Length-Weight Relationship and Condition Factor of African Big Barb <i>Labeobarbus intermedius</i> (Ruppell, 1836) in Ethiopian Freshwater Bodies: A Review

Abstract

The investigations on length-weight relationship and condition factor of the African big barb Labeobarbus intermedius (Rüppell, 1836) in Ethiopian water bodies have shown varied pattern including nearly isometric (b ≈ 3), negative (b < 3) and positive (b > 3) allometric. The Fulton condition factor (K) of L. intermedius is high (1.73) in Lake Ziway, however, declined in most rivers and lakes and also exhibits seasonal variation. Fish had a better body condition (2.73) during wet season in Angereb and Sanja Rivers. There is variation in condition factor with respect to sex in which females had better body condition (1.88) in Lake Ziway. The length-weight relationship and condition factor of L. intermedius is correlated with availability of food and water quality parameters justifying the need for effective management of this fish stock for conservation and continued fishing.Keywords Fulton Condition Factor; Length-weight; L. intermedius BackgroundThe African big barb Labeobarbus intermedius is a widely distributed fish species in Northern Kenya and in most parts of Ethiopian drainage basin (Dadebo et al., 2013). It is widely distributed in the rift valley basin, Abay basin and Baro-Akobo basin part of Ethiopia, of which Lake Tana harbors the largest number of big barb species (Vijverberg et al., 2012;Awoke, 2015). It is one of the most commercially important fish species in the country (LFDP4, 1997;Bjørklis, 2004;Desta et al., 2006). The total annual yield of L. intermedius from the total inland water bodies is estimated to be about 365 tons per year (LFDP, 1997). However, recently L. intermedius catch from rift valley lakes (Lake Hawassa and Lake Koka) declined and reported to be unsafe for human consumption due to high mercury concentration (Mengesha, 2009). The decline of the fish species due to overfishing and parasitic infection has result the less accessibility of the fish on the local markets (Desta et al., 2006;Mengesha, 2009;Dadebo et al., 2013). Length-weight relationship (LWR) is one of the most important biological tools in fishery management. It is used to estimate the average weight at which a fish can attain the given length (Lawson et al., 2013). Relationship between the two also indicates the wellbeing of fishes (Hamid et al., 2015). The difference in LWR is based on the inherited body shape and condition of individual fish. Condition factor shows the degree of wellbeing of fishes in their habitat, which is expressed by coefficient of body condition. It is a measure of various biological and ecological factors with regard to their feeding conditions (Nehemia et al., 2012). High values of condition factor indicate better body condition. However it is affected by stress, sex, season, availability of food and the quality of water where it grows (Ighwela et al., 2011).The study of length-weight relationship and condition factor of freshwater fish species is a subject of continuous research as it is a basis for the development of a successful management program on fish capture and culture (Sh...