Reproductive response of
Nile tilapia (Oreochromis niloticus) to photoperiodic manipulation;
effects on spawning periodicity, fecundity and egg size
A. Campos-Mendoza, B.J. McAndrew, K. Coward, N.
Bromage-2004
Aquaculture, 231(1-4): 299-314
Abstract:
Nile tilapia (Oreochromis niloticus) has
rapidly become an important species for aquaculture, although their
intensive culture remains constrained by poor spawning synchrony and low
fecundity, adding significant cost to hatchery production. Previous research
has indicated that spawning synchrony may be improved in some fish species
by photoperiod manipulation. There is limited information on the effects of
photoperiod manipulation on tilapia. In this paper, the reproductive
performance of 32 individually housed Nile tilapia was evaluated under four
different photoperiods: short day (6L:18D), normal day (12L:12D), long day
(18L:6D), and continuous illumination (24L:0D). Significantly larger eggs (P<
0.05) were produced under normal daylength (12L:12D) compared to other
treatment groups. Fish reared under long daylength (18L:6D) exhibited
significantly higher (P< 0.05) total fecundity (2408±70 eggs
spawn-1) and relative fecundity (7.2±0.2 eggs g-1
body weight) concomitant with a significant reduction in
inter-spawn-interval (ISI, 15±1 days) in comparison with the rest of the
trials. This investigation shows that long daylength (18L:6D) helps improve
some important reproductive traits in Nile tilapia, and suggests that such
methodology may be used to alleviate the production problems caused by low
fecundity and poor spawning synchrony, and thus play a valuable future role
in tilapia culture.
(Institute of Aquaculture, University of Stirling,
Stirling FK9 4LA, Scotland, UK, e-mail: ac7@stir.ac.uk)