STATE OF FISHERIES IN MALAWI Malawi has five major water bodies important for fish production. The annual catch from Malawi’s major fisheries is in the region of 40 to 60 thousand tonnes. In 2003, Malawi produced an estimated catch of 53 540 tonnes. Lake Malawi is the largest and most significant water body. The fish catch from Lake Malawi contributed over 75% of the total annual catch from Malawi waters in 2003. The other water bodies are: Lake Chilwa (about 750 km2), Lake Malombe (about 390 km2), Lake Chiuta (about 200 km2), and two sections of the Shire River (upper and lower). In terms of fish production in 2003, Lake Chilwa contributed about 14% of the total catch, Lake Malombe about 1.2%, Lake Chiuta about 2.4%, Upper Shire River less than 1%, and the Lower Shire River about 4.2%. All these water bodies are of high local importance. Catches by fish species in 2003, indicated that Utaka (Haplochromis spp.) contributed the highest (about 31.3%), Chambo (Oriochromis spp.) came second (about 12.7%), and Usipa (Engraulicypris sardella) came third (about 10.2%). In Lake Malawi, the dominant fish species in the 2003 catches were Utaka (Haplochromis spp.), which made up 31% of the total catch, Chambo (13%), Usipa (Engraulicypris sardella) (10%), and Mlamba (Clarias spp.) (6%). In lakes Chilwa and Chiuta, the dominant fish species in the catches were Makumba (Oriochromis spp.) (contributed 34% in Chilwa and 51% in Chiuta), Matemba (Barbus spp.) (made 52% of the catch in Chilwa and 11% in Chiuta) and Mlamba (Clarias spp) (contributed 13% of the catch in Chilwa and 7% in Chiuta). While in the Lower Shire, the dominant fish species in the catches were Mphende (Oriochromis spp.) (51% of the catch) and Mlamba (Clarias spp.) (which contributed 42% of the total catch). 5.0 ADAPTATION OF DIFFERENT FISH SPECIES Fish are known as ‘cold blooded’ or poikilothermic animals i.e. they are able to change their body temperature to suit the current environmental conditions. This process uses a lot of energy and therefore may result into decreased growth and production as more energy is spent on the regulation of the body temperature. Therefore fish must not be stressed i.e. put in a harsh environment. We have cold and warm water species. Warm water species require high levels of dissolved oxygen unlike warm water species and they are mostly carnivorous in nature e.g. Rainbow trout. Some fish are called marine species and others are freshwater species. Some fish live in deep waters e.g. Bathyclarias species. (bombe), Lethrinops species (Chisawasawa) whilst others live in mid waters e.g. Engraulicypris sardella (usipa) and yet others in shallow waters e.g. Oreochromis species (chambo). Different species of fish adapt to environments differently e.g. Clarias gariepinus (mlamba) can adapt or live in very harsh environment with low dissolved oxygen and still survive. Tilapias in general can live in a wide variation of temperatures. Most Cyprinids cannot live in areas of low dissolved oxygen. Though tilapias are known as warm water species, they can tolerate a wide range of temperatures and are hardy species i.e. they easily acclimatize to different environments.
Posted on: Tue, 22 Jul 2014 10:28:16 +0000
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