Described herein are compositions and methods for controlling, inhibiting, reducing and/or preventing rotifer growth with antimicrobial peptides. Methods for removing and/or preventing rotifer infestations in algae cultivations by controlling, inhibiting, reducing and/or preventing rotifer growth with an antimicrobial peptide (AMP) are further provided. Also described are transgenic algae comprising an expression vector comprising a nucleic acid sequence encoding an AMP. In some instances, the nucleic acid sequence encoding the AMP is codon-optimized for expression in algae.
