Effects of microcystin-LR and cyanobacterial crude extracts on embryo-larval development of zebrafish (Danio rerio)

Eggs of zebrafish (Danio rerio) were exposed to microcystin-LR at concentrations of 0.5, 5 and 50 μg litre−1 from blastula stage up to the end of embryonic development. No effects were observed during this period. After termination of exposure and transfer into microcystin-LR-free water, the evaluation at the end of the larval period showed decreased survival at 5 and 50 μg litre−1 microcystin-LR. Furthermore, concentrations of 0.5, 5 and 50 μg litre−1 microcystin-LR retarded larval growth. Far more pronounced effects occurred following exposure with various aqueous cyanobacterial crude extracts from field samples and batch cultures: gross malformations and high mortalities during embryonic development were observed.