Hatchability of eggs from
Atlantic cod, turbot and Atlantic halibut after disinfection with ozonated
seawater
S. Grotmol, E. Dahl-Paulsen, G.K. Totland-2003
Aquaculture, 221(1-4): 245-254
Abstract:
In aquaculture the risk of transmission of fish
pathogens via eggs is reduced by disinfection in ozonated seawater, but this
treatment may delay or reduce hatching. The objective of this study was to
investigate the tolerance of Atlantic cod, turbot and Atlantic halibut eggs
to ozonated seawater. Groups of eggs were treated with different
concentrations and exposure times 2 days before hatching, and the effects on
hatchability were observed. The groups of eggs of all three species that had
been exposed to 2 mg O3/l for 2 min or less showed normal
hatching. In the groups with high total exposure (4 mg O3/l for 1
min or higher), a clearly lower percentage of hatching was found.
Interspecies differences in tolerance were observed, with turbot eggs
displaying higher tolerance than eggs of either halibut or cod. Due to the
interspecies differences, the tolerance of eggs to ozonated seawater should
be carefully evaluated in controlled laboratory-scale experiments in order
to establish a basis for disinfection protocols. Two milligrams O3
per liter for 2 min and lower exposures ought to be sufficient to ensure an
excess of oxidants for efficient inactivation of fish pathogens while
avoiding negative effects on the hatchability of halibut, cod and turbot
eggs.
(Department of Zoology, University of Bergen, Allégt.
41, N-5007, Bergen, Norway, e-mail: sindre.grotmol@zoo.uib.no)