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Öğe Condition, Length-Length and Length-Weight Relationships for Four Introduced Freshwater Fish Species from an Insular Ecosystem (Gökçeada, Turkey)(2021) Ağdamar, Sevan; Gaygusuz, ÖzcanThe present study aims to investigate the condition, length-weight (LWRs) and length-length relationships (LLRs) of four introduced freshwater fish species (Carassius gibelio, Cyprinus carpio, Gambusia holbrooki, and Pseudorasbora parva) inhabited in the inland waters of Gökçeada (Çanakkale, Turkey). Fish samples were collected using electrofishing from one lentic (Büyük Stream) and four lotic (Aydıncık, Dereköy, Gökçeada, and Uğurlu Reservoirs) ecosystems between April 2019 and September 2020. The calculated values of parameter b in the LWRs were 3.275 and 3.230 for G. holbrooki (Uğurlu and Büyük populations, respectively), 3.031 and 2.937 for C. carpio (Aydıncık and Dereköy populations, respectively), 3.129 for C. gibelio and 3.047 for P. parva. Values of Fulton's condition factor (K) varied between 1.72 ± 0.23 (P. parva, Gökçeada population) and 3.60 ± 0.33 (C. carpio, Dereköy population). The coefficients of correlation (r) for all the LLR equations were greater than 0.95 and significantly linear. The present study provides the first knowledge about the selected biological parameters for four introduced freshwater fish species in Gökçeada.Öğe Erratum to: New record and rare occurrence of European eel (Anguilla anguilla) from freshwater bodies in Karaburun Peninsula (İzmir, Türkiye): Anthropogenic pressures on the fish movements(İstanbul Üniversitesi, 2022) Ağdamar, Sevan; Acar, ÜmitAfter publication of the original article [1], it came to the authors’ attention that there was an inadvertently missed information in Acknowledgement section.Öğe Growth and Feeding Ecology of Dnieper chub Petroleuciscus borysthenicus (Kessler, 1859) in Şahinkaya Reservoir, an Artificial Water Body of an Island Ecosystem (Gökçeada, Turkey)(2022) Ağdamar, Sevan; Saç, GülşahBio-ecological studies and life-history traits of small-bodied fishes are critical for the un- derstanding of their ecological role as well as the assessment of their position and continuity in the eco- systems. The current study goals to present initial data on growth and feeding habits of small-bodied Petroleuciscus borysthenicus inhabited in an island ecosystem (Gökçeada, Turkey). During the season- ally sampling surveys from May 2020 to January 2021, a total of 163 specimens were collected from Şahinkaya Reservoir using electrofishing. SL and W values of samples ranged from 2.6–10.0 cm and 0.32–25.68 g, respectively. LWR and K values were estimated for all specimens as W=0.017×SL3.114 (r=0.988) and 2.04 (±0.28), respectively. F:M sex ratio was calculated as 1:1.33 with no significant difference from the ratio of 1:1 (X2=0.02; p>0.05). Diet of the species comprised of ten different food items. Plant (63.6%) was the most preferred food item from the point of frequency of occurrence (F%), pursued by Diptera (31.8%) and Odonata (12.7%). According to IRI (%) values of food items, Diptera was the dominant food item in all seasons. B and BA values were estimated as 3.18 and 0.24, respec- tively. The results showed that P. borysthenicus was more selective on conveniently accessible food materials in the environment and its food preference was affected by seasonal food supply.Öğe Life in Extreme Conditions: Diet and Condition of the Extremophile Fish Aphanius almiriensis (Teleostei: Cyprinodontiformes) in a Thermal Rheocrene Spring(Wiley, 2025) Saç, Gülşah; Özuluğ, Oya; Ağdamar, Sevan; İnci, Harun; Yürekli, Özgün Deniz; Özuluğ, MüfitThis study aims to understand the bioecological traits of an extremophile fish, Aphanius almiriensis, in order to explore how it survives and colonizes extreme habitat conditions. To achieve this, the bioecological characteristics-condition, diet, and feeding strategy-of A. almiriensis inhabiting the Tuzla thermal spring, which is characterized by extreme habitat conditions in terms of physicochemical water parameters, were studied. Among the physicochemical parameters measured, salinity and temperature were remarkably high, ranging from 23.7 degrees C (in winter) to 42.7 degrees C (in summer) and from 47.7 ppt (in autumn) to 60.7 ppt (in winter). A total of 248 fish individuals were collected from the thermal spring, and the diet analyzed seasonally consisted of 17 different food items, and their importance values (MI% and IRI%) varied seasonally. According to the F%, IRI%, and MI% values, the population fed mainly on Diatom, Cyanobacteria, and Diptera, resulting in niche breadth with low values ranging from 0.25 to 0.54. The extreme conditions of the thermal spring indicated that the environment was poor in terms of macroinvertebrate diversity (six taxa), and fish showed food selectivity (E) for Chironomidae and Ceratopogonidae in winter, spring, and summer and for Ephydridae in autumn (E > 0; positive selectivity). Seasonally influenced fish condition was represented by high values in summer (K = 1.43 +/- 0.14) and was positively correlated with both water temperature and the increasing importance of the genus Phormidium in its diet. This study provides the first comprehensive insight into the seasonal diet and condition of A. almiriensis, shedding light on its survival strategies in harsh ecological conditions.Öğe Low Genetic and Parasite Diversity of Invasive Pumpkinseed Lepomis gibbosus (Centrarchidae) Expanding in Turkiye(Mdpi, 2024) Kvach, Yuriy; Tkachenko, Maria Yu.; Giannetto, Daniela; Mic, Robert; Bartakova, Veronika; Ağdamar, Sevan; Saç, GülşahMultiple factors can facilitate invasion success, with the absence of natural enemies, such as predators and parasites, recognised as conferring a significant advantage on invasive over native species. Pumpkinseed Lepomis gibbosus (Centrarchidae) represents one of the most successful freshwater fish invaders in Europe. Previous research has highlighted genetic differences between pumpkinseed populations in Türkiye and those in other European regions, attributed to rapid adaptation to new environmental conditions. This study aimed to investigate whether these highly adapted pumpkinseed populations in Türkiye benefit from a potential release from parasites, as proposed by the enemy-release hypothesis. Genetic characterisation of pumpkinseed populations from both European and Asian parts of Türkiye revealed that they share the same cytochrome c oxidase I haplotype as European populations. Microsatellite analysis indicated low genetic diversity, with STRUCTURE analysis confirming the clustering of all Turkish populations, suggesting a common source. Consistent with the low genetic diversity indicative of a small founding population, we observed a limited number of co-introduced parasite species, including the myxozoan Myxobolus dechtiari, the monogenean Onchocleidus dispar, and the digenean Posthodiplostomum centrarchi. Parasite infection by local parasites acquired in Türkiye was rare. Parasite diversity, species richness, and equitability were low, with only nine parasite taxa identified in all four pumpkinseed populations. The most diverse parasite community was found in Değirmenköy Reservoir, located in the European part of Türkiye, where seven parasite taxa were identified. While our study did not uncover genetically distinct pumpkinseed populations in Türkiye, the fish demonstrated resilience against most local parasite species, potentially providing them with an advantage over native species, aligning with the enemy-release hypothesis.Öğe New record and rare occurrence of European eel (Anguilla anguilla) from freshwater bodies in Karaburun Peninsula (İzmir, Türkiye): Anthropogenic pressures on the fish movements(İstanbul Üniversitesi, 2022) Ağdamar, Sevan; Acar, ÜmitObjective: Fish can be used as bio-indicators to determine whether freshwater habitat has been altered. As habitat discontinuity occurs due to the presence of mechanical barriers, species composition can be altered upstream and downstream. Since the beginning of the 1980s, the amount of European eel Anguilla anguilla entering inland waters in Türkiye and European countries has decreased significantly. Our study describes for the first time the presence of A. anguilla from the freshwater bodies in the Karaburun Peninsula. Materials and Methods: From November 2020 to August 2021, fish specimens were collected through electrofishing in one lotic system and three transitional waters of the study area. Clove oil was used to anesthetize live fish specimens after capture. Total length (TL) was measured for each sample to the nearest 1.0 mm. With a digital balance that was accurate to 0.01 g, we weighed the total body weight (W). Results: We collected four adult specimens of A. anguilla from the study area. Total lengths and body weights of the specimens were 311 mm and 62.4 g for Balıklıova Stream; 360 mm and 95.3 g for Küçükbahçe Stream; 325 mm 56.3 g for Salman Reservoir and 280 mm and 34.7 g for Yelkentaş Stream, respectively. Conclusion: We could not discuss our findings since no study has been done in the study area before, but it is thought that the low number of individuals caught may be related to the habitat degradation and different types of constructions at the stream mouths. The construction of fishways suitable for the study area can be a start to solving the distribution problem of this species.Öğe Occurrence of the Non-Native Pumpkinseed Lepomis gibbosus in a Reservoir of the Karamenderes Basin (Çanakkale, Türkiye)(Istanbul University, 2025) Kaya, Yağmur; Gökmenoğlu, Tuğba; Telci, Tuncay; Kurt, Emin; Ağdamar, SevanThis study reports the recent discovery of the pumpkinseed Lepomis gibbosus in the Bayramiç Reservoir, which is located in the Karamenderes Basin (NW Türkiye). A total of five specimens were captured with a portable electrofishing unit. Total length (TL) and body weight (W) measurements were recorded with an accuracy of 0.1 cm and 0.01 g, respectively. The length and weight ranges of the specimens were 41–88 mm and 7.2–14.3 g, respectively. The presence of this non-native species in the study area could be attributed to either natural expansion or multiple (deliberate/indeliberate) introductions.Öğe Oxynoemacheilus fatsaensis, a new nemacheilid loach from the Elekci Stream in Northern Anatolia (Teleostei: Nemacheilidae)(Elsevier GmbH, 2021) Saygun, Serkan; Ağdamar, Sevan; Özuluğ, MüfitWe report a new species, Oxynoemacheilus fatsaensis, from the Elekçi Stream, a small stream that flows to the Black Sea in Northern Turkey. It is distinguished from other Oxynoemacheilus species in the Black Sea, Upper Euphrates, and Kura-Aras River basins by having a suborbital groove in males, an axillary lobe at the pelvic-fin base, no dorsal adipose crest on the caudal peduncle, a deeply emarginate caudal fin, small inner and outer rostral barbels, and mottled flank pattern. Molecular data suggest that the new species is separated by a minimum p-distance of 3.3% from O. banarescui in the mitochondrial DNA COI barcode region.Öğe Population Genetic Structure of Petroleuciscus borysthenicus (Kessler 1859) in Northwestern Türkiye Using Mitochondrial COX1 Gene(Wiley, 2024) Ağdamar, Sevan; Saç, Gülşah; Acar, Ümit; Gaygusuz, Özcan; Doğaç, Ersin; Özuluğ, MüfitPetroleuciscus borysthenicus is a species with a wide distribution from the eastern, western, and northern Black Sea and Azov Sea basins, the Aegean Sea basin, and Northwestern Türkiye. However, there has been relatively little attention on the genetic variability of this species in their native distribution range, and nearly no study has been conducted in Türkiye despite its importance in biodiversity. The aim of this study was to elucidate the genetic variability and population structure of P. borysthenicus from Northwestern Türkiye using an integrated molecular method. A total of 72 specimens were collected from 13 localities in the Northwestern part of Türkiye. A total of six haplotypes were identified in all specimens. A relatively low level of genetic variability was found for P. borysthenicus throughout the study region based on the indices of genetic diversity including haplotype diversity and nucleotide diversity for the cytochrome oxidase subunit I (h = 0.507, pi = 0.0027). The pairwise FST values between the samples ranged from -0.123 to 1.000. Furthermore, our results revealed no provable recent demographic expansion for P. borysthenicus from Northwestern Türkiye. However, more studies using additional geographic sampling and molecular analysis are needed to enhance our knowledge of the diversity and distribution of this species.Öğe Seasonal and Spatial Variation in the Diet of Gambusia holbrooki in Different Water Bodies of Karaburun Peninsula (Western Türkiye)(MDPI, 2025) Saç, Gülşah; Ağdamar, Sevan; Acar, Ümit; Giannetto, DanielaThe Eastern mosquitofish Gambusia holbrooki Girard, 1859, has been widely introduced into tropical and temperate countries as a biological agent to control mosquitos, which are associated with diseases such as malaria and yellow fever. However, the species exhibits invasive characteristics by competing with native species for food and habitat use. This study investigates the feeding ecology of G. holbrooki populations from three distinct freshwater environments (Lake Iris, Eğlenhoca Reservoir, and Parlak Reservoir) on the Karaburun Peninsula (North-Western Türkiye), a region outside its native range. The primary aim was to evaluate seasonal and spatial variations in the diet of the species. A total of 871 specimens were analysed: 247 from Iris Lake, 318 from Parlak Reservoir, and 306 from Eğlenhoca Reservoir. Low percentages of empty stomachs (≤20%) across all populations indicate high feeding intensity. The results reveal that G. holbrooki exhibits a generalist feeding strategy, consuming a wide range of food items such as insects, zooplankton, and plant material across all the investigated environments. The relative importance of food groups (determined by the Importance Index, MI%) varied seasonally but not spatially. In all three populations, the most important food source in the spring was dipterans, followed by plants in the summer and fall, and cladocerans in the winter. Plants accounted for the largest percentage of the diet in every population (MI% >65%). These findings suggest that G. holbrooki adapts its diet to seasonal food availability.Öğe The ichthyofaunal diversity of freshwater ecosystems in Gokceada Island (NW Turkey) under the pressure of nonnative species(Turkiye Klinikleri, 2021) Ağdamar, Sevan; Saç, Gülşah; Gaygusuz, Özcan; Doğaç, Ersin; Acar, Ümit; Gürsoy Gaygusuz, Çiğdem; Özuluğ, MüfitFreshwater ecosystems have a greater value for biodiversity per surface area than terrestrial and marine ecosystems. Streams and lakes are notably prone to biodiversity loss, being the greatest threats habitat destructions and nonnative species. The aim of the present study is to assess the fish composition of lotic and lentic water systems of an island ecosystem (Gökçeada Island, Turkey), which is poorly studied, and to highlight the entry routes and possible impacts of translocated fish species in an island ecosystem. The field surveys were conducted in a total of 14 sampling sites (five reservoirs and nine streams) in the inland waters of Gökçeada Island between September 2019 and January 2021. Fish samples were collected by electrofishing (SAMUS 1000; a backpack electro-shocker). A total of eight fish species belonging to six families (Anguillidae, Atherinidae, Cyprinidae, Leuciscidae, Mugilidae, and Poeciliidae) were determined. As a result fish community of the island was mostly composed by the introduced species Carassius gibelio, Gambusia holbrooki and Pseudorasbora parva. This study provides the first detailed information on the distribution of the fish species encountered in the inland waters of Gökçeada Island. Results showed that the fish fauna of the island was predominantly shaped by fish stocking activities.
