Environmental Biology of Fishes

, Volume 61, Issue 3, pp 261–268

Growth of the Annual Fish, Cynolebias Viarius (Cyprinodontiformes), in the Natural Habitat Compared to Laboratory Conditions

  • Adriana Errea
  • Eva Danulat

DOI: 10.1023/A:1011047611009

Cite this article as:
Errea, A. & Danulat, E. Environmental Biology of Fishes (2001) 61: 261. doi:10.1023/A:1011047611009


For the first time, growth throughout the life cycle of an annual fish, Cynolebias viarius, was assessed in the wild, within a temporary pool located in eastern Uruguay. Before pools dry out at the beginning of the warm season, C. viarius deposit eggs in the sediment. Embryos hatch when precipitation fills the pools again in March–April. During 1996, at biweekly or monthly intervals, environmental conditions were monitored and the length of 20 to 55 C. viarius measured. Pool size varied between 109 and 475 m2, respectively. Water depth at its center reached between 10 (June) and 35 cm (September). Water temperatures ranged from 6°C in June to 28.8°C in November. The water was slightly acidic (pH = 6.3 ± 0.2) and subsaturated with O2 (48–88%); conductivity averaged 258 ± 39 μS cm−1. On the first field trip after inundation (May 2), mean length of C. viarius was 9.9 ± 1.0 mm. Maximum growth rate (0.66 mm per day) was determined during the following two-week-interval and was associated with relatively high water temperatures (20–22°C). While fish length remained virtually unchanged during the colder winter months, C. viarius manifested growth, specially in weight, during the last third of the life cycle. Fish were sexually mature at 8 (67%) to 18 (100%) weeks of age. In the laboratory, specimens held at 25°C grew faster and reached sexual maturity at an earlier age (11 weeks) than at 15°C (10–16 weeks). Over the 5-months study period, mortality reached 37.5% at 15°C and 100% at 25°C. Results are compared to information available from other annual fishes.

killifishes life cycle temperature environmental conditions teleosts temporary pool endemic to Uruguay 

Copyright information

© Kluwer Academic Publishers 2001

Authors and Affiliations

  • Adriana Errea
    • 1
  • Eva Danulat
    • 1
  1. 1.Facultad de CienciasUniversidad de la RepúblicaMontevideoUruguay
  2. 2.Departamento de Biología, Sección OceanografíaInstituto Na1cional de Pesca (INAPE)MontevideoUruguay
  3. 3.Institut für Hydrobiologie & FischereiwissenschaftUniversität HamburgHamburgGermany

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