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

Growth performance, survival or/and cannibalism rate of larvae are directly affected by feeding strategies, hatchery management, etc. (Mohler, King, & Farrell, 2000; Deng et al. , 2003; Leu et al. , 2018; Uriarte et al. , 2019) and thus knowing these key factors for sturgeon larviculture helps farmers to provide an appropriate condition. There are, though, a few studies on how sturgeon larviculture can be influenced by feeding/fasting, size sorting and stocking density. It is the first time given cannibalism nature of Persian sturgeon larvae has been reported. The growth and survival rate drawn from this study have been proved by previous documents regarding fish feeding frequency. The effect of feeding on final weight and mortality of sturgeon is well-defined in Siberian sturgeon (Gisbert & Williot, 1997) and white sturgeon (Deng et al. , 2003). In our study, following the feeding/fasting strategy, feeding impact were prioritized option on final weight of Persian sturgeon larvae Herein, apart from all starved treatments died in both hetero & homo-size conditions, fed large larvae survived based on food or even cannibalistic competition in hetero-size group. At the same time, the negative effect of fasting on final weight was sharped by two-fold stocking density. This decreasing pattern has been recorded around six-times in homo-size small larvae (B6: 39. 3 ± 11. 3 mg) as and four-times in homo-large (B4: 98. 6 ± 30. 4 mg) and hetero-size (B2: 80. 3 ± 19. 6 mg) treatments. In the present study, the Persian sturgeon larvae reacted adversely to the starvation much more than the feeding strategy at overcrowding situation. The reduction of growth performance in aquatic, particularly during larvae phase, at high density rearing would be probably owing to the competition either for feeding or for space (Bolasina et al. , 2006; Lee et al. , 2016; Yadata et al. , 2019). Larvae maintained at high stocking density require more food availability to have an optimal final weight. Although stocking density clearly influences Amur sturgeon (Ni, Wen, Li, Chi, Bu, Ren, Zhang, Song, & Ding, 2014), Atlantic sturgeon Acipenser oxyrinchus (Mohler et al. , 2000) and Chinese sturgeon Acipenser sinensis (Ni, Wen, Li, Chi, Bu, Ren, Zhang, Song, & Ding, 2016) by provoking growth performance, the nature of species can opt how body performance react in different stocking density (Millán-Cubillo, Martos-Sitcha, Ruiz-Jarabo, Cárdenas, & Mancera, 2016).