DIstribution of Fishes in Relation to the Depth and Substrate at Myako, East-Middle Coast of Lake Tanganyika

Abstract

Distribution of fishes were studied in the lacustrine and riverine waters of Myako in the Mahale Mountains National Park of Tanzania, east-middle coast of lake Tanganyika. One hundred and four species were recorded from the Lake by the underwater surveys and also by the overnight gill-net collections. These included 77 species of cichlids (49 mouthbrooders and 28 substrate-brooders) and 27 noncichlids in 12 families. In a small river of Myako 7 species including one cichlid were collected, 3 of which were also distributed in the lake. Based mainly on the census along 7 lines extended 100-250 m offshore (down to 12-49 m deep), the distribution of fishes were analyzed with respect to the depth and substrate. Noncichlids were much less frequently observed during the census. Most of the fishes associated with rocky areas. More than half of the mouthbrooders of cichlids restricted their distribution within shallow (<5 m) rocky areas, while substrate-brooders generally exhibited wider habitat preference both in depth and substrate. The different distribution patterns are discussed in relation to feeding and breeding habits.