WORLD AQUACULTURE 39 fish (NaFIRRI 2005, 2006, 2007), indicating a fishery under pressure because the recruitment process is disrupted. In the study area (Fig. 1), lungfish ranked third in fisheries catch after tilapia and Nile perch. However, lungfish (ebileng) captured from Lakes Opeta, Bisina and Nyaguwo (Kumi District) represents 59 percent of the catch; other species include tilapia (18 percent), Clarias spp (18 percent) and Mormyrus spp (5 percent). Two forms were commonly harvested in this region; eigolo, the giant lungfish, and ebilongotuba (P. aethiopicus), the tailless form captured while aestivating in the dry season. The average size and numbers of lungfish has fallen markedly in this area during the past decade from increased demand. For example, production from Lake Opeta fell from 3000 t (early 1990s) to 154 t, exacerbated by an increase in fishing vessels (over 400) and consequent overfishing. Also, fishermen acknowledge catching undersized but sexually mature lungfish of less than 300 g (Fig. 2) from Lakes Opeta and Bisina, suggesting a plasticity of response to increased fishing pressure. Regionally, over 90 percent of African lungfish is caught from Uganda’s natural waters, including lakes, rivers and floodplain wetlands that constitute about 20 percent of its surface area (Hecky and Bugenyi 1992). From 1975 to 2009, about 404,000 t of lungfish were harvested; 371,811 and 32,197 t from Uganda and Kenya, respectively and none from other East African countries at the time of this study (Fig. 3). Capture fisheries production of African lungfish in Uganda peaked during 1976 to 1985 but decreased thereafter (Fig. 4). Lungfish contributes only 4 percent to national fish production, as compared to the two major species of Nile perch (42 percent) and tilapia (37 percent). Lungfish Fishery Regulation The lungfish fishery is regulated under the Fish Act (Cap. 197) of 2000, which prohibits capture of immature fish. The law emphasizes tilapia and Nile perch fishing, making enforcement to protect lungfish difficult to implement. The Fish Act does not have a size limit for immature African lungfish. Fish farmers are exempt from marketing undersized fish, allowing these fish to compete favorably with wild fish. The National Environmental Statute of 1995 provides for sustainable use and conservation of the environment and natural resources of Uganda. The Aquaculture Rules of 2003 permits export of live male P. aethiopicus from Uganda, which indirectly protects local fish farmers. Lungfish Aquaculture Previous attempts to grow African lungfish in captivity provide insights into its aquaculture potential. Baer et al. (1992) succeeded in growing wild-caught gilled African lungfish Protopterus amphibious juveniles in concrete tanks that were fed on soft balls of feed containing raw, minced beef heart and cooked tilapia. In another study, marbled lungfish Protopterus aethiopicus fingerlings raised in earthen ponds grew 2.7 to 14.5 cm from 70 to 238 days and at specific growth rates of 0.048 to 0.140 percent per day, with indications of early maturation compared to wild populations (Mlewa et al. 2009). However, all fish could not be harvested because most burrowed into pond soils. Field interviews were conducted in eight districts: Kampala, Wakiso, Mukono, Kumi, Busia, Soroti, Pallisa and Jinja (Fig. 1). These districts are known to have good potential for aquaculture development and with communities known to consume African lungfish. Fish farmers (n=34) and residents of fishing communities (n=10) were interviewed to assess indigenous knowledge and practices associated with the culture and use of African lungfish. Most fish farmers in Uganda grow Nile tilapia Oreochromis niloticus and African catfish Clarias gariepinus in earthen ponds. However, in field interviews with farmers, there were three cases where lungfish were raised in captivity by individuals using indigenous knowledge. Lungfish seed are collected from around lake shores or swampy areas from July to November. It is a challenge to collect a substantial number of seed from the wild, inasmuch as fishermen observe them swimming individually rather than in schools. One farmer in Nangabo (Wakiso district) polycultured 1,000 lungfish juveniles (15-20 cm) with 400 mirror carp and 800 tilapia fingerlings in a well-constructed, 400-m2 pond. Juveniles were collected from Lake Victoria, beneath nearshore water hyacinth (Eichornia crassipes) mats, after contracting fishermen for US$ 0.20-0.50 per fish. Fish were raised for about 1.5 years using mukene (Rastrineobola argentea) powder mixed with maize bran, feeding once daily. There were no records to show amount of feed applied but about 400 adult lungfish (1-3 kg) and 381 tilapia (average 250 g) were recovered after completely draining the pond. Live farmed fish in plastic containers (1000-L) were sold in Kampala, where lungfish retailed at US$ 2.50-4.00/ kg and tilapia at US$ 1.00-1.50/kg. (CONTINUED ON PAGE 40) FIGURE 2. Large size variation (100 – 1300 g) of lungfish captured in Lake Opeta, Uganda. African lungfish is native to the natural waters of Uganda but populations are rapidly declining and the species is now endangered, mainly caused by overexploitation, environmental degradation and large-scale conversion of wetlands to agricultural land.
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