A review of the culture of Sarotherodon melanotheron in West Africa
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The paper reviews results of the culture of Sarotherodon melanotheron in West Africa and problems encountered. A parental mouth brooder living in brackish waters from Senegal to Zaire, it tolerates salinity ranges of 0 to 45 ppt but prefers 10 to 15 ppt. Females can mature at 4.0 cm SL and males at 4.5 cm SL. Mean spawning frequency is every 22°C. It will grow and reproduce at pH 3.5 to 5.2. It can feed on phytoplankton, benthic diatoms, filamentous algae, periphyton, detritus, and artificial fe eds. 4 to 5 week feeding with Methyltestosterone at 40 mg/kg feed gave over 95% males. Under culture conditions in ponds, enclosures, and cages, growth is 0.5 to 0.7 g/day until a mean weight of 25 to 35 g in ponds and 50 to 60 g in cages and enclosures when stunting occurs. In ponds, growth is the same if fed wheat bran, chicken mash, pellets at 5% of the biomass, or with an application of manure at 1.8 T/ha. Biomass did not increase beyond 1.3 T/ha, yearly production was 1.9 to 3.5 T/ha/yr; highest values from ponds harvested in the shortest time. In enclosures, males virtually ceased to grow beyond 50g. Growth of tagged fish of both sexes was inconsistent; some males lost weight. In tanks, males were smaller that females at the end of 8 month feeding trials. In cages, growth was 0.1 to 0.2 g/day beyond 50 to 60g mean weight although there was no breeding; a monosex male culture, lower density, and altering quantity and distribution of the feed did not help. Reasons for stunting in clude sexual maturity, density, feeding, and chemical factors in the water. The fish can be raised efficiently to a weight of 35 to 50g using ponds, enclosures, or cages; a limited market for this size exists. For larger fish and higher production, the acadja or brush park technique gives production of 7 to 20 T/ha/year with a size range after 1 year of 20 to 560g