Abstract:
Lake Tana is a biodiversity reservoir and freshwater supplier that
contribut significantly to the economy of Ethiopia and downstream
recipient countries (Sudan and Egypt). Due to human activities, water
quality and biodiversity of the lake was threatened. Some of the most
significant contributors to the lake pollution include domestic sewage,
agricultural inputs and outputs, industrial inputs and outputs, silt from
the agricultural activity, etc in the catchement. To asses the impact of
antropogenic activities of Lake Tana, macroinvertabrates were
analysed in dry and wet seasons at 11 sampling sites. In the analysis,
litratures indicated that the presence of more Odonata, Coleptera and
Hemipteran larvae is the indication of water quality deterioration due
pollution. From the collected organisms total numbers of tolerant
individuals were 303 (48.2 %) and Facultative individuals were 243
(38.7 %) while intolerant individual organisms were 80 (12.7 %). Most
of the taxa (48.2 %) had tolerance scores ranging from 7 to 10. In
general, all the sampling stations show the degradation of water quality
and thus needs for mitigation measures and management options to
save Lake Tana.
KEY WORDS: Macroinvertebrates; Tolerance; Lake Tana;