Seaweed farming in Africa: current status and future potential

Abstract

Global demand for seaweed and its products has increased exponentially over the last 25 years. Equally, the continent of Africa and its offshore islands have considerable potential for seaweed production to contribute to world demand. Compared with China and the rest of Asia, Africa lags behind in seaweed production and utilisation. However, for red eucheumatoid seaweeds, Africa is the third-largest producer in the world, producing about 120,000 t (FW) annually. Details are provided for 13 African countries that are currently involved in seaweed farming and harvesting, commercially or experimentally, for export or domestic utilisation. Eucheuma spp. and Kappaphycus spp. in Tanzania represent 92% and in Madagascar 4.7% of continental production, and Ulva spp. and Gracilaria spp. in South Africa represent 1.5%. Over 2000 species of seaweed have been recorded in Africa, some of which are already successfully cultivated in other parts of the world. The environmental conditions across the continent range from warm, tropical waters to the cooler, nutrient-rich waters of the southwest, enabling the cultivation of seaweeds from the tropical, carrageenan-producing eucheumatoids to temperate kelp species. Seaweed aquaculture production in Africa, led predominantly by women, has improved the livelihoods of its coastal people. Challenges through disease and pest outbreaks, as a result of climate change, and the low prices paid to farmers are highlighted as major constraints on the development of this industry. Through scaling up and expanding current efforts in production and utilisation of seaweeds, Africa has the potential to join China and Southeast Asia as a global leader in producing, processing and consuming a wide variety of seaweeds.

Porter’s Five Forces Analysis of Zanzibar’s Seaweed Industry

“…The industry is also the third largest source of revenue for the Revolutionary Government of Zanzibar [4]. The industry has existed for over thirty-three years and employs about 25,000 seaweed farmers, of which women make up more than ninety per cent of the total number of farmers [5]. The farming practice has significantly improved the livelihoods of its rural farmers, especially women [6,7,2,8,9,10,5] (Msuya, 2009).…”

“…Despite its economic and socio-economic contributions, especially in improving the livelihoods of rural farmers, the industry has failed to tap into the growing global demand for red seaweeds, thus underperforming compared to competitors in Asia [11]. ZSI's current challenges include failed production, especially on Unguja island and low returns [6,11,5] (Msuya, 2009;Songwe et al, 2017). Production challenges have been attributed to severe ecological changes on the island that have led to poor thallus growth, epiphytes, diseases (ice-ice) and high die-offs [1,12].…”

“…Production challenges have been attributed to severe ecological changes on the island that have led to poor thallus growth, epiphytes, diseases (ice-ice) and high die-offs [1,12]. The low returns challenges have been attributed to the unfavourable demand conditions in the global seaweed market and limited product utilisation properties [11,8,5]. The challenges of production and low returns have led to diminishing production and export trends on the island [11].…”

Forensic carbon accounting: Assessing the role of seaweeds for carbon sequestration

“…2019, Kelly 2020, Msuya et al. 2022). One imperative driver of expanding seaweed aquaculture, including into the open ocean, is to increase the removal of atmospheric carbon dioxide (CO 2 ) and sequester carbon, to help mitigate ongoing global warming (e.g., Chung et al.…”

“…In Asia, seaweeds are farmed in coastal waters on large scales for human food, alginates, agar, and carrageenan and can provide important ecosystem services (Chung et al 2017, Hu et al 2021). Seaweed aquaculture is being trialled by an increasing number of "nontraditional" seaweed-producing countries within the Americas, Africa, Europe, and Australasia (Buschmann et al 2008, Barbier et al 2019, Kim et al 2019, Kelly 2020, Msuya et al 2022. One imperative driver of expanding seaweed aquaculture, including into the open ocean, is to increase the removal of atmospheric carbon dioxide (CO 2 ) and sequester carbon, to help mitigate ongoing global warming (e.g., Chung et al 2011, Ahmed et al 2017, Duarte et al 2017, Hossain et al 2021, UN Global Compact 2021.…”