Abstract

This study addresses gill filament calcification in Atlantic salmon(Salmo salar) fry, a process that could erroneously be interpreted as pathological. Using various anatomical and histochemical techniques, the gills 10 clinically healthy fry from the fish farming industry in Chile were analyzed. Our results show that the calcification process begins at the base of insertion of the gill filaments, advancing towards the apices of these structures. Histologically, calcification was identified in the perichondrium and in cartilaginous matrix. This process, also observed in the rakers and bones of the gill arches, is directly related to gills' morphological plasticity, highlighting the importance differentiating between biological responses of adaptive remodeling and certain pathologies of Salmo salarat the time productive diagnoses are made. The findings reported in work contribute toward improving the understanding of physiological processes in salmon and their impact productive quality.