Journal of Limnology and Freshwater Fisheries Research

9-18

Authors: Savaş Yılmaz, Okan Yazıcıoğlu, Ramazan Yazıcı, Nazmi Polat

The white bream, Blicca bjoerkna (L., 1758) specimens (n=434) were collected from Lake Ladik between November 2009 and October 2010 in order to determine the age, growth, and reproductive season. Fork lengths and weights of these samples varied between 11.5-24.3 cm and 22.80-259.00 g, respectively. Age estimates obtained from scales and vertebrae were compared to determine the most reliable bony structure for ageing. The precision analyses indicated that scales were the most appropriate hard structures for determining the age of white bream. Ages of all the specimens ranged from I to VI years and age group III was dominant. The parameters of the von Bertalanffy growth equations were calculated as L∞ = 32.85 cm, W∞ = 707.76 g, k = 0.11 year-1 and t0 = -2.64 year, and the growth performance index (Φ') value was computed as 2.074 for combined sexes. Fork length-weight relationship was found to be W = 0.0066 FL3.317. The mean condition factor was the highest in August and the lowest in October. The gonadosomatic index values showed that the reproduction occurred between May and June.

29-35

Authors: Soner ÇETİNKAYA, Vedat YEGEN, Fuat BİLGİN, Rahmi UYSAL, Hasan BOSTAN

In this study, some growth characteristics and relationships of Sakarya bleak inhabiting different water habitats (dam, pond and creek) in the Bilecik Province of Türkiye were examined. Sample weights ranged from 0.17 to 111.25 g. Total lengths were measured between 2.70 and 19.80 cm. According to the localities, the b values varied between 2.9469±0.07 and 3.2548±0.03. R2 values were computed between 0.850 and 0.996. The relative condition factor values were similar to each other, while the Fulton’s condition factor values ranged from 0.79±0.01 to 1.29±0.03. The length-weight (LWR) and length-length relationships (LLRs) of samples were examined. According to localities, growth type of the length - weight relationships were either isometric or positive allometric.

43-48

Authors: Cafer BULUT, Ayşegül KUBİLAY, Zübeyde HANOL BEKTAŞ, Belkıs BİRDEN

Formaldehyde is commonly used as a disinfectant and also in a control of fish disease in aquaculture sector. However, this widespread use, can lead to environmental degradation and can cause negative effects on the treated fish with. In this study 250 mg/L (1 hour) and 500 mg/L (45 min) concentrations of formaldehyde were used. From the results of the histopathological findings degeneration was determined in the epithelial cells and pilar in the gill lamellae, lymphoid infiltration interlamellar necrosis and degeneration of the muscle tissue, dilatation in the liver, congestion in veins, degeneration in hepatocytes, damage in the blood vessels of fish which were treated with formaldehyde. In conclusion; formaldehyde was found to have a negative impact in histological examination in applied rainbow trout. Therefore, it was concluded that it should be used consciously and according the needs in aquaculture.

57-61

Authors: Vedat YEĞEN, Rahmi UYSAL, Abdulkadir YAĞCI, Mehmet CESUR, Soner ÇETİNKAYA, Fuat BİLGİN, Hasan BOSTAN, Meral (Apaydın) YAĞCI

The topmouth gudgeon Pseudorasbora parva is described as most invasive fish in Europe. It’s a small cyprinid fish native to East Asia. In 1982, the existence of this species was first recorded from the Thrace region of Türkiye. Todays it is recorded from Thrace to Ceyhan region. In this study was carried out Afyonkarahisar, Bilecik, Burdur, Denizli, Eskişehir, Isparta, Konya, Kütahya and Uşak provinces between 2001 and 2013. Specimens collected from various localities in these provinces. Our results are shown P. parva has invaded many freshwater systems in Türkiye. This species has a potential threat to the diversity of the ichthyofauna of Anatolia and fish farms because of causing an increased mortality pressure on some salmonids and cyprinids, and totally inhibiting spawning of existing native fish.