Recycling of wastewater provides a substantial solution to the global issue of water scarcity and high water use in aquaculture. However, this sustainable way of wastewater use has not been given much attention and exploration. This study focused on the consumer preference for fish grown in treated wastewater as well as the effect of aeration on the growth performance and economic benefit of African catfish (Clarias gariepinus) grown in treated wastewater. Two hundred (200) respondents from two communities (Chirapatre and Gyinyase) near the wastewater treatment plant in Kumasi were interviewed to determine their willingness to accept and pay for African catfish grown in treated wastewater. For the growth trial, a total of 600 fish (of average initial weight 39.12g) were stocked in two maturation ponds with 4 h (3:00am-7:00am) of aeration daily. The trial lasted for 12 weeks and variables monitored included the survival, growth performance (weight gain, specific growth rate, and yield) and water quality. Fish cultured in non-aerated wastewater ponds (NWFPs) under similar conditions as in aerated wastewater-fed ponds (AWFPs) served as control. The results indicated most important considerations for consumers in their choice of fish to consume were in order of importance; food safety, freshness of fish, taste and packaging. The proximity of consumers to the treatment plant, the price of fish, religion, and age and whether or not they were fish consumers affected their willingness to pay for African catfish grown in the treated wastewater significantly. For the growth trial, dissolved oxygen concentrations in the aerated ponds were significantly higher than in the NWFPs and this led to more than a doubling of the growth rates in the African catfish grown in the AWFPs (189.10g AE 11.32) as compared to the NWFPs (90.70g AE 11.59). The pond aeration improved fish growth significantly (p < 0.0098). On economic benefit, the aerated system yielded profits of 618.83 (€103.13) as compared to a loss of 104.99 (€17.50), which was incurred in the non-aerated ponds. Education of the consumers on the process of wastewater treatment and establishment of food safety guidelines will therefore be recommended to increase consumer interest in consuming fish from the treated wastewater.

This study assesses the microbial and heavy metal distribution in African catfish (Clarias gariepinus) cultured in waste stabilization pond, and their subsequent suitability for human consumption. Treated wastewater-fed pond (WFP) was used in the culture of the fish with a non-wastewater fed pond (NWFP), fed with ground and rain water as control. Pond water, sediments and fish tissue (gill, liver, gut and skin) samples from both sources were analyzed for pathogens and heavy metal levels. Escherichia coli populations in the sediments and water from the WFP exceeded the maximum permissible limit by 2-3 log units as expected. Significantly higher levels of pathogen contamination were detected in the gut and skin of fish from the WFP than the NWFP. Heavy metal concentrations in all samples fell within the Food and Agricultural Organization (FAO)/World Health Organization (WHO) and National Oceanic and Atmospheric Administration (NOAA) permissible limits except for iron and cadmium. There were significantly higher heavy metal concentrations in gill and liver than the muscle. Even though iron recorded the highest concentrations in fish tissue, the concentrations (0.1-2.0 mg kg) were below the expected daily nutritional requirement (1-2 mg) for humans and pose no toxicological risk. However, catfish from WFP would require precautionary measures such as cooking/grilling prior to consumption to avoid pathogen infection.

This case study documents the development of a small-scale fish farm in an attempt to highlight the efforts of a fish farmer (Mr. Poku Gyinaye, a former Fisheries officer) to establish a commercial fish farm in the Ashanti Region of Ghana. Accounts of the facilities, technology and management practices used by the farmer are described as well as his profile. The objectives of the farmer to undertake such a project were to produce fish seed for fish farmers to help them improve fish production, provide practical aquaculture training for prospective fish farmers and access to recreational fisheries for both local and foreign tourists. At the time of writing (by May 2009), Mr. Gyinaye has almost completed setting up the hatchery and has three large ponds for recreational fishing. He also has plans to start a public aquarium on the site. The main activities on his farm centre on Oreochromis niloticus and Clarias gariepinus fingerling production. He intends to stock his recreational ponds with indigenous predatory fishes.