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Size-effect, asymmetry, and small-scale spatial variation in otolith shape of juvenile sole in the Southern North Sea
While otolith shape analysis can provide a valuable tool for discriminating between fish populations, factors which may influence otolith shape, such as the effect of size, directional asymmetry in growth, and local environmental conditions, are often unknown. Here, we analyzed differences in otolith shape across three size classes of age-0 common sole Solea solea L. from nursery grounds off the Belgian coast and in the Wadden Sea. Across size classes, form-factor decreased and roundness remained consistently high in both nursery grounds, while ellipticity increased in the Belgian nursery. Directional asymmetry between left and right otoliths measured by Fourier coefficients accounted for 0.96 and 7.2% of the variance when comparing otoliths overall, and for each size class, respectively. Within the Belgian nursery, results were consistent across sampling years and locations. In addition, otolith shape was marginally different between nursery grounds, but highly variable within nursery grounds. A small divergent group, which seems partly related to
fish size, was noted at both spatial and temporal scales. Based on these results and before embarking on a study of population structure using otolith shape in age-0 common sole, we recommend testing for directional asymmetry and fish size effects across the entire region of interest.
Keyword(s)
Early-life stages, Fourier coefficients, Nursery ground, Otolith shape, Small-scale spatial structure
Full Text
File | Pages | Size | Access | |
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Publisher's official version | 14 | 944 Ko | ||
Supplementary material 1 Fig. S1 Cluster dendrogram of the similarity distances of the Fourier coefficients of ten randomly chosen otoliths of juvenile sole, based on Ward’s distance. Picture numbers | - | 562 Ko | ||
Supplementary material 2 Fig. S2 Boxplot of roundness for 314 age-0 sole juveniles of sole at three size classes for each dataset (BE2013, BE2014 and NL2014) | - | 89 Ko | ||
Supplementary material 3 Fig. S3 Cluster dendrogram of the similarity distances of the Fourier coefficients of the juvenile sole sampled at the Belgian and Wadden Sea nursery grounds in 2014 (a) and. | - | 309 Ko | ||
Author's final draft | 37 | 1 Mo |