Notes on the breeding of large Lake Tana Barbs (Labeobarbus Spp.) in nature and laboratory

Abstract

The largest lake species flock within cyprinids comprises of 16`Lake Tana (Ethiopia) Labeobarbus species differing in ecology, morphology, and sites of reproduction. Most of them migrate to rivers for spawning and head down to the lake after spawning. During 2005−2015, species composition of Lake Tana barbs was studied in five rivers and their tributaries including those so far not sampled. Our observations revealed that several species, earlier considered to spawn in the lake, were found to be riverine spawning. Results confirm the occurrence of spatio-temporal segregation in barbs‟ reproduction as previously reported as a mechanism enhancing reproductive isolation between closely related Lake Tana barbs. However, considerable overlap both in space and time of spawning in different barb species recorded in this study indicates that spatio-temporal segregation is far from complete. Breeding behavior of Tana barbs was also studied in nature and in the laboratory. Species-specific differences were revealed in the pre-mating behavior of different barb species. It is proposed that barbs participate in reproductive isolation enhancing the effects of space-temporal segregation.

Keywords/phrases: Breeding behavior, Labeobarbus, Lake Tana, Reproductive isolation, Spatio-temporal segregation