Effect of temperature on growth of the threatened annual fish Austrolebias nigrofasciatus Costa & Cheffe 2001

Abstract

This study evaluated the effect of temperature on growth of Austrolebias nigrofasciatus, an endemic and threatened annual killifish species of the Patos-Mirim lagoon system in Southern Brazil. In order to verify the effect of temperature on initial growth of A. nigrofasciatus, eggs stored in the laboratory were hatched and juveniles reared for eight weeks at 16 and 22 ºC. The standard length of newly hatched fishes was 4.67 ± 0.25 mm and after eight weeks they reached 23.68 ± 3.73 and 22.68 ± 5.36 mm, respectively at 16 and 22 ºC. However, initial growth of fish reared at 22 ºC was faster and they reached sexual dimorphism at an earlier age compared to those reared at 16 ºC. Final length of females reared at 22 ºC was 23.00 ± 2.83 mm, they were significantly larger than those reared at 16 ºC (17.91 ± 2.47 mm). Males were significantly larger than the females at 16 ºC, but there was no difference for growth between sexes of fish reared at 22 ºC. The sex ratios were 1:0.6 and 1:1.1 (M:F) at 16 ºC and 22 ºC, respectively, suggesting temperature determination of phenotypic sex. Considering the results, it appears that juveniles to be developed in captivity should be kept at 22 ºC during the first six weeks of life, thus ensuring a higher growth rate until puberty.

Seasonal dynamics in community structure, abundance, body size and sex ratio in two species of Neotropical annual fishes

“…Both species studied attain sexual maturity at a body size of 18–21 mm at the age of c . 8 weeks (Arenzon et al , ; Volcan et al , ), though the sexes can be distinguished in larger juveniles, especially in C. fulgens .…”

Incubation media affect the survival, pathway and time of embryo development in Neotropical annual fish Austrolebias nigrofasciatus (Rivulidae)

“…Studies involving the management of annual fish eggs have used various incubation media, such as water (Arenzon et al, 2002;Tingaud-Sequeira et al, 2009;Blažek et al, 2013) and Yamamoto's solution (Wourms, 1972;Podrabsky, 1999;Arezo et al, 2007;Blažek et al, 2013) for maintenance in the laboratory, as well as damp media wherein the eggs are in contact with the air in a moist chamber (Arenzon et al, 2002;Tingaud-Sequeira et al, 2009;Volcan et al, 2012;Blažek et al, 2013). Only a few studies, however, have compared the survival and development pattern of embryos in these media (Podrabsky, 1999;Arenzon et al, 2002;Blažek et al, 2013).…”

Changing patterns of growth in a changing planet: How a shift in phenology affects critical life‐history traits in annual fishes

“…Our field data are consistent with laboratory studies that have reported earlier sexual maturity and more rapid growth at higher temperature for Austrolebias spp. (Volcan et al., ). However, the positive relationship between water temperature and juvenile development is reversed when temperatures exceed an optimum of 21–24°C (Fonseca et al., ), and high ambient temperatures during juvenile growth comes at the cost of shorter lifespan.…”

“…Laboratory studies have demonstrated that annual fishes are sensitive to temperature (Fonseca, Volcan, Sampaio, Romano, & Robaldo, 2013;Volcan et al, 2012). Austrolebias adloffii, a related species from the same region, exhibited a decreased growth rate and shorter lifespan when a natural decrease in water temperature fluctuation was interrupted.…”

“…Our field data are consistent with laboratory studies that have reported earlier sexual maturity and more rapid growth at higher temperature for Austrolebias spp. (Volcan et al, 2012).…”