Spawning migration and some biological aspects of Labeobarbus species in Infranz River, Lake Tana Sub Basin, Ethiopia

Abstract

The main aim of the study is to investigate the spawning migration and some biological aspects of Labeobarbus species. Fish were sampled monthly in the non-peak spawning season and twice in the peak spawning season using gillnets and Monofilament. A total of 832 Labeobarbus specimens were collected from all sampling sites. Out of the total catch of Labeobarbus, the four dominant species contributed 83.0%. Labeobarbus intermedius was the most dominant species in all sites but L. nedgia was the second in site 2 and 3. However, L. tsanensis and L. brevicephalus were the second dominant species in site 1 and 4, respectively. The peak spawning months for Labeobarbus species was from August to October. Length-weight relationship for all of the dominant species was curvilinear and statistically significant (p<0.05). The chi-square test showed that there was significant difference between the number of females and males for L. intermedius and L. tsanensis. The average number of eggs for L. intermedius and L. brevicephalus was 9055 and 4312, respectively and the relationship of absolute fecundity with FL, was curvilinear, however, with TW and GW of the two species was linear and statistically significant (p<0.05). Labeobarbus intermedius and L. tsanensis were the first species to aggregate in the river mouth. However, Labeobarbus brevicephalus was the last species to aggregate. The first and the last migrant to upstream sites were L. intermedius and L. brevicephalus, respectively. Closing season should be strictly implemented during the spawning season from July to November. © 2013 Academic Journals Inc.