Meeting Abstract
Tidepool sculpins, Oligocottus maculosus , are found in the rocky intertidal, and juveniles are often present in the high intertidal at low tide where they are prone to experiencing emersion, both voluntary and involuntary. The substrate of the rocky intertidal zone is complex and heterogenous, a challenging environment for any organism, but particularly for a small fish. How does substrate affect the terrestrial locomotion of juvenile tidepool sculpin? We filmed a dorsal view of the terrestrial locomotion of O. maculosus on three different substrates: wet paper towel, small rocks (2-4mm), and large rocks (4mm-8mm). Sequences of two sequential strides were digitized for each habitat, where a stride consisted of a full head-tail oscillation from one side, to the other, and then back again. Tidepool sculpins move over land by utilizing movement of their trunk and tail in conjunction with their pectoral fins. Preliminary data show O. maculosus had the greatest movement of COM per stride when moving across the uniform surface and tail movements were also the least variable. As particle size and heterogeneity increased, the overall pattern of movement persisted, but fish didn’t travel as far, movement appeared more labored, and locomotor bouts became shorter in duration. The increase in particle size may decrease the effectiveness of locomotion because it hinders the movements of the pectoral fins and adds a vertical component as the largest particles start to become obstacles. Relatively few studies consider substrate effects, yet understanding how substrates affect terrestrial locomotion in this model system can help us understand functional limits to movement, which offers potential insights to the challenges of the first amphibious vertebrates.
