ACCLIMATION TRIALS OF JUVENILE ITALIAN STURGEON TO DIFFERENT SALINITIES - MORPHOPHYSIOLOGICAL DESCRIPTORS

In this study the first experimental trials of acclimation to salinities of the Italian sturgeon Acipenser naccarii are described. Preliminary observations regarding some morphological features of the gut, kidney and gills following exposure to 20 and 30 parts per thousand salinity are reported, and compared with those displayed by many teleosts in hyper- and hypoosmoregulation. Results are discussed with regard to the osmoregulatory mechanisms and to the physiological limits of adaptability of this species in the second year of its life cycle. Within the Acipenseridae, Acipenser naccarii is generally considered a euryhaline species, but nothing is known about its mechanisms of osmotic homeostasis. This species could be a good candidate for aquaculture in fresh and brackish waters owing to the recent success obtained in artificial reproduction. (C) 1995 The Fisheries Society of the British Isles.