A key to the identification of larval bream, Abramis brama, white bream, Blicca bjoerkna, and roach, Rutilus rutilus

Abstract

Intra‐ and interspecific differences in pigmentation between finfold larvae of the three most abundant cyprinids in Dutch eutrophic waters, bream, white bream and roach, were studied, using laboratory‐raised larvae in the length range 8–11 mm. Because the internal pigmentation of the larvae has been used for identification, some attention is paid to the effects of different ways of fixation and preservation on transparency. The size and the shape of the melanophores, as described in the literature, could not be used as identification characters because of too much intraspecific variation and the effects of light conditions at the moment of fixation. Three characters proved to be significant for the identification of the larvae of the three species. Roach can be distinguished from bream and white bream by the pattern of melanophores on the belly. A second character is the pigmentation of the ventral aorta, which is only found in white bream. Lastly bream shows an irregular pattern of melanophores on the dorsal side, in contrast to roach which has a regular pattern.