Aquatic Sciences Meeting, Albuquerque 2001

SS15 Biomechanics: Making the Connection Between Physics and Biology at the Organismal Level (Disciplinary Connections)

Date: Wednesday, February 14, 2001, Time: 11:45:00 AM

Location: Mesilla

Fingerut, J, T, University of California, Los Angeles Dept. of Biology, Los Angeles, USA, jtf@ucla.edu

Zimmer, C, A, University of California, Los Angeles Dept. of Biology, Los Angeles, USA,

Zimmer, R, K, University of California, Los Angeles Dept. of Biology, Los Angeles, USA, z@biology.ucla.edu

THE CONSEQUENCES OF BEHAVIORAL RESPONSES TO LIGHT AND TEMPERATURE IN THE TRANSPORT OF A LARVAL ESTUARINE PARASITE

The estuarine trematode parasite Himasthla rhigedana's life-cycle includes a cercarial larval stage that leaves its intermediate gastropod host Cerithidea californica to encyst on hard substrates subsequently ingested by a bird, the parasite's primary-host. The effects of light and temperature on vertical distributions of larvae in the water column were tested in still water, slow (U*=.2cm/s) and fast (U*=.8cm/s) flume flows under environmental conditions based on those recorded in the field. In still water experiments, temperature had the scalar effect of a twofold increase in swimming speed over a 6C change, and light produced a vector effect -- downward swimming resulting in a bottom skewed profile -- which reversed in darkness. Using laser sheet illumination and computer assisted video motion analysis these effects were also seen in slow flow (17m flume, straight channel). However, in fast flow turbulent mixing neutralized active larval movements and produced uniform vertical profiles. These experiments show that in still water and slow flow larvae can effect their vertical position, therefore impacting transport distance and ultimately settlement site.

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Aquatic Sciences Meeting, Albuquerque 2001

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