A seed rearing experiment was attempted to evaluate the effects of stocking densities in the biofilm-based system reared with pearlspot, Etroplus suratensis on different aquaculture parameters. Pearlspot advanced fry of size (4.67 ± 0.04 cm/1.71 ± 0.03 g) stocked at four different stocking densities viz 50 fish (T₁); 100 fish (T₂); 150 fish (T₃) and 200 fish (T₄) m⁻³ in the biofilm-based rearing system and at the rate of 150 fish m⁻³ in the clear water fed (CWF) system tanks. The total ammonia nitrogen and dissolved oxygen levels in biofilm tanks with different stocking density were significantly lower than CWF. Diatom was found as dominant plankton in all biofilm treatment tanks in water as well as on substrate. The growth parameters were found to significantly decrease with increasing stocking density in the biofilm-based rearing system. The significant highest individual growth parameters and significantly lowest fish biomass were found in T₁. Final fish biomass was found to increase with increasing stocking density up to 150 advanced fry m⁻³ and then reduced due to decreased survival. Body composition analysis of E. suratensis showed increased protein and decreased lipid levels in all biofilm-based rearing system treatments at different stocking densities compared with clear water fed system. The present investigation findings on plankton abundance, growth, body composition and blood parameters at different stocking densities will provide guidelines for selecting appropriate stocking density for pearlspot advanced fry to fingerling rearing in a low saline biofilm-based system without providing a supplementary diet.

中文翻译：

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放养密度对 Etroplus suratensis 生长性能、浮游生物丰度、身体成分和血液学参数的影响 (Bloch, 1790)

尝试进行种子饲养实验，以评估在用珍珠斑病Etroplus suratensis饲养的基于生物膜的系统中放养密度对不同水产养殖参数的影响。Pearlspot 高级鱼苗（4.67 ± 0.04 厘米/1.71 ± 0.03 克）以四种不同的放养密度放养，即 50 条鱼 ( T ₁ )；100 条鱼 ( T ₂ ); 150 条鱼 ( T ₃ ) 和 200 条鱼 ( T ₄ ) m ^-3在基于生物膜的饲养系统中以 150 条鱼 m ^-3的速率在清水 (CWF) 系统水箱中。不同放养密度的生物膜池中总氨氮和溶解氧水平显着低于CWF。在水中和基质上的所有生物膜处理槽中，硅藻被发现是主要的浮游生物。发现生长参数随着基于生物膜的饲养系统中放养密度的增加而显着降低。在T ₁中发现了显着最高的个体生长参数和显着最低的鱼生物量。发现最终鱼的生物量随着放养密度的增加而增加，最高可达 150 条高级鱼苗 m ^-3，然后由于存活率下降而减少。E 的身体成分分析。 苏拉特与清水喂养系统相比，在不同放养密度下，所有基于生物膜的饲养系统处理显示蛋白质增加，脂质水平降低。目前关于不同放养密度下浮游生物丰度、生长、身体成分和血液参数的调查结果将为在低盐度生物膜系统中选择合适的放养密度为珍珠斑高级鱼苗提供指导，以在基于低盐生物膜的系统中养殖鱼种，而无需提供补充饮食。