This study aimed to compare the growth performance and economic profitability of rearing Oreochromis niloticus in floating cages using three feeding strategies (5 days a week, 6 days a week, and 7 days a week) coupled with three stocking densities (20, 40, and 60 fish·m⁻³). Male monosex fish measuring 6.44 ± 0.18 cm and weighing 3.42 ± 0.7 g were used. The controls were weighed every 15 days from the 35th day of rearing until 185 days to assess zootechnical parameters. BioMar feed (Efico Cromis 832F) was used during the study, and the feed ration was adjusted for each treatment every 2 weeks. At the end of the study, the average weights varied from 293.09 g to 468.41 g for the conditions of 40 fish·m⁻³ with a 5/7-day diet and 20 fish·m⁻³ with a 7/7-day diet, respectively. The yield per m² values were between 7.11 kg and 23.17 kg, respectively. On the other hand, the economic profitability was better with the condition of 40 fish.m⁻³ with daily feeding. These results suggest that in the Toho-Todougba lagoon complex, a stocking density between 40 and 60 fish·m⁻³ coupled with daily feeding (three times a day) promotes the optimization of fish production and profitability of fish farming.

Context: Macrobrachium vollenhoveni (Herklots), a freshwater prawn native to Africa, is crucial for aquaculture and subsistence fishing. However, limited data exist on its reproductive biology in Benin’s water bodies. Aims: This research aimed to explore the breeding season, size at sexual maturity, fecundity and reproductive output of M. vollenhoveni. Methods: Prawns were sampled monthly from May 2015 to October 2016. In total, 1567 females of M. vollenhoveni were collected from the lower Ouémé (864 prawns) and the lower Mono (703 prawns). Key results: Findings showed that gonadal maturation starts in March, with peaks in July. Then spawning occurs from July to September, and even October. In both environments, ovigerous females (prawns carrying fertilised eggs in incubation) were frequently captured from July to October, with a maximum proportion in August and September. The spawning period for the two prawn populations in both sampled areas matched with an increase in water volume, salinity and pH. The size at sexual maturity was 8.48-cm total length (TL) for the lower Ouémé population, whereas in lower Mono, it was 9.00 cm TL. Absolute fecundity ranged from 3925 to 31,408 eggs in lower Mono and from 4871 to 25,902 eggs in lower Ouémé. The reproductive output was 12.87% for Mono and 11.94% for Ouémé. Conclusions and implications: This research is the first one on the reproductive biology of M. vollenhoveni in Benin and provides vital data for sustainable fishery management of this prawn species in the watersheds throughout the country.

Determination of protein and lipid requirements is crucial in prawn species aquaculture. The present study investigated the impact of six diets with different protein and lipid levels (T1, 30/08; T2, 30/12; T3, 35/08; T4, 35/12; T5, 40/08; and T6, 40/12), in triplicate, on the zootechnical performance and body composition of juvenile Macrobrachium macrobrachion over 56 days. These protein and lipid levels were chosen based on the requirements of other freshwater prawn species. The stocking density was one individual per liter. Results show that prawn survival was lower in T6 (with 40% protein and 8% lipid) compared to all others. The treatment T3 (35% protein and 8% lipid) shows higher survival (with 40.0 ± 24.0%) but not significantly different from other diets. The specific growth rate obtained in the present study was not different between diets. Negative values were recorded for treatments T2, T3, and T4 (30%, 35%, and 35% proteins and 12%, 8%, and 12% lipids, respectively) and positive values for treatments T1, T5, and T6 (30%, 40%, and 40% proteins and 8%, 8%, and 12% lipids, respectively). The protein efficiency coefficient (PEC) and the lipid efficiency coefficient (LEC) did not differ between treatments; however, there was a trend for these coefficients to be lower in T4, T5, and T6 (35%, 40%, and 40% proteins and 12%, 8%, and 12% lipids, respectively) compared with the other diets. The highest protein efficiency rates were recorded with the T3 and T4 treatments (35% proteins and 8% and 12% lipids, respectively), while the best lipid level was obtained with T4 (35% proteins and 12% lipids). According to dose–response models, the optimal protein/lipid ratio requirements for M. macrobrachion juveniles can be estimated at 35/8. This study is the first to provide relevant information on the nutritional needs of juveniles of African native freshwater prawn M. Macrobrachion. Further research is needed to optimize nutritional requirements at early stages of development.