Quick laboratory identification of juvenile flounders (Rhombosolea plebeia and R. leporina ) (note)

Abstract

A description is given of a method of differentiating between the juveniles (0‐group) of sand flounder (Rhombosolea plebeia) and yellow‐bellied flounder (R. leporina) without recourse to fin‐ray counts. The gap between the snout and first fin ray of R. plebeia is 12% of the head length, whereas in R. leporina the gap is only 4.8% of the head length. The tips of the fin rays of dorsal and pelvic fins of R. plebeia are pointed, whereas the tips of the first few rays of the dorsal fin of R. leporina are concave or branched. The method works for fish as small as 12 mm total length.

Keywords:

• Rhombosolea plebeia
• Rhombosolea leporina
• Rhombosolea retiaria
• juveniles
• fin rays
• maxilla
• flounder
• identification