Fishes that suck: comparison of the adhesive discs of three fishes of the Pacific Northwest

Abstract

There are more than ten different species of fishes in the Pacific Northwest with ventral adhesive organs that facilitate adhesion to marine substrates. The performance of these adhesive discs have been measured in three species. These include the Northern clingfish (Gobiesox maeandricus), Pacific spiny lumpsucker (Eumicrotremus orbis), and tide pool snailfish (Liparis florae). While the clingfish that lives in the intertidal zone where waves continually crash down, it is the other two who have been shown to have stronger discs. Scanning electron microscopy and photography of cleared and stained individuals was used to look for differences in morphology that might explain these performance differences. High speed videography was used to determine the mechanism of detachment for E. orbis and L. florae because this is unknown. All three species have different disc morphology (Fig. 1); E. orbis and L. florae have much large papillae than G. maeandricus and a more rigid support to their disc which may help to explain the difference in disc performance. Papillae may increase friction which prevents the disc from slipping and rigid pelvic spines resist bending of the disc. Both E. orbis and L. florae seem to use abduction of their pelvic fins and operculum to brace themselves as they pull back the anterior edge of their disc, causing failure and allowing the disc to be peeled back in the anterior direction. Modeling discs based off these morphologies could be done to create a strong, bio-inspired suction cup for human use.