Zanzibar mariculture leaps forward
Fisheries and aquaculture play a huge role in livelihood and food security in the United Republic of Tanzania and in particular in Zanzibar. In 2015, 36 321 marine coastal fishers and 147 479 inland fishers were reported; and, the total capture production of Tanzania mainland and Zanzibar was of about 405 000 tonnes. Marine catches amounted to 95 000 tonnes (61 000 tonnes from coastal Tanzania, 34 000 tonnes from Zanzibar), being the remaining 301 000 tonnes from inland fisheries. The principal fisheries exports have been Nile perch from Lake Victoria and prawns from the coast.
Total exports of fish and fishery products were valued at USD 158.7 million in 2015, while imports at USD 17.4 million. The annual per capita consumption of fish was estimated at about 7.2 kg.
In 2015, however small, aquaculture production, mainly Nile tilapia and shrimps, was close to 4 000 tonnes, with just about 4 tonnes of milkfish produced in Zanzibar.
The contribution of the seaweed industry seaweed industry is among the major economic activities in Zanzibar employing around 24,000 farmers whereby 80percent are women. Engagement in seaweed farming indicated that it played an important role in the coastal communities’ livelihood and women’s empowerment in Zanzibar, even if a decline in seaweed production and trade took place in the last six years.
Tanzania in 2013 was ranked as the 9th largest exporter of aquatic plants in the world at 0.66 per cent (FAO 2014). According to National Bureau of Statistics (NBS 2011) seaweed contributed 7.6 per cent of Zanzibar GDP, 2nd after cloves (47 percent) among cash crops in 2009.
Seaweed farming in Zanzibar started in 1989 using Eucheuma denticulatum commercially known as ‘spinosum’ and Kappaphycus alvarezii commercially known as ‘cottonii’. Both cottonii and spinosum belong to the red seaweed family Rhodophyceae, order Girgatinales. Despite higher production of spinosum, cottonii fetches higher price but its production has been declining substantially over the last six years, due to increasing of temperatures and longer hot seasons.
Since 2011, farmers have experienced serious problems of die-off and diseases resulting into decreased production from 15 088 metric tonnes in 2012 to 11 044 metric tonnes in 2013. It was mainly caused by a severe case of epiphyte infestation coupled with high incidence of ice-ice disease that occur during extremely high water temperature and high light intensity in hot-dry season.
Both maladies have long been observed by farmers and verified by the recent study conducted as part of FAO funded project “Support to seaweed diseases and die-off understanding and eradication in Zanzibar”. The study revealed that intensification of the disease occurs during the hot season and diminishes during the wet season, which revives the farms until the next hot-dry season returns.
This, in effect, makes seaweed production in Zanzibar to be highly season-dependent from what used to be a continuous year-round of plant-harvest-plant cycle done every 30–45 days, providing steady income to seaweed farmers who are 90percent women. Implementing the recommendations from the FAO Project and advice from the Institute of Marine Sciences helped recover the production in 2015 to 16 600 tonnes.
Besides selling raw seaweed, women farmers are organized in groups producing an assortment of food articles (cakes, juices, etc.) and cosmetics (soaps, massage oil, shampoo, etc.) and have developed a number of shops where the articles are being sold at relatively higher profits than the bulk export market. Shellfish farming, pearl farming and pearl and shell polishing are also being done mainly by women organized in small cooperative shops along the seaweed articles.
In 1996, very timidly and without major resources, Zanzibar people, supported by researchers of the Institute of Marine Sciences (IMS), started the systematic marine aquaculture of finfish in a very experimental basis, integrating finfish, shellfish and seaweed at Makoba Bay, Zanzibar. The preferred species were milkfish, Zanzibari tilapia and rabbit fish.
However timidly, the first results were widely disseminated and the roaring of the tam-tam for food security and nutrition, made its way to United States Agency for International Development USAID, Regional Coastal Management Programme (ReCoMaP) and other institutions who quickly responded to the call to support mariculture in the Island. Today, Zanzibar is the lead producer of milkfish in the Africa region, with only 4 tonnes per year.
Again, partners have heard the tam-tam, and FAO joined forces with the Korea International Cooperation Agency (KOICA) and the Government of Zanzibar for the development of a Multi-Species Mariculture Project that includes one commercial hatchery for the production of juveniles of milkfish, sea cucumber and mud crabs, among other species.
On 20th April 2018, the hatchery will be inaugurated and it is expected to produce about 10 million milkfish fingerlings, 1 million sea cucumber juveniles and 1 million crablets per year, from 2020. By that time it is also expected that 50 farmers will be fully operational using the same commercial production models that the FAO-KOICA funded project will instill in the community and private sector in Zanzibar.
In Africa, this hatchery is the first of its kind as a multi-species hatchery and one of the few in the world working on each of the individual species. At global level, there are milkfish hatcheries in the Philippines, Indonesia and Taiwan Province of China while hatcheries for crab are mostly in the Philippines Viet Nam, China, Malaysia and Fiji. The most known sea cucumber hatchery producers are the Philippines, Malaysia, Japan, and Madagascar.
The integrated multi-trophic aquaculture (IMTA) is done by integrating fed species (e.g. milkfish, rabbit fish, shrimps) with some extractive species such as seaweed species known for its bio-filtration efficiency for inorganic wastes (e.g. Gracilaria, Ulva, Sargassum) and bottom and filter-feeding invertebrates such as sea cucumber (e.g. Holothuria scabra), sea urchins (e.g. Tripneustes gratilla), mussels (e.g. Mytilus mytilus) and oysters (Pinctada) that remove suspended organic wastes.
Ideally, IMTA should integrate high-value species such as the ones above-mentioned to recover cost of investments and earn income for the farmers.
This project aims at developing a mariculture sector that promotes food secure, prosperous and competitive producers whistle conserving the Islands’ ecosystems and biodiversity.
In the existing shallow lagoons, where seaweed is farmed, the project will introduce sea cucumber and milkfish.
Based on the experimental results, fed species (e.g. milkfish) may be introduced in deeper waters and will be cultured in floating cages, together with seaweed and sea cucumber or other bottom-feeders.
Synergies using the current hatchery project in Zanzibar, dedicated to the production of sea cucumber and milkfish, with the established seaweed industry is beneficial to all farmers and the Island at large.
The supply of fingerlings and feeds are crucial to the success of milkfish farming, therefore, hatcheries and nurseries operated initially by the government will provide an inexpensive source of fingerlings to farmers, and, eventually the private sector will play the most important role in partnership with Government to operate business-oriented hatcheries.
In addition, feeds that need to be supplied to grow the fish from young to harvestable size can be sourced commercially and can be produced using local raw materials that include the farmed spinosum and cottonii and the green seaweed Ulva). More research to find alternative feeds, including locally available plant-based materials (e.g. seaweed, soya) could lead to the development of low-cost, high-protein feeds for fish farming.