THE LACUSTRINE SPECIES OF LABEOBARBUS PFLAI<ETt\N~(E!HIOPIA) SPAWNING AT MEGECH AND. DIRMATRIBUTARl'lUVERS

Abstract

The spawning habits of the endemic Labeobarbus species were studied in theupstreap
reaches of Dirma and Megech affluent rivers of Lake Tana. Fish and other environmental parametl#S
were sampled from February to October 2004 using various fishing gears. Collected s~imen:s w$'e
identified, dissected and sexed. Five lacustrine species of Lake Tana (1. brevicephalus, L. intermedius, ·t.
megastoma, 1. tsanensis and 1. truttiformis) migrate to upstream reaches of Dirm,a and Megech Rivers·for
spawning from August to October. Neither macro (between rivers) nor micro (within the rivers) spatial
segregation among the migrating species was observed. However, the overall comparisons or the
spawning run showed temporal patterns of segregation among these migrating species. Labeobarbus
truttiformis and L. tsanensis were the first to migrate up rivers and 1. megastoma just follows and then L.
brevicephalus was the last to migrate. Running L. intermedius were most abundant starting from the.
middle of September to end of October. Although L. nedgia was collected in Megech and its tributary
Dimaza, it was considered as a riverine dwelling fish. Four species (L. crassibarbis, L. macrophthalmus, L.
longissimus and L. surkis) were rarely caught. However, five species (1. acutirostris, L. dainellii, L.
gorgorensis, L. gorguari and 1. pwtydorsus) were missing. To sustain the riverine Labeobarbus spawners,
closing the gillnet fishery from August to October at Dirma and Megech River·mouths is strongly
recommended. Degradation of the breeding grounds (rivers) by agricultural and construction activities
should be urgently halted by applying proper land-use management system in the area