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Bio-ecological studies and life-history traits of small-bodied fishes are critical for the understanding of their ecolog-ical role as well as the assessment of their position and continuity in the ecosystems. The current study goals to present initial data on growth and feeding habit of small-bodied Petroleuciscus borysthenicus inhabited in an island ecosystem (Gökçeada, Turkey). During the seasonally 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 signifi-cant difference from the ratio of 1:1 (2=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 Dip-tera (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, respectively. The results showed that P. borysthenicus was more selective on conveniently accessible food materials in the environment and its food pref-erence was affected by seasonal food supply.

Freshwater 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.

This study aims to investigate the length-weight (LWRs) and length-length relationships (LLRs) of three endemic freshwater fish species (Squalius recurvirostris, Squalius carinus and Capoeta turani) living in Turkey. Fish samples were captured with backpack electro-shocker from June 2006 to October 2010. The calculated values of parameter b in the LWRs were 3.363 and 3.045 for S. recurvirostris (Eber and Ilgın Lake populations, respectively), 3.275 for S. carinus and 3.111 for C. turani. The coefficients of correlation (r) for all the LLR equations were greater than 0.95. The growth parameters of S. recurvirostris is provided for the first time in this study

Alburnus carinatus Battalgil, 1941 is an endangered fish species, which has a narrow distribution range in two shallow lake basins in northwest Anatolia. The present study aimed to describe the reproductive potential of this endemic fish with the relationships between body size, weight, and fecundity. A total of 101 female A. carinatus were captured from the Manyas Lake between January and June 2019. The standard length and body weight of these samples varied between 8.1– 15.0 cm and 9.38–65.45 g, respectively. The length-weight relationship of the female A. carinatus was calculated as W = 0.020 × SL2.959 (r2 = 0.866) with isometric growth. Absolute fecundity ranged from 1512 eggs (8.1 cm SL) to 3203 eggs (10.3 cm SL) with a mean of 2281 eggs (SD = 415.2). Fecundity–length relationship was F = 5.86 × SL2.67 (r2 = 0.702) and the fecundity–length relationship was F = 476.6 + 116.5 × L (r2 = 0.688). Mean relative fecundity was calculated as 244 eggs.cm−1 (SD = 34.1) (ranged from 179.8 to 310.9 eggs.cm−1) and 148 eggs.g−1 (SD = 14.9) (ranged from 115.1 to 171.8 eggs.g−1).

The length‐weight relationships (LWRs) of Alburnus istanbulensis Battalgil, 1941, Barbus tauricus Kessler, 1877, Cobitis pontica Vasil'eva & Vasil'ev, 2006, Cobitis strumicae Karaman, 1955, Gobio bulgaricus Drensky, 1926, Phoxinus strandjae Drensky, 1926 and Squalius orpheus Kottelat & Economidis, 2006 were analysed. Fish samples were collected by electroshocker (SAMUS 725 G and SAMUS 725 M portable electroshockers; frequency 50–55 Hz; 30–70 cm fishing depth) in some water bodies in Turkish Thrace from March 2012 to August 2017. The values of parameter b in the LWR equations varied from 2.916 (B. tauricus) to 3.336 (P. strandjae). This study also provides a new maximum length data for A. istanbulensis, G. bulgaricus, P. strandjae and S. orpheus.

Bu calisma ile, hem Avrupa hem de Asya kitalarinin etkisinde kalan Istanbul ilinin ic su balik faunasinin belirlenmesi amaclanmistir. Balik orneklemesi lotik ve lentik biyotoplardaki 136 farkli lokalitede DC Elektrosoker ve sade ag kullanilarak gerceklestirilmistir. Calisma sonucunda, Atherinidae, Centrarchidae, Clupeidae, Cobitidae, Cyprinidae, Esocidae, Gasterosteidae, Gobiidae, Percidae, Poecilidae, Salmonidae ve Syngnathidae olmak uzere 12 familyaya ait toplam 38 takson tespit edilmistir. Calisma alaninda, 20 takson ile Cyprinidae en fazla tur cesitliligine sahip iken, Atherinidae, Centrarchidae, Clupeidae, Esocidae, Gasterosteidae, Poecilidae, Salmonidae ve Syngnathidae familyalari birer tur ile temsil edilmistir. En yaygin rastlanan turler Cyprinidae familyasindan Petroleuciscus borysthenicus (Kessler, 1859), Rhodeus amarus (Bloch, 1782) ve Gobio kovatschevi Chichkoff 1937’dir. Bu calismayla Istanbul balik faunasi icin Cobitis strumicae Karaman, 1955 , Alburnoides kosswigi Turan, Kaya, Baycelebi, Bektas & Ekmekci, 2017 ve Salmo coruhensis Turan, Kottelat & Engin, 2010 turleri ilk defa bildirilmektedir. Elde edilemeyen 4 turle birlikte Istanbul’da yasayan ic su baligi turu sayisi 42 olmustur.

The aims of the study are to determine what the organisms Barbus cyclolepis consume as food in its feeding environments and to compare prey consumption with prey abundance in the environment. The study was conducted in the Istranca Stream located in Istanbul (Turkey) during the spring and summer of 2012. A total of 142 B. cyclolepis specimens were captured and it is determined that 94 of them had full digestive tracts. Diet analyses of B. cyclolepis showed that its food spectrum consisted of 11 different food types, and the species was found to feed on insects, mainly Diptera (IRI%= 92.26%). The most abundant macroinvertebrate organisms in the environment were Diptera and Gastropoda. The electivity index of B. cyclolepis was positive for Diptera in the spring (E= 0.49), but the value was below the expected value of 0.6 for high selectivity. The electivity values for other macroinvertebrate groups, consumed in low proportions, were negative. In summer, the fish fed on Diptera, Plecoptera, and Trichoptera, but a high electivity index value was found only for Trichoptera (E= 0.87). Results showed that B. cyclolepis mainly consumed Diptera as food and did not consume Gastropoda, although it is the second most abundant macroinvertebrate group in the environment. A relationship was determined between the proportion of food groups consumed in the digestive tracts of fish and the ratios of macroinvertebrates in the environment, and as a result, it was specified that the fish was selective on Diptera.

This study aims to investigate the length-weight (LWRs) and length-length relationships (LLRs) of three endemic freshwater fish species (Squalius recurvirostris, Squalius carinus and Capoeta turani) living in Turkey. Fish samples were captured with backpack electro-shocker from June 2006 to October 2010. The calculated values of parameter b in the LWRs were 3.363 and 3.045 for S. recurvirostris (Eber and Ilgın Lake populations, respectively), 3.275 for S. carinus and 3.111 for C. turani. The coefficients of correlation (r) for all the LLR equations were greater than 0.95. The growth parameters of S. recurvirostris is provided for the first time in this study.

Pseudophoxinus cilicicus, new species, is described from the Arsuz, Ceyhan and Seyhan river drainages in the Gulf of İskenderun. It is distinguished from other members of the Pseudophoxinus zeregi species group by having a complete lateral line with 38–45 + 2–3 scales, the lower lip usually slightly projecting beyond the tip of the upper lip, a prominent black stripe along the flank, and no black pigments below the lateral line. Pseudophoxinus cilicicus is distinguished from P. zekayi by a minimum K2P distance of 3.8% based on the mitochondrial DNA barcode region. Pseudophoxinus atropatenus and P. sojuchbulagi are returned to the genus Rutilus.

Sac, Gulsah/0000-0001-9988-1116; OZULUG, MUFIT/0000-0002-1437-3890 WOS: 000470925100017 Pseudophoxinus firati was described from one spring in the upper Euphrates River drainage in Turkey. Here we record this species from seven additional sites, three in the upper Euphrates drainage, one in the upper Seyhan and three in the upper Ceyhan River drainages. These findings largely expand the distribution area of the species and its habitats are discussed.

Sac, Gulsah/0000-0001-9988-1116; SARI, Hasan M./0000-0003-1000-514X; OZULUG, MUFIT/0000-0002-1437-3890, WOS: 000496712200008, In this study, it was aimed to determine the fish fauna of inland waters that are located in the Thrace region of Turkey and affected by the Black Sea and European fauna. the field surveys were carried out in 40 different locations in lotic and lentic biotopes located in the east of the Yildiz Mountains, between the Yalikoy in the south and the Rezve Stream in the north. Fish sampling was performed by using DC Electroshocker, gillnet, trammel-net, seine-net and fyke-net in April-September 2000, May-July 2001 and July 2009. A total of 33 taxa belonging to 14 families was identified; Acheilognathidae, Atherinidae, Centrarchidae, Clupeidae, Cobitidae, Cyprinidae, Gasterosteidae, Gobiidae, Gobionidae, Leuciscidae, Mugilidae, Poecilidae, Salmonidae and Syngnathidae. in the study area, Leuciscidae has the highest species richness with 10 taxa, while Acheilognathidae, Atherinidae, Centrarchidae, Clupeidae, Cobitidae, Gasterosteidae, Gobionidae, Poecilidae and Syngnathidae families are represented by a single species. the most common found fish species are Barbus tauricus, Gobio kovatschevi, Alburnus istanbulensis and Petroleuciscus borysthenicus. in terms of numbers of specimens, Gambusia holbrooki was followed by Phoxinus strandjae, Alburnoides tzanevi, Barbus tauricus and Alburnus istanbulensis.

Bu calismada, Buyukcekmece Rezervuari'nda yasayan 11 tatlisu baligi turunun boy-agirlik ve boy-boy iliskileri ile kondisyon faktoru degerleri tespit edilmistir. Balik ornekleri, Mart 2009 ve Subat 2010 tarihleri arasinda farkli ag goz acikliklarina sahip galsama aglari ile aylik olarak yakalanmistir. Balik turlerinin boy-agirlik iliskilerinden elde edilen b degerleri 2,727±0,020 ile 3,381±0,001 arasinda degismistir. Kondisyon faktoru en dusuk 0,74±0,08 olarak C. taenia turunde ve en yuksek 1,72±0,15 olarak C. gibelio turunde tespit edilmistir.

Roach Rutilus rutilus (Linnaeus, 1758) is a very common fish species for Turkish inland waters, especially in Buyukcekmece Reservoir (Istanbul). The species is one of the most caught fish species and holds economic consumption value even though it is mostly infected by Ligula intestinalis (Linnaeus, 1758), a pseudophyllidean cestode causing severe pathological effects on fishes. The aim of the study was to determine the presence of L. intestinalis plerocercoids in its fish host R. rutilus and investigate the effects of the parasite on the condition of the fish. With this purpose, the fish specimens have captured from Buyukcekmece Reservoir with using gillnets having different mesh sizes (10×10 mm, 20×20 mm, 30×30 mm, 40×40 mm and 50×50 mm) from March 2009 to February 2010. The fork length and body weight of fish specimens (n=1857) were varied between 6.0–29.2 cm and 2.53 – 561.00 g, respectively. In total, 4.52% of specimens were infected by the plerocercoids. Infection by L. intestinalis was observed during summer, autumn and winter months but not spring. P arasite-host index (PSI %), prevalence (%) and mean intensity of plerocercoids for infected fishes were calculated, monthly. PSI (%) was estimated maximum in January as 18.49% while prevalence (%) was 32.31% in July and mean intensity of plerocercoids is 6.0 in October. Statistically s ignificant differences between K values of non-infected and infected specimens among length groups and months were recorded (Mann-Whitney U Test, p

GAYGUSUZ, Ozcan/0000-0001-6861-6221; Copp, Gordon/0000-0002-4112-3440; Gaygusuz, Ozcan/0000-0001-6861-6221; Sac, Gulsah/0000-0001-9988-1116; Yapici, Sercan/0000-0003-2288-5084; Tarkan, Ali Serhan/0000-0001-8628-0514; Filiz, Halit/0000-0003-0096-6123 WOS: 000301429900009 The underlying mechanisms responsible for ecological plasticity and consequent invasive character of non-native freshwater fish species, variations in growth and life history traits in gibel carp Carassius gibelio (Bloch) were compared in natural and artificial water bodies of Turkey. Females significantly outnumbered males in all natural and most artificial waters. Discriminate function analysis differentiated gibel populations into three separate groups (natural lakes, artificial water bodies and running waters), with significant differences among separated groups in growth index, standard length and age at maturity, relative fecundity and gonado-somatic index, but not in egg diameter and both generalised and relative condition. Growth features (e.g. growth index and relative condition) and reproductive features (e.g. relative and absolute fecundity) positively correlated with water body area. No correlations were found for any growth or life history trait with depth, latitude and altitude. With the exception of smaller size at maturity, all traits were higher in populations from artificial water bodies than those inhabiting running waters, suggesting gibel carp is required to exert more reproductive effort to invade natural ecosystems than artificial waters. Mugla UniversityMugla Sitki Kocman University [09/28]; Istanbul UniversityIstanbul University [BYPF-6-6/160606]; UK Department for Environment, Food & Rural Affairs (Defra)Department for Environment, Food & Rural Affairs (DEFRA) Elaborated within the framework of an international network initiated with a NATO Science Programme 'Collaborative Linkage Grant' (awarded to GHC) on the use of life-history traits to assess the risks of non-native fishes, the present study was funded jointly by Mugla University (Project No: 09/28), Istanbul University (Project No: BYPF-6-6/160606), with the participation of GHC funded by the UK Department for Environment, Food & Rural Affairs (Defra). Special thanks go to N. Gokalp and members of Ildeniz Fisheries for assistance in the field.

Gibel carp, Carassius gibelio (Bloch), impacts on native fish species have been reported but little studied despite a long history of introductions in Europe. This species is able to reproduce gynogenetically, which involves the use of sperm from males of other species to activate egg development, so reproductive competition is a likely but virtually unstudied impact of gibel carp on native fishes. This study evaluates the impact of introduced C. gibelio on the population biology of native fishes over a 6-year period in a mesotrophic drinking water reservoir in north-western Turkey. A dramatic decrease in the relative density (i.e. catch per unit effort) of native species correlated significantly with an increase in C. gibelio relative density. Growth characteristics (back-calculated ages, growth index and relative condition) and length at maturity did not differ significantly among years in C. gibelio and native fishes. Relative density, duration of spawning, reproductive effort and gonado-somatic index of C. gibelio increased with some water quality variables (total phosphorus (TP); chlorophyll-a (Chl-a)) and coincided with decreasing trends for natives. However, TP and Chl-a were not correlated with growth features in C. gibelio or natives fishes. The results suggest that the decline in the reservoir's native cyprinid populations is likely due to a combination of degrading environmental conditions and a disparity in reproductive effort, with introduced C. gibelio invasion facilitated by gynogenetic reproduction and an observed interference with native fishes during spawning.

The big-scale sand smelt, Atherina boyeri Risso, 1810 was recorded for the first time from Bü yü kç ekmece Reservoir (İstanbul, Turkey) in 1982. However, recent studies on the fish fauna of Bü yü kç ekmece Reservoir indicated that A. boyeri did not exist in the reservoir. In the present study, which was originally planned for determining biological features of perch, Perca fluviatilis Linnaeus, 1758 in the reservoir, existence of A. boyeri was determined in the stomach contents of two P. fluviatilis individuals captured in October and November 2009. Possible reasons for reappearance of the species are discussed.

As First Revisers, we give priority to Aphanius fontinalis over A. altus and A. litoralis and to A. meridionalis over A. parvus. A neotype is designated from Lake Egirdir for Aphanius iconii . Family groups in the deeply polyphyletic fish family Cyprinodontidae are discussed. Aphaniidae, Cubanichthyidae and Orestiidae are proposed as distinct families, restricting the family Cyprinodontidae to the New World genera Cualac , Cyprinodon , Floridichthys , Jordanella and Megupsilon.

Five freshwater fishes, Carassius gibelio (Bloch, 1782), Gobio bulgaricus Drensky, 1926, Leucaspius delineatus (Heckel, 1843) Phoxinus strandjae Drensky, 1926 and Rutilus rutilus (Linnaeus, 1758) were recorded for the first time for Istranca Stream which is emptying to Lake Durusu in ?stanbul. With the result of present study, the number of the fish species living in the basin has increased to 33.

WOS: 000264185900019 Length-weight relationships are given on six freshwater fish species (Phoxinus phoxinus, Cobitis vardarensis, Neogobius gymnotrachelus, Proterorhinus marmoratus, Petroleuciscus borysthenicus and Gambusia holbrooki) from four streams flowing into Lake Sapanca, north-western Turkey. Istanbul UniversityIstanbul University [BYPF-6-6/160606)] We are greatly indebted to Carl Smith and Rowena Spence, who kindly checked the language in the manuscript. We also would like to thank Martin Reichard, who helped us in the field sampling. This work was supported by Research Fund of the Istanbul University (Project Number BYPF-6-6/160606).