Background. The zope (blue bream), Abramis ballerus (L., 1758), is a cyprinid fish without economic importance, and its morphology has been poorly known. The monophyly of the genus Abramis is still unclear; therefore any new contribution to the knowledge on the morphology of zope could shed a new light on the phylogeny of this group of fishes. The aim of the present study was to learn and describe meristic- and morphometric futures of zope and to compare the results with published data. Materials and methods. A total of 40 specimens of the zope, Abramis ballerus, were caught in the middle stretch of the Odra River, near the city of GĹ‚ogĂłw, western Poland, in October 2002. For each fish, 21 biometric features were measured and selected meristic features (external and internal) were determined. Cephalic sensory canals were studied and their pores were counted. Results. The coefficient of variation for the body proportions of zope from the middle stretch of the Odra River ranged from 3.89% to 19.13% and its principal features were as follows: D III 8-10; A III 34-43; P I 14-18; V II 7-9; l.l. 62-75. It had one row of pharyngeal teeth, most frequently, in 5-5 pattern. The total number of vertebrae ranged from 46 to 48, (mean 47.38). The preoperculo-mandibular canal (CPM) and infraorbital canal (CIO) had the highest number of pores. Conclusion. The presently reported study shows that the sample analysed did not differ significantly from the population of the Dniepr River, although it differed significantly (in body proportions) from those of Lake DÄ…bie. The majority of values of meristic features did not differ significantly from those found in literature. However, there is still too little comparative material regarding internal meristic features and especially its osteology.

fish, blue bream, zope, Abramis ballerus, meristics, biometry