WWW.WAS.ORG • WORLD AQUACULTURE • SEPTEMBER 2016 25 Aquaculture in the Zanzibar Islands of Tanzania (Fig. 1) takes place mainly in the marine environment. The main types of farmed organisms are seaweed (Eucheuma denticulatum, Kappaphycus striatum, and Kappaphycus alvarezii), marine finfish (milkfish Chanos chanos and mullet Mugil cephalus), bivalve shellfish (pearl oyster Pinctada martensii, P. margaritifera, Pteria penguin, Isognomon, and Anadara spp.), crabs (mangrove crab Scylla serrata), sea cucumbers (Holothuria scabra, Actinopyga mauritiana, A. miliaris), and tilapia farmed in seawater. The greatest aquaculture production in Zanzibar is of seaweed, followed by finfish. Historical Perspective Seaweed has been farmed commercially since 1989. Commercial farming was preceded by studies on the potential of seaweed farming during the 1970s, followed by experimental farming in the early 1980s (Mshigeni 1976, 1992). In 1990, the first exports of dry seaweed (808 t) from Zanzibar occurred. Production has been increasing since then and by 2014 production was 13,000 t. Finfish mariculture started in the 1980s with a study of rabbitfish cage culture. In 1996, experiments were conducted by the Institute of Marine Sciences (IMS), working with several partners, using earthen ponds. The 1996 experiments culminated in establishment of the first finfish-shellfishseaweed integrated system in Makoba Bay, north of Zanzibar town, and formulation of the first marine fish feed (Mmochi et al. 2001). Species used then were finfish (rabbitfish Siganus and later milkfish Chanos chanos), shellfish (Anadara antiquata); and seaweeds (Eucheuma denticulatum, Kappaphycus alvarezii, Gracilaria crassa, Ulva spp., Chaetomorpha crassa, and Codium sp.). Following the establishment of the integrated system, several multidisciplinary studies were conducted using the integrated system, including an Status of Aquaculture in the Zanzibar Islands, Tanzania Flower E. Msuya, Hashim Muumin and Salum Hamed investigation of environmental and pesticide issues (Mmochi and Mwandya 2003, Mmochi et al. 2002), live food (Kyewalyanga 2003, Kyewalyanga and Mwandya 2002), and seaweed (Msuya and Neori 2002, Msuya et al. 2006). Shellfish farming that started in 1996 in the IMS integrated system expanded to reach some villages in Unguja and Pemba. Crab fattening started in the 1990s and sea cucumber farming around 2010. Unlike other forms of aquaculture, commercial seaweed farming started much earlier and, therefore, the experiments on integrating seaweed and fish were a step forward by the industry. Current Situation Seaweed Seaweed species farmed in Zanzibar in order of production are Eucheuma denticulatum, Kappaphycus striatum, and Kappaphycus alvarezii. The number of farmers, number of villages farming seaweed and production differ between the two islands. Pemba, with a population of 406,808 according to the 2012 census, has more farmers and greater production than Unguja, with a population of 896,721 although the number of villages that farm seaweed is less (Table 1). Similarly, the number of women farmers differs between the two islands. The number of villages farming seaweed in Pemba is less than in Unguja but the number of farmers is more than double that in Unguja (Table 1). In Unguja, the proportion of farmers that are women is 93 percent whereas in Pemba the proportion is 36 percent, reflecting differences between the two islands. The reason for fewer men farmers in Unguja than Pemba is that men in Unguja have more alternative job opportunities related to the more developed (CONTINUED ON PAGE 26) FIGURE 1. Map of Tanzanian coast showing aquaculture sites. Netting threaded with seaweed seedlings.
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