10-2 Sat Jan 2 Stick to it: Comparisons of passive adhesion in waterfall-climbing fishes on challenging substrates Palecek-McClung, AM*; Schoenfuss, HL; Blob, RW; Clemson University, Clemson, SC; Saint Cloud State University, Saint Cloud, MN; Clemson University, Clemson, SC apalece@g.clemson.edu
In Hawaiian waterfall-climbing gobies, the pelvic fins fuse into a sucker that allows all four species to produce passive adhesion. This allows some species to climb waterfalls 10s-100s of meters in height, resulting in elevation-dependent species stratification. Adhesive performance is likely modulated by a variety of factors including substrate characteristics, sucker morphology, and behavior. We investigated the influence of two substrate characteristics (wettability and roughness) on the passive adhesive performance of four species of waterfall-climbing gobies with varying climbing abilities. Passive adhesion varied by species and substrate, where all species had higher shear pull-off forces on rough substrates than smooth substrates. Moreover, the species found at the highest-elevation stream sites (best climbers) had higher pull-off forces than those found in lower-elevation streams (poor climbers or non-climbers). Differences in passive adhesive performance may explain why some species are capable of invading upstream habitats.
