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    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, Abdulkadir
    Background. 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.
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    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, Ozcan
    Background. 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.
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    Effects of Ulva Meal on Growth Performance of Gilthead Seabream (Sparus aurata) at Different Levels of Dietary Lipid
    (Central Fisheries Research Inst, 2013) Emre, Yilmaz; Ergün, Sebahattin; Kurtoglu, Adem; Guroy, Betul; Guroy, Derya
    A nutrition trial was carried out to investigate the effects of inclusion of Ulva meal at different dietary lipid levels on growth performance, feed utilization and body composition of juvenile gilthead seabream, Sparus aurata. In this study, gilthead seabream with an average weight of 8.5 +/- 0.01 g were fed experimental diets for 7 weeks. The Eight isonitrogenous diets (crude protein 50%) were designed to provide 13% (13), 16% (16), 19% (19) and 22% (22) crude lipid with or without 4% inclusion of Ulva meal (13U, 16U, 19U and 22U). Final mean weight and specific growth rate (SGR) of gilthead seabream fed 22L-U were higher than that of 13L and 13L-U groups. The mean feed conversion ratio varied from 0.92 (22L-U) and 1.33 (13L and 13L-U). The present study shows that dietary low level (4%) Ulva meal at all dietary lipid levels could be used in juvenile gilthead seabream without causing any adverse effects on growth and feed utilization.