Aim: 

To probe the effect of light cycles on both, egg incubation time and larval development as a part of a study about N. korthausae (Cyprinodontiformes, Pisces) life cycle and aging.

Methods: 

Eggs from two varieties (red and yellow) of N. korthausae were hold in incubators with three different photoperiods: 24L, 12L:12D and 24D at 29°C. Egg maturation stage was determined each 15 days. Hatching rate, survival and growth rate per week were recorded from newborn larvae.

Results: 

(1) Red variety showed slow embryonic development.

(2) Photoperiods 24D and 12L:12D delayed egg maturation (mainly 24D) with respect to 24L treatment.

(3) The very few eggs found at intermediate stage of development suggest that this phase is very short.

(4) Photoperiod did not affect hatching rate.

(5) Survival rate decreased in larvae from 24D treatment between 4 and 16 days of development.

(6) Larval growth was not affected by photoperiod treatment during incubation.

Conclusion: 

Photofase increases embryonic development and survival but it seems not to affect hatching rate and larval growth.

Acknowledgements: 

This project was funded by Seneca Foundation (PI/05700/07), by Instituto de Salud Carlos III (RETICEF, RD06/0013/0019), and by the Ministry of Education and Science (BFU2007-60658/BFI).