Dataset: Swimming kinematics of krill exposed to guano and food odor
Deployment: LMG2211

Krill were collected with an Isaacs-Kidd midwater trawl (IKMT) net from the RV Laurence M Gould (cruise LMG 22-11) and from the RV Nathaniel B. Palmer (10/22) from Wilhelmina Bay in the Bransfield Strait where they were held in tanks at ambient conditions with ambient flowing seawater during transport to Palmer Station. Adult krill were filmed in 3d using orthogonally mounted cameras and their swimming speeds, turns and headings calculated from the 3d paths reconstructed using DLTdv8. The flow channel used to collect the data was constructed of stainless steel and plexiglass. A stainless steel contraction section provided a smooth narrowing to a final width 25 cm of the working section (35 x 25 cm), with an additional 25 cm exit section terminating in a tail gate with a 3 inch bulkhead through with the water flowed into a sump. The upstream end of the working section was a stainless steel mesh with a roughly 5 mm mesh size, which primarily served to prevent krill from entering the contraction section, while the downstream end of the working section had similar mesh to prevent the krill moving into the exist section. The reservoir (a 55 gallon clean hdpe barrel) contained a 1 hp Tsurumi pump which returned the water to the upwelling section via 2 inch pvc hose). A ball valve on pump output regulated flow velocity. Horizontal flow velocities for these trials were 3 and 6 cm s-1 (medium. high) with the following chemical treatments:  chl a (food) only (3 mg L-1 ), guano (0.1 ug L-1) chlorophyll and guano (3 mg L-1 and 0.1 ug L-1).  Krill were filmed using infrared lighting with a measured light intensity of 0.0088 W m-2 in the 400-700 nM range.