Cost of fish production can be reduced by replacement of high-priced fishmeal (FM) with insects sourced ingredients. Four months feed experiment was conducted at a fish farm in Baringo County, Kenya to investigate effects of substituting fishmeal (FM) with black soldier fly larvae meal (BSFLM) on survival and growth performance of C. gariepinus under aquaponic system. Three test diets 35% crude protein content (CP) in which FM was substituted by BSFLM at 25%, 50% and 75% were formulated and experimented with commercial diet of 35% CP. Four weeks old C. gariepinus were stocked in 12 tanks at a density of 50 fish/tank and subjected to the diets. Fish were sampled every three weeks; water parameters were sampled weekly and mortality recorded on occurrence. Diet with 50% BSFLM obtained better FCR for formulated diets with no significance (P<0.05) for FCR and survival. Weight gain of control diet (97.07 g) was significant (P<0.05) compared to formulated diets 64.09g, 69.78g and 67.77g for 75%, 50% and 25% of BSFL replacement respectively. Growth performance and survival demonstrated that BSFLM has potential to substitute FM up to 75%. The fish productivity can be improved and feed cost reduced by incorporating fully defatted BSFLM with CP higher than 25.3% used for the diets.

Cage fish farming, a recent development in aquaculture, has enhanced fisheries production due to its higher stocking densities than traditional pond and open-water systems. Although it can enhance production, the system can pose biodiversity threats when there is an unintentional or intentional release of stocked fish into the wild. In this review, we examine the expansion of Nile tilapia (Oreochromis niloticus L.) cage aquaculture in Africa and the potential threats that this may have on congeneric Oreochromis species. Threats such as interspecific competition, disease transmission and hybridisation, which are drivers of genetic diversity loss among native fish populations, have been reported. However, most studies have focused on investigating cage fish production, water quality and the associated economics, but research assessing the genetic and ecological impacts imposed by the escaped fish from cages on native species is still limited across African countries. While direct evidence of hybridisation due to cage fish farming is lacking, genetic mixing of Nile tilapia with native Oreochromis species has been reported in some African water bodies. Further, only Egypt, Kenya and Uganda have functional Fisheries and Aquaculture regulations for guiding the aquaculture activities. Thus, there is an urgent need to institute regulatory frameworks that not only provide clear guidelines on aquaculture production but also balance between environmental conservation and economic sustainability

Capture fisheries and aquaculture have remained important sources of food, nutrition, income and livelihoods to millions globally, with annual per capita consumption of fish in developing countries having increased from 5.2 kg in 1961 to 18.8 kg in 2013. On the contrary, low income food-deficit countries annual fish per capita consumption rose from 3.5 to 7.6 kg against 26.8 kg among industrialized countries. Increased demand for animal protein and declining capture fisheries has seen aquaculture grow rapidly than any other food production sector over the past three decades. Rapid global aquaculture growth is directly related to levels of technological advancement, adoption and adaption prompting aquaculture transition from semi-intensive to intensive and super intensive production systems among developing and developed countries. In light of the aquatic environment economic potential, cage culture in Lake Victoria is fast gaining prominence in aquaculture production contribution. This began with trials by Kenya Marine and Fisheries Research Institute and Uganda's National Fisheries Resource Research Institute and later by private investors at Dunga and Obenge beaches of Kenya, Source of the Nile in Uganda and Bulamba Beach Management Units in Bunda District of Tanzania. However, only Kenya has so far documented cage culture development recording 3,696 cages across the five riparian counties with an estimated production capacity of 3,180 MT valued at Kshs 955.4 Million (9.6 million USD), created over 500 jobs directly and indirectly created income opportunities for over 4,000 people. The sub-sector's value chain, its supportive value chains and associated enterprises are rapidly expanding thus creating jobs, enhancing incomes and ensuring food security in rural and urban areas. As cage culture commercialization takes root, there is urgent need to address issues such as introduction of alien species, diseases, marine parks and maximum carrying capacity among other aspects. This will require trans-boundary policy to ensure sustainable utilization of the lake as a common resource.

Global interest in using duckweed (Lemna minor) as a substitute for fish, livestock, and human diets has spurred research on the mass culture of the species. There is a scarcity of information on the L. minor fatty acid composition in different aquaculture settings. A comparative study was carried out to investigate the fatty acid composition of L. minor cultured in indoor plastic tanks and outdoor earthen ponds for 30 days. During the culture period, culture facilities were fertilized using livestock manure. Fatty acid characterization was done using gas chromatography method. Fifteen fatty acids: five saturated (SAFAs), five monounsaturated (MUFAS), and five polyunsaturated (PUFAs) were identified. Fatty acid compositions varied between indoor and outdoor settings. Percentage composition of L. minor PUFAs cultured outdoor (37.13) was higher than that of indoor (21.96) settings. L. minor SAFAs percentage composition was higher in the indoor culture at 41.63% while that of outdoor was 33.75%. The composition of L. minor MUFAs in indoor tanks was higher (36.32%) than in outdoor earthen ponds (29.10%). This study indicated the presence of docosahexaenoic, eicosapentaenoic, linoelaidic, and eicosanoic acids in L. minor seldom reported in past studies. Paired Students’ t‐test indicated that the means of the fatty acid composition were significantly different (p < 0.05) in both settings, with docosahexaenoic showing the highest paired mean difference.

A polyculture experiment with African carp (Labeo victorianus) and Nile tilapia (Oreochromis niloticus) was conducted for 24 weeks in 12 earthen ponds measuring 150 m²to assess their compatibility. Monoculture treatments T1 and T4 forL. victorianusandO. niloticus,respectively, were the controls for the two species, while treatments T2 and T3 were a polyculture ofL. victorianusandO. niloticusat a ratio of 1:2 and 2:1, respectively. All treatments were carried out in triplicate, with feedings performed twice daily at 09:00 hr and 16:00 hr at 10%, 5% and 3% body weight distributed evenly over the 24‐week growth period. Fish sampling was conducted monthly, while water quality was measured biweekly. Treatment T3 (1L: 2T) had a significantly (p < .05) higher survival (L = 49% and T = 87%), compared to T2 (L = 31% and T = 69%, 2L: 1T).O. niloticusmonoculture treatment (T4) exhibited a significantly higher survival (p < .05) and higher growth (80%; 79 ± 20.04 g) thanL. victorianusmonoculture (T1) (50%; 13.12 ± 4.49 g). Dawn and afternoon temperatures ranged between 20.16–24.49°C and 23.76–31.07°C, respectively. The lowest temperatures were recorded in the months of June, July and August. TheNH₃concentration was zero at 14:00 hr for all treatments throughout the growth period, but significantly higher (p < .05) in T1 at 06:00 hr. ThepHandDOlevels at 06:00 hr and 14:00 hr were significantly different in all the treatments (p < .05). The slow growth ofL. victorianuscan be associated with the low temperatures andDOlevels. However, there is need to identify other factors that may have contributed to the poor growth ofL. victorianus. Accordingly, this study recommendsL. victorianusgrowth trials in other culture systems, coupled with different feed formulations, to identify optimal culture conditions.