Brief Description of Oreochromis Niloticus (Linnaeus, 1758), Clarias Gariepinus (Burchell. 1822) and Lates Niloticus (Linnaeus, 1758).

Oreochromis Niloticus (Linnaeus, 1758)

Nile tilapia, (local name Korosso)

Family Cichlidae

Orochromis niloticus (Linnaeus, 1758) or the Nile tilapia, is an inland water fish inhabiting the littoral zone of lakes, mainly up to 5 meters deep. It has a wide range of distribution from about 8° S to 32 N and from 6000 ft. altitude to sea level. Oreochromis niloticus has a wide salinity tolerance range from fresh water to brackish water, as it is also found in the Ne Delta. It is widespread in many African water bodies, including lakes and rivers. The Nile tilapia feeds mainly on phytoplankton and benthic algae but also takes epiphytic algae and diatoms according to the conditions of its habitat.

Oreochromis niloticus, locally known as “Korosso, is a widely distributed and economically most important and popular fish in Ethiopia. It is found in almost all the lakes and most of the important river systems in the country. It is taken to be the “typical fish”, because of its perch-like body structure. It stands first in quantity of commercially expolited fish in the country, providing significant contribution in terms of income generation for a large number of people and food security to the rural community.

In Ethiopia, Oreochromis niloticus mostly breeds throughout the year, with peak spawning during the main rainy season. The size of the fish at maturity and the maximum size varies in the different water bodies. Maximum fish size varies in the different lakes but large sizes reaching a maximum of 60 cm total length and 4 kg by weight are found in Lake Chamo, Ethiopia and Lake Turkana, Kenya. In other lakes maximum sizes range between 35 and 45 cm and weight of 1.5-2 kg. Oreochromis niloticus (“Korosso”) has the highest consumer preference over all the other fish species, except Nile perch, brought to the market. Gill netting is the main fishing method used and recommended in Ethiopia although beach seining is also practiced in some of the Rift Valley Lakes. Traditionally fish is consumed highest during the long fasting season before Easter, when all other animal products are forbidden for consumption by the followers of the Orthodox Religion

clarias gariepinus (Burchell, 1822)

African catfish, (local name Ambaza)

Family Clariidae

Clarias gariepinus (Burchell, 1822) commonly called the African arican catfish is widely distributed in most African rivers and from North to South. It is mostly distributed in the deeper part of the lakes but is also found in swamps under low dissolved Solved oxygen condition. It possesses accessory breathing organ that enables it breath air when very active or under dry condition.

Clarias gariepinus feeds mainly of fish as well as on plants zooplankton. It is an omnivorous indiscriminate feeder of fish insects, crabs snails, young brids, rotting flesh of fish offal, plants and fruit as available in its habitat. It is ported to reach a maximum length of 150 cm and weight of 60 kg.

In most Ethiopia the catfish, Clarias gariepinus, (locally known as Ambaza), is found in most water bodies and ranks second only to the Nile tilapia in its distribution coverage and abundance e country. It is commercially exploited in Lakes Tana, ingano, koka, Awassa, Zewai, Beseka and River Baro. It has Significant contribution to food security for the rural imunity living along the many rivers inhabiting the catfish. le size of the fish in the commercial catch ranges from about 90 cm and weight of 3 to 8 kg. The catfish, Clarias gariepinus, is mainly fished using longline and gill nets. ever, it has low consumer preference in most areas and is only sold filleted, fresh or frozen, and at lower price compared to tilapia

In Lake Tana, Ethiopia, Clarias gariepinus breeds in the newly inundated inshore areas, with the rise of the lake water level soon after the onset of the big rainy season. During this reporduction period the fish migrates from the deeper water into the vegetated shore area where it aggregates and becomes highly vulnerable to fishing by scooping or simple basket traps. In Lake Tana it has a very defined short spawning time, during the first two weeks of July.

Lates niloticus (Linnaeus, 1758)

Nile perch (local name Netch asa)

Family Centropomidae.

The Nile perch, Lates niloticus (Linnaeus, 1758) is a top predatory tropical freshwater fish of significant commercial importance. It is widespread in many river systems in Africa from the Congo Basin in the south to the Nile delta in the North including the Rivers Nile, Chad, Senegal, Volta and Zaire. It is also found in Lakes Albert and L. Turkana and has been introduced to Lakes Kyoga and Victoria where it has success Tully established and become a major commercial landing. The Nile perch grows to very large sizes and reports indicate range of individual weight from 104 kg to 164 kg caught in different water bodies.

Generally the adult Nile perch is found in the deeper open waters while the juveniles are found in the shallower vegetated parts of the lakes. In some water bodies the fish breeds throughout the year with peak spawning during the warm summer season. Spawning occurs in sheltered peripheral areas and the pleagic larvae migrate to the more open areas of the lake during development. Lates niloticus shows marked changes in diet with size, season and habitat. It feeds on a wide range of organisms including Crustacea, Insects, Mollusks and various fish species including its own young. in Ethiopia Lates niloticus, locally known as Netch asa, IS found in the Rift Valley Lakes of Abaya and Chamo and in Riy Omo flowing into Lake Turkana and River Baro flowing to the White Nile. The Nile perch fetches the highest price in the market, thus being selectively fished from the lakes in the Rift Valley. Gill netting and hook-and-line are main fishing methods employed for catching Lates niloticus in Lake Chamo.