Ecological Conditions and Benthic Macroinvertebrates of Lake Tinishu Ababya, Ethiopia

The ecological condition of Lake Tinishu Abaya was assessed using benthic macroinvertebrates as well. The results from this aspect of the study showed that a total of 5735 benthic macroinvertebrate specimens comprising of 23 taxa were collected from all the study sites. There was spatial effect on the number and distribution of benthic individuals (p <0.05). It was high at Dacha riverside (n=2089) followed by Bobodo riverside (n=1145), Reference site (n= 963), Badober riverside (n= 859), and Maingate side (n=679). The abundance of benthic communities significantly varied between the study seasons (p<0.05). Higher individuals were observed during the wet season (n=3583) than in the dry season (n=2152). The Hemiptera family were the predominant macroinvertebrates that contributed the largest number (n=2546) of the total samples followed by Diptera (n=878), Coleoptera (n=835, 14.56%) and Gastropoda (n=631). The Ephemeroptera (n=172), Hirudinae (n=335) and Oligochates (n=116) were represented by low number of animals. The majority (about 70%) of the benthic communities of Lake Tinishu Abaya are composed of pollution tolerant species as compared to the presence of pollution sensitive ones (<30%) in most of the sampling sites. This indicated that the existence of organic pollution and thus Lake Tinishu Abaya is undergoing environmental stresses. This obviously calls for participatory and interdisciplinary actions of watershed management and wise use of aquatic resources with compliance to commonly set agenda of sustainable use of natural resources.