The effects of dinoflagellate bioluminescence on the swimming behavior of a marine copepod1

Abstract

The horizontal swimming patterns of groups of Acartia hudsonica were tracked and described using a video‐computer system. The patterns were compared in the presence of clones of bioluminescent and nonbioluminescent Protogonyaulax tamarensis. Bioluminescent dinoflagellates increased the number of high‐speed swimming bursts by the copepods and thus decreased the amount of slow‐speed swimming characteristic of their grazing behavior. With bioluminescent dinoflagellates, swimming paths were less circuitous and swimming speeds higher. This behavior may tend to move copepods away from bioluminescent dinoflagellates in nature. Both changes in swimming behavior should result in reduced grazing by the copepods on bioluminescent dinoflagellates.