Carbon, nitrogen and phosphorus loadings from tilapia fish cages in Lake Malawi and factors influencing their magnitude

摘要: Abstract Lake Malawi is a great lake not only because of its large size (30,800 km 2 ); but also it hosts between 700 and 1000 fish species, mostly endemic cichlids. The are most abundant more diverse in the littoral zone. Cage aquaculture started 2004 nearshore waters southeast arm. Approximately 50 cages were operational by 2009 harvesting about 20 tons fresh fish/cage/year. In 2007, data aggregated from cage feed production records to produce mass balance for carbon (C), nitrogen (N) phosphorus (P) added form juvenile 22 cycles. Nutrient losses surrounding environment accounted 81 91% C, 59 80% N 85 92% P. Production strategies such as stocking density feeding rates analysed assess their effect on harvests nutrient loads cages. study showed that significant can be exacerbated poor quality, overstocking, premature use lower than recommended grow target sizes. inefficient necessitated longer cycles (376 ± 42 days) usage achieve market sizes ≥ 300 g/fish if generally followed. If continues expand, will become an important new source nutrients, locally, lake-wide basis.