Life along the fish lateral line and beyond

The author came to lateral line research rather by chance, yet this sensory system ended up as the main research focus of my entire scientific career. This paper is not a review article. Instead, it gives an overview of some of the major research topics that the author, collaborators, and students have worked on for more than 4 decades. During the last century, lateral line research was mostly approached by using mono-frequency water motions generated in still water with a stationary vibrating sphere. At the beginning, this approach was necessary and useful. During studies, it became apparent that the fish lateral line can only be fully understood if more natural hydrodynamic stimuli (including natural hydrodynamic noise) were applied. Better methods, like particle image velocimetry, are then needed in the research of lateral line systems. Finally, how a biomimetic approach can be used to investigate lateral line function is discussed. In the final paragraph, some research gaps and hence, opportunities that still exist in the research of the lateral line systems are highlighted.