Larvacean kinematics: a biological model of flapping flexible foils

Larvaceans are marine organisms found throughout the world's oceans that create mucus houses to filter food (e.g., small plankton, detritus, and particulates) from adjacent waters. Estimates indicate that discarded mucus houses, which are eventually abandoned by larvaceans, are responsible for one\textunderscore third of the particulate transported to the bottom of Monterey Bay in Central California. Once houses are abandoned, larvaceans swim freely to another location before generating a new one. Here we conduct a study of an undescribed larvacean, Bathocordaeus sp., to examine their free\textunderscore swimming and in-house behaviors, and how changes in their body kinematics may alter fluid interactions. High\textunderscore definition videos captured by remotely operated vehicles (ROVs) in Monterey Bay (from 2003 to present) are analyzed to extract the kinematics of larvacean tail motion during these two distinct swimming behaviors. Using in-house Matlab algorithms, we reveal significant differences in stroke dynamics as traveling waves propagate along the larvacean tail. These kinematic differences may have important implications for swimming performance and fluid filtration rates through larvacean mucus houses.