The experiment was conducted to determine the effects of aeration systems for ponds cultured with Nile tilapia Oreochromis niloticus in the period from April 1 st to the end of June, 2020.Three treatments were used T 1 (non-aerated ponds), T 2 and T 3 (aerated ponds). Growth performance of tilapia O. niloticus in terms of length, weight, weight gain, specific growth rate and production were estimated to be significantly (p<0.05) higher in the ponds of T 2 and T 3 compared to T 1 . The average final length of Tilapia was 15.7±2.1 , 17.9±2.4 and 17.8±2.6 cm in T 1 , T 2 and T 3, respectively. The mean final weight at the end of 90 days was 75.3, 127.1 and 127.8g for fish of treatments T 1 , T 2 and T 3, respectively. The length-weight relationship equation was W = 0.0153*L 3.0646 ، W = 0.0093*L 3.2817 and W = 0.0013*L 3.1877 for T 1 , T 2 and T 3, respectively. The respective condition factor values were 1.94, 2.22 and 2.26. There was a significant difference (P < 0.05) in survival rates of non-aerated and aerated.

Veranda nets are major technique in Bardawill lagoon, may be due to its ability to target different fish species and less effort required in operating it despite the majority of catching them in this study were non targeted (small size and immature). To manage marine fisheries effectively, we must assess and manage by catch. Data were collected monthly from three specified fishing vessels of Veranda nets of (Mugil cephalus) it operated in Bardawill lagoon for each fishing unit from May to November 2018-2019. Average catch of Flathead Grey Mullet (Mugil cephalus) from juvenile and adult was 513.6 kg (24.7% of total catch by veranda nets) and 620.3 kg (29.8% of total catch by veranda nets) in spring; 838.5 kg (19% of total catch by veranda nets) and 1363.8 kg (31% of total catch by veranda nets) in summer and 400.5kg (15.2% of total catch by veranda nets) and 832.3 kg (31.5% of total catch by veranda nets) in autumn, respectively. Our results indicated that, the landing of Flathead Grey Mullet juvenile leads to more losses of stock biomass which formed 76835.1 12544.3 and 59919.4 Kg for spring, summer and autumn, respectively and the ≈ 10.5 million LE losses in one fishing season 2018 and 2019.