| Summary: | A new stereo camera system, encompassing a Sonde, acoustic Doppler current profiler (ADCP), and high-resolution-imaging cameras, was developed to improve our understanding of in situ Antarctic krill behaviors and distribution. Krill were observed on 18 deployments in 3 bays in the Western Antarctic Peninsula from May-June 2013. Observation conditions varied, including time of day, clear to stormy surface conditions, temperatures (-1.2ºC to 0.8ºC) and salinities (33.5ppt to 34.8ppt). Krill were observed in 61% of profiles. Krill distributions were found in two distinct profiles with regards to where highest abundances occurred: Type I profiles had maxima in the middle of the water column (200 to 350 meters), and Type II profiles had the greatest abundances at the bottom of the water column (200 to 800 meters). Occurrence of Type I and Type II profiles was strongly linked with time of day: Type I during dark and Type II during light periods. Krill were never observed shallower than 100m, indicating that krill reside deeper in the water column during the winter period.
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