Abstract
The relationship between fish size and otolith size was established for nine species from different geographical areas, the Mediterranean basin, Kerguelen Islands and the tropical Pacific Ocean. For all species, a significant linear relationship was found between fish size and otolith size. However, the ‘lake ecotype' of the brown trout (Salmo trutta fario) from Kerguelen did not show such relationship, contrary to the two other ‘ecotypes' from rivers and mixed biotopes. The reasons for such a pattern remain unknown. For a given species, comparisons of slopes of the relationship and Y-coordinate at the origin revealed differences according to studied sites or individual fish size. This suggests an influence of environmental and/or ontogenetic factors on the parameters of the relationship between fish size and otolith size.