Recently settled turbot Psetta maxima and brill Scophthalmus rhombus are difficult to distinguish, as they are almost identical in appearance and lack the diagnostic adult characteristics. Fin ray counts, which can be used as an aid in the identification of flatfish juveniles, are reported to show some overlap between turbot and brill. 0-group flatfish were collected from sandy beaches along the west coast of Ireland by beach seining in 2009. When counted and plotted, the dorsal and anal fin ray counts clearly separated the specimens into two groups. The two groups were assumed to be brill and turbot on the basis of literature data, suggesting higher dorsal and anal fin ray counts occur in brill. This confirmed that fin ray counts can probably be used as a diagnostic tool in these 0-group flatfish from west of Ireland waters. Additionally, temporal and spatial variability in fin ray counts was also revealed in the present study, emphasizing that regional difference need to be taken into account when using this diagnostic method.
