Reproductive biology of Garra regressus and Garra tana (Cypriniformes: Cyprinidae) from Lake Tana, Ethiopia

Abstract

The reproductive biology of Garra regressus and Garra tana was investigated by collecting monthly samples (January to December 2006) from the southern Gulf of Lake Tana, where these species are endemic. Garra regressus has an extended breeding time from April to October while G. tana breeds throughout the year with a peak from March to July. The mean size at maturity in both the species was not significantly different between the sexes, but G. tana had a significantly lower mean size at maturity than G. regressus in female specimens. Absolute fecundity estimates for G. regressus ranged from 580.8–1800, while those for G. tana ranged from 538.9–2968. Egg size frequency distribution revealed that G. regressus is a multiple spawner, while G. tana is a single spawner. The sex ratio in the total catch of G. regressus was found to be skewed in favour of females (Chi-square, P< 0.05), while those for G. tana was not significantly different from 1:1. The mean size at maturity was not significantly different between the sexes for G. tana.

Keywords

• Conservation
• cyprinid
• endemism
• spawning
• threatened.