Abstract:
Diversity, abundance, fish species composition and fishing activities of Angereb River were studied in dry and wet seasons from September 2017 to April 2018. Gillnet with mesh size of 6, 8 and 10 cm, hook and cast net were used to catch the fish species in three selected sites called Mollalie, Tikur and Medemamir bahrs. Shannon diversity index was used to determine species diversity in all sites of the River between seasons and Sorenson’s coefficient used to show the species similarity. ANOVA, descriptive statistics and t- test were used to test species composition and abundance difference in all sites of the River between sites and seasons. A total of 16 fish species belonging to 5 orders and 8 families were recorded. The dominant fish in all sites was Labeobarbus intermedius, Labeo forskalii, Oreochromis niloticus, Labeo horie and Labeo niloticus. The most common fish species in wet and dry seasons in all the three sites was Labeobarbus intermedius. The total fish specimens collected in the studied area was more in dry season (879) than wet season (595). Seasonal variation in the diversity of fish species between the three study sites was not statistically significant (p>0.05). The highest number of fish species diversity was recorded in Medemamer both during the wet and dry seasons. There was high community similarity in the three sampling sites in both seasons. The overall community similarity of the three sampling sites was (0.95).The most important fish species which were preferred by the local population include L.intermedius, L.horie and L.forskalii but the other species were not needed because of the culture of the community. There was significant variation (ANOVA, P<0.05) in the mean weight of L. forskalii, O.niloticus, L. niloticus and L.horie.
Fishing activity in Angereb River was carried out mainly seasonally starting from the post rainy season to the end of dry seasons and January-March were good seasons for fishing for fishers. Addition of chemical, lack of training and spoilage of fish were problems of fishers.
Keywords: Abundance, Angereb, Diversity, Fish, Season and species composition