Seaweed farming in Zanzibar: addressing the common challenge of aquaculture and marine conservation

Published: 31 July 2022
Last edited: 31 July 2022
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Since 1990, Zanzibar has become a primary seaweed producer in Africa. Seaweed farming activities are usually small-scale and carried out in the intertidal zones largely in marine conservation areas, near mangroves and coral reefs. Eighty-eight per cent of seaweed farmers are women, making this an important activity to elevate their economic status and role in the community. New approaches to aquaculture and marine conservation have emerged only recently (in terms of concrete projects since 2014), with the case in Zanzibar serving as a first attempt to test the level of adherence of seaweed farming with the IUCN Global Standard for Nature-based Solutionsᵀᴹ.


East and South Africa
Scale of implementation
Coral reef
Marine and coastal ecosystems
Biodiversity mainstreaming
Ecosystem services
Fisheries and aquaculture
Gender mainstreaming
Local actors
Science and research
Standards/ certification
Sustainable livelihoods
Other theme
Gender mainstreaming
Nature-Based Solutions
Ocean warming and acidification
Lack of alternative income opportunities
Unemployment / poverty
Sustainable development goals
SDG 1 – No poverty
SDG 5 – Gender equality
SDG 8 – Decent work and economic growth
SDG 10 – Reduced inequalities
SDG 14 – Life below water
Aichi targets
Target 7: Sustainable agriculture, aquaculture and forestry
Target 19: Sharing information and knowledge


Unguja Ukuu Kaepwani, Zanzibar Central/South, Tanzania
North Pemba, Tanzania


Local communities, and especially seaweed farmers, many of whom are women, face a number of environmental, social and economic challenges. These include climate change, weak representation of women producers, difficulties in accessing international markets and insufficient protection of coastal ecosystems.  In response, an integrated coastal management approach and blue economy strategy are applied in Zanzibar. They aim to protect coastal ecosystems and habitats, enhance artisanal fisheries and mariculture. However, shortcomings in the management remain.


seaweed farmers (88% are women), coastal communities, rural women fishers, tourism sector

How do the building blocks interact?

The building blocks highlight a number of key insights that emerged from the assessment of seaweed farming in Zanzibar against the criteria and indicators of the IUCN Global Standard for Nature-based Solutionsᵀᴹ. The co-management approach and inclusion of women in particular was considered a strength of the intervention. However, it fell short in a number of other other areas for which corrective actions need to be taken. While the building blocks do not give a full picture of what can be considered a Nature-based Solution as they do not go into details on all criteria of the Standard, they illustrate how the Standard can be used as a tool to assess the design, implementation and current status of an intervention and whether it can be considered a Nature-based Solution. The assessment was particularly useful in helping to identify additional information and data needs to strengthen the intervention.


This case study is currently not in adherence with the IUCN Global Standard for Nature-based Solutionsᵀᴹ as it falls short in two criteria, namely criteria 3 (biodiversity net gain) and 6 (balancing trade-offs). It should also be noted that the self-assessment was carried out as a desk review towards the end of the IUCN AquaCoCo project. Further, means of verification were not always available, as data relating to certain indicators were not gathered. To conduct a more comprehensive assessment, local stakeholders should be involved as key informants. Nevertheless, the self-assessment provided insights into areas for improvement as to how interventions are designed, implemented and monitored. It also provided insights into knowledge and data gaps, which prompted critical questions and corrective actions that need to be addressed going forward.


F. Simard

Seaweed farming provides cash income for many women of local communities in Zanzibar. Usually, seaweed harvested in Zanzibar is dried and exported to various parts of the world which used seaweed for pharmaceutical products and in the cosmetics industry. This woman is producing artisanal soap made of seaweed that she will sell on local markets and direct sales into resorts to tourists visiting the archipelago. This exploration of the development of local value chains is quite inspiring and can generate more direct incomes for them. Other attempts to diversify the revenues from seaweed farming are made to propose field visits of mariculture sites within the marine and conserved areas in Zanzibar to tourists.


Mwanaisha Makami, seaweed farmer (traditional peg and rope, off-bottom technique) and processor: “I am currently a member of the Seaweed Cluster Initiative. I started farming immediately after I left school, and processing in 2012. I dry and grind seaweed for making soaps, creams etc. It is a good business that brings income. We have a local market as well as a tourist market.  I use the money to pay for the school fees and a house. It doesn’t depend on anybody. We need to encourage the young generation [to do it]”. 

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Kristin Meyer International Union for Conservation of Nature (IUCN)

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International Union for Conservation of Nature (IUCN)