Bu çal›flmada, kababurun bal›¤› (Chondrostoma regium Heckel, 1843)’n›n tüketti¤i besin çeflitlerinin nisbî önemini analiz etmek amaçlanm›flt›r. 145 kababurun bal›¤› örne¤i Nisan 1993 – Mart 1994 tarihleri aras›nda Suat U¤urlu Baraj Gölü’nden yakalanm›flt›r. Kabababurun bal›¤›n›n besin olarak tüketti¤i organizmalar› tan›mlamak için mide içeri¤i analiz metodu kullan›lm›flt›r. Besin miktarlar›n›n nisbî ölçümleri iki farkl› yaklafl›mla hesaplanm›flt›r. Bunlar; nisbî önem indeksi (IRI) ve geometrik önem indeksleridir (GII). Bu bileflik indislerden elde edilen sonuçlar karfl›laflt›r›lm›fl ve besin tercihi için en güvenilir hesaplama yöntemi tart›fl›lm›flt›r. Navicula, Cymbella ve Synedra en fazla tüketilen organizma olarak tespit edilmifltir. Kababurun bal›¤› genellikle Bacillariophyta ile beslenen planktivor bir bal›kt›r. Ayr›ca, besin tercihindeki mevsimsel de¤iflimler incelenmifl ve yaflla iliflkisi araflt›r›lm›fl, kemiksi yap›lardaki annulus oluflum periyodu ve beslenme aktivitesi aras›ndaki iliflki incelenmifltir. Sonbaharda besin çeflitlerindeki azalmayla birlikte hyalin halkalar›n olufltu¤u tespit edilmifltir

In this study, we analyzed the relative importance of food items of Chondrostoma regium Heckel, 1843. A total of 145 individuals were sampled between April 1993 and March 1994 in Suat Uğurlu Dam Lake. Stomach content analysis was used to determine dietary composition. Relative measures of food item quantity were estimated by two different approaches: the Index of Relative Importance (IRI) and the Geometric Index of Importance (GII). The results from these indices were compared and the most reliable way of estimating dietary composition was discussed. Navicula, Cymbella and Synedra were the most frequently consumed organisms. As C. regium mostly feeds on Bacillariophyta, it can be defined as planktivorous. Furthermore, ontogenic variations and the seasonal variation of food consumption were examined. The relation between the time of annulus formation on bony structures and feeding activity were also investigated. The deposition of hyaline rings were found to be synchronous with decrease in food diversity in autumn.