- 0.13 g/100 mL, males 13.0 +/- 0.16 g/100 mL; erythrocyte (RBC) count, females 1050263.4 +/- 5857.20 mm(3), males 1046081.13 +/- 6319.89 mm(3); leukocyte (WBC) count, females 15797.4 +/- 259.11 mm(3), males 16545.0 +/- 354.54 mm(3); mean corpuscular volume (MCV), females 363.2 +/- 3.12 mu m(3), males 358.8 +/- 3.57 mu m(3); mean corpuscular hemoglobin (MCH), females 123.0 +/- 1.16 pg, males 124.3 +/- 1.48 pg; mean corpuscular hemoglobin concentration (MCHC), females 33.7 +/- 0.17 g/100 mL, males 34.8 +/- 0.22 g/100 mL. Hematological parameters differed significantly (P<0.05) between reproduction periods and between seasons. For both, male and female horse mackerel, the Hct, Hb, RBC, WBC, MCV, and MCH values increased significantly (P<0.05) with size and age. The WBC increased significantly (P<0.05) with increasing sea water temperature in both sexes. In this study, the reference values of hematological parameters were obtained and it was concluded that these parameters were affected by physiological (fish size, age, reproduction) and environmental (season, temperature) factors. Such factors as well as the reference values should be taken into consideration when hematologic studies for horse mackerel is to be conducted.
Estimation of Economic Losses in Trammel Nets Fisheries Using the Length-weight Relationship
(Springer Int Publ Ag, 2024) Şen, Yusuf; Özekinci, Uğur
Trammel nets are used with nearly five days of soaking time to increase the catching efficiency of demersal fish under the control of commercial fishers in the Marmara Sea, Turkiye. The long soaking times can be deteriorate or damage individuals of fish species and economic losses. In this situation, the length and weight of fresh individuals can be measured, but damaged individuals can not be measured in length and weight or both. These losses can be revealed by relating of the length-weight relationship. The current study aimed to determine economic losses by estimating the length-weight relationships of known length and weight of fresh individuals, and by calculating the weight of damaged individuals depending on the length-weight relationships. The catching operations with different soaking times were conducted firstly from December 2020 to December 2021 and secondly from the winter and spring seasons of 2022 in the Marmara Sea, Turkiye. A total of 654 individuals of all species were caught and 185 of them were determined to be damaged. This shows that 30% of those caught were damaged individuals. The total weight of the damaged individuals was calculated to be 91.3 kg. The damaged fish were caught with a total of 2000 m trammel nets and it was determined that they caused an economic loss of 355.3 USD. When we consider the decline and overexploitation of fish stocks, these economic losses and damaged individuals with long soaking times for trammel nets are significant. So, the negative effects of long soaking times on catchable stocks should be evaluated by fisheries managers, and the long soaking times of trammel nets should be regulated for sustainable fisheries.
Evaluation of the health of Mediterranean mussels ( Mytilus galloprovincialis Lamarck, 1819) distributed in the Çanakkale strait, Turkey
(Elsevier Sci Ltd, 2024) Gürkan, Mert; Ertürk Gürkan, Selin; Künili, İbrahim Ender; Acar, Seçil; Özel, Osman Tolga; Düzgüneş, Zehra Duygu; Türe, Mustafa
The observation of mortality in Mediterranean mussels ( Mytilus galloprovincialis ) distributed in the Çanakkale Strait in recent years was influential in developing the research question for this study. In this study, the presence of bacteria ( Vibrio spp.) and parasites ( Marteilia spp. and Haplosporidium spp.) in mussels collected from Kumkale, Kepez, and Umurbey stations in the Çanakkale Strait was investigated seasonally. Microbiological findings, histopathology, oxidative stress enzymes and their gene expressions, lipid peroxidation, lysosomal membrane stability, and changes in haemolymph were examined. In summer samples, both the defence system and the extent of damage were higher in gill tissue. In winter samples, enzyme activities and lipid peroxidation were found to be predominantly higher in digestive gland tissues. Histological examinations and Hemacolor staining revealed the presence of protozoan cysts, and for bacterial examination, molecular analysis performed after culturing revealed the presence of 7 Vibrio species. While the total numbers of heterotrophic bacteria detected in all samples were at acceptable levels, the predominance of Vibrio spp. numbers among the total heterotrophic bacteria detected in almost all samples were noteworthy. The total hemocyte count was calculated as 5.810(4) +/- 0.58 (cells/mm 3 ) in winter and 7.210(4) +/- 1.03 (cells/mm 3 ) in summer. These factors are considered to be possible causes of mussel mortality.
A new species of Pseudorientalia (Gastropoda: Hydrobiidae) from midwestern Türkiye with notes on Pseudorientalia natolica (Küster, 1853)
(Magnolia Press, 2024) Odabaşı, Deniz Anıl; Mercan, Deniz; Odabaşı, Serpil; Arslan, Naime
The members of the genus Pseudorientalia Radoman, 1983 are small hydrobiid species with characteristic features of the penis and female genitalia. The type locality of the genus is the southern Marmara region, northwestern T & uuml;rkiye. In this study, sampling was carried out in the upper Sakarya River Basin, western -middle Anatolia to obtain hydrobiid specimens, which yielded a new Pseudorientalia . The shell, penis, and female genitalia of the new species are described. The measurement of some shell characters is compared with the other representatives of the genus from T & uuml;rkiye, northern Greece, and some Aegean islands: Samos, Chios and Lesvos. In addition, notes on Pseudorientalia natolica are also given from examination of the type specimens.
The effects of Capsicum annuum oleoresin, as a dietary carotenoid, on growth, gut microbiome, intestinal histomorphometry, and sensory characteristics of Oncorhynchus mykiss
(Wiley, 2024) Yılmaz, Sevdan; Şanver Çelik, Ekrem; Ergün, Sebahattin; Gürkan, Mert; Kesbiç, Fevziye Işıl; Abdel-Latif, Hany M. R.
This study was designed to explore the dietary effects of Capsicum annuum oleoresin (CAO) on growth, body composition, sensory characteristics, gut microbiome, and intestinal histomorphometry of rainbow trout. Fish (195.13 +/- 1.55 g) were fed diets with various CAO levels (0.0-Control, 7.0- g kg (-1) C7, 14.0 g kg (-1) -C14, 21.0 g kg (-1)-C21, and 28.0 g kg (-1)-C28) for a 30-day period. Results revealed that the maximum growth was achieved in C7 and C14 groups. Nevertheless, the growth parameters were similar in other groups compared to the control. Moreover, there were significant increases in dry matter and crude lipid contents in all CAO groups compared with the controls. The mean abundances (%) of the prevalent bacteria at the genus level in the intestinal trout samples presented no significant changes among the test groups. Dietary CAO significantly changed the intestinal histological structure, and was manifested by an increased number of goblet cells in the CAO-supplied groups. However, there were intestinal villus epithelial deformations associated with increasing dietary CAO, and were most prominent in the C28 group. The sensory attributes of cooked trout fillets showed that capsicum's pungent odor and taste was evident in the C14 group and subsequently increased with increasing dietary CAO levels. Accordingly, the results showed, for the first time, that dietary CAO at levels (7-14 g kg(-1)) can enhance the growth of rainbow trout without negative effects on the sensory characters and gut health.
Cheliped loss and abnormalities of the narrow-clawed crayfish, Pontastacus leptodactylus (Eschscholtz, 1823) (Crustacea: Decapoda: Astacidae)
(Soc Brasileira Carcinologia, 2024) Berber, Selçuk; Kale, Semih; Acarlı, Deniz
Heterochely is an important phenomenon in decapod crustaceans. Nevertheless, it was rarely examined in freshwater crayfish. Therefore, the aim of this study was to investigate cheliped loss and abnormalities of the narrow -clawed crayfish, Pontastacus leptodactylus. The crayfish samples were captured using 17 mm mesh -sized fyke-nets from Atikhisar Reservoir in canakkale, Turkey between July 2020 and June 2021. The cheliped loss was classified and compared between sexes and length groups. The cheliped surface was calculated for each specimen for both the right and left cheliped. Results of the study indicate that the percentages of the sampled individuals were 5.46% for the right cheliped missing group, 5.23% for the left cheliped missing group, 10.37% for both chelipeds missing group, and 78.94% for both chelipeds present group. There was a statistical difference between cheliped loss and size groups (p < 0.05). Although cheliped loss is almost non-existent in low -size groups (10.0-29.9 mm), it reaches high values in the 40.0-69.9 mm size groups. The most intense loss occurs in the 40.0-49.9 and 50.0-59.9 mm size groups. It was determined that 10.69% of the sampled individuals examined had a single cheliped (10.03% female, 11.14% male). A statistically significant difference was found between cheliped loss and sex (p < 0.05). The percentage of female and male individuals with no chelipeds is 9.83% for females and 10.73% for males, and with both chelipeds it is 80.14% for females and 78.14% for males. While the number of abnormalities observed in chelipeds was higher in males, abnormalities in both chelipeds were higher in females. Moreover, it was found that cheliped loss significantly differed according to the months of collection (p < 0.05). Cheliped losses increased in July, August, and September when feeding was comparatively intense. In conclusion, the fact that the individuals were obtained alive, was an indication that the abnormalities detected did not significantly affect their vital activities directly. However, morphological abnormalities in the appendages, especially in the chelipeds, may impair their functional use compared to a healthy cheliped. This abnormal condition is assumed to share the disadvantageous limitations experienced by the absence of a cheliped.
The length-weight relationship and condition factors of coastal small-sized adult and juvenile fish species following dense mucilage in the Sea of Marmara, Türkiye
(Tubitak Scientific & Technological Research Council Turkey, 2024) Şen, Yusuf; Daban, İsmail Burak; Öztekin, Alkan; Ayaz, Adnan; Altınağaç, Uğur; İşmen, Ali; Yüksek, Ahsen; Özekinci, Uğur; Çakır, Fikret; Demirkıran, Tekin; Uğur, Gençtan Erman; Ayaz, Oğuzhan; Selçuk, Buminhan Burkay
To understand the ecosystem health of the Sea of Marmara following the dense mucilage event in 2021, growth indicators (length-weight relationships and condition factors) of coastal fish species were investigated. For this purpose, individuals were sampled during experimental fishing trials with beach seine nets between November 2021 and March 2022 from the Sea of Marmara, Turkiye. A total of 32 fish species belonging to 19 families were obtained. A total of 12 juvenile and 20 small-sized adult coastal fish species were identified, and condition factors and length-weight relationships (LWRs) were calculated. The LWR results of this study reveal the first findings as Gasterosteus aculeatus for Mediterranean marine waters, as Umbrina cirrosa for Turkish waters, and as Pomatoschistus marmoratus and Pomatoschistus minutus for the Sea of Marmara. The b value of 17 species ranged between 2.586 and 3.566, all distributed within the expected range (2.5 and 3.5) for healthy stocks. In addition, the CF values were found slightly lower from the results of the previous studies. These differences may be a result of abnormal environmental conditions which cause mucilage to form and/or address varied life phases (juvenile/adult) of this study and compared previous studies. To better understand, multidisciplinary studies should be conducted that include case history as well as back-calculated predictions, as in this study.
Description of Bithynia gonensis sp. nov. (Gastropoda: Bithyniidae) from Gönen Çayı, north-western Türkiye
(E Schweizerbartsche Verlagsbuchhandlung, 2024) Odabaşı, Deniz Anıl; Odabaşı, Serpil; Ergül, Halim Aytekin; Zilifli, Aytuğ
This study aims to reveal the freshwater mollusc assemblages from 6 sites sampled along Gonen cayi, a stream which flows into the southern Marmara Sea in north-western Turkiye. The stream was sampled using the multi-habitat sampling method with a hand net. Ten species of freshwater molluscs, most of which are widely distributed in Turkiye, were found in the study area. Among these taxa was an unidentified species of Bithynia, which was only present at 1 site. Its shell and anatomy were compared with other Bithynia species from Turkiye and neighbouring countries and found to differ, which revealed that it is a new species. The discovery of the new species increases the diversity of Bithynia in northern Turkiye to 4 species, and to 11 species for Turkiye. This paper highlights the diversity and endemism of freshwater molluscs in Turkiye and emphasizes the need for further research on the distribution of bithyniid species in the country.
A new species within the genus Bithynia (Gastropoda: Bithyniidae) from northwestern Turkiye
(Taylor & Francis Ltd, 2024) Akay, Enis; Odabaşı, Deniz Anıl; Dalkıran, Nurhayat
In Turkiye, the family Bithyniidae is represented by two genera: Bithynia (Leach, 1818) and Pseudobithynia (Gloer & Pesic, 2006). Recent studies have shown that Bithyniidae species have a broad distribution across southeastern Europe, including Greece, Montenegro, and Bulgaria. In Turkiye, a total of 14 species have been documented so far, with nine belonging to the genus Bithynia and five to Pseudobithynia. We found a new Bithynia species in Kocacay Stream, situated in the southern Marmara Region. This newly identified species has been compared with all known congeners from nearby ecosystems in Turkiye and neighbouring countries.
Phenotypic and Genotypic Antibiotic Resistance of Staphylococcus warneri and Staphylococcus pasteuri Isolated from Stuffed Mussels
(Istanbul University Press, 2024) Kahraman Yılmaz, Dilek; Berik, Nermin
This study aimed to assess the presence of Staphylococcus species in stuffed mussel samples sold in Çanakkale province and to determine the antibiotic resistance of the isolates. A total of 246 stuffed mussel samples were examined, and two different Staphylococcus (S. warneri and S. pasteuri) were isolated from 12.19% of the samples. Among the Staphylococcus isolates, S. warneri was detected at a rate of 73.33% and S. pasteuri at 26.67%. Bacterial isolates (N=30) were examined for their resistance to amoxicillin/clavulanic acid (30 µg), ampicillin (10 μg), erythromycin (15 µg), clindamycin (10 µg), vancomycin (30 µg), oxacillin (5 µg), tetracycline (30 µg), doxycycline hydrochloride (30 µg), chloramphenicol (30 µg), streptomycin (10 µg), gentamicin (10 µg), kanamycin (30 µg), nalidixic acid (30 µg), ciprofloxacin (5 µg), meropenem (10 µg), imipenem (10 µg), sulfamethox/ trimethoprim (25 µg), cefotaxime (30 µg), cephalothin (30 µg), ceftriaxone (30 µg), and levofloxacin (5 µg) antibiotics. Resistance to amoxicillin/clavulanic acid and erythromycin was found in all S. warneri isolates. In addition, all S. pasteuri isolates were found to be resistant to amoxicillin/ clavulanic acid. In S. warneri isolates, at least three resistance genes (BlaTEM, tetB-6, tetK-8) and up to eight resistance genes (BlaTEM, tetB-6, tetK-8, strA-strB, aphAI-IAB, ermC) were identified. All S. pasteuri isolates exhibited blaTEM, strA-strB, and aphAI-IAB resistance genes. In conclusion, it was determined that antibiotic-resistant S. warneri and/or S. pasteuri contaminates stuffed mussel samples. This study will serve as a valuable resource for enhancing monitoring strategies in stuffed mussel production. Further studies should be conducted to determine whether the products are suitable for food safety. Therefore, it is necessary to clarify the disease effects and mechanisms of the pathogens identified in stuffed mussels.
Evaluation of the Antimicrobial Effects of Olive Mill Wastewater Extract Against Food Spoiling/Poisoning, Fish-Pathogenic and Non-Pathogenic Microorganisms
(Mdpi, 2024) Kahraman Yılmaz, Dilek; Kesbiç, Fevziye Işıl; Çelik, Ekrem Şanver; Odabaşı, Deniz Anıl; Yılmaz, Sevdan; Abdel-Latif, Hany M. R.
Although antibiotics are the main therapy for bacterial infections, the reports showed that the overuse (or misuse) of antibiotics will results in several problems such as the development of antibiotic-resistant strains, persistence of drug residues, and numerous environmental concerns. Therefore, finding antibiotic alternatives is considered of vital importance. Investigation of the antimicrobial properties of several plant substances and extracts is of great value to replace antibiotics. With this objective, this study aimed to evaluate the antimicrobial activities of an ethanolic extract prepared from olive mill wastewater (OMWW), which is a by-product of olive oil production with considerable environmental burden, against 38 bacterial strains, including fish-associated pathogens, non-pathogenic isolates, collection strains, and one yeast strain, Candida albicans. Disk diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal/fungicidal concentration (MBC/MFC) tests were used to determine the antimicrobial activity of the OMWWE. According to the results, OMWWE provoked strong inhibitory effects against Shewanella baltica strain SY-S145. It also showed a moderate inhibitory effect on Plesiomonas shigelloides strain SY-PS16 and Vibrio anguillarum strain SY-L24. The MIC and MBC of OMWWE on Shewanella baltica SY-S145, Vibrio gigantis strain C24, and V. anguillarum strain SY-L24 were 500 mu g/mL. The MIC and MBC on V. parahaemolyticus ATCC 17802 were 1000 mu g/mL, whereas the values for Aeromonas salmonicida ATCC 33658 were 500 mu g/mL and 1000 mu g/mL, respectively. To put it briefly, the OMWW extract showed high antimicrobial activity and can act as an environmentally friendly additive for the control and prevention of diseases caused by A. veronii, A. hydrophila, P. shigelloides, S. baltica, V. anguillarum, and V. parahaemolyticus. Its active agents also prevented infections of both fish-associated pathogens and food spoiling bacteria, which means it can not only help in the disease control mechanism but also in improving the safety of food by reduction of the microbial contamination.
Effects of traditional and alternative mesh sizes in trammel nets on selectivity and catchability of Penaeus kerathurus (Forskal, 1775) in the Marmara Sea
(Elsevier, 2025) Şen, Yusuf
Penaeus kerathurus is one target species caught with trammel nets by small-scale fishers in the Marmara Sea. Generally, 40 mm mesh size is used in trammel nets. In the present study, alternative mesh sizes (36 mm, 44 mm) were compared with the 40 mm traditional mesh size for their effects on selectivity and catchability. A total of 27 species comprising 3777 individuals and weighing 123615 g were caught. Penaeus kerathurus constituted 72.4 % of the total number of individuals and 58.3 % of the total weight. The mean (+/- Ss) catch-per-unit-of-effort (CPUE) for the 40 mm mesh size for commercial fishers was determined to be 7.73 +/- 4.99 g/m.operation(-1), and 9.92 +/- 4.47 g/m.operation(-1) for the present study. The CPUE values for the 36 mm and 44 mm alternative mesh sizes were determined as 4.83 +/- 2.67 and 7.77 +/- 4.92 g/m.operation(-1), respectively. The highest CPUE value for individuals was detected with the 40 mm mesh size. The mean carapace length, total length and total weight of P. kerathurus significantly increased with mesh size. The model lengths of P. kerathurus were found to be larger than the carapace length at first sexual maturity in the Marmara Sea. So, traditional and alternative mesh sizes can be used to catch P. kerathurus. As a result, P. kerathurus fisheries in the Marmara Sea were described for the first time. Alternative mesh sizes did not significantly affect catch and bycatch composition, selectivity, but they decreased catching efficiency. New and additional modifications, innovations or changes can be made to trammel nets to promote sustainable P. kerathurus fisheries.

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