Meeting Abstract
84.2 Monday, Jan. 6 10:45 Organismal-, ciliary- motion and resulting fluid disturbances of freely swimming veligers CHAN, K.Y.K.*; PADILLA, D.K. ; JIANG, H.S. ; Woods Hole Oceanographic Inst. ; Stony Brook Univ. ; Woods Hole Oceanographic Inst. kchan@whoi.edu
Planktonic larvae of marine invertebrates play significant roles in shaping abundance and distribution of benthic adult populations. To successfully recruit to adult populations, these larvae need to efficiently filter and gather food particles while minimizing predation risk. Many larvae use ciliated structures to generate flow for both propulsion and particle capture, suggesting a potential tradeoff. In the face the common challenge of “to eat and not be eaten”, we hypothesize that larval from different taxonomic groups follow similar optimized scaling rules to balance the need to feed and to swim. By adapting small-scale, particle image velocitmetery techniques, previously applied on larger holoplankton such as copepods, we quantified swimming speeds and feeding currents of veliger larvae. The focal species were the Atlantic slipper shell, Crepidula fornicata, and the Atlantic oyster, Crassostrea virginica. Both species have larvae that use cilia arranged on elongated structures, the velum, for swimming and feeding. At the same day post-hatching, the larger C. fornicata veligers had greater variability in average swimming speed (0.6- 4 body length s-1). Velar lobe extension and orientation affected swimming speed but not ciliary beat frequency. Such independency between swimming and feeding at the ciliary level may aid in “cryptic swimming” of larval C. fornicata. C. fornicata had a relatively shorter convergence distance in particle paths in the wake of the larval shell compared to C. virginica, and hence, a smaller area of fluid of disturbance. Differences in fluid disturbance could translate into different predation risk. Quantification of larvae-fluid interaction is therefore essential for understanding larval feeding, predation, and transport.
