Phytoplankton odor modifies the response of Euphausia superba to flow
Antarctic krill, Euphausia superba, are critical components of the Antarctic food web as well as important targets for conservation and management. Krill behavior has important effects on demographic properties and aggregation characteristics, but remains incompletely known. Krill clearly respond to different environmental stimuli such as light, flow and chemicals, but few studies have quantified these behaviors. We examined the behavior of krill in well-quantified current speeds in a laboratory flume and examined interactions of phytoplankton odor and flow. Krill are sensitive to flow speeds as low as 1 mm s−1, and flow polarizes krill swimming and orientation in the up-current direction. Phytoplankton odor increases the sensitivity of krill to flow, and induces area-restricted search behaviors that presumably allow krill to exploit food patches efficiently. The ability to quantify krill behavior could have important consequences for understanding demographic processes and the properties of krill aggregations.
KeywordsBehavior Chemical cues Orientation Palmer station Rheotaxis
DMF was supported by NSF Award # 1537579, and JY by NSF Award PLR-1246296. This work would not have been possible without the outstanding efforts of the crew of the RV Laurence M. Gould and the staff at Palmer Station. Their support, as well as that of the United States Antarctic Program is gratefully acknowledged. Madison Luker assisted in analyzing krill kinematics, and Dr. Jun Zhang designed and fabricated the flume.
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Conflict of interest
The authors declare they have no conflicts of interest regarding this work.
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