Abstract

HERNANDEZ-RUBIO, María Cecilia  and  FIGUEROA-LUCERO, Gerardo. Effects of temperature and salinity during the embryonic period of Chirostoma humboldtianum and Chirostoma riojai (Atherinopsidae) until hatching. Hidrobiológica [online]. 2013, vol.23, n.3, pp.365-373. ISSN 0188-8897.

Effects of incubation temperature (18, 20, 22 and 24 °C) and salinity (0, 4, 8, 12, 16, 20 and 24 g/L) on survival, development time and hatching size, during the embryonic period until hatching, of two freshwater endemic Mexican aterinopsids: Chirostoma humboldtianum (Valenciennes, 1835) and Chirostoma riojaiSolórzano and López (1965) were investigated. Embryos of both species did not survive at salinities up to 12 g/L. Hatching percentage was the highest at 22 °C and 0 g/L salinity, in both species (87%) and the lowest at 18° and 4-8 g/L in C. humboldtianum (39.95%) and at 24 °C and 12 g/L in C. riojai(33.23%). Hatching times were inversely proportional to incubation temperature increase; it was 15.5 ± 0.26 days in C. humboldtianum, and 12.4 ± 0.31 days in C. riojai, at 18 °C. At 24 °C, this period was 9.8 ± 0.11 and 7.8 ± 0.24 days, respectively. Hatching size was larger on high temperature and smaller on high salinity. The optimal temperature-salinity combination for hatching size was 24° C and 0 g/L in C. humboldtianum and 24 °C and 4 g/L in C. riojai. There was an interactive effect of temperature and salinity on percentage hatching and on hatching size. Although these species have low salinity tolerance, the use of salt has prophylactic uses for controlling pathogens sensitive to salt. C. humboldtianum and C. riojai are potential candidates for aquaculture for restocking purposes.

Keywords : Atherinopsidae; embryo; silverside; survival; tolerance.