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Öğe AGE AND GROWTH OF CAPOETA ERHANI (ACTINOPTERYGII: CYPRINIFORMES: CYPRINIDAE) FROM THE MENZELET RESERVOIR, TURKEY(Wydawnictwo Akad Rolniczej W Szczecinie, 2014) Ayyildiz, Hakan; Emre, Yilmaz; Ozen, Ozcan; Yagci, AbdulkadirBackground. Capoeta erhani Turan, Kottelat et Ekmekci, 2008 has an economic importance in commercial and recreational fisheries in Turkey. Knowledge of the biology of this species is very scarce. Despite the importance of this species, no research on the population dynamics such as age and growth rates has been conducted. The aim of this study was to determine the age, growth rate, and the relations between the fish size and the otolith size for C. erhani from the Menzelet Reservoir, Turkey. Materials and methods. This study was carried out seasonally in the Menzelet Reservoir, between January and December 2012. Samples were collected using gill nets with mesh sizes ranging from 18 to 30 mm. Results. A total of 134 otoliths obtained from Capoeta erhani that ranged from 15 to 33.8 cm TL were used in the analyses. The overall male : female ratio (M : F = 1.25 : 1.00) was biased in favour of males. The Mann-Whitney test revealed significant differences between sexes, regarding TL (P < 0.05). The calculated length-weight relations were W = 0.0097TL(3.0015) (r(2)= 0.986) for females, W = 0.0054TL(3.2011) (r(2) = 0.975) for males and W = 0.0075TL(3.0892) (r(2) = 0.979) for all specimens. The von Bertalanffy growth models were L-infinity = 33.83 cm (TL), K = 0.964, t(0) = -0.573 for females; L-infinity = 32.02 cm (TL), K = 0.843, t(0) = -0.562 for males; L-infinity = 33.85 cm (TL), K = 0.821, t(0) = -0.482 for all specimens. Conclusion. This study provides the first information on age, growth, and otolith morphometric parameters of Capoeta erhani. Determining the parameters of C. erhani age and growth rates will lead to the estimates of relevant parameters of population dynamics and to better understanding of the long-term changes of the stock sizes.Öğe AGE AND GROWTH OF CAPOETA PESTAI (ACTINOPTERYGII: CYPRINIFORMES: CYPRINIDAE) IN A SMALL RIVER ENTERING LAKE EGIRDIR, TURKEY(Wydawnictwo Akad Rolniczej W Szczecinie, 2016) Emre, Yilmaz; Altin, Aytac; Ayyildiz, Hakan; Dolcu, Burak; Kucuk, Fahrettin; Ozen, OzcanBackground. Capoeta pestai (Pietschmann, 1933) is commercially important fish species in Turkey. The knowledge of the biology of this species is very scarce. This species has a 'critically endangered' status on the IUCN Red List. The objective of this study was to determine the age and growth rates of C. pestai, and to evaluate whether otolith morphometrics could be used as an age predictor. Material and methods. Fish were collected from a small river entering Lake Egirdir between January and December 2012. Fish samples were obtained from shallow parts of the river (30-40 cm depth) seasonally in a single station by using an electrofishing devise. Results. Annual growth increments were counted on the otoliths of 154 specimens, ranging from 6.2 to 26.8 cm total lengths. Estimated ages ranged from 0+ to 7+ years old. The von Bertalanffy growth curve was fitted to the age/total length data as follows: L-infinity = 47.83 cm (TL), K = 0.081, t(0) = -1.840, for females; L-infinity = 41.25 cm (TL), K = 0.086, t(0) = -1.99 for males; L-infinity = 52.45 cm (TL), K = 0.067, t(0) = -1.84 for all specimens. No significant differences in morphometric measures (length, width, and mass) were found between left and right otoliths (paired t-test, P > 0.05). Otolith length and width showed significant linear relations with the total length while otolith mass represented by power model. Conclusion. This study provides the first information on age, growth and otolith morphometric parameters of C. pestai. In addition, otolith morphometric measurements could possibly be used in future as an age predictor for C. pestai.Öğe Age and Growth of Red Porgy, Pagrus pagrus from the Island of Gokceada, North Aegean Sea(Istanbul Univ Press, Fac Aquatic Sciences, 2020) Ayyildiz, Hakan; Altin, Aytac; Kizilkaya, BayramThe aim of this study was to describe the age, growth and relationships between otolith morphometry and fish length, weight and age of the red porgy, Pagrus pagrus. This study was carried out from the shores of Gizli liman to Kefalos Cape in the north of Gokceada Island, between March and June 2018. The samples were collected at depths of 40-120 m by long lines. The 66 individuals obtained from red porgy ranged in total length (TL) from 13.5 to 50 cm. The calculated length-weight relationship was determined as W=0.016TL(2.9653) (R-2=0.98). Individual ages were macroscopically determined by counting the annuli of sagittal otoliths. Estimated ages ranged from 1-12 years. The von Bertalanffy growth curve was fitted to the age/total length data as follows: L-infinity=51.48 cm, K = 0.18 and t(0)=-0.27. The red porgy sagittal otolith length, width and mass were measured between 4.96-14.72 mm, 3.49-7.85 mm and 0.0199-0.2460 g, respectively. No significant differences in otolith morphometry were found between left and right otoliths. This study provides valuable data for the stock assessment of common pandora in the fishing grounds of Gokceada Island located in the North Aegean Sea.Öğe Age and growth rates at the early life stages of common pandora (pagellus erythrinus) based on analysis of otolith microstructure(Natl Marine Fisheries Service Scientific Publ Office, 2018) Ayyildiz, Hakan; Altin, AytacWe investigated young-of-the-year (YOY) growth, age, and hatching distributions of common pandora (Pagellus erythrinus) by analyzing otolith microstructure. This study was carried out in shallow waters (0-20 m) off the island of Gokceada, Turkey, from June 2013 through June 2014. A total of 231 YOY common pandora were measured and aged. These fish ranged from 12 to 110 mm in total length and from 38 through 242 d in age. The indices for determining variability in daily age estimates (average percentage error and coefficient of variation) were 4.9% and 3.4%, respectively. Average daily growth rate was calculated from a linear regression of the age-length data set as 0.52 mm/d. A linear relationship was found between otolith morphometric measurements (otolith length, width, and radius) and total length for YOY common pandora. The hatching times of common pandora were back-calculated to occur from February through October, and 2 main hatching cohorts were evident in spring (March) and summer (August).Öğe Daily age and growth rates of larval and juvenile annular seabream, diplodus annularis inhabiting the gökçeada shallow waters(Centenary University, 2020) Ayyildiz, Hakan; Altin, AytaçThis study was carried out between June 2013 - June 2014 from Gökçeada shallow waters (0 - 20 m). A total of 190 larvae with a total length of 2.01 mm to 10 mm and 923 juvenile annular seabream with a total length of 11-140 mm were caught by using a plankton net and beach seine. The length-weight relationships of the obtained individuals were calculated as W = 8E-06TL3.1029 (R2 = 0.975). Estimated daily ages ranged from 2 and 19 days for larvae and 18 and 296 days for juveniles. The daily growth rates of larval and juvenile annular seabreams were estimated as 0.398 mm/day and 0.371 mm/day, respectively. Hatching time of the larval annular seabream was estimated to occur during April - September period and reached maximum level in June while the juveniles continued during February - September period and reached maximum level in May. The larval and juvenile annular seabream instantaneous mortality coefficient was calculated as 0.231027 and 0.02984, which represented around 23.1% and 2.98% of daily mortality. Daily survival rates were found as 0.769 for larvae and 0.9701 for juveniles. © 2020, Centenary University. All rights reserved.Öğe Daily growth rates and hatch date distributions of common two-banded seabream, Diplodus vulgaris inhabiting the Canakkale shallow waters of Turkey(Cambridge Univ Press, 2015) Ayyildiz, Hakan; Ozen, Ozcan; Altin, AytacOtolith microstructure analysis was used to determine daily age, growth rate and hatching periods of young of the year (YOY) common two-banded seabream, Diplodus vulgaris, collected at two sites by using beach seine from Canakkale shallow waters between January and December 2007. Total length of the YOY D. vulgaris was between 12 and 86 mm and the daily ages ranged between 42 and 313 days. Somatic growth rate estimated by fitting a linear regression to the age-length data set was calculated as 0.273 mm day(-1). According to the length-age regression analysis, maximum daily growth rates were found 0.277 mm day(-1) in the lowest sea temperature period and minimum values of 0.274 mm day(-1) were observed in the declining sea temperature period. Analysis of covariance indicated that there were no significant differences in the linear growth equations for the two cohorts (F = 0.4008, P = 0.527). Hatching period of the YOY was estimated to occur between October and March with relatively higher frequency in January. This study has shown that YOY D. vulgaris is a winter spawner in the Canakkale shallow waters.Öğe Feeding habits and diet overlap of juveniles of 2 sparids, Diplodus puntazzo (Walbaum, 1792) and Diplodus vulgaris (Geoffroy Saint-Hilaire, 1817), from the North Aegean Sea of Turkey(Tubitak Scientific & Technological Research Council Turkey, 2015) Altin, Aytac; Ozen, Ozcan; Ayyildiz, Hakan; Ayaz, AdnanThe stomach contents of juvenile sharpsnout seabream, Diplodus puntazzo, and juvenile two-banded seabream, Diplodus vulgaris, were investigated in order to determine feeding habits and diet overlap among them. Fish were collected from October 2008 to August 2009 using a beach seine net from the Canakkale coasts of Turkey. A total of 129 juvenile D. puntazzo (ranging from 13 mm to 77 mm total length) and 951 D. vulgaris (ranging from 15 mm to 97 mm total length) were collected during the sampling periods in the study area. The stomach content analyses showed that the diet of both species mainly comprised copepods and amphipods. In addition, algae were found in the stomach contents. No significant differences were found between the feeding habits of juvenile D. vulgaris and D. puntazzo (ANOSIM; global R statistic = -0.0158; P > 0.05). An important overlap in the diet calculated using the Schoener index was recorded as 0.75 for D. puntazzo and D. vulgaris. Consequently, there was a significant diet overlap and competition for available resources among the feeding habits of D. vulgaris and D. puntazzo in juvenile periods.Öğe FEEDING HABITS OF THE MARBLED GOBY, POMATOSCHISTUS MARMORATUS (ACTINOPTERYGII: PERCIFORMES: GOBIIDAE), IN THE CANAKKALE STRAIT, NORTHERN AEGEAN SEA, TURKEY(Wydawnictwo Akad Rolniczej W Szczecinie, 2015) Altin, Aytac; Ozen, Ozcan; Ayyildiz, Hakan; Daban, I. BurakPomatoschistus marmoratus (Risso, 1810) is a small demersal fish and one of the dominant species inhabiting shallow waters of the Mediterranean. Information, however, on their feeding habits are still scarce. In this study, the stomach contents of P. marmoratus were investigated in order to determine feeding habits according to seasons and sizes. The fish were collected monthly from 3 stations between October 2008 and August 2009, using a beach seine, from the shallow waters of the Canakkale Strait, Turkey. A total of 383 P. marmoratus, ranging from 13 to 69 mm TL, were analysed. The most important prey items in the stomach contents were copepods and amphipods. The numerical abundance of each food item in the stomach contents varied significantly with season. The diet of juvenile P. marmoratus consisted mainly of copepods. The occurrence of largest prey items such as amphipods and bivalves appeared relatively higher in adults. However, no significant differences were found between the feeding habits of juveniles and adults.Öğe First record of Gobius couchi Miller & El-Tawil, 1974 from the Aegean Sea (Pisces: Gobiidae)(Max Kasparek Verlag, 2009) Ozen, Oezcan; Ayyildiz, Hakan; Tuncay, Dogan; Bilecenoglu, Murat[Anstract Not Available]Öğe Fish biodiversity in the shallow waters around the Gokceada Island, Turkey(Arman Darya Inc, 2020) Altin, Aytac; Ayyildiz, Hakan; Kale, SemihThe aim of the current study is to determine the fish biodiversity in the shallow waters (0 - 20 m) of Gokceada in the North Aegean Sea. The samples were collected monthly between June 2013 - June 2014 using by a beach seine (0 - 2 m) and beam trawl (5 - 20 m). Field sampling was carried out in two stages. A preliminary sampling survey was carried out in the first phase (March-April 2013). During this period, sampling was conducted in each station around the entire island where sampling gear was feasible to use, and the most productive sampling stations were determined. The second stage was the biodiversity monitoring work. During the study period, 13-monthly sampling surveys were carried out at six seine and dredge stations around the island. During the whole period, a total of 30509 individuals belonging to 80 species were sampled. From the seine samplings (0-2 m), 18702 individuals from 40 species were obtained. The beam trawl samplings (5-10 and 10-20 m) identified 11807 individuals from 66 species. Biodiversity indices were calculated, and species diversities and abundances were determined for the seasons. The most copious seasons in terms of number of species abundance was identified in fall and summer. Fish species diversity and abundance maps were generated for each station. As a result, it was determined that the coastal ecosystems of Gokceada, northern Aegean Sea, incorporated many important habitats that is rich in biodiversity. In addition, many commercial species that had been over-exploited in the region was determined to use these coastal habitats for feeding, breeding, sheltering, and growing.Öğe Growth and hatching of annular seabream, Diplodus annularis, from Turkey determined from otolith microstructure(Cambridge Univ Press, 2014) Ayyildiz, Hakan; Ozen, Ozcan; Altin, AytacOtolith microstructure analysis was used to determine daily growth rate and hatching periods of young of the year (YOY) annular seabream, Diplodus annularis, collected by using beach seine from Canakkale shallow waters between January and December 2007. Total length of the YOY D. annularis was between 20 and 85 mm and the daily ages ranged between 27 and 205 d. Somatic growth rate, estimated by fitting a linear regression to the age-length data set, was calculated as 0.369 mm d(-1). Seasonal changes in the growth rate of the YOY D. annularis have been found to be 0.381, 0.369, 0.357 and 0.308 mm d(-1) for individuals that hatched in spring, summer, autumn and winter, respectively. Analysis of covariance indicated that there were no significant differences (P > 0.05) in the growth rates between the seasons. Hatching period of the YOY D. annularis was estimated to occur between March and September, with relatively higher hatching frequency in June.Öğe Growth, mortality and hatch-date distributions of striped sea bream Lithognathus mormyrus inhabiting the Canakkale Strait, Turkey(Cambridge Univ Press, 2014) Ayyildiz, Hakan; Ozen, Ozcan; Altin, AytacThis paper studies age, growth and hatch date distributions of young of the year striped sea bream Lithognathus mormyrus from Canakkale near shores by using a beach seine during September 2006-December 2007. Using otolith microstructure analysis, a total of 416 specimens ranging from 20 to 103mm L-T were aged and found to be between 30 and 307 days old. Average growth rates were estimated to 0.325mmd(-1). The juvenile instantaneous mortality coefficient was found to be 0.0219, which corresponds to a daily mortality of 2.16%. The hatching period of the striped sea bream was determined to occur between April and January, with relatively higher hatching frequency in August.Öğe Hatching Time and Early Growth of Diplodus sargus sargus Inhabiting a Coastal Area of Gokceada Island, Turkey(Springer International Publishing Ag, 2020) Ayyildiz, Hakan; Altin, AytacDaily growth increments in sagittal otoliths were used to estimate the age and growth of young of the year (YOY) white seabream, Diplodus sargus sargus collected between June 2013 and June 2014 at 6 different locations in the shallow waters (<20 m) off Gokceada, Turkey. Estimated ages from otolith daily growth increments (DGI) were found 42-238 days old. The mean daily growth rate of YOY D. sargus sargus was estimated as 0.046 cm/day. ANCOVA indicated that there was significant difference in daily growth rates between the locations (F = 22.92, df = 5, P < 0.001). The maximum daily growth rate of 0.055 cm/day was found in the location 2, while the minimum value of 0.037 cm/day was observed in the location 4. Hatching time was determined by subtracting the daily age of the fish from the sampling date and then hatch date frequency distributions were determined to occur from January through June, and 2 main hatching peaks were observed from the different locations. Linear relationships between otolith morphology (otolith length; OL, width; OW and radius; OR) and fish length (TL) were obtained.Öğe Length-weight relationships of forty-nine fish species from shallow waters of Gokceada Island, northern Aegean Sea(Tubitak Scientific & Technological Research Council Turkey, 2015) Altin, Aytac; Ayyildiz, Hakan; Kale, Semih; Alver, CenkLength-weight relationships (LWRs) of 49 fish species belonging to 18 families from the shallow waters (0-20 m) of Gokceada Island were reported. Fish specimens were sampled monthly with a beach seine (0-2 m) and beam trawl (5-20 m) between June 2013 and June 2014. The b values estimates varied between 2.66 and 3.59. Five of the 49 species (Arnoglossus kessleri, Scorpaena maderensis, Symphodus ocellatus, Symphodus rostratus, and Gobius geniporus) presented maximum length values that exceeded their maximum lengths listed in FishBase.Öğe Monofilament gillnet selectivity parameters for European chub (Leuciscus cephalus L.1758) in Atikhisar Reservoir, Canakkale, Turkey(Asian Network for Scientific Information, 2007) Ozekinci, Ugur; Altinagac, Ugur; Ayaz, Adnan; Cengiz, Ozgur; Ayyildiz, Hakan; Kaya, Hasan; Odabasi, DenizSelectivity parameters of gillnets used for fish catching are very important for fisheries management in lakes. The main purpose of the present study was to estimate the selectivity parameters of monofilament gill nets mesh size of 56, 64 and 72 mm (stretched mesh size) used for European chub (Leuciscus cephalus L.1758) in Atikhisar Reservoir, Canakkale, Turkey. The indirect method proposed by Holt was used for the estimation of the selectivity parameters. The common selection factors and common standard deviation of monofilament gill nets were determined as 4.25 and 2.37, respectively. For sustainable fisheries of european chub, the minimum mesh size of monofilament gill nets must be greater than 47 mm stretched mesh size. © 2007 Asian Network for Scientific Information.Öğe Spatial distribution modelling of juvenile common pandora (pagellus erythrinus linnaeus, 1758) in relation to habitat in the shallow waters of gökçeada using GIS(CEUR-WS, 2015) Kale, Semih; Altin, Aytac; Ayyildiz, Hakan; Ozen, OzcanThe distribution of juvenile Pagellus erythrinus (Linnaeus, 1758) species was studied by the abundance, density and habitat preferences in the shallow waters of Gökçeada. Fish samples were obtained in experimental beach seine and beam trawl surveys carried out between 2013 June to 2014 May in the shallow waters of Gökçeada. To understand the habitat preferences of the species, sediment samples were collected and sediment composition was determined by grain size distribution analysis. The spatial distribution of juvenile Pagellus erythrinus species in relation to the habitat structure was estimated and modelled using Geographic Information System (GIS) and geostatistical tools. It was observed that juvenile Pagellus erythrinus species prefer the rocky areas which in 5-10 m water depth in the shallow waters of Gökçeada. Copyright © 2015 for the individual papers by the papers' authors.Öğe Temporal Variations of the Demersal Fish Community in the Shallow Waters of Canakkale Strait, North Aegean Sea, during the Course of a Mucilage Event(Central Fisheries Research Inst, 2015) Altin, Aytac; Ozen, Ozcan; Ayyildiz, HakanThe main aim of this study was to determine the mucilage event effect on the temporal variations of the shallow water demersal fish community in the Canakkale Strait. Sixty-one different demersal fish species were collected with a beach seine between September 2006 and August 2009. Mucilage event was observed between September 2007 and July 2008 (mucilage period) in the shallow waters of Canakkale Strait. Species abundance and richness decreased in winter and increased in spring and in summer and was related to water temperature variations. Demersal fish species composition was significantly different between seasons but these differences were mainly related to water temperature variations. For the same seasons in different years (pre-mucilage, during mucilage, and post-mucilage), no differences of fish abundance and species richness were evident. In conclusion, the fish community data from our shallow water samplings during the course of a mucilage event does not suggest any significant change in the abundance and species richness of the shallow water demersal fish assemblage in Canakkale Strait.Öğe Validating daily otolith increment formation in young of the year pagellus acarne in the Çanakkale region(Arman Darya Inc, 2024) Ayyildiz, Hakan; Kurtkaya, Emre; Celik, Pinar; Altin, AytacAccurate age estimation is essential for population dynamics modeling and fisheries management. Otoliths serve as a critical resource for age determination in ichthyological studies, capitalizing on the embedded growth increments. The periodicity of these increments, however, requires thorough validation to confirm the accuracy of age assessments. This study validated daily increment deposition in sagittal otoliths of young-of-year Pagellus acarne from & Ccedil;anakkale, Turkey using Alizarin Red S (ARS), a fluorescent calcium-binding marker. Specimens (n=107; 1.8-4.7cm TL) were exposed to ARS concentrations of 0 (control), 50, 100, 150, 200, and 300mg/L for 24h, then reared 13 days. After a recovery period of 13 days, the second dyeing was performed with the aim of having a specific fluorescent mark to test the 13 rings found between the 2 fluorescent marks. Otoliths were examined under fluorescent microscopy. ARS marks were detectable in 81.57% of otoliths at >= 100mg/L, with the highest visibility at 300mg/L. Survival exceeded 84.2% across treatments. Increment counts between the first and second ARS marks (13 days) and from the second mark to the edge (20 days) matched elapsed time. Ages from wild fish (n=95) ranged 39-201 days with a growth rate of 0.176mm/day. This research demonstrates ARS is an effective, low-impact tool for periodicity validation and provides the basis for accurate age determination and population modeling of this ecologically important species in the region.Öğe Validation of Daily Growth Increment Deposition in Sagittal Otoliths of the Young of the Year Lithognathus mormyrus(Springer Int Publ Ag, 2024) Ayyildiz, Hakan; Kurtkaya, Emre; Celik, Pinar; Altin, Aytac; Bulut, MusaThis paper aims to validate the micro increment deposition in the sagittal otoliths of young of the year (YOY) Lithognathus mormyrus in the shallow waters of canakkale, Turkey. Wild YOY specimens of L. mormyrus were captured and reared to validate the daily micro increment formation in sagittal otoliths. The formation of daily sagittal micro increments was validated using by alizarin Red S (ARS), at a concentration of 0 (control), 50 mg/lt, 100 mg/lt, 150 mg/lt, 200 mg/lt and 300 mg/lt. The natural photoperiod was applied, and no food was given throughout the marking period. The tanks kept strongly aerated to maintain the pH similar to 7. YOY fish were kept in different aquariums for 17 days post-dyeing and then re-dyeing as before and kept alive for a further 20 days. ARS marks were clearly observed in 71.7% of the YOY L. mormyrus sagittal otoliths under a fluorescent microscope. However, no mark could be observed in any of the samples of 50 mg/lt ARS treatment. Chi2 tests revealed that the linear regressions of the number of micro increments between ARS marks against number of elapsed times was not statistically significant. This result showed that micro increment deposition on the sagitta were laid down daily under the experimental conditions and can be used to detect the daily age information for YOY L. mormyrus.
