Hopkins Marine Station Student Paper

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(full paper is archived in the Miller Library)

Title: Ground effect during liftoff of the sanddab citharichthys sordidus
Student Author(s): Hullar, Tim
Faculty Advisor(s): Denny, Mark
Pages: 21
Location: Final Papers Biology 175H
Date: June 1989
Keywords: nearshore fishes
Abstract: The flatfish Citharichthys sordidus (Pacific Sanddab) is a bottom dweller dependent on camouflage and quick escape response to protect it from danger. In an attempt to determine the nature of the substrate's role in the quick liftoff of the sanddab from the ocean bottom, an experimental fish lifted off alternately from a porous and a solid substrate. The sanddab displayed similar displacement, velocity, and acceleration vectors in both x- and y-directions when lifting off from either substrate. The similarity of movement on both substrates indicates that a ground effect, or force caused by hydraulic flows redirected by the nearby solid substrate is of little consequence to the sanddab as it lifts off from its substrate. I suggest three possible mechanisms, each independent of substrate, that may contribute to the liftoff of the sanddab.