Hopkins Marine Station Student Paper

Browse Titles | Search Citations & Abstracts

(full paper is archived in the Miller Library)

Title: Rheotaxis in Citharichthys sordidus - A dab into hydrodynamics
Student Author(s): Ueland, Fred
Faculty Advisor(s): Gilly, William
%E Baxter, Chuck
%E Denny, Mark
Pages: 33
Location: Final Papers Biology 175H
Date: June 1984
Keywords: movement
Abstract: Pacific Sand dabs exibit postural change when introduced to flow. The rheotaxis and the underlying hydrodynamics are not well studied for flatfish. No known values for lift or drag exist. In this study force transducers were used to measure drag and lift on the sand dab, and corresponding drag and lift coefficients were calculated. The lift is remarkably variant with altered posture and drag is virtually unchanged. It is this four fold lift reduction for head to tail flow that enables the sand dabs to stay in place in currents up to 40% to 50% faster. The sand dab is equally efficient with flows in the opposite direction; this is essential to accommodate the bidirectional surge. A mechanism for lift reduction, or more importantly for increased slipping velocity is proposed.