Lake Malawi is a deep, meromictic lake set within the East African rift valleys. The lake supports over 800 species from 14 families, and almost all of the cichlids are endemic (Ribbink, 2001). The pelagic community is dominated by adult cichlids that fill both zooplanktivore and piscivore niches (Nsiku, 1999) while the nearshore tilapiine complex known locally as chambo (Oreochromis karongae, O. squamipinnis, and O. lidole), once dominated the Lake Malawi fisheries, has been greatly reduced in abundance (Darwall and Allison, 2002; Weyl et al., 2005).
Fish and Fisheries
Fish are important as a source of food and income across the African Great Lakes. In Lake Malawi, average landings in 2000 were 70,000 tonnes and provided food and income for more than 240,000 people (Banda et al., 2005). There is also substantial export trade in ornamental fishes locally known as mbuna (Banda et al., 2005; Munthali, 1997).
Fisheries in Lake Malawi include commercial, small-scale subsistence, and traditional (or artisanal) operations. Commercial fisheries use pair- and stern-trawlers that primarily operate in the southern part of the lake (FAO, 1993). Non-commercial operations occur across the lake using gill nets, beach seines, purse seines (known locally as chilimira nets) used during the day and at night with light attraction, and longlines in vessels that are primarily canoes and plank boats that may be motorized (FAO, 1993; Weyl et al., 2004). In 1989, there were 6,612 fishers earning their livelihoods in southern Lake Malawi using between 1,500–1,600 vessels (Tweddle et al., 1994). Mean annual catch between 1976 and 1996 was approximately 30,000 tonnes/year (Fig. 1) of which 8% comes from commercial operations and 92% from traditional fishers (Weyl et al., 2005).
Population Growth and the EconomyThe human population around the East African Great Lakes has been steadily increasing. More than 10 million people reside in the Lake Malawi catchment with the highest concentration in the southern and central regions that provide the best fishing and agricultural land (National Statistical Office, 1999). In the countries of the Lake Malawi watershed (Malawi, Mozambique, and Tanzania) fishing employs more than 300,000 people and beach value of landed fish is estimated at $15 million US (Banda et al., 2005). Prior to the collapse of chambo, fish provided over 70% of the annual protein for residents in the basin (Bland and Donda, 1995) but this was reduced by at least 20% after the collapse (Banda et al., 2005). Agricultural production plays a more significant role than fisheries which only contributes about 4% to Malawi's GDP (Munthali, 1997).