The use of formaldehyde for the disinfection of maternally incubated eggs of noble crayfish (Astacus astacus)

The high mortality of maternally incubated eggs represents a serious problem that prevents the development of noble crayfish (Astacus astacus) farming in Italy. In this experiment, formaldehyde bath technique has been tested with maternally incubating females. The survival rate of maternally incubated eggs, exposed to progressively reduced concentrations of formaldehyde (4000, 3000, 2000, 1000, 1500 and 500 mg l-1), has been compared with that of untreated controls for two consecutive years (2010 and 2011). The formaldehyde treatments were administered as disinfection baths, for a period of 15 min, twice a week. A concentration of formaldehyde of 500 mg 1-1, or greater, was found to be effective in controlling egg mortality, without apparent harming the female broods.