In 1987 about 50 tons of farmed tilapia were produced in the Northern Province per year. The per capita consumption of farmed tilapia in most of the producing households would be of the order of 2–4 kg per annum. However, as most households consumed tilapia before they started culturing, it would not be correct to consider the entire 2–4 kg as an addition to the consumption level of fish in the concerned households. The information collected indicates that the quantities purchased have been reduced. A considerable part of the “net increase” in tilapia consumption, that farming of the fish causes, will have come in “neighbouring” rural households.
The above production estimates are based on the reported culture methods (use of both feed and organic fertilizers). However, as their rate of application are not known (but are known to depend on their availability in the household), a modest rate of production is used: 1 000 kg/ha/year.
This production rate has been applied to the average water area per farmer obtained through the survey. The area is 929m2. The area may include one or more ponds. This area has been then applied to the estimate of total number of active fish farmers. (67.7% of 731 = 495).
A relatively large number (37% of respondents) of practising farmers reported that they were constructing additional ponds. This alone should lead to production increase. The amount of effort spent on managing the ponds will remain steady even if the alternative of producing cash crops improve. However such a change probably will reduce the rate of increase in the number of ponds. This will not change until tilapia becomes a true cash crop and farmers can rely on traders purchasing fish at reasonable prices. At the moment sales are not made to traders.
There are two major ways of increasing the output of tilapia from fish ponds in the Northern Province. The first is to bring more ponds under production; the second to increase the rates of production. The second method would seem more of a possibility for government than the first. Pond construction and rehabilitation is at the discretion of farmers.
Present pond production of tilapia in rural areas is almost exclusively of a continuous type with intermittent fishing. This means in most cases that (i) the ponds are not regularly drained, and that (ii) the tilapia reproduce in the ponds, and therefore as the farmer sees it, there is no need to purchase and stock fingerlings. Thus in older ponds, inbreeding may have had a degenerating effect (exception made for those ponds to which tilapia specimens arrive regularly with the river water inflow).
There are two good reasons for supporting the farmers' present intermittent harvesting system. First, tilapia is easier to sell frequently in small volumes than in large quantities at longer intervals. The ponds are seldom large enough, even under optimum management procedures and batch harvesting, to warrant the efforts of a fish trader to venture to the pond site.
Second, with this system a sizeable share (now reported frequently to be of the order of half or more) remains and is consumed within the household. It seems less likely that this would continue to be the case if a batch production system was introduced.
A possible strategy to improve productivity levels under the continuous harvesting system would be to simultaneously stock farmers' ponds with fingerlings of proven tilapia strains (in addition to those already in the pond - but then possibly after a partial harvest) and then demonstrate and instruct in adequate quantity, quality, frequency and timing for providing feed and fertilizers.
