African catfish (Clarias gariepinus) has been growing in popularity as a culture species globally. Although considerable research has been carried out on this species’ feeding preferences, no research has been carried out on optimum water level for growth. This is particularly surprising given this species' benthic nature. This study assessed the effect of different combinations of water levels and types of feed on the growth performance of African catfish. The study employed a 3 × 2 factorial design with three ponds of different water levels (0.5, 1 and 1.5 m) and two types of feeds (floating and sinking). Twelve earthen ponds (1 × 2 m) were each stocked with 16 catfish fingerlings (mean weight ~100 g), and their growth was monitored for 12 weeks. The fish cultured in the shallowest water grew significantly faster than those cultured in the deepest ponds. At the same time, fish cultured in the shallowest ponds had the lowest feed intake rates and consequently the lowest feed conversion ratios. Catfish fed sinking pellets grew faster than those fed floating pellets although the difference was not significant. There was no significant interaction between pond water depth and feed type. The results of this study suggest that the growth and feeding efficiency of C. gariepinus can be optimized using culturing in fairly shallow ponds (0.5 m).

Kenya’s inland aquaculture sector is one of the most productive in Africa. Efforts are currently being made at the national level to expand and intensify the sector. Despite the drive to develop Kenyan inland aquaculture, the sector continues to encounter barriers to sustainability and economic profitability. Fish welfare is also highly neglected which has implications for fish health and overall sector productivity. This review documents the current state of inland aquaculture in Kenya, covering its considerable growth since 2009 to the current day and looking at both intensive and extensive forms of fish farming, paying special attention to the challenges faced in terms of animal welfare. Given that the inland aquaculture sector in Kenya has been earmarked for further rapid growth, with considerable economic and strategic support in place to foster this, some of the core issues of sustainability must be recognised and addressed. This review focuses on one of those, namely animal welfare.

The farming of sturgeon to produce caviar is increasing globally, even though little is known about the welfare implications of aquaculture for these unique, long-living, and large animals. The use of non-lethal methods for egg harvesting is increasing, as these methods are thought to offer a more ethical alternative to traditional methods where the female is killed. However, these “non-lethal” methods raise significant welfare concerns including routine handling, surgical procedures, and painful procedures, and could potentially perpetuate suffering. Consequently, there is an urgent need for significant exploration and research into this field. This review presents and discusses some of the welfare concerns associated with producing caviar from sturgeon, including the traditional and non-lethal methods of egg harvesting and the concerns associated with rearing them in aquaculture systems. It concludes in stating that the welfare issues involved with non-lethal caviar production are too sizeable to warrant its description as an “ethical or humane” alternative to traditional caviar production.

The food industry and the frozen fish sector in particular have benefitted greatly from advancements in food processing technologies. This study investigated the effect of adding natural antioxidants such as rosemary and thyme oil to frozen fillets of Nile tilapia (Oreochromis niloticus) in order to preserve their quality for consumers. Fillets were treated with rosemary and thyme at two concentrations (1% and 1.5%) and then were stored at 4°C. Samples were analyzed over 4 days for bacteriological (aerobic plate count, psychotropic count, and coliform count), chemical (determination of pH, thiobarbituric acid reactive substances-TBARS, and total volatile base nitrogen-TVB-N), and sensory quality examination (color, texture, and odor). Significant differences (P<0.05) were observed among different groups in terms of aerobic plate count, psychotropic count, and coliform count during the storage. Moreover, pH, TVB-N, and TBARS mean values in the treated groups were lower than those in the untreated group. The best sensory quality was obtained at the highest concentrations (1.5%) of thyme and rosemary oil.