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Öğe A comparison of ageing techniques to improve precision of age estimation from fish scales(2005) Gaygusuz, Çiğdem Gürsoy; Tarkan, Ali Serhan; Gaygusuz, Özcan; Acıpınar, HasanKızılkanat, Scardinius erythrophthalmus (L, 1758), gümüşi havuz balığı Carassius gibelio (Bloch, 1782) ve kızılgöz, Rutilus rutilus (L, 1758) balıklarının pulları iki farklı habitattan elde edildi. Tüm balık türlerine iki yaş tayini yöntemi uygulandı. Bu yöntemler arasında uyuşmazlıklar bulundu. Farklı okuyucuların yaş tayinleri arasındaki uyum, pul basma yönteminde pul temizleme metodundakinden daha iyiydi. Pul basma metodu yaş hesaplamalarının doğruluğu bakımından en iyi sonuçları ortaya çıkardı. Bunun yanı sıra hızlı kullanım, verileri saklama, ve kolay geri-hesaplama gibi birçok avantajları görüldü.Öğe A Comparison of Ageing Techniques to Improve Precision of Age Estimation from Fish Scales(Ege Univ, Fac Fisheries, 2005) Gursoy, Cigdem; Tarkan, Ali Serhan; Gaygusuz, Ozcan; Acipinar, HasanScales of rudd, Scardinius erythrophthalmus (L, 1758), prussian carp, Carassius gibelio ( Bloch, 1782) and roach, Rutilus rutilus (L., 1758) were sampled from two different habitats. Two methods of determining age from scales of fish were applied for all fish species. There was disagreement between methods. The agreement between the determinations of different age readers was better with the impressing scale method than cleaning scale method. Impressing method produced the best results in terms of precision of the age estimates besides it had many advantages such as quick - apply, storing data and easy back-calculation.Öğe A warning note on frequent mistakes in the authority of scientific names of fish(2003) Tarkan, Ali Serhan; Gaygusuz, Özcan; Gaygusuz, Çiğdem Gürsoy; Acıpınar, Hasan; Bilge, GökçenMaking parentheses mistakes in the authority of scientific names of fish is quite frequent. To determine this kind of errors, titles in Cumhuriyet Dönemi Su Ürünleri Bibliyografisi book and abstracts in ASFA (Aquatic Sciences and Fisheries Abstracts) in year of 1998 were studied. Both datasets gave unexpectedly high percentages of authority errors. For some species, the error percentages were up to 96%. Logically, omitting parentheses was more common than adding them. These statistics should be taken into account in the authority of scientific names. To prevent these kinds of mistakes, some recent references and websites should be taken into consideration before using authority of fish.Öğe Changes in the fish community of the Ömerli Reservoir (Turkey) following the introduction of non-native gibel carp Carassius gibelio (Bloch, 1782) and other human impacts(Regional Euro-Asian Biological Invasions Centre, 2007) Gaygusuz, Özcan; Tarkan, Ali Serhan; Gaygusuz, Çi?dem GürsoyChanges in the relative density (catch per unit effort; CPUE) of introduced gibel carp Carassius gibelio (Bloch, 1782) and native fish species were monitored over four years in the Ömerli Reservoir, a temperate drinking-water reservoir in northwestern Turkey. Following the species' introduction, the CPUE of gibel carp increased significantly with the decrease in CPUE of large-bodied native fish species. © 2007 The Author(s).Öğe Characteristics of a eurasian cyprinid, shemaya, chalcalburnus chalcoides (güldenstädt, 1772), in a mesotrophic water reservoir(2005) Tarkan, Ali Serhan; Gaygusuz, Özcan; Acıpınar, Hasan; Gürsoy, ÇiğdemAge, growth and reproduction of the Shemaya, Chalcalburnus chalcoides, was studied in the Ömerli Reservoir, a large drinking water system located in Istanbul province (Turkey). The von Bertalanffy growth function displayed variation in growth rates between the sexes. Asymptotic lengths calculated for both sexes were high, probably due to the lack of large predatory fishes and lack of fishing in the reservoir. Females dominated all age classes with the exception of the second age, and this phenomenon is characteristic of species from unstable and variable environments. The condition factor and the gonadosomatic index indicated that reproduction occurred around May-June. The estimated mean lengths at first maturity (LT50) were 14.83 cm and 15.98 cm for males and females, which corresponded to 1 and 2 years of age for both sexes. Natural mortality was 0.47/year. Fishing mortality as well as exploitation rate was negligible since fishing activity is prohibited throughout the year. © 2005 Taylor & Francis Group, LLC.Öğe Conversions of total, fork and standard length measurements based on 42 marine and freshwater fish species (from Turkish water)(2006) Gaygusuz, Özcan; Gaygusuz, Çiğdem Gürsoy; Özuluğ, Müfit; Tarkan, Ali Serhan; Acıpınar, Hasan; Bilge, Gökçen; Filiz, HalitRelationships between total (TL), fork (FL) and standard (SL) lengths belonging 19 families from Aegean and Marmara coast of Turkey were presented for 42 fish species. The relationships between TL, FL and SL were all linear and they were all highly significant (P<0.001) with all $r^2$ values being >0.90. There were significant differences in the slope of length – length relationships between some localities and type of length conversions for the fish species.Öğe Economic costs of non-native species in Türkiye: A first national synthesis(Academic Press Ltd- Elsevier Science Ltd, 2024) Tarkan, Ali Serhan; Baycelebi, Esra; Giannetto, Daniela; Ozden, Emine Demir; Yazlik, Ays; Emiroglu, Ozgur; Aksu, SadiBiological invasions are increasingly recognised as a major global change that erodes ecosystems, societal wellbeing, and economies. However, comprehensive analyses of their economic ramifications are missing for most national economies, despite rapidly escalating costs globally. T & uuml;rkiye is highly vulnerable to biological invasions owing to its extensive transport network and trade connections as well as its unique transcontinental position at the interface of Europe and Asia. This study presents the first analysis of the reported economic costs caused by biological invasions in T & uuml;rkiye. The InvaCost database which compiles invasive non-native species' monetary costs was used, complemented with cost searches specific to T & uuml;rkiye, to describe the spatial and taxonomic attributes of costly invasive non-native species, the types of costs, and their temporal trends. The total economic cost attributed to invasive non-native species in T & uuml;rkiye (from 202 cost reporting documents) amounted to US$ 4.1 billion from 1960 to 2022. However, cost data were only available for 87 out of 872 (10%) non-native species known for T & uuml;rkiye. Costs were biased towards a few hyper -costly non-native taxa, such as jellyfish, stink bugs, and locusts. Among impacted sectors, agriculture bore the highest total cost, reaching US$ 2.85 billion, followed by the fishery sector with a total cost of US$ 1.20 billion. Management (i.e., control and eradication) costs were, against expectations, substantially higher than reported damage costs (US$ 2.89 billion vs. US$ 28.4 million). Yearly costs incurred by non-native species rose exponentially over time, reaching US$ 504 million per year in 2020-2022 and are predicted to increase further in the next 10 years. A large deficit of cost records compared to other countries was also shown, suggesting a larger monetary underestimate than is typically observed. These findings underscore the need for improved cost recording as well as preventative management strategies to reduce future post -invasion management costs and help inform decisions to manage the economic burdens posed by invasive non-native species. These insights further emphasise the crucial role of standardised data in accurately estimating the costs associated with invasive non-native species for prioritisation and communication purposes.Öğe Genetic differentiation of non-native populations of Gibel Carp,Carassius gibelioin Western Turkey by ISSR and SRAP markers(Taylor & Francis Ltd, 2020) Agdamar, Sevan; Baysal, Omur; Yildiz, Aysegul; Tarkan, Ali SerhanFreshwater fish are one of the most frequently translocated and introduced aquatic animal groups and exhibit higher establishment ratios than many other taxa. Introductions are usually irreversible. One of common non-native fish species in Turkey is the Gibel Carp,Carassius gibeliowhich was introduced in the 1980s and is now widespread. We tested dominant markers (ISSR and SRAP) for genetic characterisation of Gibel Carp samples collected from eight locations in western Turkey. ISSR and SRAP marker sets showed that the level of gene flow between these populations (N-m= 0.45 /N-m= 0.47) is low and that the level of genetic differentiation (G(ST)= 0.53 /G(ST)= 0.52) is high. Inter-population variation detected by ISSR and SRAP markers constituted half part of the population (46.88 / 50.00%), while the rest was at intra-population level. These results indicate that the present population of the Gibel Carp is the result of several colonization events originating from the different sources. The phylogenetic relationship among the populations suggest that there were two independent major introduction events, one in the Marmara Region and the other in southern Turkey.Öğe High genetic diversity in an invasive freshwater fish species, Carassius gibelio, suggests establishment success at the frontier between native and invasive ranges(Elsevier Gmbh, 2019) Agdamar, Sevan; Tarkan, Ali SerhanNon-native freshwater fish introductions can have direct and indirect negative effects on native flora and fauna, ecosystems, and national economies. Although invasions are paradoxical from an evolutionary standpoint, population genetics could be useful to understand invasion scenarios of non-native species. One of the most common introduced fish in Europe and Turkey is the gibel carp Carassius gibelio, which was first introduced from East Asia in the 17th century. To find out the origin and distribution pattern and characterise the genetic variation of gibel carp in Turkey, the aim of this study was to identify haplotype the species' diversity and distribution in the country. Three mitochondrial (COI, Cyt-b and D-loop) and one nuclear (ITS1) DNA markers were used in 20 populations sampled from 18 different geographic locations, resulting in eight newly-identified haplotypes. The present results: (i) suggest high genetic diversity across regions at both the mitochondrial (29 haplotypes, h = 0.9058, pi = 0.0152) and nuclear (3 haplotypes, h = 0.6365, pi = 0.0094) level; (ii) confirm previous findings that this species may have entered Turkey directly either from its native or through its invasive range; (iii) suggest that, given the distribution of the identified haplotypes by geographic location, the majority of individuals not only originated from the northern (European) part of Turkey but also from the southern (Mediterranean) part of the country. Understanding the genetic characterisation of gibel carp can contribute to more efficient management actions for this species, including prevention of (multiple) introductions and eradication/control of those populations with relatively low genetic diversity. (C) 2019 Elsevier GmbH. All rights reserved.Öğe Interactions of invasive pumpkinseed with a riverine endemic fish indicate trophic overlap but minimal consequences for somatic growth and condition(EDP Sciences, 2023) Karakuş, Uğur; Tarkan, Ali Serhan; Yalçın-Özdilek, Şükran; Top-Karakuş, Nildeniz; Partal, Nurbanu; Britton, John RobertThe North American invasive fish pumpkinseed Lepomis gibbosus has been associated with some detrimental ecological consequences in some parts of its invasive range. Here, we tested the trophic interactions of pumpkinseed with the endemic stream fish Aegean chub Squalius fellowesii ('chub') in a Mediterranean-type water course in SW Anatolia, Turkey, using a bulk stable isotope approach (d13C, d15N). Seven sampling sites were able to be grouped as chub in pumpkinseed presence (n=2) and absence (n=3), and pumpkinseed in chub absence (n=2). Across these groups, stable isotope metrics revealed that chub trophic (isotopic) niche size was similar in pumpkinseed presence/absence, but pumpkinseed had a larger niche in chub presence. In sites where they are co-habited, their niches showed some convergence, but with no apparent consequences for their growth or body condition, suggesting there were minimal ecological consequences of this sharing of food resources. These results suggest that the trophic consequences of this riverine invasion of pumpkinseed on this endemic chub was minimal.Öğe Interannual variability of fecundity and egg size of an invasive cyprinid, Carassius gibelio(Taylor & Francis Inc, 2007) Tarkan, Ahmet Nuri; Gaygusuz, Ozcan; Tarkan, Ali Serhan; Gursoy, Cigdem; Acipinar, HasanA population of the invasive Prussian carp (Carassius gibelio) was examined over a three-year period in a mesotrophic reservoir to find out interannual variations of fecundity and egg size and the influence of maternal condition (total length, TL, and age class) and environmental factors (water temperature and fish density) on these variables. Prussian carp reproduction was synchronous, with only a single batch, and fecundity ranged from 1,250 to 62,400 eggs per female. Relative fecundities and egg size showed no significant between-year differences. Fecundity increased with age, whereas egg diameter remained unchanged with age and TL. Fecundity was affected positively by TL and negatively by fish density, whereas temperature had no significant effect. Egg size was not affected by fish density or temperature.Öğe Preference of zebra mussel, Dreissena polymorpha in the diet and effect on growth of gobiids(Foundation Environmental Protection & Research-Fepr, 2007) Gaygusuz, Oezcan; Gaygusuz, Cigdem Cuersoy; Tarkan, Ali Serhan; Acipinar, Hasan; Turer, ZeynepWe investigated presence of zebra mussel, Dreissena polymorpha, which is considered as harmful for two freshwater ecosystems (Omerli Reservoir and Lake Sapanca), in the food preferences of several gobiid species namely; Neogobius melanostomus, Neogobius gymnotrachelus, and Neogobius fluviatilis. In Lake Sapanca, zebra mussel was the dominant food component in the diet of gobiids. However, in Omerli Reservoir, plant with macropyhtes and algea were the dominant food sources both studied gobiids. Intraspecific diet overlap indices showed that gobiid species from the same lake preferred similar food types (S > 0.8). However, when we compared the lakes, the diet overlap index between N.fluviatilis (Lake Sapanca) and N. gymnotrachelus (Omerli Reservoir) was not significant (S= 0.5) which indicates different food choices. The relationships between total length and weight, which had slope values >3 in all but one case, differed significantly between species. One exception was between N. fluviatilis (Lake Sapanca) and N. melanostomus (Omerli Reservoir). In generally, slopes of the relationships in fish species from Lake Sapanca were bigger than those of Omerli Reservoir. This result suggests that gobiids fed with mostly zebra mussel had better weight gain compared to gobiids fed with mostly plant-based food. This study showed that gobiid fishes are an important consumer of zebra mussel and their predation would affect the mussel populations, especially in the ecosystems where zebra mussel is abundant.Öğe Preference of zebra mussel, Dreissena polymorpha in the diet and effect on growth of gobiids: A comparative study between two different ecosystems(Ekoloji, 2007) Gaygusuz, Özcan; Gaygusuz, Çi?dem Gürsoy; Tarkan, Ali Serhan; Acipinar, Hasan; Türer, ZeynepWe investigated presence of zebra mussel, Dreissena polymorpha, which is considered as harmful for two freshwater ecosystems (Ömerli Reservoir and Lake Sapanca), in the food preferences of several gobiid species namely; Neogobius melanostomus, Neogobius gymnotrachelus, and Neogobius fluviatilis. In Lake Sapanca, zebra mussel was the dominant food component in the diet of gobiids. However, in Ömerli Reservoir, plant with macropyhtes and algea were the dominant food sources both studied gobiids. Intraspecific diet overlap indices showed that gobiid species from the same lake preferred similar food types (S ? 0.8). However, when we compared the lakes, the diet overlap index between N. fluviatilis (Lake Sapanca) and N. gymnotrachelus (Ömerli Reservoir) was not significant (S = 0.5) which indicates different food choices. The relationships between total length and weight, which had slope values >3 in all but one case, differed significantly between species. One exception was between N. fluviatilis (Lake Sapanca) and N. melanostomus (Ömerli Reservoir). In generally, slopes of the relationships in fish species from Lake Sapanca were bigger than those of Ömerli Reservoir. This result suggests that gobiids fed with mostly zebra mussel had better weight gain compared to gobiids fed with mostly plant-based food. This study showed that gobiid fishes are an important consumer of zebra mussel and their predation would affect the mussel populations, especially in the ecosystems where zebra mussel is abundant.Öğe Threatened fishes of the world(Springer, 2008) Tarkan, Ahmet Nuri; Tarkan, Ali Serhan; Bilge, Gokcen; Gaygusuz, Oezcan; Gursoy, Cigdem[Anstract Not Available]Öğe Trophic Interactions of Two Ponto-Caspian Gobies in the Turkish Part of Their Native Range(Central Fisheries Research Inst, 2018) Tarkan, Ali Serhan; Karakus, Ugur; Tepekoy, Erdi Gokhan; Top, Nildeniz; Ozdilek, Sukran Yalcin; Partal, Nurbanu; Britton, John RobertSeveral Ponto-Caspian gobiids have expanded from their native distribution ranges to Europe and North America. As knowledge on their bio-ecological features in their native range is still limited, the trophic ecology of monkey goby Neogobius fluviatilis and Western tubenose goby Proterorhinus semilunaris was studied in three natural lakes in the Marmara Region of NW Turkey using the stable isotopes of delta C-13 and delta N-15. In two of the lakes, the trophic niches ( as the isotopic niche) of the gobies were highly divergent with co-existing native fishes, with no overlap. Moreover, mixing models suggests considerable inter-specific dietary differences. In all lakes, the trophic niches of gobies were never significantly larger than those of coexisting fishes. These results suggest that when introduced outside of their natural range, the gobies might integrate into new fish communities via exploiting resources that are underexploited by native fishes or will initially share resources with these species before their niches diverge, perhaps through competitive displacement.Öğe Two new records for the fish fauna of lake Sapanca Basın (Sakarya, Turkey)(2007) Özuluğ, Müfit; Tarkan, Ali Serhan; Gaygusuz, Özcan; Gaygusuz, Çiğdem GürsoyTwo freshwater fish species, Phoxinus phoxinus (Linnaeus, 1758) and Gambusia holbrooki Girard, 1859, were recorded for the first time from Lake Sapanca Basin. P. phoxinus were captured from Mahmudiye stream while G. holbrooki was captured from Maşukiye stream. The measural and meristic characters of the specimens were similar to those reported elsewhere for the species. P. phoxinus known as predator of trout’s eggs was caught in big numbers in same stream with Salmo trutta macrostigma. The inclusion of these species has increased the species list of fish fauna of Lake Sapanca.Öğe Use of bone and otolith measures for size-estimation of fish in predator-prey studies(Inst Vertebrate Biology As Cr, 2007) Tarkan, Ali Serhan; Gaygusuz, Cigdem Guersoy; Gaygusuz, Oezcan; Acipinar, HasanTo estimate the size of fish taken as prey by piscivorous predators, linear or non-linear relationships between bone measures (pharyngeal, opercula, cleithra, anal and dorsal spine bones, otoliths) and body length were elaborated for eleven Eurasian cyprinid fish species captured in three lakes of Turkey: rudd Scardinius erythrophthalmus, Baltic vimba Vimba vimba, Danube bleak Chalcalburnus chalcoides, gibel carp Carassius gibelio, roach Rutilus rutilus. silver bream Blicca bjoerkna, common carp Cyprinus carpio, chub Leuciscus cephalus, Dnieper chub Petroleuciscus borysthenicus, tench Tinca tinea and tarek Alburnus tarichi (endemic species for Lake Van). All calculated regressions were highly significant, with coefficients of determination >81 % in most of cases. The results suggest that the biometric relationships between fish length and some bones (pharyngeal, opercula, cleithra) are well suited for use in prey-predator studies of all the studied species, but otoliths and the dorsal and anal spines can be used for some fish species only (rudd, Baltic vimba, roach, silver bream, gibel carp).
