Aim: The formation history of Africa's current river basins remains largely unknown. In order to date changes in landscape and climate, we studied the biogeography of the African freshwater fish with the largest natural distribution. We also validated biogeographical units.Location: Continental Africa.Taxon: Clarias gariepinus sl.Methods: We investigated mitochondrial cytb sequences of 443 individuals from 97 localities, using a haplotype network and a genetic landscape analysis. We inferred a dated phylogeny using maximum likelihood and Bayesian inference approaches and reconstructed ancestral areas with S‐DEC and S‐DIVA models. Microsatellite genotyping complemented the mitochondrial approach in the Congo basin, where the latter revealed complex patterns.Results: Limited differentiation is found in northern and south‐western Africa, and sharp genetic differentiation in the continent's east and centre. Populations with affinities to neighbouring basins occur at the edges of the Congo province. High diversity exists in the south of the Congo basin. The Zambezi province is partitioned into eastern, central and western sectors. In the east, specimens were related to those from the Congo. In the west, they were similar to Southern representatives. Phylogenetic inference placed the origin of C. gariepinus in the East Coast, with intraspecific diversification starting around the Great Lakes. These events occurred ca. 4.8–1.65 and 2.3–0.8 MYA respectively.Main conclusions: Clades of C. gariepinus sl. show a clear geographical signature. The origin of C. gariepinus in the East Coast and diversification around the Great Lakes coincided with the periods of increased aridity. Low genetic differentiation in northern and southern Africa may result from connectivity during recent periods of higher rainfall. In contrast to other widespread African freshwater fish, colonization rather than extinction seemed to mediate distribution patterns. This can be explained by a high ecological tolerance. We highlight the species’ suitability to study landscape and climate evolution at various scales.

The aim of this study was to evaluate the effects of cassava, yam and sweet potato peels on Black Soldier Fly Larvae (BSFL) production. Four different treatments were performed in triplicate in a completely random block consisting of soy bran (TSB), cassava peel (TCP), yam peel (TYP) and sweet potato peel (TPP). A density of 1 larva/g of substrate was used with a uniform ratio of 100 mg/larva/day. Larval growth duration was ten days, and growth monitoring was carried out every 2 days. The daily weight gain (DWG) ranged from 2.19 ± 0.09 g/day (TYP) to 4.53 ± 0.02 g/day (TSB). The production of these BSFL ranged from 43.90 ± 1.87 g/kg of substrate (TYP) to 90.56 ± 0.54 g/kg of substrate (TSB). The degradation rate ranged from 36.00 ± 2.30% (TYP) to 65.00 ± 2.88% (TSB), and the survival rate ranged from 77.66 ± 1.45% (TYP) to 99.00 ± 0.28% (TSB). According to the Z correlation test, there was a strong correlation between the organic matter content of the substrates and the DWG (99.1%). It was also observed that phosphorus content was strongly correlated with DWG (92.9%). Regarding the nutritional quality of the larvae, the protein content varied from 33.51 ± 0.94% (TYP) to 40.64 ± 032% (TSB), and the lipid content varied from 26.24 ± 0.35% (TYP) to 30.44 ± 0.18% (TSB). A significant difference (p < 0.05) between the different treatments depending on the parameters were noticed. This study revealed that cassava, yam and sweet potato peels can be used for BSFL production, but the best growth of BSFL was obtained with the cassava peel substrate that presented also the best degradation rate.

Black soldier fly larvae are exceptional ingredients, often used to replace fish meal. They can be easily cultured using waste and by-products. This study assesses the effect of black soldier fly larvae (BSFL) meal on the growth of Oreochromis niloticus raised in captivity, as well as the economic impact of replacing fish meal with BSFL meal in its diet. Black soldier fly larvae (BSFL) were produced for 15 days after egg hatching. The substrate of BSFL production was Soy bran that is a byproduct obtained by processing soy cheese. The larvae of Oreochromis niloticus of average initial weight 0.012 ± 0.00 g were randomly distributed in 15 tanks at a rate of 50 larvae per tank. Five different treatments were applied, with TR (imported feed); T0 (diet with 0% incorporation of black soldier fly larvae meal); T40; T50 and T60 are diets with 40%, 50% and 60% incorporation of black soldier fly larvae meal. The feeding frequency was 4 times/day. Each treatment was tested in triplicate for 28 days. The specific growth rate obtained during the experiment varied significantly (P < 0.05) with the treatments from 2.88 ± 0.09 (T40) to 4.50 ± 0.12%/day (TR). The feed conversion rate (FCR), ranged from 2.25 ± 0.05 (T40) to 1.08 ± 0.04 (T60). The protein efficiency ratio (PER) showed a significant difference (P < 0.05) with the treatment. It ranged from 0.81 ± 0.07 (T40) to 2.34 ± 0.06 (TR). The survival rates varied from (T0) (92.66 ± 3.52) to (T50) (100.00 ± 0.00). The economic conversion ratio (ECR) presented a significant difference (P < 0.05). The best ECR was obtained with T60 (1.62 ± 0.09) and T50 (2.42 ± 0.17). Based on the parameters studied, diet with 40%, 50%, and 60% of BSFL meals showed better performance compared to treatment containing fish meal at 54% (T0). The cost production analyses were used to evaluate the economic impact of utilizing BSFL meal instead of fish meal in O. niloticus feeding. It is recommended to use 50% and 60% substitution rates for better economic profitability.

Une étude sur la dynamique socio-économique et environnementale de la pêche artisanale au Burundi a été effectuée dans le nord-ouest du Lac Tanganyika, coté burundais, dans la province de Makamba, Commune de Nyanza-lac, aux sites de débarquement (plages) de Muguruka et Mvugo entre mars et juillet 2013. Les objectifs étaient d’actualiser l’information sur les pêcheurs, leurs associations, les engins utilisés et l’évolution des prises en vue de la comparer avec des données plus anciennes, et d’analyser les coûts et revenus des unités actives, motorisées ou non motorisées, afin de préciser leur rentabilité. Dans l’ensemble, 130 personnes ont été interrogées et 6 400 poissons ont été mesurés. Stolothrissa tanganicae (adultes et juvéniles) et Lates stappersii juvéniles ont dominé dans les captures avec respectivement 68% et 26,7% à Muguruka, 81,5% et 16,7% à Mvugo. L'étude estime la capture par unité d’effort de l’unité Appolo à 152 kg/nuit de pêche, 80 kg/nuit de pêche pour le catamaran motorisé et 50 kg/nuit pour le catamaran non motorisé. Après la vente des produits de la pêche, le profit net estimé (PNE) par unité de pêche artisanale s’élève à 8 300 ± 222 $US. avec un revenu annuel net par pêcheur d’environ 691 $US pour le catamaran non motorisé et de 4 380 ± 654 $US, avec un revenu annuel net par pêcheur de 274 $US pour le catamaran motorisé ; tandis que pour l’unité Appolo, le PNE s’élève à 11 670 ± 2 500 $US avec un coût salarial par pêcheur de 645 $US. On constate que les unités non motorisées sont plus rentables dans la zone proche des rives. Quant aux unités Apollo pêchant au large en pleine zone pélagique, les captures sont nettement plus élevées mais leur rentabilité n’est guère supérieure aux unités non motorisées. Mots clés : Capture, Clupéidés, effort de pêche, investissement, rentabilité.

The rapid proliferation of water lettuce, Pistia stratiotes, poses significant ecological challenges. This study investigates the use of Pistia stratiotes as a substrate for producing black soldier fly larvae. The experiment used 40 g of black soldier fly larvae (BSFL) pupae for all five substrates (T0, T25, T50, T75, and T100). Each treatment had three replicates. The physicochemical parameters, such as the temperature and pH, ranged from 27.30 °C to 27.40 °C and from 7.03 to 7.60, respectively. The survival rates ranged from 90.13% to 94.73%. The biochemical parameters showed significant differences, including dry matter, organic matter, ash, crude protein, crude lipid, crude fiber, carbohydrate, and energy (p < 0.05). Regarding the larvae’s growth and substrate use, the BSFL production varied depending on the rearing substrate. The highest growth was observed in substrates without water lettuce leaf (WLL) (T0), followed by those in treatment at 25% (T25) and 50% (T50) inclusion of WLL and then the substrate made solely of WLL (T100). The substrates degradation rate in this study varied significantly, ranging from 46.40% to 67.38%. The physicochemical characteristics of the substrates are associated with the growth performance of the BSFL, and the inclusion of WLL influenced the nutritional composition of the larvae.