Demineralization of the vertebral skeleton in Atlantic salmon Salmo salar L. during spawning migration

In Atlantic salmon, Salmo salar, the mineral rate of vertebrae in a given f ish varies according to the position of the vertebra along the rachidian ax is. Indeed, the mean rate goes from 49% in the anterior vertebrae and raise s to 51% in post-truncal vertebrae. Although no significant difference in t he mineral rate was noticed between males and females either in the lower r iver basin or after spawning, the mineral rate of vertebral bone decreased significantly (1-2%) during spawning migration. Vertebrae, like scales, are an important reservoir of calcium from which fasting salmon draws the mine rals and organic materials necessary for the substantial remodeling of cran ial bones in males and for sexual maturation. We hypothesize that mineral d ecrease in vertebrae may be the result of a halastasic demineralization of the vertebral tissues. (C) 2000 Elsevier Science Inc. All rights reserved.