The Effect of El-Niño on Reservoir fish production in Ethiopia. A Review paper

Drought is defined as the protracted absence, deficient or poor distribution of precipitation and it is a natural phenomenon that occurs for prolonged period of abnormally low precipitation. The underlying causes of most droughts can be related to changing weather patterns manifested through the excessive buildup of heat on the earth’s surface, meteorological changes which result in a reduction of rainfall, and reduced cloud cover, all of which results in greater evaporation rates. Nowadays drought is the main problem in the world and also recently in Ethiopia. Ethiopia has experienced droughts for hundreds of years, with major events (i.e., ones involving famine or documented suffering) including 1888-92, 1899-1900, 1920-22, 1933-34, 1973-74, 1983-84, 1987-88, 1990-91, and 1993-94. Currently, Ethiopia has faced the ugliest drought in 2015/2016 which affects the environment and humans. Mostly the occurrence of drought in Ethiopia is related to El Nino Southern Oscillation (ENSO) events. Reservoirs are essential components of most irrigation systems worldwide and, together with those built for flood control and power generation, retain large volumes of water. In addition to their roles in power generation and provision of water for agriculture, industry and homes, most of these reservoirs also play an important role in fish production and contribute significantly to the livelihoods of the communities along their shores. It is known that Ethiopia has huge reservoir fish production potential which is not revealed and unexploited. One of these reservoirs, Tendaho Reservoir, is found in Afar region located between Dubti and Mile. This large reservoir has faced a great problem being highly vulnerable for drought in which it has dried, at least, once in the last two years. Recently, in February 2016, it has totally dried due to El Nino and all living organisms in the reservoir were damaged. It has distracted community structure, habitat loss, decline and huge fish population has died out. In this area, there is a knowledge gap on cause and effect of El Nino in reservoir ecology; therefore it needs depth research which could be conducted on drought impact in reservoir in order to develop prevention techniques during drought season.Therefore, the purpose of this review paper was to identify effects of El Nino on reservoir fish production by synthesizing current knowledge on effects of drought on reservoirs that would ultimately be used to recommend and identify research direction.