Testing Stocking Densities in North American Sturgeon (Polyodon spathula ) Culture in the Post-Embryonic Development Period

Abstract

The paper presents the results obtained during the growth of the North American sturgeon Polyodon spathula during the period of post-embryonic development. Stugeon larvae aged 5 days old of P. spathula obtained by artificial reproduction at SCDP Nucet, were stocked and raised until the age of 30 days in two experimental variants: variant 1 (V1): 1000 ex/m 3 , respectively 1500 ex/tank ; variant 2 (V2): 2000 ex/m 3 respectively, 3000 ex/tank in 10 Ewos type fiberglass tanks (useful volume -1500 liters/tank). The water temperature during the experiments was between 17.0-22.5°C. In both experimental variants, the sturgeon fry were fed both zooplankton and artificial feed. The zooplankton administered came from specially prepared cultures. The technological indicators obtained at the end of the post-embryonic development period (30 days) were as follows: in variant 1 (V1) fry with an average mass of 6.95 g/ex were obtained (survival rate of 19.8 %) and in the variant 2 (V2) the fry recorded an average mass of 4.8 g/ex (survival rate 12.3 %). The differences recorded in survival between the two experimental growth variants were due to the fact that the adaptation to feeding with artificial feed became more difficult. Also, overcrowding causes typical manifestations that consist in the appearance of large differences between individuals that favor cannibalism.

Keywords

• ewos tanks
• polyodon spathula
• stocking density
• sturgeon larvae