Abundance variations and life history traits of two sympatric species of Neotropical annual fish (Cyprinodontiformes: Rivulidae) in temporary ponds of southern Brazil

Abstract

We investigated abundance variations and life history traits (body size, sex ratio, length–weight relationships and condition factor) of two species of annual fish (Austrolebias minuano Costa and Cheffe and Cynopoecilus fulgens Costa) in temporary ponds of southern Brazil. Six samples were taken from small temporary ponds during three annual seasons over 2 years (2008–2009). A total of 104 individuals of A. minuano and 433 individuals of C. fulgens were collected. The abundance of both species tended to decrease from autumn to spring in the 2 years. The overall sex ratio of A. minuano and C. fulgens were 1.0 male to 1.8 females and 1 male to 1.04 females, respectively. Juveniles of both species occurred only in autumn over the two years and no adult was observed during this season. While the length–weight relationship of A. minuano indicated hyperallometric growth, the relationship of C. fulgens indicated values close to isometric growth.

Keywords:

• Austrolebias
• Cynopoecilus
• killifish
• restricted range fish
• endangered fish species

Acknowledgements

This research was supported by funds from UNISINOS (02.00.023/00-0) and CNPq (52370695.2). Leonardo Maltchik holds a Brazilian Research Council-CNPq Research Productivity grant. The data from this study were obtained as part of the master’s dissertation project of the first author (CNPq process number 132343/2009-6). The annual fish collection complied with Brazilian current laws (IBAMA – 02001.001148/2007-61). We thank two anonymous referees for helpful comments on the manuscript.