Meeting Abstract
Fishes use skin as their first line of defense against predation or hazards in their habitat, and scales have evolved to armor the skin against potential dangers. Flatfishes are a particularly interesting group in which to examine resistance to tearing, because they rest on the substrate with their “blind” (eyeless) side in direct contract with the substrate. We examined the ability of the skin of two flatfishes, Platichthys stellatus (n=6) and Isopsetta isolepis (n=6), with two different scale types, tuberculate and ctenoid, to resist tearing. The tuberculate scales of P. stellatus are rigid, protruding scales that are sparsely distributed, while the ctenoid scales of I. isolepis are overlapping thin scales that cover the entire body. We hypothesized that scale type may affect how the skin resists tearing. Squares of skin were taken from each side (blind or eyed) of the specimen and torn in two different directions (along the dorso-ventral or anterior-posterior axis). Work and extension were measured for each trial and compared across side, species, axis, and organism size. Overall, the species differed (p < 0.001) in work required to tear the skin; however, size of the individual also had an effect on work (p < 0.01). Because Platichthys specimens tended to be larger than Isopsetta, the work required to tear a skin sample may be confounded by organism size. The extension of the skin during tearing varied based on the direction the skin was torn (p < 0.05); the skin extended more when torn along the anterior-posterior axis vs. the dorso-ventral axis. Ultimately, observations of how scale type influences resistance could yield insights into animal-environment interactions and generate bio-inspired materials for human use.
