Cemil Kara

Age and growth of the European catfish (Silurus glanis) in a Turkish Reservoir and comparison with introduced populations

The European catfish, Silurus glanis, is native to eastern Europe and western Asia and is among the largest freshwater fish in the world. Despite its increasing economic importance and its frequent introductions, the ecology and life-history of this species is poorly known due to the difficulty of sampling such a large species in large rivers and standing waters. Our study provides the first data on age and growth of this species in Turkish waters, where it is native. We report the length-weight relationships and age and size structure of this population, which were significantly different between females and males. A marginal increment analysis indicated that annulus formation occurred between May and June. The estimates of three growth functions (von Bertalanffy, logistic and Gompertz) are reported, with the von Bertalanffy growth providing a better fit and more realistic parameter estimates. Growth rates were significantly higher in males than in females and were overall higher compared to other native populations but similar to introduced populations of similar latitude.

Kahramanmaraş Kumaşır Gölü’nde Yaşayan Melanopsis buccinoidea buccinoidea (Olivier, 1801)’nın (Gastropoda:Melanopsidae) Konkometrik ve Sistematik Özellikleri

Bu calismada Kumasir golu’nden toplanan 60 adet Melanopsis buccinoidea buccinoidea bireyinde morfometrik olcumler yapilmistir. Ortalama olarak; kabuk yuksekligi, kabuk genisligi, apertur yuksekligi, apertur genisligi, vucut helezon yuksekligi ve spir yuksekligi sirasiyla; 25.95 mm, 12.18 mm, 14.13mm, 8.02 mm, 18.47 mm, 8.01 mm’dir. Incelenen bireylerin ortalama agirliklari ise 2.05 g’dir. Kabuk yuksekligi-kabuk agirligi iliskisi KY=20.995W0.3187 (r=0.943), kabuk genisligi-kabuk agirligi iliskisi ise KG=9.274W0.4059 ( r=0.957) olarak bulunmustur. Gol ekosisteminin devamliligi acisindan Melanopsis buccinoidea buccinoidea’ nin korunmasi gerektigi sonucuna varilmistir.