The in£uence of stocking density (1, 2, 4, 6 and 8 kgm À 2 ) was investigated on haematological parameters, growth and ¢n erosion of great sturgeon (Huso huso) juveniles for a period of 8 weeks. The mean weight of ¢sh at the start of trial was 93.13 AE 1.04 g. After 8 weeks of rearing, the mean weight was 362.4, 319.7, 267, 242.1 and 211.1 in densi-ties1^8 kg m À 2 respectively. The results of this study showed that growth parameters, including condition factor, weight, weight gain, feed conversion ratio, speci¢c growth rate and body weight increase, had a statistically signi¢cant di¡erence among treatments (Po0.05). A signi¢cant di¡erence (Po0.05) was observed in haematocrit, but the other haematological parameters, including red blood cells, white blood cells (WBC), haemoglobin concentration, mean corpuscular haemoglobin, mean corpuscular volume, mean corpuscular haemoglobin concentration and di¡erential WBC count, showed no signi¢cant e¡ect with stocking density (P40.05). At the end of the experiment, stocking density had no signi¢cant e¡ect on plasma cortisol and glucose concentration. The ¢n length (dorsal, anal, ventral, pectoral and caudal) of ¢sh was measured to calculate the ¢n index. According to this index, dorsal, anal, ventral and pectoral ¢ns showed no signi¢cant di¡erence among treatments (P40.05), but the erosion of the caudal ¢n was signi¢cantly di¡erent between ¢sh held on 6 and 8 kg m À 2 (Po0.05). These results showed that rearing density has a major e¡ect on the growth indices of H. huso. Unlike many other ¢sh, great sturgeon exhibited lower stress responses to high stocking density. This indicates that they are more tolerable to rearing conditions in high stocking densities.With respect to the various e¡ects that density causes on growth, ¢n erosion and physiological and haematological parameters, better understanding of these phenomena considering di¡erent levels of density could have a bene¢cial impact on many rearing steps of this species.
