High‐resolution stock discrimination of Atlantic herring (Clupea harengus) based on otolith shape, microstructure, and genetic markers

One of the most rapidly developing applications of otolith research is shape analysis, often used for population discrimination as well as for species identification. Otolith shape is influenced by the environment through physiology, but also shows consistent and temporally stable differences between populations, which suggest genetic control as well.

Thus otolith shape serves as a population marker, suitable for individual assignment. Here we use otolith morphological characteristics (otolith shape and larval otolith microstructure) combined with genetic markers to discriminate between different populations of Atlantic herring (Clupea harengus) in the western Baltic and adjacent waters.

We analyse a baseline (spawning individuals from several populations validated by genetic markers) for separation of adult herring (2+) based on otolith shape and juveniles using genetically validated otolith shape characteristics as separation parameters. Otolith shape was found to clearly discriminate between individuals at all ages from different spawning populations.

The identified distances between populations based on otolith shape matched previously obtained genetic distances and were, when combined with the otolith microstructure, able to discriminate between populations that are spatially different but spawning in the same season