The composition of fish communities of nine Ethiopian lakes along a north-south gradient: threats and possible solutions

Abstract

Fish populations of nine Ethiopian freshwater lakes were quantitatively sampled with a standardized protocol, using multi-mesh gill nets. In total, 27 species were identified, but only 14 species were common. Based on the common species, the fish communities showed large differences in their species composition, except for Lake Abaya and Lake Chamo which were similar. Most fish species were observed in only one or two lakes. Compared with the information reported in literature the present study generally underestimated the species richness. The empirical model of Amarasinghe and Welcomme (2002) for African lakes was used to estimate fish species richness, which was compared with species presence reported in literature. Biodiversity in the two northern highland lakes is low, but not lower than the model estimate. Lake Tana has a high biodiversity which is close to what is estimated by the model, but three Rift Valley lakes have low biodiversity, lower than estimated by the model. There are also strong indications for the Rift Valley lakes that species richness was higher in the past because the species richness reported in the older literature was generally much higher than those observed by us in the present study and those reported in the more recent literature. Threats like overfishing, high sediment load and degradation of habitats were identified. It is recommended that Ethiopia should develop guidelines for fishery legislation and implement it through an enforcement agency. Moreover, catchments management should be practiced to save the water bodies and their fish communities.

Intra‐ and interspecific niche variation as reconstructed from stable isotopes in two ecologically different Ethiopian Rift Valley lakes

“…Although the observed difference in fish species richness between both lakes is in line with earlier investigations that report higher richness in Abaya than in Chamo (Golubtsov & Habteselassie ; Vijverberg et al . ), the number of species observed by us was considerably lower than the richness reported by Golubtsov & Habteselassie (). Similar to our study, Vijverberg et al .…”

Assessing Sustainable Fishing Yields Using Length-based Analytical Models: A Case Study with Nile Tilapia in Lake Hawassa (Ethiopia)

“…Unlike the other southern rift valley lakes in Ethiopia, Lake Hawassa harbors low fish species diversity [23]. Only six species are currently known: Nile tilapia, Oreochromis niloticus; African catfish, Clarias gariepinus; Labeobarbus intermedius (Ruppell 1835); Barbus paludinosus (Peters 1852); Garra quadrimaculata (Ruppell 1835) and the black lampeye, Aplocheilichthys antinorii (Vinciguerra 1883).…”

Fishery Management Problems in Ethiopia: Natural and Human Induced Impacts and the Conservation Challenges

“…The policy; however, left the resources open for fishermen. In 2003, recognizing dangers posed on most water bodies, National Fisheries Proclamation was ratified by the Federal Parliament to provide broad guideline related to resource conservation, food safety, and aquaculture development (Vijverberg et al, 2012). This is the principal legal tool for the management of fishery resources in Ethiopia.…”