Abstract:
ABSTRACT
Spawning migration of Labeobarbus species was studied from August to December 2013 in some tributary
rivers (Qimon, Guanta, Shini, and Chibirna) of Lake Tana. Fish specimens and physico-chemical parameters
were measured bimonthly in August and September but monthly from October to December. Adult fish specimens
were caught using 6 and 8 cm stretched mesh size monofilament gillnets and 6, 8, 10 and 12 cm mesh
size multifilament gillnets. A total of 933 adult Labeobarbus specimens were collected during the study period.
Labeobarbus intermedius was the most abundant species followed by L. brevicephalus. The peak spawning
season of L. intermedius was from fourth week of August to end of September and for L. brevicephalus
it was from fourth week of August to beginning of October. Both species were found to spawn in all sampling
rivers. However L. truttiformis spawned only at Guanta and Qimon Rivers during August while L.
nedgia in Shini and Chibirna Rivers at the end of September. This implies the presence of micro-spatial segregation
among species. Pair-wise comparison of Labeobarbus species showed temporal segregation in all
sampling months, except L. brevicephalus and L. nedgia. The present findings showed that small tributary
rivers and streams are the main spawning grounds for Labeobarbus species of Lake Tana. Therefore, main
spawning grounds or routes should be protected from the deleterious effects of anthropogenic activities like
illegal fishing, irrigation and sand mining for wise use of the fish resources.
