Swimming in formation in krill (Euphausiacea), a hypothesis: dynamics of the flow field, properties of antennular sensor systems and a sensory-motor link

• Published in: Journal of Plankton Research
• Main Authors: Patria, Mufti P., Wiese, Konrad
• Format: Text
• Language: English
• Published: Oxford University Press 2004
• Subjects: ORIGINAL ARTICLES; Antarctic; Antarc*; Antarctic Krill; Euphausia superba; North Atlantic
• Online Access: http://plankt.oxfordjournals.org/cgi/content/short/26/11/1315; https://doi.org/10.1093/plankt/fbh122

The act of swimming in formation by species such as Euphausia superba , Antarctic krill, is assumed to be regulated by a sensitivity to the characteristic and spatially elaborate flow field produced by this species of shrimp. We used a related species, Meganyctiphanes , North Atlantic krill, to visualize the flow field produced by tethered shrimps in an aquarium. In this situation, the propulsion jet flow some centimeters behind the shrimp is surrounded by a vortex ring of recoiling water motion from which, if the vortex is also produced by unrestrained swimming shrimp, a following shrimp hypothetically can draw forces of lift and propulsion to decrease energy expense in long-distance migration. Two antennular sensitivities to water vibration in frequency ranges 5–40 and 40–150 Hz were calibrated, and the activity of connected interneurons was traced into the abdominal pleopod-carrying segments. Water oscillation of 3–10 Hz frequency, applied to the antennules, was shown to entrain a closely synchronous pleopod beat in the stimulated specimens.