Service Pilot 3: Aquaculture in Tanzania

Members of the Zanzibar Seaweed Cluster Initiative. Photo source: Dr. Flower MsuyaAquaculture now accounts for nearly 50% of the world's food fish consumption . In Europe aquaculture provides 1.25million tonnes of seafood annually, valued at over 4 billion euro. Diminishing supply of wild captured fish and fish products and global increase in demand for fish and fish products provides an incentive to increase the supply through development and promotion of sustainable aquaculture in Africa. Throughout the world, aquaculture has proven to be a success, evidenced by the global increase in the contribution of shellfish, fish and fish products from aquaculture in recent years . However, some of the major fishing countries in Africa (the United Republic of Tanzania, Egypt and the Democratic Republic of the Congo) have reported reduced catches in inland waters. Such decreases are directly attributed to pollution, environmental degradation and, limited habitat leading to overfishing.

The aquaculture service pilot will be undertaken with the FAO Fisheries and Aquaculture Resources Use and Conservation Division and FAO’s partner in Tanzania – the Institute of Marine Sciences at the University of Dar es Salaam. The trial in Tanzania is designed to extend existing FAO activities in Tanzania thereby creating synergies between the FS-TEP project and FAO’s activities.

Trial Service: Mapping of previously developed and currently in-use coastal aquaculture sites

Monitoring the aquaculture industry is needed in order to understand the health of the aquaculture sector towards food security goals. To gather information and monitor the aquaculture sector on a national level requires a large amount of coordination and resources. In this trial service, remote sensing techniques will be trialled as a technique for identifying previously used and currently in-use coastal aquaculture sites. This information will be used as inputs to FAO’s National Aquaculture Sector Overview  (NASO) inventory processes. 

In Tanzania, mangroves may be cleared to increase production of fish, prawn and crab aquaculture. The clearing of mangroves for aquaculture use is not recommended as intact mangroves provide essential habitat for fisheries and other vital ecosystem services. As such, mangrove classification maps will be created for all coastal areas in Tanzania on an annual basis (2017 and 2018), with change detection done to observe where mangrove habitat may have been lost due to aquaculture developments.  

Trial Service: Site Suitability for moving seaweed production in Zanzibar further offshore

On the islands of Zanzibar in Tanzania, the livelihoods of thousands of women and their families depend on farming seaweed. According to the government, the sector used to employ 23,000 people, 90% of whom were women (BBC, 2014) . In this conservative Muslim society where men hold most of the jobs, seaweed farming changed the position of the women in the society. Women previously stayed indoors and waited for their husbands to bring all that is required at home, but farming seaweed allowed women farmers to improve their standards of living in several ways including sending children to school, improve their houses, and purchase high quality foods (Msuya, 2013).

Recent changes in the world market and the farming environment are threatening this industry. In particular, Eucheuma cottonii – the most profitable seaweed species – is now failing to grow in areas where it used to, due to changes in environmental conditions (Figure 9). These changes include the rise in seawater temperatures, epiphytism, and fouling. Some farmers, especially men, are leaving seaweed farming while others, mostly women, are carrying on with lower expectations (Msuya, 2012). In the village of Paje, there are just 150 seaweed farmers left, down from 450 twenty years ago (Reed, 2017).
Seaweeds in Tanzania are farmed using primarily the peg and line (off-bottom) method, which is the most common farming method worldwide. The off-bottom method, however, has suffered high production losses in Zanzibar due in part to rising seawater temperatures.  To increase production, moving seaweed farms to cooler water further from shore is being considered. However, the move further from shore has a wide variety of constraints which will be included in the geospatial analysis of this problem, including: 

  • Gender constraints, including that women are rarely taught how to swim in the communities currently involved in seaweed farming adding access and safety constraints;
  • Ocean currents and water quality considerations (such as sea-surface temperature, turbidity and salinity) play a role in seaweed growth;
  • the islands of Unguja and Pemba have different geographical features so may experience climate change at different rates; 
  • conflicts with hotels, dive sites and historic sites should be minimised; and
  • shipping channels and other common marine traffic routes should be avoided.