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and letting the seaweed attach itself to the rock and grow and 2 the “broadcast method” which involves placing seaweed in fences made of netting materials.
3.2 Economic performance
The economic performance of two seaweed K. alvarezii farming methods used in Tanzania are examined below. One is the traditional off-bottom method; the other is
deep-water floating lines method. Comparison of costs was achieved using data from Zuberi 2000, Msuya et al. 2007a, Msuya 2006b, Msuya 2009b, and the current
study through interviews with seaweed buying companies and a number of NGOs.
Capital cost The traditional off-bottom method remains the most widely used technique in
Tanzania. This method uses 4-mm diameter lines with varying lengths between 4 and 20 m, depending on the characteristics of the site and the ability of farmers. In Zanzibar
and in some mainland areas, farmers only use 4- or 5-m lines. However, in areas such as Bagamoyo, Tanga, Mtwara and Lindi, farmers use long lines 10−20 m, see Figure 7
to which buoys are sometimes attached.
Table 1 summarizes the investment requirements and the corresponding amortized annual capital costs i.e., depreciation of an off-bottom farm. The farming system
comprises ropes, tie-tie, floaters and stakes. Thirty pieces of 10-m ropes are needed. One roll of tie-tie is required for every three lines of 10-m rope. Floaters are made of
recycled plastic water bottles. Two floaters per line are required for a total of 60 floaters one floater per 5-m length of line. Floaters normally need to be replaced after three
months; hence totally 180 floaters are needed for one year of operation. Two stakes per line are required, which normally need to be replaced after 6 months; hence 120 stakes
in total are needed for one year of operation.
TABLE 1
Initial investment and amortized annual capital costs for an off-bottom farm
Items Quantity
Unit cost TZS Total
investment cost TZS
Lifespan years
Annual amortized
capital costTZS
Farming system 19 490
19 490
Ropes m 300
27.8 8 340
1 8 340
Tie-tie roll 10
275.0 2 750
1 2 750
Floaters 180
30 5 400
1 5 400
Stakes pegs 120
25 3 000
1 3 000
Boat and equipment 20 500
7 328
Boat construction 1
7 413.8 7 414
10 741
Boat maintenance 1
86.2 86
1 86
Diving masks 1
10 000.0 10 000
2 5 000
Knife 1
1 000.0 1 000
2 500
Machete 1
2 000.0 2 000
2 1 000
Post-harvest facilities 20 000
6 900
Drying rack frame 1
7 000.0 7 000
5 1 400
Palm fronds for rack 30
50.0 1 500
1 1 500
Tarps m 10
1 000.0 10 000
4 2 500
Plastic bags 10
150.0 1 500
1 1 500
Total 54 890
33 718
Source: Modified from Msuya et al. 2007.
Non-motorized boats are routinely used by farmers; the cost of constructing one boat is TZS 430 000. In the case of the 58-member cooperative, each farmer
would contribute TZS 7 413.80. The useful life of the boat is about 10 years and boat maintenance is performed once a year at a cost of TZS 5 000 each cooperative member
contributes TZS 86.21 per year.
Equipment and tools include knives and machetes for cutting and sharpening the stakes, snorkelling masks for inspecting the plots during high tide, and gloves and
rubber shoes to prevent scratches in hands and legs. Traditionally, seaweeds are dried on palm fronds and cloth materials placed directly
on the ground Figure 10. To improve quality, drying racks made of wooden stakes and palm fronds that elevate the drying surface off the ground are recommended
Ask, 1999; MNRT, 2005; Msuya, 2006b. Farmers have begun constructing racks as they learn the importance of thorough drying. Thus the cost of constructing a drying
rack is included in this analysis. A drying rack frame is built using two bundles of wooden stakes, each costing TZS 2 000, 15 palm fronds at a cost of TZS 50 per frond
the palm fronds are normally changed every three harvests, thus a total of 30 palm fronds are required, and two rolls of rope, each costing TZS 500. The labour cost for
the construction of one rack is approximately TZS 2 000. In the rainy season, plastic materials i.e., tarps are needed to cover the seaweed while it is drying. Plastic bags
10 pieces are used for transporting the wet seaweed from the farm to the drying area and for storage of the dry seaweed.
Table 2 summaries the investment requirements and the corresponding amortized annual capital costs of a deep-water floating-lines farm with 30 pieces of 12-meter lines.
The raft frames require one roll of 12-mm lines for the frame, one roll of 10-mm anchor lines, one roll of 8-mm lines for tying anchors, and three rolls of 4-mm lines for tying
seaweed. Anchors consist of fertilizer bags filled with sand or stones depending on the availability of sand and the nature of the tidal flat environment muddy bottoms
would demand more frequent replacement of the sand bags. Recycled oil cans are used both as large buoys and markers while the plastic water bottles are used as floaters. A
commercially profitable floating system should be at least 20×10m.
The boat, equipment and post-harvest facilities used in the floating-lines system are assumed to be the same as the off-bottom farm.
FIGURE 10
Drying seaweed in Kiuyu Pemba Island, with storage sheds shown at the background
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TABLE 3
Initial investments and amortized annual capital costs: off-bottom vs. floating lines
Items of capital investments
Total investment cost Amortized annual
capital cost Capital cost
per km Total cost
USD Share of total
cost Annual cost
USDyear Share of
Annual cost Total
USDkm Annual
USDyear km
Off-bottom 30×10 m
- Farming system 15.5
32 15.5
58 51.8
51.8 - Vehicle and equipment
16.3 34
5.8 22
54.4 19.5
- Post-harvest facilities 15.9
33 5.5
20 53.1
18.3
Total 47.8
100 26.9
100 159.3
89.6 Floating lines 27×12 m
