Browsing by Author "Çetinkaya, O."

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A Freshwater Mussel Species Unio Stevenianus Krynicki 1837 (Mollusca: Bivalvia: Unionidae) From the River Karasu Flowing Into Lake Van, Turkey
(TUBITAK, 1996) Çetinkaya, O.
Lake Van, the biggest soda lake of the earth and its drainage area is located in Eastern Turkey. The River Karasu is one of the main inlets of the lake. In this study, a freshwater mussel species was collected from downstream parts of The River Karasu and identified as Unio stevenianus Krynicki 1837. Morphological investigaitons and morphometric measurements were carried out. Some characteristics of the habitat as well as its ecological relations with other species and its environment were observed. This species is a new record for this basin and for Turkey among fresh water bivalves.
Histological Investigation of Gonad Development of Chalcalburnus Tarichi (P., 1811)
(1999) Ünal, G.; Çetinkaya, O.; Elp, M.
In this study, gonad development of Chalcalburnus tarichi, an anadromus, endemic fish species of the Lake Van and its inlets was histologically investigated. During oogenesis, six different development phases were histologically identified: chromatin-nucleolus, perinuclear, cortical alveolar, vitellogenic, ripening and ovulation phases. The diameters of oocytes were determined between 31 to 957 μm until the ovulation phase. According to the investigated sepcimens, vitellogenic phase started onward October and first ovulation was taken place in May-June 36 months and older females. It was found that some unspawned ova remained and formed atretic follicles in ovary after ovulation. Three different development phases were observed during spermatogenesis in testes: as unripened, ripening and ripened. Sperms started to form onward December and were released in May-June by 36 months and older males.
Histological Study of the Organogenesis of the Digestive System and Swim Bladder of the Chalcalburnus Tarichi Pallas, 1811 (Cyprinidae)
(2001) Ünal, G.; Çetinkaya, O.; Kankaya, E.; Elp, M.
The histological development of the digestive system and swim bladder of Chalcalburnus tarichi larvae and their histology in adults were studied under light microscopy. After hatching, the digestive tract is a simple undifferentiated tube. Exogenous feeding started on the 6th day. The yolk sac was absorbed completely on the 9th day. The goblet cells appeared first in the bucco-pharyngeal cavity and oesophagus on the 4th day, in the anterior on the 9th day and in the posterior intestine on the 5th day. The digestive tract was differentiated as the buccal cavity, pharynx, oesophagus post-eosophageal swelling and intestine on the 5th day. At the same time taste buds and pharyngeal teeth also started to form. In the oesophagus, the circular muscle was observed on the 9th day and the longitudinal muscle in one-year-old fish. In the intestine, the circular muscle was observed on the 35th day and the longitudinal muscle in two-year-old individuals. The wall of the digestive tract is composed of epithelial, submucosa, muscle and serosa layers. The liver lobules formed on the 3rd day and the cells began to reserve glycogen on the 10th day. The pancreatic acina formed on the 5th day and the tubular in one-year-old fish. The liver and pancreas ducts opened into the anterior intestine before the exogenous feeding started. The swim bladder was observed as one lobuled on the 4.5th day and two lobuled on the 35th day.
A Study of the Some Growth Parameters of Barbel (Barbus Plebejus Ercisianus, Karaman, 1971) Living in the Koçköprü Dam Lake Basin-Turkey
(2006) Elp, M.; Çetinkaya, O.; Kankaya, E.; Şen, F.; Ünal, G.
This study was carried out to determine some growth parameters of barbel populations living in the Koçköprü Dam Lake and its inlets between April 2000 and October 2001. The barbel species are shown a widespread distribution in Turkey. The species is native in study area, has economic value and is fished local fishermen. A total of 324 individuals were sampled. The maximum age of individuals was determined as VII, fork length was 33.8 cm and weight was 428.0 g. Females were found larger than males in size. Condition factor values were determined as 1.210±0.009 for males, 1.266±0.017 for females and 1.293±0.030 for juveniles. In overall, condition factor of females was higher than males. Length-weight relationship was determined for whole samples as logW = -1.841+2.934 logL. © 2006 Asian Network for Scientific Information.