Meeting Abstract

S7-1.3  Saturday, Jan. 5  Swimming dynamics of squids throughout ontogeny BARTOL, I.K.; Old Dominion University, Norfolk, VA ibartol@odu.edu

Squids encounter vastly different flow regimes throughout ontogeny as they undergo critical morphological changes to their two locomotive systems: the fins and jet. Squid hatchlings (paralarvae) operate at low and intermediate Reynolds numbers (Re) and typically have rounded bodies, small fins, and relatively large funnel diameters, whereas juveniles and adults operate at higher Re and generally have more streamlined bodies, larger fins, and relatively small funnel diameters. To determine how these morphological changes and different flow environments impact swimming strategies, digital particle image velocimetry (DPIV) and kinematic data were collected from an ontogenetic range of long-finned squid Doryteuthis pealeii and brief squid Lolliguncula brevis swimming in a holding chamber or water tunnel. Although their fins were active, paralarvae relied predominantly on a vertically directed, high frequency jet as they bobbed up and down in the water column. During these preferred station-holding behaviors, a series of jet-generated isolated vortex rings with rapid dissipation rates were frequently observed. Juvenile and adult squid exhibited a more diverse range of swimming strategies involving greater overall locomotive reliance on the fins and use of arms-first and tail-first swimming modes. Distinct hydrodynamic fin and jet gaits with more complex vortex ring structures than those detected in paralarvae were observed in juveniles/adults, especially during tail-first swimming. The differences in swimming approaches between paralarvae and older life history stages reflect their unique adaptations to their resident flow regimes.