Keeping Daphnia out of the surface film with cetyl alcohol

Some Daphnia species are difficult to culture due to a tendency to become trapped in the surface film. A low level of cetyl alcohol (1.26 ± 0.12 mg) was shown to be highly effective in reducing the surface film entrapment of a Daphnia species typically susceptible to such a problem (D.rosea). In a species that does not exhibit surface film problems (D.pulicaria), a low level of cetyl alcohol had no effect, indicating that this substance is not toxic to Daphnia in low quantities. However, a high level (10.6 ± 1.0 mg) of cetyl alcohol was shown to decrease the survival of both species and reproduction of the susceptible species.