Cage fish culture in Lake Victoria: A boon or a disaster in waiting?

Abstract

Fish catches in Lake Victoria have been on the decline while demand for fish has been increasing. Cage culture with >3,000 cages, over 3 million tilapias and valued at US$ 12 million is trying to fill the gap. This study reviews the development of cages and the need to develop a decision support tool for effective management. Existing literature and data on fisheries and cage culture held by the Kenya Marine and Fisheries Research Institute (KMFRI) were used in the analysis. Cage culture is a promising venture that may increase productivity, offer employment and enhance economic well‐being. However, site suitability for the installation of cages is poorly regulated with most developments (>45%) located within 200 m of the shoreline that are breeding grounds of fish and conflict with other lake users. Waste feed increases eutrophication, and enhances growth of algae and water hyacinth in the lake. Recent isolated fish kills were attributed to low dissolved oxygen concentrations (<0.64 mg/L), and an increasing occurrence of fish disease are signs of poor management practices among cage farmers. Cage culture may turn into an environmental disaster if not managed well, and there is need for robust policies and increased awareness to reduce environmental impacts.

Spatio‐temporal trends of nutrients and physico‐chemical parameters on lake ecosystem and fisheries prior to onset of cage farming and re‐opening of the Mbita passage in the Nyanza Gulf of Lake Victoria

“…Cage fish farming is practiced in several areas of the lake (Aura et al., 2018; Njiru et al., 2018), contributing to improved fish production and livelihoods of the communities dependent on the lake fisheries resources. Fish cage culture in the Kenyan portion of Lake Victoria began around 2005, and fish cage farming continues to expand in this area up to the present time, with a 262% increase in the number of fish cages (Hamilton et al, 2020).…”

“…Accordingly, the present study presents trends on the nutrient status of the Gulf, contributing to a better understanding of eutrophication and its effects on fisheries production, with the goal of discussing the nutrient sources amid the potential emergence of new challenges from the developments in fisheries (e.g., cage fish farming) and potential resurgences of water hyacinth along its bays. Recent studies indicate an increasing number of fish cages (Aura et al., 2018; Hamilton et al., 2020; Njiru, Aura, & Okechi, 2018). There also are growing concerns regarding the water quality around those areas attributable to non‐adherence to best practices in cage fish farming (Musinguzi et al., 2019).…”

Towards sustainable fisheries and aquaculture management in the African Great Lakes

“…Respondents recognised the increasing contribution of aquaculture to food supply, with rapid expansion throughout the AGL region, especially more recently in cage culture (Njiru et al, ). Concerns were expressed over sustainability of cage farming because of wastes from farms resulting in eutrophication and anoxia, the latter causing severe fish kills on farms.…”

“…Failure to regulate aquaculture growth is a major challenge facing development of the sector in the AGLs (Njiru et al, ). There is a need for proper planning procedures to be formulated and implemented both locally and basin‐wide and linked to best practice guidelines (Aura et al, ).…”

Using fish landing sites and markets information towards quantification of the blue economy to enhance fisheries management

“…Fisheries occupy a significant place in the socio‐economic development of many countries (Aura et al., ; Njiru, Aura & Okechi, ; Woodhead, Abernethy, Szaboova & Turner, ). For example, Kenya's fisheries sector contributes about 4.7% of the country's Gross Domestic Product (GDP) (Mulatu, Oel, Odongo & van der Veen, ).…”