INFLUENCE OF STOCKING DENSITY AND WATER PARAMETERS ON GROWTH OF JUVENILE BELUGA STURGEON (HUSO HUSO, LINNAEUS, 1758)

I. Vasilean, V. Cristea, Lorena Sfetcu

Abstract
The main purpose of the present experiment consist in evaluation of growth performances of beluga sturgeon juveniles (obtained from the artificial reproduction of mature sturgeons with origins in the Danube-Pontic basin) reared in different stocking densities in a recirculating aquaculture system. The influence of stocking density and water quality on the growth of beluga fingerlings was studied during 30 days. The two experimental variants (V1 and V2) were formed by two rearing units each with a different fish density: 30 exemplars (initial average weight -34g) in first two aquaria (V1) and 10 exemplars (initial average weight -25g) in the following two aquaria (V2). The fish were fed a 55% protein feed to a feeding rate of 3 % body weight/day. During experiment water quality parameters (pH, O₂, T, NH₃-N, NO₂-N, NO₃-N) were recorded an a daily basis and, every 2 weeks, the fish were weight individually, and weight gain was recorded. Beluga growth performances were evaluated through analysis of various technological indicators: W (weight gain), FCR (food conversion ratio), SGR (specific growth rate), PER (protein efficiency ratio). The body profile was evaluated through allometric factor.

Key words: recirculating system, sturgeons, artificial feed

INFLUENTA DENSITATII SI A PARAMETRILOR APEI ASUPRA CRESTERII PUIETULUI DE MORUN (HUSO HUSO, LINNAEUS, 1758)

I. Vasilean, V. Cristea, Lorena Sfetcu

Rezumat
Obiectivul principal al acestui experiment consta în evaluarea performantelor de crestere a puietului de morun (obtinuti din reproducerea artificiala a sturionilor proveniti din bazinul Dunarii) crescuti în diferite densitati într-un sistem recirculant. Influenta densitatii si a calitatii apei asupra cresterii puietului de morun a fost studiata timp de 30 de zile. Am creat doua variante de experimente (V1 si V2), iar pentru fiecare varianta câte doua unitati de crestere cu densitati diferite: 30 exemplare (greutate medie initiala de 34 g/ex.) În primele doua acvarii (V1) si 10 exemplare (greutate medie initiala 25 g/ex.) în celelalte doua acvarii (V2). Pestii au fost hraniti cu o ratie de 3% din biomasa pe zi, furajul administrat continând 55% proteina. În tipul experimentului parametrii apei (pH, O₂, T, NH₃-N, NO₂-N, NO₃-N)), au fost înregistrati într-o baza de date zilnica si, la doua saptamâni, cântarita greutatea individuala a exemplarelor si calculat sporul de crestere. Performantele de crestere a morunilor au fost evaluate cu ajutorul diferitor indicatori tehnologici W (spor de crestere), FCR (rata de conversie a hranei), SGR (rata specifica de crestere), PER (raportul eficientei proteice). Performantele de crestere au fost evaluate prin factori biometrici.

Cuvinte cheie: sistem recirculant, sturioni, hrana artificiala