Effect of water treatment
and aeration on the percentage hatch of demersal, adhesive eggs of the
bullseye puffer (Sphoeroides annulatus)
C. Komar, J.F. Turnbull, A. Roque, E. Fajer, N.J.
Duncan-2004
Aquaculture, 229 (1-4): 147-158
Abstract:
The bullseye puffer (Sphoeroides annulatus) is
a species with potential for aquaculture. However, preliminary studies on
the biology and reproduction of the species in captivity have failed to
produce consistent success at hatching. In this study, the effect of
aeration and water treatment (filtration and ultraviolet (UV) sterilisation)
on percentage hatch was assessed in a replicated experiment repeated on two
occasions. Four treatments were used, filtered water (5 µm) treated with
UV, in an aerated system (AT) and a static system (ST); water that had been
coarse-filtered (20 µm) and not exposed to UV kept in aerated system (ANT)
and a static system (SNT). The percentage hatch was ranked 87.5±5.0>80.6±9.4>77.2±12.8>62.8±10.4
(mean of all replicates from both experiments±S.D.) for the respective
treatments AT>ST>ANT>SNT. However, percentage hatch for AT was only
significantly (P<0.05) higher than ANT and SNT, while hatch for ST
was only significantly higher (P<0.05) than SNT. A GLM analysis
showed the use of treated water (filtered and UV treated) in the incubators
and aeration had a significant positive effect on percentage hatch. These
effects were additive with no significant positive or negative interaction.
There was no significant differences in bacterial counts among treatments
(AT, ANT, ST, SNT), but significant differences (P<0.05) were
observed among days. There was no significant interaction between days and
treatments to affect bacterial counts. There was no correlation between
bacterial counts and percentage hatch. The water treatments significantly
improved percentage hatch, but did not affect bacterial counts. This paper
reports an incubation system that consistently resulted in more than 80%
successful hatching for bullseye puffer eggs. These results should help to
improve the hatching success of this species and possibly others with
demersal adhesive eggs.
(CIAD A.C. Unidad Mazatlan, AP 711, Mazatlan CP 82000,
Sinaloa, Mexico, e-mail of N.J. Duncan: nduncan@victoria.ciad)