Seed stunting of rohu, Labeo rohita (Ham.) carried out for 6 months in 24 large (50 m²) concrete tanks using 20 and 40 fry m⁻² rearing densities under open and shade (50% light incidence) conditions. A significant influence of tank shading observed on all the water quality parameters, unlike the density effect only on the dissolved oxygen content in water. Highly significant stunting effects of both higher density and shading observed on juvenile growth and survival after 2-, 4- and 6-month stunting. Doubling the density caused 22.9 and 27.8% weight suppression after 6-month stunting under open and shaded conditions respectively. Similarly, shading caused 31.7 and 36.1% suppressed body weight after 6 months in the low- and high-density groups respectively. However, the best stunting effect observed through a compounded effect of high density and shading as 50.7–57.0% growth suppression recorded within 2–6 months stunting. The study revealed both higher rearing density (two times) and tank shading (50% light incidence) to be effective tools for rohu juvenile stunting, while a combination of these factors yielded greater stunting effect. Such protocol can be used for production of stunted carp juveniles to ensure their round-the-year availability for stocking grow-out ponds.

中文翻译：

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水箱遮荫和饲养密度对罗胡、Labeo rohita（汉密尔顿）发育迟缓幼鱼生长的影响

rohu, Labeo rohita (Ham.) 在 24 个大型 (50 m ² ) 混凝土罐中使用 20 和 40 苗米^-2进行了 6 个月的种子发育迟缓开放和遮荫（50% 光入射）条件下的饲养密度。与仅对水中溶解氧含量的密度影响不同，观察到的水箱阴影对所有水质参数都有显着影响。在 2、4 和 6 个月的发育迟缓后，观察到较高密度和阴影对幼鱼生长和存活的高度显着的发育迟缓影响。在开放和遮荫条件下生长发育迟缓 6 个月后，将密度加倍导致体重下降 22.9% 和 27.8%。同样，在低密度组和高密度组 6 个月后，阴影分别导致 31.7% 和 36.1% 的体重受到抑制。然而，通过高密度和阴影的复合效应观察到的最佳发育迟缓效果是 50.7-57.0% 的生长抑制记录在 2-6 个月发育迟缓内。研究表明，较高的饲养密度（两倍）和水箱遮光（50% 光入射）都是罗湖幼鱼发育迟缓的有效工具，而这些因素的结合产生了更大的发育迟缓效果。此类协议可用于生产发育迟缓的鲤鱼幼鱼，以确保它们全年可用于放养养成池。