![Sample our Earth Sciences journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5930/TOC-Subject-Sample-2021-Earth-Sciences.jpg"})
Abstract
The effect of three rearing systems, floating cages, cement tanks and earth ponds, on the growth rate, feeding efficiency and mortality rates of hybrid tilapia — Tilapia zillii (male) × T. guineensis (female) — was evaluated for 233 days. Fish of average weight 12.59g were stocked at a density of 20 fish m−3 and were fed a 30% protein pelleted commercial feed. The pH, degree of aeration and transparency were monitored. The mortality rate, final mean weight, daily weight gain, and feed conversion ratios were significantly different among rearing systems. The highest potential was in earth ponds (2.86%, 171.70g, 0.74g d−1, 5.42, respectively), the cages were of intermediate potential (7.50%, 137.22g, 0.57g d−1, 7.70) and the lowest potential was in cement tanks (31.86%, 45.23g, 0.15g d−1, 10.28). These differences could be linked to the relevant physical and chemical characteristics of the three different rearing systems.