The feeding/fasting strategy, size heterogeneity, and stocking density impact on body performance and cannibalism rate of Persian sturgeon (Acipenser persicus) larvae

The aim of this study was to evaluate different aspects of larviculture of Persian sturgeon (Acipenser persicus). With this regard, the growth performance, e.g., final weight, specific growth rate (SGR), and cannibalism rate of Persian sturgeon were assessed. The study was performed using two separate strategies; size heterogeneity and feeding/fasting strategy (experiment-A), besides implementing stocking density (experiment-B). In the experiment-A, twelve circular tanks (9.6 L) were considered as following: A₁ (5 large starved fish +5 small starved fish); A₂ (5 large fed fish +5 small fed fish); A₃ (all 10 large starved fish); A₄ (all 10 large fed fish); A₅ (all 10 small starved fish) and A₆ (all 10 small fed fish). In experiment-B, the stocking density was doubled for all groups in the same tanks: B₁ (10 large starved fish +10 small starved fish); B₂ (10 large fed fish +10 small fed fish); B₃ (all 20 large starved fish); B₄ (all 20 large fed fish); B₅ (all 20 small starved fish) and B₆ (all 20 small fed fish). Data were collected at the end of the 7th and 14th days. Growth performance increased significantly in all fed treatments of experiment-B in comparison to starved treatments (P < 0.05). The highest final weight and SGR was observed in B₂ (363.5 ± 130.1 mg in 14th day) and B₆ (26.5 ± 1.0% day⁻¹ in 7th day), respectively. Cannibalism rate was increased in Persian sturgeon larvae maintained at low density, in which the highest rate was observed in the starved groups (A₁ [27.5%], A₃ [35.0%], A₅ [40.0%]). Size heterogeneity leads to disappear/die all small larvae, in both low- and high-density only in the starved group, regardless of size, died at the end of the second week. In conclusion, in Persian sturgeon, cannibalistic behavior is more affected by stocking density. To manage larviculture of this species, optimizing the stocking density to prevent the cannibalistic interaction, besides having continuous feeding is a paramount.