The effect of temperature and duration of incubation
on the hatching of diapause eggs of Centropages hamatus (Lilljeborg)
(Copepoda, Calanoida)
S.-G.
Jo, N.H. Marcus-2004
Aquaculture Research, 35(5): 432-435
Abstract:
Diapause
eggs of Centropages hamatus were used to investigate the effect of
temperature and duration of incubation on egg hatching. Eggs were incubated
for 10, 12, 14, 16, 20, 24, 28, 32, 36 and 40 h at 15°C and 14L-10D.
After incubation for the designated period, eggs were transferred to 25°C
and monitored periodically to determine egg hatching. Control eggs were
incubated solely at 15°C and monitored for egg hatching. The greatest daily
hatching success of eggs occurred within 1 or 2 days after transfer from 15°C
to 25°C, while the controls required 3-4 days. The cumulative hatching
success of eggs was significantly lower than the control, with the exception
of eggs held for at least 36 h at 15°C before transfer to 25°C. These
results indicate that overall time to hatching of diapause eggs of C.
hamatus can be reduced by transferring the eggs to a higher temperature,
for example, 25°C, following a minimum period of time (36 h) at
reduced temperature, for example, 15°C. Exposure to 15°C for only 10 h
does not appear to be sufficient to result in any subsequent hatching at
higher temperature.
(School
of Marine Science, Kunsan National University, Kunsan 573-701, Korea.
E-mail: sgjo@kunsan.ac.kr)