Spawning of European hake (Merluccius merluccius) and megrim (Lepidorhombus whiffiagonis and L. boscii) overlap in time and space. Their eggs are morphologically similar, so genetic identification is needed for purposes of stock assessment based on plankton surveys. Amplification fragment sizes of a partial sequence within the 16S rRNA genes are different for Merluccius merluccius, Lepidorhombus boscii, and L. whiffiagonis. Species-specificity of the pattern was confirmed after analysing adult individuals from all distribution areas of the three species. After Chelex-based DNA extraction and...

Spawning of European hake (Merluccius merluccius) and megrim (Lepidorhombus whiffiagonis and L. boscii) overlap in time and space. Their eggs are morphologically similar, so genetic identification is needed for purposes of stock assessment based on plankton surveys. Amplification fragment sizes of a partial sequence within the 16S rRNA genes are different for Merluccius merluccius, Lepidorhombus boscii, and L. whiffiagonis. Species-specificity of the pattern was confirmed after analysing adult individuals from all distribution areas of the three species. After Chelex-based DNA extraction and PCR amplification, fragment sizes at this gene were successfully determined from 85% formaldehyde-fixed eggs and larvae recovered from plankton samples. Species-specificity was resolved using an ABI genetic analyser. The results were 100% reproducible. This methodology for genetic identification of hake and megrim eggs can be very useful for stock assessment of these three commercially important fish species.