ABSTRUCT
Many fish species have suffered continuing declines in abundance and distribution. These declines in abundance are commonly attributed to factors such as general habitat degradation, modified patterns of stream flow, interrupted migratory pathways, reduced water quality and pollution, introduction of alien fish and diseases, illegal fishing and commercial over fishing and altered biotic interactions. From May 2023 to April 2024 a cross-sectional study of physical, chemical and biological components (fish) of the Gilgel Abay River and its tributaries will investigate the life history traits/patterns of fish species in the study catchment. Study sites will be selected using purposive and systematic sampling methods. As per the preliminary survey, six sampling sites along the Gilgel Abay River and two sampling sites in each two (Jamma and Arib) rivers and four sampling points in each two (Ashar and Kelti) rivers will be selected. This study is aimed at contributing to the management of the river fishery by providing critical baseline information on life history traits of fishes in the Gilgel Abay River and its tributaries, Lake Tana Sub-Basin, Ethiopia. Fish samples will be collected in the four seasons of the year using a standard set of nets with different mesh sizes. The collected fish samples will be preserved in 5% formalin to identified at the family and species level and biology of fishes will be studied. The collected data will be analyzed by using appropriate statistical methods and statistical soft wares.